JP6477069B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In the manufacturing process of the semiconductor device, the semiconductor wafer is attracted to the mounting surface of the electrostatic chuck stage by an electrostatic force by the electrostatic chuck, and processes such as film formation and etching are performed. After the completion of such processing, when the electrostatic chuck is stopped by the electrostatic force, the semiconductor wafer is released from the electrostatic chuck stage and is transferred to another stage by the wafer transfer susceptor.

  However, even when the chucking by the electrostatic chuck is stopped, the state in which the semiconductor wafer is sucked to the electrostatic chuck stage may be maintained due to static electricity remaining between the semiconductor wafer and the electrostatic chuck stage. In this case, if the semiconductor wafer is transferred by the wafer transfer susceptor, the semiconductor wafer attracted to the electrostatic chuck stage may not be transferred appropriately.

  Therefore, after the electrostatic force is stopped by the electrostatic chuck, there is a method in which the semiconductor wafer adsorbed on the electrostatic chuck stage is lifted by a lift pin protruding from the mounting surface and released from the remaining electrostatic force (for example, Patent Document 1).

JP 2010-212678 A

However, when the method disclosed in Patent Document 1 is used, if the semiconductor wafer is sufficiently thin, the semiconductor wafer may be damaged by the lift pins.
In addition, when a sufficiently thin semiconductor wafer is attracted to the electrostatic chuck stage after the electrostatic force is stopped by the electrostatic chuck and is attempted to be transported to another stage by the wafer transport susceptor, the semiconductor wafer is impossible. There is a risk of being damaged by force.

  The present invention has been made in view of such a point, and an object thereof is to provide a method for manufacturing a semiconductor device capable of preventing damage to a semiconductor wafer when the semiconductor wafer is transported.

According to one aspect of the present invention, an element structure is formed on a main surface, and a step of adhering a semiconductor wafer warped by the element structure to a mounting surface of a stage provided with a distance sensor by suction, Stopping suction, measuring the first distance between the mounting surface and the semiconductor wafer by the distance sensor, and determining whether the semiconductor wafer can be transferred from the stage based on the first distance a step, was closed, measurement point of the semiconductor wafer to the first distance is measured, the prior suction, second distance between the semiconductor wafer and the mounting surface before measured by the distance sensor is a maximum A method for manufacturing a semiconductor device is provided in which a half of the second distance is equal to or greater than a thickness of the semiconductor wafer .

  According to the disclosed technology, it is possible to prevent damage to the semiconductor wafer and improve the yield of the semiconductor device.

It is a figure for demonstrating the manufacturing method of the semiconductor device of 1st Embodiment. It is a figure which shows the hardware structural example of the manufacturing apparatus of the semiconductor device of 2nd Embodiment. It is a figure which shows an example of the film-forming chamber with which the manufacturing apparatus of the semiconductor device of 2nd Embodiment is provided. It is a figure which shows an example of the conveyance mechanism with which the manufacturing apparatus of the semiconductor device of 2nd Embodiment is provided. It is a figure which shows an example of the semiconductor wafer of 2nd Embodiment. 12 is a flowchart (part 1) illustrating a process executed by the method for manufacturing a semiconductor device according to the second embodiment; 12 is a flowchart (part 2) illustrating a process executed by the method for manufacturing a semiconductor device according to the second embodiment; It is a figure which shows an example of the semiconductor wafer according to the presence or absence of the electrostatic chuck of 2nd Embodiment. It is a flowchart which shows the semiconductor wafer curvature state detection process performed with the manufacturing method of the semiconductor device of 2nd Embodiment. It is a flowchart which shows the semiconductor wafer adsorption | suction detection process performed with the manufacturing method of the semiconductor device of 2nd Embodiment. It is a flowchart which shows the semiconductor wafer curvature determination process performed with the manufacturing method of the semiconductor device of 2nd Embodiment. It is a graph which shows the distance of the semiconductor wafer from the electrostatic chuck stage according to the presence or absence of the electrostatic chuck of 2nd Embodiment. It is a flowchart which shows the semiconductor wafer curvature determination process performed with the manufacturing method of the semiconductor device of 3rd Embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
[First Embodiment]
A method of manufacturing the semiconductor device according to the first embodiment will be described with reference to FIG.

FIG. 1 is a diagram for explaining the method of manufacturing the semiconductor device of the first embodiment.
1A shows a side view when the semiconductor wafer 10 is placed on the stage 20, and FIG. 1B shows a side view when the semiconductor wafer 10 is attracted to the stage 20. FIG. 1C shows the case where the suction of the semiconductor wafer 10 is released after the suction stop by the stage 20. FIG. 1D shows the case where the suction of the semiconductor wafer 10 is not released after the suction stop by the stage 20. Each side view of the case is shown.

