JP4386983B2 - Substrate processing apparatus, multi-chamber substrate processing apparatus, and electronic device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus used when manufacturing an electronic device such as a semiconductor integrated circuit, and more particularly to a multi-chamber type substrate processing apparatus having a plurality of processing chambers.
[0002]
[Prior art]
Various processes are performed on a substrate when manufacturing a semiconductor integrated circuit or the like. For example, when forming a conductive film for wiring, many film forming processes such as sputtering and chemical vapor deposition (CVD) are performed, and an etching process using a reactive gas is performed when forming a wiring pattern. Has been actively conducted.
[0003]
As one type of substrate processing apparatus for performing such processing, a multi-chamber type substrate processing apparatus is already known. FIG. 15 is a schematic plan view showing a configuration of a conventional multi-chamber type substrate processing apparatus (hereinafter, multi-chamber substrate processing apparatus). The multi-chamber substrate processing apparatus includes a separation chamber 1 provided in the center, a plurality of processing chambers 2 provided around the separation chamber 1, a pair of load lock chambers 3 and the like.
[0004]
Each processing chamber 2 and a pair of load lock chambers 3 are hermetically connected to the separation chamber 1. A gate valve (not shown) is provided at each boundary portion between the separation chamber 1, each processing chamber 2, and the pair of load lock chambers 3. Each chamber is evacuated to a predetermined pressure by a dedicated or combined exhaust system (not shown).
[0005]
The separation chamber 1 separates the processing chambers 2 from each other in an airtight manner to prevent cross-contamination of the internal atmosphere, and serves as a space for transporting the substrate to the processing chambers 2 and the load lock chamber 3. That is, in the separation chamber 1, a transfer robot 11 that transfers the substrate Sb to each chamber is provided.
[0006]
Each load lock chamber 3 is provided with an in-lock cassette 31 storing a predetermined number of substrates Sb. The transfer robot 11 takes out the substrates Sb one by one from the in-lock cassette 31 in one load lock chamber 3 and sequentially sends them to each processing chamber 2. The substrate Sb is processed in stages in each processing chamber 2, and the substrate Sb is returned to the original or other load lock chamber 3 by the transfer robot 11 and accommodated in the in-lock cassette 31. Yes.
[0007]
In addition, an autoloader 4 is provided for transporting the substrate Sb between the external cassette 41 and the in-lock cassette 31 provided on the atmosphere side. The autoloader 4 includes a holding finger 42 that holds a single substrate Sb and a moving mechanism 43 that moves the holding finger 42.
In many cases, the moving mechanism 43 is an articulated robot including an arm that can rotate around a vertical rotation axis. The moving mechanism 43 can move the substrate Sb in the rotational radius direction (r direction), the axial direction (z direction), and the rotational direction (θ direction) of the arm.
[0008]
With such a configuration, the autoloader 4 takes out the substrates Sb one by one from the external cassette 41 and stores them in the in-lock cassette 31 in one of the load lock chambers 3. The load lock chamber 3 has a gate valve (not shown) that is opened and closed when the substrate Sb is taken in and out of the atmosphere side. When the gate valve is open, the gate valve at the boundary with the separation chamber 1 is closed.
[0009]
In the conventional multi-chamber substrate processing apparatus described above, it is required to always keep the position where the substrate Sb is loaded into each processing chamber 2 at the same position. This is because, generally speaking, if the substrate Sb is not always disposed at the same position in the processing chamber 2 to perform the processing, a problem may occur in terms of process reproducibility.
[0010]
In many cases, the substrate Sb is placed on the upper surface of a table-like substrate holder provided in the processing chamber 2 and processed. At this time, for example, in the case of a film forming process, the thin film is also deposited on the surface area of the substrate holder that is not covered with the substrate Sb. Therefore, if the mounting position of the substrate Sb is different, the previous formation is performed. The substrate Sb is placed on the thin film deposited by the film treatment, which causes particles (granular dust) to adhere to the back surface or the like of the substrate Sb.
[0011]
In the case of the etching process, the surface region of the substrate holder is subjected to etching-resistant surface treatment other than the region where the substrate Sb is placed, but the region where the substrate Sb is placed. In consideration of the thermal contact property and the like, such surface treatment is not applied. Therefore, when the mounting position of the substrate Sb is shifted, a portion that is not subjected to the surface treatment is exposed, and the substrate holder is etched to generate particles.
[0012]
On the other hand, the substrate Sb is always arranged at the same position, and the arrangement position in the circumferential direction (position in the rotation direction when the center of the substrate Sb is rotated about the rotation axis) is always required to be the same position. Yes. This point is also generally from the point of process reproducibility. Further, when the substrate Sb is arranged and there is a member having a shape suitable for the shape of the outline of the substrate Sb in the vicinity, if the arrangement position in the circumferential direction of the substrate Sb is shifted, there is a problem of interference with the member. is there. For example, when the substrate Sb is a semiconductor wafer having an orientation flat (hereinafter referred to as an orientation flat), and the substrate holder has a recess adapted to the shape and the substrate Sb is dropped into the recess, the orientation flat portion If the distance is deviated, the substrate Sb is not dropped into the recess, resulting in a conveyance error.
[0013]
In order to meet such a demand, in a conventional multi-chamber substrate processing apparatus, a certain reference position is set, the center of the substrate Sb is positioned at the reference position (hereinafter referred to as center positioning), and the periphery at that position is set. It is necessary to perform alignment in which the directional position is set to a predetermined position (hereinafter referred to as circumferential positioning). Conventionally, this alignment is performed using a mechanism called a positioner.
[0014]
As shown in FIG. 15, the positioner 5 is provided between the external cassette 41 and the load lock chamber 3. FIG. 16 is a schematic perspective view illustrating a more detailed configuration of the positioner 5 shown in FIG.
The positioner 5 integrally supports the stage 51 on which the substrate Sb is placed, the support column 52 that supports the stage 51, the rotation mechanism 53 that rotates the support column 52, and the stage 51, the support column 52, and the rotation mechanism 53. A supporting base 54, an X-direction moving mechanism 55 that moves the supporting base 54 in the X direction, a Y-direction moving mechanism 56 that moves the support base 54 in the Y direction, and a sensor (not shown) that detects the position of the substrate Sb. The control unit mainly includes a control unit (not shown) that controls the X-direction moving mechanism 55 and the Y-direction moving mechanism 56 in accordance with signals from the sensors.
[0015]
The stage 51 has a disk shape smaller than the substrate Sb. The holding finger 42 has a substantially U shape whose inner width is larger than the diameter of the stage 51. When the substrate Sb is placed on the stage 51, the stage 51 is positioned inside the U shape of the holding finger 42. It becomes a state to do. When the substrate Sb is placed on the stage 51, the center of the holding finger 42 is positioned on a rotation axis set so as to penetrate the center of the stage 51 vertically.
[0016]
The center position of the substrate Sb is detected by detecting how much the point where the rotation axis of the stage 51 passes through the surface of the substrate Sb (hereinafter referred to as the rotation center) and the center of the substrate Sb are shifted. This is done by driving the X-direction moving mechanism 55 and the Y-direction moving mechanism 56 so as to coincide with each other.
The driving of the X-direction moving mechanism 55 and the Y-direction moving mechanism 56 is performed according to detection results of a sensor (not shown). The sensor configuration differs depending on the detection method, but is divided into a case where a plurality of photo sensors are used and a case where an image sensor such as a CCD sensor is used. Among these, when a plurality of photosensors are used, the plurality of photosensors are evenly arranged on the circumference with the rotation axis as the center. The photo sensor is disposed on the circumference of a diameter slightly larger than the diameter of the substrate Sb.
[0017]
When the substrate Sb is placed on the stage 51, the rotation mechanism 53 rotates the stage 51 via the support column 52. The substrate Sb rotates as the stage 51 rotates. During this rotation, the peripheral edge of the substrate Sb periodically obliquely transmits or transmits the plurality of photosensors according to the deviation between the rotation center and the center of the substrate Sb. At this time, since it is known which photosensor is obliquely transmitted or transmitted at what timing, the deviation between the center of rotation and the center of the substrate Sb is obtained by calculation. A control unit (not shown) performs this calculation to obtain a deviation between the center of rotation and the center of the substrate Sb, and sends drive signals to the X-direction moving mechanism 55 and the Y-direction moving mechanism 56 so as to correct this deviation. Then, the holding finger 42 removes the substrate Sb from the stage 51 in a state where the center of the holding finger 42 and the center of the substrate Sb coincide.
