JP7790897B2 - Substrate Processing Equipment - Google Patents

Description

The present invention relates to a substrate processing apparatus for processing substrates such as semiconductor wafers.

When the holding surface of a holding table installed in a processing device is worn down or when the holding surface is ground to adjust its shape, the height of the holding surface decreases. Grinding devices in particular perform self-grinding, which grinds the holding surface to adjust its shape or to remove processing debris that has accumulated on the holding surface (see, for example, Patent Document 1), but this self-grinding reduces the height of the holding surface.

JP 2018-062048 A

Conventionally, the height at which the transfer arm that transports substrates within a processing device transfers the substrate to the holding surface of a holding table is set to a fixed value. Therefore, if the holding surface is ground and the height of the holding surface drops, the transfer arm may not be able to properly transfer the substrate to the holding surface.

In particular, for substrates that are warped toward the periphery, if the substrate is not pressed against the holding surface and held by suction on the holding surface, a vacuum leak will occur and the substrate will not be held properly. In other words, if the height of the holding surface is lower than it was initially, but the transfer height at which the transport arm places the substrate on the holding surface remains constant, the substrate will not be pressed properly against the holding surface, and the holding table will not be able to hold the warped substrate by suction.

One option is to set the transfer arm height lower than necessary so that the substrate can be pressed against the holding surface even if the height of the holding surface is lowered, but this could result in the pressing force being too strong and damaging the substrate.

Therefore, a challenge for substrate processing apparatuses is to ensure that substrates can be properly transported and transferred to the holding surface even when the height of the holding surface is lowered.

In order to solve the above problems, the present invention provides a substrate processing apparatus including at least a holding table having a holding surface for holding a substrate having a protective tape attached to its underside and having an element whose outer periphery is warped up , a height measuring unit for measuring the height of the holding surface, a transport arm for transporting the substrate relative to the holding table, a drive unit for lowering the transport arm to a transfer height at which the substrate is placed on the holding surface, and a control unit,
The holding table includes a porous member having a diameter smaller than that of the protective tape, and a frame that surrounds and supports the porous member, the transport arm includes a holding pad that has an adsorption surface on its underside and holds a central region of the substrate, and an outer periphery pressing portion that surrounds the holding pad and presses the outer periphery of the substrate toward the holding surface, and an annular accommodating groove is formed on the underside of the outer periphery pressing portion, and an O-ring is accommodated in the accommodating groove with its lower portion exposed from the accommodating groove, and the control portion is configured to, when the height of the holding surface drops, measure the height measured by the height measuring portion. When the transfer height of the transport arm holding the substrate having the warping element is controlled to be lowered by the distance that the height of the holding surface is lowered from the previously recognized height of the holding surface , the O-ring comes into contact with the warped outer periphery of the upper surface of the substrate, and then the transport arm is further lowered so that the suction surface, the underside of the O-ring, and the underside of the outer periphery pressing portion become flush with each other, and the exposed surface of the porous member is tightly covered by the protective tape on the underside of the substrate, eliminating vacuum leaks from the holding surface .
For example, the substrate processing apparatus may further include a grinding unit on which a grinding wheel for grinding the holding surface is rotatably mounted.
Preferably , the holding pad and the outer peripheral pressing portion are formed to include an elastic member.

In the substrate processing apparatus according to the present invention, even if the height of the holding surface of the holding table is lowered by a predetermined distance due to self-grinding or the like, the transfer arm also lowers the same distance to place the substrate on the holding surface and transfer it, preventing damage to the substrate during transfer to the holding surface. In particular, for warped substrates, a force is required to press the substrate against the holding surface. This is because the substrate is pressed against the holding surface and the holding surface applies suction to hold the substrate properly without vacuum leaks. However, if the height at which the transfer arm transfers the substrate is previously set low to prevent vacuum leaks even when the holding surface is lowered, the pressing force is too strong, which has traditionally led to damage. However, in the substrate processing apparatus according to the present invention, the transfer height is lowered in response to the lowering of the holding surface, eliminating the need to previously set the transfer position low due to concerns about vacuum leaks. The pressing force can be adjusted to an optimal level, eliminating this problem.
In addition, the transport arm has a holding pad that holds the central region of the substrate, and an outer periphery pressing portion that surrounds the holding pad and presses the outer periphery of the substrate toward the holding surface, making it possible to more reliably suction-hold a warped substrate on the holding surface without vacuum leakage.
Furthermore, by forming the holding pad and the outer peripheral pressing portion to include an elastic member, it becomes possible to further reduce the impact on the substrate when the substrate is transferred to and from the holding surface of the holding table.