  A semiconductor wafer 10 to be described later is placed on the stage 20, and processes such as impurity implantation, film formation of an electrode layer and an insulating film, etching, and the like are performed on the semiconductor wafer 10. For example, distance sensors 21 a to 21 c are provided in the mounting surface 23 of the stage 20. The distance between the placement surface 23 and the semiconductor wafer 10 placed on the placement surface 23 can be measured using the distance sensors 21a to 21c. Further, the stage 20 is provided with suction devices 22 a and 22 b such as an electrostatic chuck and a vacuum chuck for sucking the semiconductor wafer 10 to the mounting surface 23. The electrostatic chuck charges the mounting surface 23 of the stage 20 to attract the semiconductor wafer 10 to the mounting surface 23 by electrostatic force (Coulomb force). The vacuum chuck sucks the semiconductor wafer 10 onto the mounting surface 23 by suction.

  The semiconductor wafer 10 has a thickness of 30 μm to 150 μm, for example, and a semiconductor element structure or the like is formed on at least one of the main surfaces 11 and 12. Since the semiconductor wafer 10 is sufficiently thin, its strength is reduced, and a semiconductor element structure or the like is formed on at least one of the main surfaces 11 and 12 to cause stress and warp. The above-described thickness of the semiconductor wafer 10 is an example, and is such a thickness that warp occurs when the semiconductor element structure or the like is formed on at least one of the main surfaces 11 and 12.

As shown in FIG. 1A, such a semiconductor wafer 10 is placed on the placement surface 23 of the stage 20, for example, in a convex state downward.
Next, the suction devices 22a and 22b of the stage 20 are turned on. The semiconductor wafer 10 is adsorbed by the adsorbing devices 22a and 22b and attached to the mounting surface 23 as shown in FIG. Processing such as impurity implantation, film formation, and etching can be performed on the main surface 12 of the semiconductor wafer 10 that is attached to the mounting surface 23 and thus becomes horizontal.

When such processing is completed, the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped.
At this time, when the suction to the semiconductor wafer 10 is appropriately released, the semiconductor wafer 10 is caused to have a structure as shown in FIG. 1 due to the stress caused by the semiconductor element structure or the like formed on at least one of the main surfaces 11 and 12 of the semiconductor wafer 10. As shown in (C), warping occurs again.

  On the other hand, for example, when the suction devices 22a and 22b are electrostatic chucks, the charging between the semiconductor wafer 10 and the mounting surface 23 is maintained even if the suction by the suction devices 22a and 22b is stopped. There is. When the suction devices 22a and 22b are vacuum chucks, the vacuum between the semiconductor wafer 10 and the mounting surface 23 may be maintained even if the suction by the suction devices 22a and 22b is stopped. In these cases, as shown in FIG. 1D, the semiconductor wafer 10 remains attached to the mounting surface 23 even though the suction by the suction devices 22a and 22b is stopped. Is done. If an attempt is made to transfer the semiconductor wafer 10 attached to the mounting surface 23 from the stage 20 by the wafer transfer susceptor 30, an excessive force is applied to the semiconductor wafer 10 and the semiconductor wafer 10 is broken. There is a risk of receiving. As a result, the yield of the semiconductor device is reduced.

Therefore, in the following, a method for specifying that the suction of the semiconductor wafer 10 to the mounting surface 23 is released after the suction is stopped and for reliably transporting the semiconductor wafer 10 will be described.
After the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped, the first distance b between the mounting surface 23 and the semiconductor wafer 10 is measured using, for example, the distance sensor 21c.

  When the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped and the suction to the semiconductor wafer 10 is appropriately released, the semiconductor wafer 10 is warped as described above (FIG. 1C). For this reason, the first distance b from the mounting surface 23 to the semiconductor wafer 10 can be measured using the distance sensor 21c. That is, if the measured first distance b is sufficiently large, the semiconductor wafer 10 is warped, and it is considered that the suction to the semiconductor wafer 10 is appropriately released. Therefore, after the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped, the semiconductor wafer 10 can be transported when the first distance b from the mounting surface 23 to the semiconductor wafer 10 is measured using the distance sensor 21c. Is determined.

  On the other hand, if the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped and the suction to the semiconductor wafer 10 is not properly released, as described above, the semiconductor wafer 10 is not warped and the placement surface 23 is not caused. (FIG. 1D). For this reason, for example, the first distance b from the mounting surface 23 to the semiconductor wafer 10 measured using the distance sensor 21c is zero or almost zero. That is, if the measured first distance b is zero or almost zero, it is considered that the semiconductor wafer 10 remains adhered to the mounting surface 23 and the suction to the semiconductor wafer 10 is not properly released. Therefore, when the first distance b from the mounting surface 23 to the semiconductor wafer 10 measured using the distance sensor 21c after the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is zero or almost zero, the semiconductor wafer It is determined that 10 is not transportable.