[0018]
Further, when a CCD sensor is used, the CCD sensor is arranged so as to capture an image of a specific area on the periphery of the substrate Sb. Then, the CCD sensor is fixed, and the substrate Sb is rotated by the rotation mechanism 53. In accordance with the difference between the rotation center and the center of the substrate Sb, the image of the periphery of the substrate Sb captured by the CCD sensor is shaken. The deviation between the center of rotation and the center of the substrate Sb is obtained by calculation from the amount of the shake and the information on the rotation angle of the substrate Sb when the shake occurs. Similarly, a drive signal is sent to the X-direction moving mechanism 55 and the Y-direction moving mechanism 56, and the substrate Sb is removed from the stage 51 in a state where the center of the holding finger 42 and the center of the substrate Sb coincide.
[0019]
Further, from the information on the amount of shake and the rotation angle of the substrate Sb when the shake has occurred, information on how far a specific location on the periphery of the substrate Sb such as orientation flat is away from a reference angular position is also calculated. Is obtained. Accordingly, the stage 51 is rotated by a predetermined angle based on the result of this calculation, and then the holding finger 42 removes the substrate Sb from the stage 51. As a result, the substrate Sb is positioned in the circumferential direction.
[0020]
The holding finger 42 removes the substrate Sb from the stage 51 in a state where the center position and the circumferential position are determined in this way, and transports the substrate Sb to the in-lock cassette 31 in the load lock chamber 3. As shown in FIGS. 15 and 16, two autoloaders 4 as described above are provided. One positioner 5 is provided between the two autoloaders 4.
[0021]
[Problems to be solved by the invention]
In the conventional multi-chamber substrate processing apparatus described above, since the positioner 5 is provided between the external cassette 41 and the load lock chamber 3, the space between the external cassette 41 and the load lock chamber 3 is widened. For this reason, the moving distance of the autoloader 4 also becomes long. For this reason, there is a drawback that the space occupied by the mechanism outside the load lock chamber 3 becomes large.
In addition, since the center positioning and the circumferential positioning are performed in the process of transporting the substrates Sb from the external cassette 41 to the load lock chamber 3 one by one, it takes a long time to transport and the lead time (one substrate Sb There is a disadvantage that the total time from when it is put into the apparatus to when it is collected becomes longer.
[0022]
Furthermore, center positioning and circumferential positioning are required when the substrate Sb is processed in the processing chamber 2, but in a conventional apparatus, at a time much before the time when the substrate Sb is transferred to the processing chamber 2. Center positioning and circumferential positioning are performed. For this reason, there is still a high possibility that the substrate Sb is displaced from the original position in the process from the center position positioning and the circumferential position positioning to the process chamber 2 being transported. When the deviation occurs, the substrate Sb is not correctly arranged in the processing chamber 2, and the center positioning and the circumferential positioning performed are wasted. For example, if the substrate Sb is displaced on the holding finger 42 or the transfer robot 11 for some reason after the center positioning and the circumferential positioning, the arrangement position in the processing chamber 2 is also shifted.
[0023]
The invention of the present application has been made to solve such a problem, and is a multi-chamber substrate processing apparatus in which a substrate is always arranged correctly at a predetermined position in a processing chamber. The object is to provide a practical device with excellent performance.
[0024]
[Means for Solving the Problems]
  In order to solve the above problems, the invention according to claim 1 of the present application includes a processing chamber,
  Provided in the processing chamber, The upper surface is provided with a recessSubstrate holder,
  In the processing chamberCan be accommodated in the recess,A stage on which the substrate is placed;
  After lowering the stage on which the substrate is placed and placing the substrate on the upper surface of the substrate holder, the stage can be accommodated in the recess.An elevating mechanism for elevating the stage;
  A rotation mechanism for rotating the stage;
  An optical position detection means having a light emitter and a light receiver;
  From the stageA transfer robot for transferring substrates;
  A control unit for controlling the transfer robot;
Comprising
  The light emitter emits light having a width so as to be partially blocked at the periphery of the substrate placed on the stage, and the light receiver receives the blocked light. ,
  The elevating mechanism raises the stage on which the substrate is placed to position the substrate at a detection position higher than the substrate placement surface of the substrate holder,
  The rotating mechanism rotates the stage with the substrate positioned at the detection position by the lifting mechanism,
  The optical position detection means detects the position information of the substrate from the light reception result of the light receiver when the substrate rotates with the rotation of the stage at the detection position,
  The control unit is based on the position information of the substrate detected by the optical position detection unit.
It has a configuration that controls the operation of the transfer robot.
  In order to solve the above-mentioned problem, the invention according to claim 2 of the present application has a configuration in which, in the configuration of claim 1, the position information includes a center position of the substrate and a circumferential position of the substrate.
  In order to solve the above problems, the claims of the present application3The invention described is the above-mentioned claim 1,Or 2In the configuration, the substrate holder includes a heater for heating the substrate.
  In order to solve the above problems, the claims of the present application4The invention described is the above-mentioned claims 1 to3In any configuration, the light emitter and the light receiver are respectively attached to the ceiling wall and the side wall of the processing chamber so that light directed from the light emitter toward the light receiver is not shielded by the substrate holder. It has a configuration.
  In order to solve the above problems, the claims of the present application5The invention described in claims 1 to4The processing chamber described is a heat chamber for heating a substrate, and has a configuration in which it is a multi-chamber substrate processing apparatus including a sputtering chamber or a CVD chamber for forming a thin film in addition to the heat chamber.
  In order to solve the above problems, the claims of the present application6The described invention is claimed.5An electronic device is manufactured using the described multi-chamber substrate processing apparatus.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 is a plan view showing a schematic configuration of a multi-chamber substrate processing apparatus according to an embodiment of the present invention. The multi-chamber substrate processing apparatus shown in FIG. 1 is similar to the conventional apparatus shown in FIG. 15 in that a separation chamber 1 provided in the center and a plurality of processing chambers 6, 7, 8, provided around the separation chamber 1 are provided. 9 and a chamber arrangement comprising a pair of load lock chambers 3.
[0026]
The apparatus of the present embodiment is a thin film forming apparatus in which sputtering and CVD are combined. The plurality of processing chambers 6, 7, 8, and 9 include two sputtering chambers 8 and two CVD chambers 9. Yes. One of the processing chambers is a heat chamber 6 that pre-heats the substrate Sb, and the other one etches and removes a natural oxide film or a protective film on the surface prior to thin film formation. An etching chamber 7 is provided.
[0027]
The substrate Sb is sent from one load lock chamber 3 to the heat chamber 6, the etching chamber 7, the sputtering chamber 8, and the CVD chamber 9 in this order by the transfer robot 11 in the separation chamber 1. Then, after the predetermined film forming process is completed, the substrate Sb is returned to the other load lock chamber 3.
[0028]
Now, one of the major feature points of the apparatus of the present embodiment is that the substrate Sb is temporarily transferred until it is transferred to the processing chamber where the substrate Sb needs to be processed in the state where the center position and the circumferential position are positioned. Center positioning and circumferential positioning within another processing chamber carried into the chamber. Specifically, in the apparatus of the present embodiment, the etching chamber 7, the sputter chamber 8, and the CVD chamber 9 need to be centered and circumferentially positioned, and heat before the substrate Sb is carried in before that. Centering and circumferential positioning are performed in the chamber 6. In other words, the heat chamber 6 includes means for performing center positioning and circumferential positioning (hereinafter referred to as positioning means).
[0029]
The configuration of the heat chamber 6 will be described with reference to FIG. FIG. 2 is a schematic side view illustrating the configuration of the heat chamber 6. The heat chamber 6 is an airtight box-shaped vacuum vessel, and is connected to the separation chamber 1 in an airtight manner with a gate valve 61 interposed.
[0030]
A substrate holder 62 for placing and heating the substrate Sb is provided in the heat chamber 6. The substrate holder 62 includes a heating block 622 in which a heater 621 is incorporated, an upper surface block 623 provided on the upper side of the heating block 622, and the like.
The heating block 622 is a disk-shaped member larger than the substrate Sb, and is made of a metal such as stainless steel. In the case where the heating block 622 is configured by combining blocks made of different metals such as stainless steel and copper having good thermal conductivity, it is preferable to join the two because of good thermal contact according to the diffusion bonding method. .