FIG. 1 is a perspective view showing an example of a grinding device. 10 is a cross-sectional view illustrating a state in which the substrate held by suction on the holding pad of the transport arm is positioned above the new holding table. FIG. 10 is a cross-sectional view illustrating a state in which the transport arm, which holds the substrate by suction with the holding pad, is positioned at a transfer height at which the substrate is transferred to the holding surface of the new holding table. FIG. 10 is a cross-sectional view illustrating a state in which the height of the holding surface of the holding table after self-grinding is measured by a height measuring unit. FIG. FIG. 10 is a cross-sectional view illustrating a state in which the substrate held by suction on the holding pad of the transport arm is positioned above the holding table after self-grinding. 10 is a cross-sectional view illustrating a state in which the transfer arm, which holds the substrate by suction with the holding pad, is positioned at a corrected transfer height at which the substrate is transferred to the holding surface of the holding table after self-grinding. FIG.

In the substrate 90 shown in Fig. 1, for example, made of silicon as a base material, an upper surface 900 of the substrate 90 is molded with, for example, epoxy resin. The substrate 90, which is circular in plan view, is warped and curved as a whole due to the contraction force of the molding resin. That is, as shown in Fig. 2, the warp of the substrate 90 gradually increases from a central region 908 of a lower surface 902 of the substrate 90, which is held by suction, toward an outer peripheral region 907 (hereinafter referred to as the outer peripheral portion 907). The upper surface 900 of the substrate 90 is the surface to be ground, and a protective tape 91 is attached to the lower surface 902 of the substrate 90 to protect the lower surface 902.
The substrate 90 is not limited to a silicon wafer, and may be made of gallium arsenide, sapphire, ceramics, resin, gallium nitride, silicon carbide, or the like. A device may or may not be formed on the lower surface 902 of the substrate 90. The substrate 90 does not have to have the above-described warpage. The warpage of the substrate 90 may be, for example, gradually decreasing from a central region 908 of the lower surface 902 of the substrate 90, which is held by suction, toward an outer periphery 907.

1 is an apparatus that grinds a substrate 90 held on a holding table 30 using a grinding unit 41. The front (-Y direction side) of a base 10 of the substrate processing apparatus 1 is a load/unload area where the substrate 90 is loaded/unloaded onto/from the holding table 30, and the rear (+Y direction side) of the base 10 is a processing area where the grinding unit 41 performs grinding of the substrate 90 held on the holding table 30. The substrate processing apparatus 1 is a so-called fully automatic grinder.
The substrate processing apparatus according to the present invention is not limited to a single-axis type grinding unit 41 like the substrate processing apparatus 1, but may be a grinding apparatus with two or more axes including a rough grinding unit and a finish grinding unit, and capable of positioning the substrate 90 below the rough grinding unit or the finish grinding unit using a rotating turntable. Alternatively, the substrate processing apparatus 1 may be a manual type grinding apparatus. Furthermore, the substrate processing apparatus 1 may be a polishing apparatus that polishes the substrate 90 with a polishing pad.

A first cassette stage 150 and a second cassette stage 151 are provided on the front side (-Y direction side) of the base 10. A first cassette 157, which stores a plurality of unprocessed substrates 90 in a shelf-like arrangement, is placed on the first cassette stage 150, and a second cassette 158, which stores a plurality of processed substrates 90 in a shelf-like arrangement, is placed on the second cassette stage 151.