[0031]
In the present embodiment, a resistance heating type heater is used as the heater 621. The heater 621 is linear, and is provided in a shape such as a spiral shape or a concentric circumference around the central axis of the heating block 622. A heater power source (not shown) is connected to the heater 621 so as to generate heat when energized.
The upper surface block 623 is a member on which the substrate Sb is placed on the surface during heating. The upper surface block 623 has a disk shape having substantially the same diameter as the substrate Sb. The upper surface block 623 is formed of alumina or the like in terms of material, and is joined to the heating block 622 with good thermal contact properties by interposing a cushioning material such as a carbon sheet.
The substrate holder 62 is fixed to the bottom surface of the heat chamber 6 by a holder fixing portion 624. Further, the substrate holder 62 may be water-cooled for rapid cooling of the substrate holder 62 or temperature adjustment.
[0032]
In addition to the substrate holder 62, a stage 63 on which the substrate Sb is placed is provided on the surface. The stage 63 is a disk-shaped member having a smaller diameter than the substrate Sb. On the surface of the upper surface block 623, recesses (not shown) are formed as shown in FIG. The recess is a circle slightly larger than the diameter of the stage 63, and the stage 63 is positioned in the recess when the substrate Sb is heated.
[0033]
A column 631 is fixed to the stage 63. The column 631 extends downward with its tip fixed to the center of the back surface of the stage 63. The upper surface block 623 and the heating block 622 are formed with a through hole (not shown) extending vertically in the center. The cross-sectional area of the through hole is slightly larger than the cross-sectional area of the column 631, and the column 631 extends downward through the through-hole.
[0034]
A rotating mechanism 64 and a lifting mechanism 65 are provided at the lower end of the column 631. First, the rotation mechanism 64 will be described. The rotation mechanism 64 outputs a driven gear 641 provided so as to rotate integrally with the column 631, a drive gear 642 engaged with the driven gear 641, and a drive gear 642. A rotation motor 643 fixed to the shaft, a holding plate 644 holding the entire rotation mechanism 64, and the like are included.
[0035]
The holding plate 644 is provided with a through hole through which the column 631 is inserted. In addition, a substantially cylindrical frame 645 is fixed to the holding plate 644 so as to extend downward from the periphery of the through hole. The frame 645 has a shape having a bottom. The frame 645 forms a substantially cylindrical airtight internal space below the through hole. And the lower end part of the support | pillar 631 is arrange | positioned in the internal space of this flame | frame 645. FIG. The frame 645 and the column 631 are coaxial.
A flange-like protruding portion (not shown) is formed on the outer surface of the frame 645, and the driven gear 641 is locked to the protruding portion via a bearing (not shown). The driven gear 641 has a substantially cylindrical shape as a whole, and gear teeth are provided at a portion protruding outward. As shown in FIG. 2, the column 631 is slightly thicker at the lower end portion. And the lower surface of the support | pillar 631 is latched by the bottom face of the flame | frame 645 via the bearing.
[0036]
Further, the outer peripheral surface of the column 631 and the inner peripheral surface of the driven gear 641 face each other in a narrow space with the frame 645 interposed therebetween. The outer peripheral surface of the column 631 and the inner peripheral surface of the driven gear 641 are magnetically coupled. That is, magnets (not shown) having different magnetic poles are provided on the outer peripheral surface of the column 631 and the inner peripheral surface of the driven gear 641. In addition, the thickness of the frame 645 is thin at the portion where the outer peripheral surface of the column 631 and the inner peripheral surface of the driven gear 641 face each other. Therefore, when the outer driven gear 641 rotates, the inner support 631 also rotates by magnetic coupling. Accordingly, when the rotation motor 643 rotates and the drive gear 642 rotates, the support 631 is rotated by the rotation of the driven gear 641. The frame 645 is fixed to the holding plate 644 and does not rotate.
When the column 631 rotates, the stage 63 also rotates together, and the substrate Sb on the stage 63 also rotates. The substrate Sb rotates integrally with the stage 63 without slipping due to the frictional force between the back surface of the substrate Sb and the surface of the stage 63. Alternatively, the substrate Sb may be electrostatically attracted by inducing static electricity on the surface of the stage 63.
[0037]
An auxiliary rod 648 is provided so as to protrude downward from the driven gear 641. The auxiliary rod 648 is coaxial with the column 631 and rotates integrally with the driven gear 641 and the column 631. The auxiliary rod 648 is held by the auxiliary holding plate 646 via a bearing. A rotary encoder 647 is provided at the lower end of the auxiliary rod 648. When the column 631 rotates as described above, the auxiliary rod 648 also rotates together, and the rotation angle is detected by the rotary encoder 647.
[0038]
Next, the lifting mechanism 65 will be described. The lifting mechanism 65 includes a driven body 651 that holds the holding plate 644 that holds the rotating mechanism 64, a ball screw 652 to which the driven body 651 is screwed, and a joint 653. And an elevating motor 654 coupled to a ball screw 652. When the raising / lowering motor 654 rotates, the ball screw 652 rotates through the joint 653, whereby the driven body 651 moves linearly up and down. As a result, the rotation mechanism 64, the column 631, the stage 63, and the like held by the holding plate 644 are moved up and down as a whole.
A bellows 66 is provided between the holding plate 644 and the heat chamber 6. The bellows 66 prevents leakage from the opening of the bottom plate portion of the heat chamber 6 through which the column 631 is inserted.
[0039]
As described above, when the elevating mechanism 65 raises the column 631, the stage 63 held by the column 631 also rises, and the substrate Sb placed on the stage 63 also rises. In the apparatus of the present embodiment, a pair of light emitters 671 and light receivers 672 are provided so that the edge of the substrate Sb at a predetermined elevated position is located on the optical path.
[0040]
First, the light emitter 671 uses a semiconductor laser in this embodiment, and has an oscillation wavelength of 780 nm. The light emitter 671 is fixed to the heat chamber 6 by a frame body 673. In addition, an emission window 674 is provided on the front surface of the light emitter 671. The frame body 673 and the exit window 674 are airtightly attached to the heat chamber 6 so that there is no vacuum leak in the heat chamber 6. Note that an exit-side opening through which light from the light emitter 671 passes is provided on the wall of the heat chamber 6 with a sufficient size.
[0041]
As the light receiver 672, one having sufficient detection sensitivity with respect to light emitted from the light emitter 671 is used, and specifically, a photodiode array is used in the present embodiment. An incident window 675 is provided on the front surface of the light receiver 672, and the incident window 675 and the light receiver 672 are airtightly provided in the heat chamber 6 by a frame body 676 like the light emitter 671. The entrance wall of the heat chamber 6 is also provided with a sufficiently large entrance-side opening through which light incident on the light receiver 672 passes.
[0042]
The light emitted from the light emitter 671 enters the heat chamber 6 through the emission window 674, and a part of the light is blocked by the edge of the substrate Sb at the predetermined rising position, while the other part of the light enters the incident window 675. And enters the light receiver 672. The intensity of the light received by the light receiver 672 is amplified by an amplifier in the light receiver 672 and then sent to the computer 68. In addition, a signal from a rotary encoder 647 is also input to the computer 68.
[0043]
In the apparatus of this embodiment, the stage 63, the support 631, the rotation mechanism 64, the lifting mechanism 65, the light emitter 671 and the light receiver 672 provided in the heat chamber 6, and the computer 68 and the stage 63 are connected. Elements such as an arm of the transfer robot 11 that transfers the substrate Sb constitute positioning means. The configuration of the positioning means will be described while explaining the center positioning method and the circumferential positioning method using these elements.
[0044]
In the case of positioning, after the substrate Sb is placed on the stage 63 by the transfer robot 11 in the separation chamber 1, the substrate Sb is brought to a predetermined height (hereinafter referred to as positioning level) by the lifting mechanism 65. Position. Next, the substrate Sb is rotated by the rotation mechanism 64 while operating the light emitter 671. The computer 68 processes an output signal (hereinafter simply referred to as an output signal) obtained by converting the light incident on the light receiver 672 into an electrical signal, and is located when the arm of the transfer robot 11 receives the substrate Sb. Is identified. Then, when the transfer robot 11 actually receives the substrate Sb at this position and removes it from the stage 63, the positioning is completed.
[0045]
In the following description, processing programs stored mainly in the computer 68 will be described.
First, calculation of the distance from the rotation center to each point on the peripheral edge of the substrate Sb (hereinafter referred to as peripheral distance) will be described with reference to FIGS. FIG. 3 is a diagram for explaining the calculation of the peripheral distance, and is a schematic plan view showing the light receiving surface 677 of the light receiver 672. FIG. 4 is a schematic side view showing the relationship between the centered substrate Sb and the optical axis 670.
[0046]
As described above, in this embodiment, a photodiode array is used as the light receiver 672. The light receiving surface 677 of the light receiver 672 is an elongated rectangle as shown in FIG. The light receiver 672 is accurately positioned with respect to the optical axis 670 so that the light receiving surface 677 is perpendicular to the optical axis 670 and the center of the light receiving surface 677 is located on the optical axis 670.
[0047]
On the other hand, the light emitter 671 incorporates an optical system such as a beam expander and a collimator lens, and the light emitted from the light emitter 671 is denoted by L in FIG._maxIt becomes the parallel light of the width shown by. The light receiving surface 677 shown in FIG. 3 is slightly larger than the cross-sectional area of the parallel light beam, and is in a posture perpendicular to the optical axis 670 so that all the beams are incident perpendicularly. . Further, as shown in FIG. 3, the optical axis 670 is set to pass through the center of the light receiving surface 677.
[0048]
Here, the magnitude of the output signal generated when a part of the beam from the light emitter 671 is shielded by the substrate Sb and the rest is incident on the light receiver 672 corresponds to the position of the substrate Sb with respect to the optical axis 670. ing. This point will be specifically described below.
[0049]
First, the magnitude of the output signal when the beam from the light emitter 671 is incident on the light receiver 672 without being shielded by the substrate Sb is defined as S._maxThen, S_maxThe size of the beam width L_maxDepends on. That is,
S_max= KL_max... (1)
It becomes. In equation (1), k is a proportionality constant determined by the sensitivity of the light receiver 672 and the like.
[0050]
Further, as shown in FIG. 4, when the substrate Sb is at the level of the positioning level and the center of the substrate Sb coincides with the rotation center (when the center positioning is performed), the edge of the substrate Sb is It is positioned on the optical axis 670 connecting the light emitter 671 and the light receiver 672. The output signal when the center position is set₀Then, half of the beam from the light emitter 671 is shielded by the substrate Sb, and the other half is incident on the light receiver 672. That is, light is incident on a half region of the light receiving surface as indicated by hatching in FIG. Therefore, the receiver output signal S₀ Is
S₀ = S_max/ 2 = kL_max/2...(2)
It becomes. Note that the width w of the light-receiving surface 677 shown in FIG. 3 is sufficiently smaller than the curvature of the substrate Sb, and the contour of the beam shielded by the substrate Sb can be treated as a straight line.
[0051]
Then, as shown by a dotted line in FIG. 4, when the center of the substrate Sb does not coincide with the rotation center and the substrate Sb is shifted outward with respect to the rotation center, the beam from the light emitter 671 is changed to the substrate Sb. The amount to be shielded increases. As a result, the amount of beam incident on the light receiver 672 is reduced and the output signal is also reduced. At this time, the width of the beam incident on the light receiver 672 is L, and the magnitude of the output signal generated by the beam of width L is S._dThen,
S_d= KL (3)
It becomes. Further, if the peripheral distance is D and the distance from the rotation center to the optical axis 670 in the surface direction of the substrate Sb is R, as is apparent from FIG. 4, L = L_max/ 2− (D−R) sinθ_LTherefore, equation (3) becomes
S_d= K {L_max/ 2−k (D−R) sinθ_L} ... (4)
Can be rewritten.
Considering equation (2), equation (4) is
S₀−S_d = K (D−R) sinθ_L... (5)
It becomes. And from equation (1), k = S_max/ L_maxTherefore, equation (5) is
S₀−S_d= Α (D−R) (6)
It becomes. However, in equation (6), α = S_maxsinθ / L_maxIt is.
[0052]
From the above equation (6), the peripheral distance D is
D = R + (S₀−S_d) / Α (7)
Can be calculated as In the above equation (7), R is a design matter and is known as described above. S₀With respect to, a beam is made incident on the light receiver 672 with the substrate Sb arranged so that the center of the substrate Sb coincides with the center of rotation while using a laser distance meter, and the value of the output signal at that time is obtained. Keep it. Also for α, L is a design matter and known, and S_maxCan be obtained in advance. Therefore, the value of α is also known. R, S like this₀And α are stored in advance in the computer 68 as constants and output S_dThe peripheral distance D is calculated from the magnitude of the signal in accordance with the equation (7).
[0053]
FIG. 5 is a diagram showing an example of the calculation result of the peripheral distance D, and specifically shows the calculation result of the peripheral distance D when the substrate Sb is a circular substrate such as a semiconductor wafer having an orientation flat. Yes. The horizontal axis in FIG. 5 represents the rotation angle of the stage 63, and the vertical axis represents the peripheral distance D.
When the center of the substrate Sb does not coincide with the rotation center and the substrate Sb rotates eccentrically, the distance from the rotation center to the edge of the substrate Sb is not constant with respect to the optical axis 670 as described above. This change is periodic, and the change in the peripheral distance D when the stage 63 is rotated 360 degrees is almost sinusoidal as shown in FIG. That is, while rotating the stage 63, S is set at a predetermined sampling period._dWhen D is calculated according to the above program, the curve drawn by D becomes as shown in FIG.
[0054]
Next, a program for obtaining the position of the center of the substrate Sb and the position of the reference point of the periphery of the substrate Sb from the data of the peripheral distance D will be described. The position of the center of the substrate Sb can be calculated by using three data among the data of the peripheral distance D sampled as described above. However, if the data in the non-circumferential part such as orientation flat is included in the three data, it cannot be calculated correctly. Further, it is necessary to specify the position of a non-circumferential portion such as orientation flat as a reference point for positioning in the circumferential direction. Therefore, first, calculation for obtaining the position of the non-circumferential portion is performed.
[0055]
As an example, a case where the non-circumferential portion is an orientation flat will be described. When calculating the position of the non-circumferential portion, an operation for first-order differentiation of the curve of the peripheral distance D shown in FIG. 5 is performed. As a result, the curve shown in FIG. 6 is obtained. FIG. 6 shows a curve obtained by first-order differentiation of the curve shown in FIG. FIG. 7 is a diagram for explaining the calculation for obtaining the orientation flat center from the data shown in FIGS. 5 and 6.
[0056]
When first derivative of the curve of the peripheral distance D shown in FIG. 5, the periodic change becomes very small and flat as shown in FIG. 6 (hereinafter, this data is referred to as D '). And the change of the output signal in the orientation flat portion is sharply expressed. The rotation angle θmin and θmax when the minimum value D'min and the maximum value D'max of the D 'data are obtained are the rotation angles when the orientation flat start point and end point are located on the optical path. It corresponds to an angle.
The orientation flat center is often used as a reference point for positioning in the circumferential direction. However, the intermediate angle between the rotation angles θmin and θmax does not correspond to the midpoint position of the orientation flat. Therefore, the following calculation is performed to specify the position of the midpoint of the orientation flat.
[0057]
In FIG. 7, in order to simplify the description, the origin of the rectangular coordinates is taken as the rotation center O. And the starting point of orientation flat is F₁, End point F₂And the midpoint of the orientation flat is F_mAnd F from the origin₁Distance to₁, F from origin₂Distance to OF₂And In addition, the origin and F₁ΘF is the angle that the line connecting₁, Origin and F₂ΘF is the angle that the line connecting₂, Origin and F_mΘF is the angle that the line connecting_mAnd
Where origin and F_mIf the slope of the straight line passing through is a, the slope a is
a ＝ tanθF_m
It becomes. F₁Perpendicular to the x-axis (F₁X₁) Where E) intersects the straight line y = ax₁Then,
F₁E₁＝ ｜ OF₁sinθF₁−OX₁tanθF_m｜
＝ ｜ OF₁sinθF₁−aOX₁｜
It becomes. OX₁= OF₁cosθF₁So,
F₁E₁＝ ｜ OF₁sinθF₁−aOF₁cosθF₁| (8)
It becomes.