As shown in FIG. 1, the base 10 is covered by a housing 100 that is formed with a viewing window that allows the operator to see inside and an access door for accessing the inside. A touch panel 104 is provided on the front surface (-Y direction side) of the housing 100, allowing the operator to input processing conditions and setting data to the control unit 19 that controls each component of the substrate processing apparatus 1. It can also display processing conditions, a layout diagram of each component of the apparatus, the status of the substrate 90, etc.

A robot 155 is disposed behind the opening on the +Y direction side of the first cassette 157. This robot 155 removes unprocessed substrates 90 from the first cassette 157 and loads processed substrates 90 into the second cassette 158. A temporary storage area 152 is provided adjacent to the robot 155, and an alignment unit 153 is disposed in the temporary storage area 152. The alignment unit 153 uses a diameter-reducing alignment pin to align (center) the substrates 90 removed from the first cassette 157 and placed in the temporary storage area 152 to a predetermined position.

A transfer arm 2, which is composed of a suction pad or the like and transports the substrate 90 to the holding table 30, is located adjacent to the alignment unit 153. Next to the transfer arm 2, an unloading arm 29 is located, which unloads the substrate 90 from the holding table 30.

The transport arm 2 shown in Figures 1 and 2 comprises an arm bar 22 that extends parallel to the horizontal direction and has a holding pad 20 attached to the underside of its tip; a pivot shaft 24 whose axis is in the Z-axis direction and which rotates the arm bar 22 horizontally; the holding pad 20 that uses its underside to suction-hold, for example, the central region 908 (see Figure 2) of the upper surface 900 of the substrate 90; and an outer periphery pressing section 25 that surrounds the holding pad 20 and presses the outer periphery 907 of the substrate 90 against the holding surface.

As shown in FIG. 2, a pad support plate 220, which is circular in plan view, is bolted to the underside of the distal end of the arm bar 22, for example. A coil spring 204, which is an elastic member for absorbing impact when the pad support plate 220 comes into contact with the substrate 90, is attached to the center of the pad support plate 220 so that it can expand and contract in the Z-axis direction. It should be noted that a rubber column may be used as an elastic member instead of the coil spring 204.

2 is formed to have a smaller diameter than the substrate 90, and its flat lower surface serves as an adsorption surface 200 made of a porous material such as porous alumina. The adsorption surface 200 is connected to a suction source 209 such as a vacuum generator via a flexible resin tube or joint (not shown) that is flexible so as not to interfere with the movement of the transfer arm 2.
The holding pad 20 may be, for example, a suction cup made of a deformable elastic material such as rubber and formed into a circular shape in a plan view, and in this case, a suction hole is formed at the center thereof so as to penetrate in the thickness direction. The suction hole may be connected to the suction source 209.

The underside of the circular pad support plate 220 has an annular protrusion 251 that protrudes downward in an annular shape relative to the central region, forming the outer periphery pressing portion 25. An annular accommodating groove 254 is cut into the underside of the annular protrusion 251. The accommodating groove 254 has an inverted trapezoidal cross section, for example, and accommodates an O-ring 255, an annular elastic member, within it. The O-ring 255 is formed with a thickness greater than the opening width of the accommodating groove 254, and is accommodated in the accommodating groove 254 to prevent it from falling out. The O-ring 255 is capable of being crushed and deformed within the accommodating groove 254, and a portion of its lower side is exposed downward from the accommodating groove 254.

For example, a drive unit 28 is connected to the lower end of the pivot shaft 24 shown in FIG. 1. The drive unit 28 is, for example, an electric cylinder composed of a servo motor, ball screw, encoder, etc., and lowers the transport arm 2 in the Z-axis direction to the transfer height at which the substrate 90 is placed on the holding surface 302 of the holding table 30. It also raises the transport arm 2.

As shown in FIG. 1, a single-wafer spinner cleaning mechanism 156 is located near the unloading arm 29 to clean the processed substrates 90 transported by the unloading arm 29. The spinner cleaning mechanism 156 holds the protective tape 91 side of the substrate 90 on a spinner table and cleans the top surface 802 of the substrate 90 by spraying cleaning water from a swivel nozzle that can swivel above the held substrate 90. The substrate 90 is then dried, for example, by spraying air from the swivel nozzle. The substrate 90 that has been cleaned and dried by the spinner cleaning mechanism 156 is transported into a second cassette 158 by a robot 155.