Meanwhile, F₂Perpendicular to the x-axis (F₂X₂) And the point where it intersects the straight line y = ax is E₂Then,
F₂E₂＝ ｜ OF₂sinθF₂−OX₂tanθF_m｜
＝ ｜ OF₂sinθF₂−aOX₂｜
It becomes. Similarly, OX₂= OF₂cosθF₂So,
F₂E₂＝ ｜ OF₂sinθF₂−aOF₂cosθF₂| (9)
It becomes.
[0058]
As is clear from FIG.₁E₁= F₂E₂Therefore, assuming that the squares of the left sides of (8) and (9) are equal,
(OF₁ ²cos²θF₁−OF₂ ²cos²θF₂A²
-2 (OF₁ ²cosθF₁sinθF₁−OF₂ ²cosθF₂sinθF₂A
+ OF₁ ²sin²θF₁−OF₂ ²sin²θF₂
= 0 (10)
Is obtained.
In the above formula (10), OF₁, OF₂, ΘF₁, ΘF₂Is the peripheral distance data described above, and is a constant. Accordingly, a is obtained by substituting these data into the equation (10) and solving the quadratic equation of the equation (10). And mid point F of orientation flat_mRotation angle of stage 63 (hereinafter referred to as orientation flat midpoint detection angle) θF when is positioned on the optical path_mIs θF_m= Tan^-1Calculated in (a).
[0059]
Next, as another example of the non-circumferential part of the edge of the substrate Sb, a position calculation method when the non-circumferential part is a small notch (hereinafter referred to as a notch) will be described.
FIG. 8 shows the calculation result of the peripheral distance when the substrate Sb is a circular substrate such as a semiconductor wafer having a notch. The horizontal axis in FIG. 8 indicates the rotation angle of the stage 63, and the vertical axis indicates the peripheral distance D.
[0060]
When first derivative of the curve of the peripheral distance D shown in FIG. 8, the curve shown in FIG. 9 is obtained. FIG. 9 shows a curve obtained by first-order differentiation of the curve shown in FIG.
As shown in FIG. 9, when the first-order differentiation of the curve shown in FIG. 8 is performed, the periodic change becomes very small and flat (hereinafter, this data is referred to as D ″). The width of the notch is sufficiently smaller than the circumference of the substrate Sb, and the shape of the notch is often triangular, semicircular, semielliptical, etc. Therefore, in the case of orientation flat The rotation angle of the stage 63 when the notch is positioned on the optical path as follows (hereinafter referred to as the notch detection angle θ) is not performed._n) Is calculated.
That is, first, the rotation angles θmin and θmax when the minimum value and the maximum value of the data D ″ are obtained are obtained. Then, returning to the data before differentiation shown in FIG. 8, the rotation angles θmin to θmax are obtained. The rotation angle when the value of the peripheral distance becomes the minimum value is the notch detection angle θ_nAnd
[0061]
Next, calculation for obtaining the center of the substrate Sb from the data of the peripheral distance will be described. FIG. 10 is a plan view for explaining the calculation for obtaining the center of the substrate Sb from the peripheral distance data.
The center of the substrate Sb can be calculated by extracting and using three pieces of data from the peripheral distance data. However, if this data contains non-circumferential data, it cannot be calculated correctly.
[0062]
Specifically, the orientation flat midpoint detection angle θF obtained as described above._mOr notch detection angle θ_nData on the peripheral distance at three rotation angles that are 60 degrees, 180 degrees, and 240 degrees away from each other are employed. Three points on the periphery of the substrate Sb corresponding to this data are represented by P₁, P₂, P_ThreeIf the non-circumferential part is a notch, the three points P₁, P₂, P_ThreeThe positional relationship between the notch and the notch can be illustrated as shown in FIG.
[0063]
In FIG. 10, the center of the substrate Sb is C, the distance from the rotation center O to C is M, and the angle formed by the line segment connecting O and C with respect to the x axis is A. In FIG. 10, a point S at which the periphery of the substrate Sb intersects the x axis on the + side corresponds to a point at a rotation angle of 0 degrees (or 360 degrees) in the peripheral distance data shown in FIGS. ing. Therefore, the angle A is an angle indicating how much the stage 63 rotates clockwise and the straight line passing through the center C of the substrate Sb is positioned on the optical axis 670.
[0064]
The center C of the substrate Sb can be specified by obtaining the angle A and the distance M. Specifically, in FIG. 10, the rotation centers O and P₁, P₂, P_ThreeEach distance of r₁, R₂, R_ThreeAnd O and P₁, P₂, P_ThreeThe angle formed by the line segments that connect to the line OS (the + side of the x axis) is θ₁, Θ₂, Θ_ThreeAnd And the coordinates of the three points
P₁ (R₁ cosθ₁ , R₁ sinθ₁ ) = (P_1x, P_1y)
P₂ (R₂ cosθ₂ , R₂ sinθ₂ ) = (P_2x, P_2y)
P_Three (R_Three cosθ_Three, R_Three sinθ_Three ) = (P_3x, P_3y)
And the coordinates of point C are (McosA, MsinA).
[0065]
Since C is the center of the substrate Sb, CP₁ = CP₂ = CP_Three It is. Therefore,
√ {(McosA−r₁cosθ₁)²+ (MsinA−r₁sinθ₁)²}
= √ {(McosA−r₂cosθ₂)²+ (MsinA−r₂sinθ₂)²}
= √ {(McosA−r_Threecosθ_Three)²+ (MsinA−r_Threesinθ_Three)²}
It becomes.
Transform this,
M²−2 Mr₁cosAcosθ₁−2 Mr₁sinAsinθ₁+ R₁ ²
= M²−2 Mr₂cosAcosθ₂−2 Mr₂sinAsinθ₂+ R₂ ²
= M²−2 Mr₁cosAcosθ_Three−2 Mr_ThreesinAsinθ_Three+ R_Three ²
Is obtained.
From (first side)-(second side) in the above formula,
r₁ ²−r₂ ²
= 2M (r₁cosAcosθ₁+ R₁sinAsinθ₁−r₂cosAcosθ₂−r₂sinAsinθ₂)
= 2M {(r₁cosθ₁−r₂cosθ₂) CosA + (r₁sinθ₁−r₂sinθ₂) SinA} ... (11)
Is obtained. From (second side)-(third side)
r₂ ²−r_Three ²
= 2M (r₂cosAcosθ₂+ R₂sinAsinθ₂−r_ThreecosAcosθ_Three−r_ThreesinAsinθ_Three)
= 2M {(r₂cosθ₂−r_Threecosθ_Three) CosA + (r₂sinθ₂−r_Threesinθ_Three) SinA} ... (12)
Are obtained respectively.
[0066]
r₁ ²−r₂ ²= K₁, R₂ ²−r_Three ²= K₂And k₂ / K₁When calculating (12) / (11),
k₂ / K₁
= {(R₂cosθ₂−r_Threecosθ_Three) CosA + (r₂sinθ₂θ_L−r_Threesinθ_Three) SinA}
/ {(R₁cosθ₁−r₂cosθ₂) CosA + (r₁sinθ₁−r₂sinθ₂) SinA} ... (13)
It becomes.
Dividing the numerator denominator on the right side of equation (13) by cosA,
k₂ / K₁
= {(R₂sinθ₂−r_Threesinθ_Three) + (R₂cosθ₂−r_Threecosθ_Three) TanA}
/ {(R₁sinθ₁−r₂sinθ₂) + (R₁cosθ₁−r₂cosθ₂) TanA}
= {(P_2y−P_3y) + (P_2x−P_3x) TanA}
/ {(P_1y−P_2y) + (P_1x−P_2x) TanA} ... (14)
It becomes.
From equation (14)
k₂{(P_1y−P_2y) + (P_1x−P_2x) TanA}
= K₁{(P_2y−P_3y) + (P_2x−P_3x) TanA}
It is. Therefore,
{K₂(P_1x−P_2x-K₁(P_2x−P_3x)} TanA
= K₁(P_2y−P_3y-K₂(P_1y−P_2y)
It becomes.
Therefore,
tanA
= {K₁(P_2y−P_3y-K₂(P_1y−P_2y)}
/ {K₂(P_1x−P_2x-K₁(P_2x−P_3x)}
Tan^-1The angle A is obtained by A.
[0067]
From equation (11),
M = [k₁/ {(P_1x−P_2x) CosA + (P_1y−P_2y) SinA}] / 2
Thus, the magnitude of M is obtained from the obtained angle A according to this equation. In this way, the position of the center C of the substrate Sb is specified by obtaining the angle A and the size of the line segment M.
[0068]
Then, by controlling the transfer robot 11 so that a specific point of the arm of the transfer robot 11 coincides with the position of the center of the substrate Sb specified in this manner, the arm receives the substrate Sb. The dispensing operation is completed. However, since the circumferential position of the substrate Sb remains random as it is, the circumferential positioning is performed as follows.
[0069]
11, 12 and 13 are explanatory diagrams of the circumferential positioning. In the present embodiment, the arm of the transfer robot 11 includes a fork 111 (see FIGS. 12 and 13) at the tip thereof, and the substrate Sb is placed on the fork 111 and moved.
The specific point of the arm described above is the center point of the fork 111 (hereinafter, fork center) A₀Is set to The fork 111 has a shape in which a U-shaped notch is provided in a rectangular plate material. Fork center A₀Is set at the center of the U-shaped arc portion.
[0070]
The transfer robot 11 moves the fork center A to the center C of the substrate Sb specified as described above.₀The fork 111 is moved so that the two coincide with each other (more precisely, on the same vertical line), and the substrate Sb is placed on the fork 111 and held. At this time, the substrate Sb is rotated by a predetermined angle so that the circumferential positioning is performed, and then the fork 111 is moved to hold the substrate Sb. The rotation operation for positioning in the circumferential direction will be described below.
[0071]
First, calculation is performed to determine in which position in the circumferential direction the reference point of the peripheral edge of the substrate Sb is in a state before rotation for positioning in the circumferential direction. This calculation will be described using an example in which the peripheral reference point is a notch. FIG. 11 is an explanatory diagram of calculations necessary for positioning in the circumferential direction, and is a diagram illustrating calculations for obtaining the position of the reference point on the periphery of the substrate Sb before rotation.
[0072]
In FIG. 11, the angle formed by the line segment connecting the notch N as the reference point and the center C of the substrate Sb with respect to the x-axis is θ._NThen,
tanθ_N= (D_nsinθ_n-MsinA) / (D_ncosθ_n-McosA) ... (15)
It becomes. In equation (15), D_nIs the notch detection angle θ_nIs known from the data of the peripheral distance, and M and A are already required. Therefore, by substituting these values into equation (15), tan^-1Angle θ_NIs required. Although FIG. 11 shows an example of a notch, the same applies to the orientation flat.
[0073]
On the other hand, as shown in FIGS. 12 and 13, the movement of the fork 111 of the transfer robot 11 to receive the substrate Sb is set with reference to the operation reference point of the transfer robot 11. In the present embodiment, an articulated robot is used as the transfer robot 11, and the operation reference point of the transfer robot 11 is set on a fixed rotation axis that is positioned closest to the hand of the articulated arm. This operation reference point (indicated by Q in FIGS. 12 and 13) is located on the central axis of the separation chamber 1 shown in FIG.
[0074]
The x axis in FIG. 11 described above coincides with the direction connecting the operation reference point Q and the rotation center O in FIGS. 12 and 13. That is, with the direction connecting the operation reference point Q and the rotation center O in FIGS._NIs calculated.
Positioning in the circumferential direction is to place the reference point of the peripheral edge of the substrate Sb at a predetermined position in the circumferential direction. This predetermined position is set based on the posture of the fork 111 when holding the substrate Sb. ing. Specifically, the fork 111 is a U-shaped plate as described above, and the fork center A₀The depth direction of the U-shape passing through is the reference. Hereinafter, this direction is referred to as a fork reference direction.
[0075]
On the other hand, the line connecting the calculated center C of the substrate Sb and the operation reference point Q is the fork approach line A._LSet as Fork 111 is fork entry line A_LMove along a straight line along fork center A₀The substrate Sb is received at a position coincident with the center C of the substrate Sb. At this time, the fork 111 has a fork reference line whose fork entry line A is_LIt is designed to move in a straight line in a state that matches. That is, as shown in FIGS. 12 and 13, the fork approach line A_LCorresponds to the fork reference direction.
Therefore, in the present embodiment, the position of the notch N that is the reference point of the peripheral edge of the substrate Sb is the fork entry line A._LThe angle is set with reference to. That is, as shown in FIGS. 12 and 13, a line segment connecting the notch N and the center C of the substrate Sb is a fork entry line A._LThe angle K formed with respect to the angle specifies the circumferential position of the notch N, and this angle (hereinafter referred to as the positioning angle) K can be set to a predetermined value (hereinafter referred to as K ′) in the circumferential direction. This is a positioning operation.
[0076]
The positioning angle K changes when the substrate Sb is rotated around the rotation center O. Accordingly, the fork 111 receives the substrate Sb after the substrate Sb is rotated to set the positioning angle K to a predetermined value K ′. To what extent the substrate Sb is rotated, K = K ′ can be obtained in advance by the following calculation.
12 and 13 are diagrams for explaining the calculation for obtaining the rotation angle for positioning in the circumferential direction. Among these, FIG. 12 shows a state before rotation. FIG. 13 is a diagram showing a state in which the positioning angle K is rotated by θ from the state of FIG. 12 in order to set the positioning angle K to a predetermined value K ′.
[0077]
When the substrate Sb is rotated by θ from the state shown in FIG. 12, the center C, the peripheral point S, and the notch N of the substrate Sb are also rotated around the rotation center O by θ as shown in FIG. And as a result of the rotation of center C, fork approach line A_LWill also change. Further, the positioning angle K also changes. However, angle θ_N, The angle A and the size of the line segment M do not change. With these values stored, the substrate Sb rotates.
Here, the fork approach line A with respect to the line connecting the operation reference point Q and the rotation center O_LAngle G, positioning angle K, angle θ obtained as described above_NAnd the rotation angle θ, the relationship of the following formula (16) always holds regardless of the rotation of the substrate Sb.
θ_N+ Θ = K + G (16)
What should be noted in this equation (16) is that not only K but also G changes when the substrate Sb is rotated. That is, G is a function of θ and is expressed as G (θ).
[0078]
If equation (16) is transformed taking this into account,
K = θ-G (θ) + θ_N(17)
It becomes.
In equation (17), θ_NIs already required as described above. Therefore, this value is a constant in equation (17). The rotation angle θ for positioning in the circumferential direction can be obtained by substituting K = K ′ and solving the equation (17). However, it is difficult to obtain the value of θ by directly solving the equation (17). Therefore, a repetitive calculation method using the computer 68 is used. That is, the right side of the equation (8) is calculated by sequentially substituting the value of θ in the range of −180 ° to 180 ° as the value of θ, for example, in increments of 1 °. Then, the value of θ when the value is closest to K ′ is obtained. G (θ) is calculated by the following equation (18), as is apparent from FIGS.
G (θ)
= Tan^-1[Msin (A + θ) / {OL + Mcos (A + θ)}] ... (18)
[0079]
When the rotation angle θ is obtained in this way, the stage 63 is rotated by this angle θ. As a result, the positioning angle K is substantially coincident with the predetermined angle K ′.
[0080]
Then, a distance T between the operation reference point Q and the center C of the substrate Sb is calculated from the distance OL and the angle G between the operation reference point Q of the transfer robot 11 and the rotation center O of the stage 63. This distance T is obtained from T = {Mcos (A + θ) + OL} secG. Note that the transfer robot 11 has an arm approach line A._LFork center A at a point that is a predetermined short distance from the operation reference point Q (hereinafter referred to as the fork operation origin)₀Is positioned and the fork reference direction is arm entry line A_LThe fork 111 is arranged so as to match the above. Then, the fork 111 is moved from this state. Accordingly, if the distance from the operation reference point Q to the fork operation origin is t, the movement distance of the fork 111 is T−t, and a signal is sent from the computer 68 so that the fork 111 moves by this distance.
[0081]
In this way, arm entry line A_LFork center A in the direction of distance (T-t)₀Fork center A₀The substrate Sb is placed on the fork 111 in a state where the center C of the substrate Sb coincides with the center C of the substrate Sb. More precisely, the fork center A on a vertical straight line passing through the center C of the substrate Sb.₀Is positioned, the fork 111 is raised, and the substrate Sb is placed on the fork 111. As a result, the substrate Sb is placed on the fork 111 in a state where the circumferential positioning is performed together with the center positioning.
[0082]
In summary, the program is executed in the order of calculation of the peripheral distance, calculation of the orientation flat center or notch N position, calculation of the center C of the substrate Sb, and calculation of the circumferential positioning rotational angle θ.