A column 11 is erected on the rear side of the base 10 shown in FIG. 1, and a vertical movement unit 43 is disposed on the front surface of the column 11 on the -Y direction side, which moves the grinding unit 41 in the vertical direction (Z-axis direction) perpendicular to the holding surface 302 of the holding table 30. The vertical movement unit 43 is composed of a ball screw 430 whose axial direction is the Z-axis direction, a pair of guide rails 431 extending parallel to the ball screw 430, a motor 432 connected to the ball screw 430 and rotating the ball screw 430, and a lift plate 433 whose internal nut threads onto the ball screw 430 and whose sides slide against the pair of guide rails 431. When the motor 432 rotates the ball screw 430, the lift plate 433 is guided by the guide rails 431 and moves back and forth in the Z-axis direction, and the grinding unit 41 attached to the lift plate 433 also moves back and forth in the Z-axis direction.

The grinding unit 41, which grinds the substrate 90 held by the holding surface 302 of the holding table 30, includes a rotating shaft 410 whose axial direction is in the Z-axis direction, a housing 411 that rotatably supports the rotating shaft 410 using an air bearing or the like formed inside, a motor 412 that rotates the rotating shaft 410, a disk-shaped mount 413 connected to the lower end of the rotating shaft 410, a grinding wheel 414 that is detachably attached to the underside of the mount 413, and a holder 415 that supports the housing 411 and is connected to the lift plate 433.

The grinding wheel 414 comprises a wheel base 416 and a number of roughly rectangular parallelepiped segment grinding wheels arranged in a ring shape on the bottom surface of the wheel base 416. The segments are formed by, for example, fixing diamond abrasive grains with a resin bond or vitrified bond. The multiple annularly arranged segments form an annular grinding wheel 417. It is also possible to arrange circular grinding wheels with no gaps, i.e., grinding wheels in a so-called continuous arrangement, on the underside of the wheel base 416.

A flow path (not shown) is provided inside the rotating shaft 410 in the axial direction of the rotating shaft 410, which is connected to the grinding water supply source and serves as a path for grinding water. The flow path further passes through the mount 413 and opens at the bottom of the wheel base 416 so that grinding water can be sprayed toward the annular grinding wheel 417.

The holding table 30 shown in FIG. 1 has, for example, a circular outer shape and includes a circular plate-shaped porous member 300 that adsorbs the substrate 90, and a frame 301 made of ceramics or the like that surrounds and supports the porous member 300. The porous member 300 is connected to a suction source (not shown) such as a vacuum generator. The suction force generated by the operation of the suction source (not shown) is transmitted to a holding surface 302 made up of the exposed surface of the porous member 300 and the upper surface of the frame 301, which is formed flush with the exposed surface, and the holding table 30 holds the substrate 90 by suction on the holding surface 302. The holding surface 302 is an extremely gentle conical slope with its apex at the center of rotation of the holding table 30, so that it is not discernible to the naked eye.

As shown in Figure 1, the holding table 30 is surrounded by a cover 39 and can be moved back and forth in the Y-axis direction on the base 10 by a Y-axis movement unit (not shown), such as an electric slider, disposed under the cover 39 and a bellows cover 390 connected to the cover 39 and extending and contracting in the Y-axis direction.

A thickness measurement unit 38 that contact-measures the thickness of the substrate 90 during grinding is disposed near the grinding wheel 414, which has been lowered to the height required for grinding the substrate 90. The thickness measurement unit 38 includes, for example, a pair of thickness gauges (height gauges), namely, a height measurement unit 381 for measuring the height of the holding surface 302, which is the upper surface of the holding table 30, and a substrate height measurement unit 382 for measuring the height of the upper surface 900 of the substrate 90 held by the holding table 30.

The height measurement unit 381 and the substrate height measurement unit 382 each have a contact at their tip that moves up and down and makes contact with each measurement surface. The height measurement unit 381 (substrate height measurement unit 382) is supported so that it can move up and down, and can be pressed against each measurement surface with an appropriate force. The thickness measurement unit 38 uses the height measurement unit 381 to detect the height of the holding surface 302, which serves as the reference surface, and the substrate height measurement unit 382 to detect the height of the upper surface 900 of the substrate 90 being ground. By calculating the difference between the two detected values, the thickness measurement unit 38 can sequentially measure the thickness of the substrate 90 during grinding. Note that the thickness measurement unit 38 may also be a non-contact thickness measurement device.

The substrate processing apparatus 1 includes a control unit 19 that controls at least the drive unit 28. The control unit 19 is composed of a CPU that performs calculations according to a control program, a storage unit 190 such as a memory, and other components. The control unit 19 is electrically connected to the servo motor of the drive unit 28, which is, for example, an electric cylinder, via, for example, a wired or wireless communication path. That is, an operation signal is supplied to the servo motor of the drive unit 28 from the output interface of the control unit 19, which also functions as a servo amplifier, and the servo motor rotation speed detected by the encoder is output as an encoder signal to the input interface of the control unit 19. The control unit 19 then receives the servo motor rotation speed as an encoder signal, and can accurately position the transport arm 2, which is raised and lowered by the drive unit 28, to the desired height in the Z-axis direction. The motor of the drive unit 28 may be a pulse motor (stepping motor), and the control unit 19 may control the height of the transport arm 2 by counting the number of pulse signals sent to each pulse motor from a pulse oscillator (not shown).

The operation of the substrate processing apparatus 1 shown in FIG. 1 when grinding a substrate 90 held on, for example, a new holding table 30 having a predetermined thickness will be described below.
First, the robot 155 takes out one substrate 90 from the first cassette 157 and moves the substrate 90 to the temporary placement area 152 .

After the alignment unit 153 centers the substrate 90 on the temporary placement area 152, the transport arm 2 suction-holds the central region 908 of the upper surface 900 of the substrate 90 shown in Figure 2 and transports it onto the holding table 30. The holding table 30 and the substrate 90 are then aligned in the horizontal direction on the holding surface 302 so that the holding surface 302 of the holding table 30 and the center of the substrate 90 approximately coincide.

For example, information about the height Z1 of the holding surface 302 of a new holding table 30 shown in Figure 3 is input into the control unit 19 by an operator in advance and stored in the memory unit 190 of the control unit 19. Therefore, under control of the drive unit 28 by the control unit 19, the transport arm 2 is lowered to a height Z2 (transfer height Z2) that the control unit 19 has previously determined to correspond to the height Z1 of the holding surface 302. The transfer height Z2 is a height that has been experimentally, empirically, or theoretically determined so that the substrate 90 can be pressed against the holding surface 302 without being damaged, and so that a vacuum leak does not occur from the holding surface 302 when the warped substrate 90 has been transferred to the holding surface 302.

Specifically, as shown in FIG. 3, under the control of the drive unit 28 by the control unit 19, the drive unit 28 lowers the transport arm 2 at a predetermined speed. Then, the central area of the underside of the protective tape 91 on the underside 902 of the substrate 90, which is held by suction by the holding pad 20 of the transport arm 2, first comes into contact with the holding surface 302 of the holding table 30. Furthermore, the coil spring 204, which is an elastic member, contracts to absorb the impact when the substrate 90 comes into contact with the holding surface 302.

Furthermore, the O-ring 255 constituting the outer periphery pressing portion 25 comes into contact with the warped outer periphery 907 of the upper surface 900 of the substrate 90, pressing the outer periphery 907 downward toward the holding surface 302 and causing it to deform as if crushing. Then, when the transport arm 2 descends to the transfer height Z2 previously recognized by the control unit 19, for example, the suction surface 200 of the holding pad 20, the lower surface of the O-ring 255, and the lower surface of the annular protrusion 251 become flush or nearly flush. Furthermore, when the outer periphery 907 of the substrate 90, which includes a warped element, comes into contact with the upper surface of the frame 301, the exposed surface of the porous member 300 is tightly covered by the protective tape 91 on the lower surface 902 of the substrate 90, eliminating vacuum leaks from the holding surface 302.