[0083]
Next, returning to FIG. 1, the configuration of another processing chamber in the apparatus of this embodiment will be described. First, the etching chamber 7 includes a gas introduction unit (not shown) that introduces a gas such as argon or nitrogen, a plasma formation unit (not shown) that forms high-frequency energy or the like to the introduced gas, and a substrate. It is mainly composed of a high-frequency power source (not shown) that applies a high-frequency voltage to Sb and applies a negative self-bias voltage to the substrate Sb by the interaction between plasma and high-frequency.
[0084]
Positive ions in the plasma are extracted by a negative self-bias voltage and enter the substrate Sb, and the natural oxide film or protective film on the surface of the substrate Sb is etched. As a result, the clean surface of the original material of the substrate Sb is exposed.
[0085]
The sputter chamber 8 is configured to create a predetermined thin film on the surface of the substrate Sb by magnetron sputtering. Specifically, a target (not shown) is provided such that the front surface to be sputtered is exposed in the sputter chamber 8, and a negative DC voltage or a high-frequency voltage is applied to the target. Then, an unillustrated magnet mechanism is provided behind the target to form an arch-shaped magnetic field line penetrating the target in a circumferential shape. Further, a gas introduction means (not shown) for introducing a gas such as argon or nitrogen into the sputter chamber 8 is provided.
[0086]
The introduced gas is discharged by the voltage applied to the target, and plasma is formed. The positive ions in the plasma sputter the target, and the sputtered target material reaches the substrate Sb. As a result, a thin film made of the target material is formed on the surface of the substrate Sb. In some cases, the sputtered target material reacts with the gas to form a thin film of a reaction product on the surface of the substrate Sb.
[0087]
The CVD chamber 9 includes a gas introduction unit (not shown) for introducing a predetermined reactive gas therein, and an energy application unit (not shown) for applying energy to the introduced gas to cause a predetermined gas phase reaction. Configured to provide. In the case of plasma CVD, the energy applying means is means for forming plasma by applying high-frequency energy or the like to the gas. Composed.
[0088]
Next, the configuration of the autoloader 4 that is preferably employed in the above-described multi-chamber substrate processing apparatus of the present embodiment will be described. FIG. 14 is a schematic perspective view illustrating an autoloader that is preferably employed in the multi-chamber substrate processing apparatus of the present embodiment.
[0089]
A major feature of the autoloader 4 shown in FIG. 14 is that a plurality of substrates Sb can be collectively conveyed from the external cassette 41 to the in-lock cassette 31. That is, the autoloader 4 mainly includes a plurality of holding fingers 44 and a moving mechanism 45 that moves the plurality of holding fingers 44 integrally. Each holding finger 44 is a substantially U-shaped member.
[0090]
The plurality of holding fingers 44 are arranged so as to overlap in the vertical direction at regular intervals. Each holding finger 44 is provided with an electrostatic adsorption mechanism for adsorbing the substrate Sb by static electricity as necessary. Such a holding finger 44 is integrally held by a finger holding body 46. The finger holder 46 is connected to the moving mechanism 45.
As the moving mechanism 45, many articulated robots are employed, and the finger holder 46 can be positioned at an arbitrary position within the operation range of the robot.
[0091]
The external cassette 41 and the in-lock cassette 31 have the same positional relationship between the substrates Sb in the accommodated state. That is, both the cassettes 31 and 41 hold the substrates Sb in a horizontal posture so as to overlap each other at a predetermined interval. The spacing between the substrates Sb is the same for the two cassettes 31 and 41.
[0092]
The operation of the autoloader 4 having the above configuration will be described. First, the finger holder 46 is moved by the moving mechanism 45, and each holding finger 44 is inserted below each substrate Sb in the external cassette 41. Then, the finger holders 46 are raised so that each substrate Sb is placed on each holding finger 44. In this state, the finger holder 46 is moved, and the plurality of substrates Sb are collectively transferred to the in-lock cassette 31. In the in-lock cassette 31, the finger holder 46 is slightly lowered so that the substrates Sb are placed on the protrusions of the respective steps of the in-lock cassette 31. Thereafter, each holding finger 44 is retracted from the in-lock cassette 31 and returned to a predetermined standby position.
[0093]
When the autoloader 4 having the above-described configuration is used, the efficiency of conveyance is dramatically increased, so that a significant improvement in productivity can be expected. On the other hand, as in the prior art, it is difficult for the positioner 5 to perform center positioning and circumferential positioning one by one when transporting from the external cassette 41 to the in-lock cassette 31. Therefore, the configuration including the positioning means having the above configuration eliminates the disadvantages of using the autoloader 4 having the above configuration, and has a synergistic effect.
[0094]
Next, the overall operation of the multi-chamber substrate processing apparatus according to the present embodiment having the above configuration will be schematically described.
First, a plurality of substrates Sb are collectively conveyed to one in-lock cassette 31 by the autoloader 4 described above. The transfer robot 11 in the separation chamber 1 takes out the substrates Sb one by one from the in-lock cassette 31 and sends them to the heat chamber 6.
[0095]
In the heat chamber 6, the stage 63 that has received the substrate Sb is lowered, and the substrate Sb is placed on the upper surface block 623 of the substrate holder 62. The heater 621 in the heating block 622 is operated in advance, and the mounted substrate Sb is heated by the heat from the heater 621. The temperature of the substrate Sb is monitored by a radiation thermometer (not shown) or a thermocouple, and the heater 621 is controlled to maintain a predetermined heating temperature for a predetermined time.
[0096]
When a predetermined time elapses, the elevating mechanism 65 operates to raise the stage 63 and position the substrate Sb at the level of the positioning level. Then, the positioning means described above operates, the position of the center C of the substrate Sb is calculated as described above, and the magnitude of the circumferential positioning rotational angle θ is calculated. Then, the stage 63 rotates by the circumferential positioning rotational angle θ. After that, the transfer robot 11 in the separation chamber 1 has its fork center A as described above.₀Moves so as to coincide with the center C of the substrate Sb and receives the substrate Sb. This completes center positioning and circumferential positioning.
[0097]
Thereafter, the transfer robot 11 sends the substrate Sb in this state to the etching chamber 7. As described above, after the natural oxide film or protective film on the surface is removed by etching, the substrate Sb is sent to the sputter chamber 8 by the transfer robot 11. As described above, after film formation by sputtering is performed in the sputtering chamber 8, the substrate Sb is sent to the CVD chamber 9, and film formation by CVD is performed. Thereafter, the substrate Sb is returned to the original or other load lock chamber 3. In addition, when it is conveyed from the CVD chamber 9 to the load lock chamber 3, it may be carried into the cooling chamber and cooled.
[0098]
In this way, the substrates Sb are taken out one by one from the one load lock chamber 3 and sequentially processed, and finally returned to the load lock chamber 3. When a predetermined number of substrates Sb are stored in the in-lock cassette 31 of the load lock chamber 3, the autoloader 4 is operated to carry out the predetermined number of substrates Sb all at once to the external cassette 41.
[0099]
As an example of the substrate processing in the above operation, continuous formation of a contact film barrier film is described. The contact film barrier film is, for example, interposed between the channel surface and the contact wiring as a base in an electrode portion of an FET (field effect transistor), etc. This prevents mutual diffusion of both. In general, a titanium film is employed as a contact film interposed mainly for improving electrical conduction. Further, titanium nitride is usually adopted as a barrier film interposed mainly for preventing mutual diffusion. Therefore, a multilayer film structure in which a titanium nitride film is laminated on a titanium film is required.
[0100]
In the case of forming this structure, argon gas is introduced into the sputtering chamber 8 and a titanium target is sputtered to form a titanium film on the surface of the substrate Sb. Then, the substrate Sb is transferred to the CVD chamber 9 through the separation chamber 1 in a vacuum. In the CVD chamber 9, plasma CVD is performed by introducing a gas obtained by mixing a titanium compound gas such as titanium chloride and nitrogen gas. While the titanium compound gas is decomposed in the plasma, titanium and nitrogen react, and titanium nitride adheres to the surface of the substrate Sb to form a titanium nitride film.
[0101]
In the multi-chamber substrate processing apparatus of the present embodiment related to the above configuration and operation, the etching chamber 7 is provided with positioning means. This configuration performs center positioning and circumferential positioning as soon as possible before being transferred to a processing chamber (hereinafter referred to as “positioning required chamber”) that needs to be processed with the center positioning and circumferential positioning performed. It has significance as. In other words, since the path and operation from the positioning to the substrate Sb being carried into the required positioning chamber are shortened, the possibility of misalignment due to some circumstances is considerably lower than in the past. .