Next, the suction force generated by the operation of a suction source (not shown) is transmitted to the holding surface 302, which is composed of the exposed surface of the porous member 300 and the upper surface of the frame body 301, which is formed flush with the exposed surface, and the holding table 30 suction-holds the substrate 90 on the holding surface 302 without vacuum leakage.

The holding table 30 holding the substrate 90 is moved in the +Y direction by a Y-axis movement unit (not shown) to below the grinding unit 41. The center of rotation of the grinding wheel 417 of the grinding unit 41 is then shifted horizontally by a predetermined distance relative to the center of rotation of the substrate 90, and the grinding wheel 417 is positioned so that its rotational trajectory passes through the center of rotation of the substrate 90.

The motor 412 rotates the rotating shaft 410 at a predetermined rotational speed, causing the grinding wheel 414 to rotate accordingly. The grinding unit 41 is then moved in the -Z direction by the vertical movement unit 43, and the rotating grinding wheel 417 comes into contact with the upper surface 900 of the substrate 90, thereby performing grinding. During grinding, the holding table 30 rotates at a predetermined rotational speed, causing the substrate 90 held on the holding surface 302 to also rotate, allowing the grinding wheel 417 to grind the entire upper surface 900 of the substrate 90. Grinding water is also supplied to the contact area between the grinding wheel 417 and the substrate 90 to cool and clean the contact area. After the substrate 90 has been ground to the desired thickness, the vertical movement unit 43 lifts the grinding unit 41 upward, causing the grinding wheel 417 to separate from the substrate 90, completing the grinding process.

After the substrate 90 has been ground to the desired thickness, the holding table 30 is moved in the -Y direction and positioned near the unloading arm 29. The substrate 90, held by suction by the unloading arm 29, is then transported to the spinner cleaning mechanism 156. After the top surface 900 of the substrate 90 is spin-cleaned by the spinner cleaning mechanism 156, the substrate 90 is air-dried or spin-dried. The substrate 90 is then loaded into the second cassette 158 by the robot 155.

For example, if the above-described grinding process is performed successively on multiple substrates 90 one by one, grinding debris may become clogged on the holding surface 302 of the holding table 30, reducing the thickness accuracy of the substrates 90 after grinding. Therefore, self-grinding is performed at an appropriate timing, such as after grinding of a certain substrate 90 is completed and before grinding the next new substrate 90, to grind the holding surface 302 to adjust its shape and to remove grinding debris from the holding surface 302.

The holding table 30 not holding the substrate 90 shown in FIG. 1 is moved in the +Y direction to below the grinding unit 41. The center of rotation of the grinding wheel 414 is then shifted horizontally by a predetermined distance relative to the center of rotation of the holding surface 302, so that the rotational path of the grinding wheel 417 passes through the center of rotation of the holding surface 302. Furthermore, to form the holding surface 302 into the desired shape, if necessary, the outer periphery of the holding table 30 may be slightly raised using a tilt adjustment means (not shown), thereby tilting the holding surface 302 of the holding table 30 and the underside of the grinding wheel 417 of the grinding unit 41 by a predetermined angle relative to each other. Before performing self-grinding, it is preferable to remove the grinding wheel 414 used to grind the substrate 90 and replace it with another grinding wheel suitable for grinding the holding surface 302.

Next, the holding table 30 rotates, and the vertical movement unit 43 lowers the grinding unit 41 at a predetermined grinding feed rate. The rotating grinding wheel 417 presses against and grinds the holding surface 302, which is composed of the upper surface of the porous member 300 and the upper surface of the frame 301. The grinding wheel 417 constantly passes through the center of the holding surface 302, grinding the entire surface of the holding surface 302. After the predetermined grinding time, the grinding unit 41 moves in the +Z direction and separates from the holding table 30. The holding surface 302 then assumes a very gentle, invisible conical shape with its apex at the center of rotation of the holding surface 302 and sloping outward, completing self-grinding. The amount of self-grinding may be controlled by time, or by detecting the height of the holding surface 302 using the height measurement unit 381 (in this embodiment, the height of the upper surface of the frame 301, which constitutes the holding surface 302 and is flush with the exposed surface of the porous member 300).

Next, as shown in FIG. 4, the height measuring unit 381 measures the height of the holding surface 302 after self-grinding (in this embodiment, the height of the upper surface of the frame 301, which is flush with the holding surface 302). Here, by having the height measuring unit 381 measure the height of the upper surface of the frame 301, the exposed surface (upper surface) of the porous member 300 that suction-holds the substrate 90 is not damaged. The height of the holding surface 302 after grinding measured by the height measuring unit 381 is then assumed to be height Z3.

The height measurement unit 381 sends the measurement information to the control unit 19 shown in Figure 1, and the control unit 19 calculates the difference between the height Z1 of the holding surface 302 before grinding, which is stored in the memory unit 190 and recognized in advance, and the height Z3 of the holding surface 302 after self-grinding, as the distance L1 by which the height of the holding surface 302 has dropped.

Then, the robot 155 shown in FIG. 1 pulls out one substrate 90 from the first cassette 157, and the substrate 90 is moved to the temporary placement area 152 and centered. Then, as shown in FIG. 5, the transport arm 2 suction-holds the central region 908 of the upper surface 900 of the substrate 90 with the holding pad 20, and then transports the substrate 90 onto the holding table 30, where it is aligned horizontally so that the holding surface 302 of the holding table 30 and the center of the substrate 90 are approximately aligned.

Next, under the control of the drive unit 28 by the control unit 19, the transport arm 2 is lowered to a height Z4 corresponding to the height Z3 of the holding surface 302 after grinding, i.e., a height Z4 that is a distance L1 below the previously determined transfer height Z2 (hereinafter referred to as the corrected transfer height Z4). Specifically, as shown in FIG. 6 , under the control of the drive unit 28 by the control unit 19, the drive unit 28 lowers the transport arm 2 at a predetermined speed. Then, the central region of the underside of the protective tape 91 on the underside 902 of the substrate 90, which is suction-held by the holding pad 20 of the transport arm 2, first comes into contact with the holding surface 302 of the holding table 30. Furthermore, the coil spring 204 contracts to absorb the impact when the substrate 90 comes into contact with the holding surface 302. Furthermore, the O-ring 255 comes into contact with the warped outer periphery 907 of the upper surface 900 of the substrate 90, pressing the outer periphery 907 downward toward the holding surface 302 and deforming it. Then, by lowering the transfer arm 2 to the corrected transfer height Z4, the suction surface 200 of the holding pad 20, the lower surface of the O-ring 255, and the lower surface of the annular protrusion 251 become flush or nearly flush. Furthermore, the outer periphery 907 of the substrate 90, which has a warping element, comes into contact with the upper surface of the frame 301, so that the exposed surface of the porous member 300 is completely covered by the protective tape 91 on the lower surface 902 of the substrate 90, eliminating vacuum leaks from the holding surface 302. Here, the control unit 19 controls the transfer height to be lowered from the transfer height Z2 shown in FIG. 6 to the corrected transfer height Z4. While the holding surface 302 corrects the warpage of the substrate 90, the transfer arm 2 does not apply excessive pressure to the substrate 90 that could damage the substrate 90.

Then, the holding table 30 suction-holds the substrate 90 on the holding surface 302 to which the suction force has been transmitted, without any vacuum leaks. After that, grinding of the substrate 90 is carried out in the same manner as described above.