[0102]
In addition, another reason for positioning in the center and circumferential position by providing positioning means in the heat chamber 6 is that productivity is achieved by positioning in a substrate other than the processing chamber that controls the single wafer processing of the substrate Sb. This is for the purpose of preventing the decrease of the above. That is, the time required to process one substrate Sb in each processing chamber varies depending on the content of the processing. Then, the loading / unloading operation of the substrate Sb to / from each processing chamber is rate-controlled by the processing time of one processing chamber that takes the most time. In other words, the substrate Sb in the other processing chamber is not transferred to the next processing chamber until the processing in the processing chamber (hereinafter referred to as the rate-determining chamber), which takes the longest time, is completed. Stays in the processing chamber.
Therefore, in the present embodiment, positioning means is provided in a processing chamber other than the rate limiting chamber, and positioning is performed in a vacant time until it is transferred to the next processing chamber. For this reason, the tact time does not become long, and the decrease in productivity is prevented.
[0103]
In the above-described example, the positioning is performed after the heat treatment of the substrate Sb, but it may be performed before the heat treatment. Specifically, when the substrate Sb is carried into the heat chamber 6 by the transfer robot 11 and placed on the stage 63, the stage 63 is positioned and positioned at a height level to rotate the stage 63. Then, as described above, the calculation of the position of the center C of the substrate Sb, the calculation of the center of the orientation flat or the notch of the substrate Sb, and the calculation of the circumferential positioning rotational angle θ are performed. Then, the stage 63 is lowered and the substrate Sb is placed on the substrate holder 62 and heated for a predetermined time. Thereafter, the stage 63 is raised and the stage 63 is rotated by the amount of the circumferential positioning rotational angle θ, and then the fork center A of the transfer robot 11 is moved.₀Is made to coincide with the center C of the substrate Sb so that the fork 111 receives the substrate Sb.
[0104]
In the above case, it is more preferable to heat the substrate Sb by changing the position of the substrate Sb by the transfer robot 11 before heating the substrate Sb. Specifically, after the calculation of the position of the center C of the substrate Sb and the calculation of the circumferential positioning rotational angle θ, the stage 63 is rotated by the circumferential positioning rotational angle θ, and the fork center A₀Is made to coincide with the center of the substrate Sb, and the fork 111 once receives the substrate Sb.
[0105]
After that, fork center A to rotation center O₀, The substrate Sb is placed on the stage 63 again. Then, the stage 63 is lowered and the substrate Sb is placed on the substrate holder 62 and heated. Thus, the heat treatment is performed in a state where the center axis of the substrate holder 62 and the center C of the substrate Sb coincide with each other and the circumferential position of the substrate Sb is also a predetermined position. Therefore, the reproducibility of the heat treatment is also improved.
[0106]
In the configuration in which the positioning means is provided in the heat chamber 6 described above, the space in the heat chamber 6 is effectively used. Space can be saved as compared with the configuration in which is provided.
In particular, the configuration in which positioning is performed by placing and rotating the substrate Sb on a stage 63 provided coaxially separately from the substrate holder 62 does not require a large space in the heat chamber 6 and heat There is an effect of suppressing the enlargement of the chamber 6. Further, it is preferable because the mechanism for rotation is simplified compared to the case where the substrate holder 62 incorporating the heater 621 rotates.
[0107]
【The invention's effect】
  As described above, according to the invention of claim 1 of the present application, since the position is detected in the processing chamber, space saving can be achieved.It isIn addition to the above effects, an increase in the size of the processing chamber is suppressed and the configuration of the rotation mechanism is simplified.
[Brief description of the drawings]
FIG. 1 is a plan view showing a schematic configuration of a multi-chamber substrate processing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic side view illustrating the configuration of a heat chamber 6;
3 is a diagram for explaining calculation of a peripheral distance, and is a schematic plan view showing a light receiving surface 677 of a light receiver 672. FIG.
FIG. 4 is a schematic side view showing a relationship between a substrate Sb that has been centered and an optical axis 670;
FIG. 5 is a diagram illustrating an example of a calculation result of a peripheral distance D, and specifically shows a calculation result of a peripheral distance when the substrate Sb is a circular substrate Sb such as a semiconductor wafer having an orientation flat. Yes.
6 shows a curve obtained by first-order differentiation of the curve shown in FIG.
7 is a diagram for explaining a calculation for obtaining the center of the orientation flat from the data shown in FIGS. 5 and 6. FIG.
FIG. 8 shows the measurement result of the peripheral distance when the substrate Sb is a circular substrate Sb such as a semiconductor wafer having a notch.
9 shows a curve obtained by first-order differentiation of the curve shown in FIG.
FIG. 10 is a plan view for explaining the calculation for obtaining the center of the substrate Sb from the peripheral distance data.
FIG. 11 is an explanatory diagram of calculation necessary for positioning in the circumferential direction, and is a diagram illustrating calculation for obtaining the position of a reference point on the periphery of the substrate Sb before rotation.
FIG. 12 is a diagram for explaining calculation for obtaining a rotation angle for positioning in the circumferential direction, showing a state before rotation.
13 is a diagram for explaining a calculation for obtaining a rotation angle for positioning in the circumferential direction, and showing a state in which the positioning angle K is rotated by θ from the state of FIG. 12 in order to set the positioning angle K to a predetermined angle. It is.
FIG. 14 is a schematic perspective view for explaining an autoloader preferably employed in the multi-chamber substrate processing apparatus of the present embodiment.
FIG. 15 is a schematic plan view showing a configuration of a conventional multi-chamber type substrate processing apparatus.
16 is a schematic perspective view illustrating a more detailed configuration of the positioner 5 shown in FIG.
[Explanation of symbols]
1 Separation chamber
11 Transport robot
3 Load lock chamber
31 Cassette in lock
4 Autoloader
41 External cassette
44 Holding fingers
45 Movement mechanism
46 Finger holder
6 Heat chamber
61 Gate valve
62 Substrate holder
621 Heater
622 Heating block
63 stages
64 Rotating mechanism
65 Lifting mechanism
66 Bellows
671 Light emitter
672 Receiver
68 computers
7 Etching chamber
8 Sputter chamber
9 CVD chamber
Sb substrate

Claims (6)

A processing chamber;
A substrate holder provided in the processing chamber and provided with a recess on the upper surface ;
A stage on which a substrate is placed, which can be accommodated in the recess in the processing chamber;
An elevating mechanism that lowers the stage on which the substrate is placed, places the substrate on the upper surface of the substrate holder, and then raises and lowers the stage so that the stage can be accommodated in the recess ;
A rotation mechanism for rotating the stage;
An optical position detection means having a light emitter and a light receiver;
A transfer robot for transferring a substrate from the stage ;
A control unit for controlling the transfer robot,
The light emitter emits light having a width so as to be partially blocked at the periphery of the substrate placed on the stage, and the light receiver receives the blocked light. ,
The elevating mechanism raises the stage on which the substrate is placed to position the substrate at a detection position higher than the substrate placement surface of the substrate holder,
The rotating mechanism rotates the stage with the substrate positioned at the detection position by the lifting mechanism,
The optical position detection means detects the position information of the substrate from the light reception result of the light receiver when the substrate rotates with the rotation of the stage at the detection position,
The control unit is based on the position information of the substrate detected by the optical position detection unit.
A substrate processing apparatus for controlling an operation of the transfer robot.   The substrate processing apparatus according to claim 1, wherein the position information includes a center position of the substrate and a circumferential position of the substrate. The substrate processing apparatus according to claim 1 , wherein the substrate holder includes a heater for heating the substrate. The light emitter and the light receiver are respectively attached to a ceiling wall and a side wall of the processing chamber so that light directed from the light emitter to the light receiver is not shielded by the substrate holder. The substrate processing apparatus according to any one of 1 to 3 . The processing chamber of claim 1 to 4, wherein is a heat chamber for heating the substrate, in addition to the heat chamber, multi-chamber substrate processing, characterized in that a sputtering chamber or CVD chamber to form a thin film apparatus. An electronic device manufacturing method, wherein an electronic device is manufactured using the multi-chamber substrate processing apparatus according to claim 5 .

Images