In this way, in the substrate processing apparatus 1 of the present invention, when the height of the holding surface 302 decreases, the control unit 19 controls the transfer height of the transport arm 2 to decrease by the distance L1 that the height Z3 of the holding surface 302 measured by the height measurement unit 381 has decreased from the previously recognized height Z1 of the holding surface 302. Therefore, even if the height of the holding surface 302 of the holding table 30 decreases due to self-grinding or the like, the transport arm 2 also decreases by the same distance L1 that the height of the holding surface 302 has decreased, and the substrate 90 is placed on the holding surface 302 and transferred, so that the substrate 90 will not be damaged when transferred to the holding surface 302. In particular, in the case of a warped substrate 90 as in this embodiment, a force is required to press the substrate 90 against the holding surface 302 to prevent vacuum leaks. If the height at which the transfer arm 2 transfers the substrate 90 was previously set low, the pressing force would be too great and the substrate 90 would likely be damaged. However, the substrate processing apparatus 1 according to the present invention can adjust the pressing force to an optimum level, preventing damage to the substrate 90.

In addition, the transport arm 2 has a holding pad 20 that holds the central region 908 of the substrate 90, and an outer periphery pressing portion 25 that surrounds the holding pad 20 and presses the outer periphery 907 of the substrate 90 against the holding surface 302, making it possible to more reliably suction-hold a warped substrate 90 on the holding surface 302 without vacuum leakage.

Furthermore, the holding pad 20 is provided with an elastic member such as a coil spring 204, and the outer peripheral pressing portion 25 is provided with an elastic member such as an O-ring 255, which makes it possible to further reduce the impact on the substrate 90 when the substrate 90 is transferred to and from the holding surface 302 of the holding table 30.

The substrate processing apparatus 1 according to the present invention is not limited to the above embodiment, and may, of course, be embodied in a variety of different forms within the scope of its technical concept. Furthermore, the process of grinding the substrate 90 using the substrate processing apparatus 1 can also be modified as appropriate within the scope of the effects of the present invention.

1: Substrate processing apparatus 10: Base 100: Housing
150: First cassette stage 151: Second cassette stage
152: Temporary placement area 153: Alignment unit 155: Robot 19: Control unit 190: Memory unit
2: Transport arm 20: Holding pad 204: Coil spring 209: Suction source 22: Arm bar 220: Pad support plate 24: Rotation axis
25: Outer periphery pressing portion 251: Annular protrusion portion 254: Storage groove 255: O-ring 28: Drive portion 29: Unloading arm 30: Holding table 300: Porous member 301: Frame body 302: Holding surface 38: Thickness measuring unit 381: Height measuring portion 382: Substrate height measuring portion 41: Grinding unit 43: Up and down movement unit
90: Substrate 900: Upper surface of substrate 902: Lower surface of substrate 907: Peripheral portion 908: Central region
91: Protective tape

Claims (3)

A substrate processing apparatus comprising at least a holding table having a holding surface for holding a substrate having a protective tape attached to its underside and having an element whose outer periphery is warped up , a height measuring unit for measuring the height of the holding surface, a transport arm for transporting the substrate relative to the holding table, a drive unit for lowering the transport arm to a transfer height at which the substrate is placed on the holding surface, and a control unit,
the holding table includes a porous member having a diameter smaller than that of the protective tape, and a frame that surrounds and supports the porous member;
the transport arm has a holding pad having an adsorption surface on its underside and holding a central region of the substrate, and an outer periphery pressing portion surrounding the holding pad and pressing the outer periphery of the substrate against the holding surface, an annular accommodating groove is formed on the underside of the outer periphery pressing portion, and an O-ring is accommodated in the accommodating groove with its lower portion exposed from the accommodating groove;
When the height of the holding surface decreases, the control unit controls the transfer height of the transport arm holding the substrate having the warping element to decrease by the distance that the height of the holding surface measured by the height measuring unit has decreased from the previously recognized height of the holding surface.After the O-ring comes into contact with the warped outer periphery of the upper surface of the substrate, the transport arm further decreases, so that the suction surface, the lower surface of the O-ring, and the lower surface of the outer periphery pressing unit become flush, and the exposed surface of the porous member is tightly covered by the protective tape on the underside of the substrate, eliminating vacuum leaks from the holding surface . The substrate processing apparatus of claim 1, further comprising a grinding unit to which a grinding wheel for grinding the holding surface is rotatably mounted. 2. The substrate processing apparatus according to claim 1 , wherein the holding pad and the outer periphery pressing portion are formed to include an elastic member.