  As described above, in the semiconductor device manufacturing method, the element structure is formed on the main surface, and the semiconductor wafer 10 warped by the element structure is adsorbed to the mounting surface 23 of the stage 20 provided with the distance sensors 21a to 21c. Paste with. The suction is stopped, the first distance b between the mounting surface 23 and the semiconductor wafer 10 is measured by the distance sensors 21a to 21c, and it is determined whether the semiconductor wafer 10 can be transferred from the stage 20 based on the first distance b. To do.

  Thereby, it is possible to specify whether or not the semiconductor wafer 10 is attracted to the mounting surface 23 after the suction is stopped. The semiconductor wafer 10 is transported from the stage 20 when not attracted, and the semiconductor wafer 10 is not transported from the stage 20 when attracted. For this reason, an excessive force is not applied to the semiconductor wafer 10, the occurrence of damage to the semiconductor wafer 10 is suppressed, and the yield of the semiconductor device is improved.

  By the way, as described above, after the suction by the suction devices 22a and 22b is stopped, when the semiconductor wafer 10 is properly released from the placement surface 23, as in the case before the suction by the suction devices 22a and 22b, It will be warped again. From such a point of view, it can be determined as follows whether or not the semiconductor wafer 10 has been sucked from the mounting surface 23 after the suction by the suction devices 22a and 22b is stopped.

  First, when the semiconductor wafer 10 is placed on the stage 20 (FIG. 1A), the distance from the placement surface 23 to the semiconductor wafer 10 is measured by the distance sensors 21a to 21c. The warped state of the semiconductor wafer 10 is determined by specifying the measured distances in the longest order. In the case of FIG. 1A, it is specified that the second distance a measured by the distance sensor 21c is the longest, and the distances measured by the distance sensors 21b and 21a are successively longer.

  Next, the suction devices 22a and 22b of the stage 20 are turned on. The semiconductor wafer 10 is attracted to the stage 20 and attached to the mounting surface 23 as shown in FIG. Processing such as impurity implantation, film formation, and etching can be performed on the main surface 12 of the semiconductor wafer 10 that is attached to the mounting surface 23 and thus becomes horizontal. When such processing is completed, the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped, and the distance between the mounting surface 23 and the semiconductor wafer 10 is again measured by the distance sensors 21a to 21c.

  After the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped, if the suction to the semiconductor wafer 10 is appropriately released, the semiconductor wafer 10 is warped (FIG. 1C). At this time, the semiconductor wafer 10 (FIG. 1C) when the suction is stopped warps in the same manner as the semiconductor wafer 10 placed on the stage 20 (FIG. 1A). Therefore, in the case of FIG. 1C, the first distance b measured by the distance sensor 21c is the longest, and then the distances measured by the distance sensors 21b and 21a are sequentially increased. At this time, the warpage amount of the semiconductor wafer 10 (FIG. 1C) may be smaller than the warpage amount of the semiconductor wafer 10 (FIG. 1A). However, the amount of warpage of the semiconductor wafer 10 (FIG. 1C) that has been properly desorbed exceeds at least half of the amount of warpage of the semiconductor wafer 10 (FIG. 1A). It needs to exceed the thickness.

  Therefore, the longest distance (second distance a) measured by the distance sensor 21c on the semiconductor wafer 10 placed on the stage 20 (FIG. 1A) is the semiconductor wafer 10 after the suction stop (FIG. 1C). It is determined whether or not the suction of the semiconductor wafer 10 is released according to how much the change has occurred. That is, when the following inequality (1) is satisfied, it can be determined that the suction from the mounting surface 23 of the semiconductor wafer 10 is released.

First distance b> second distance a * 1/2> thickness of semiconductor wafer 10 (1)
In the case of the semiconductor wafer 10 after the suction stop (FIG. 1C), it is determined that the semiconductor wafer 10 can be transferred because the inequality (1) is satisfied and the suction of the semiconductor wafer 10 is released. Is done.

  On the other hand, in the case of the semiconductor wafer 10 (FIG. 1D) at the time of suction stop, since the first distance b is zero or almost zero, the inequality (1) is not satisfied. For this reason, after the suction of the semiconductor wafer 10 by the suction devices 22a and 22b is stopped, the first distance b from the mounting surface 23 to the semiconductor wafer 10 measured using the distance sensor 21c is zero or almost zero. It is determined that the wafer 10 cannot be transferred.

  Therefore, even with such a method, it is possible to specify whether or not the semiconductor wafer 10 is attracted to the mounting surface 23 after the suction is stopped. The semiconductor wafer 10 is transported from the stage 20 when not attracted, and the semiconductor wafer 10 is not transported from the stage 20 when attracted. For this reason, an excessive force is not applied to the semiconductor wafer 10, the occurrence of damage to the semiconductor wafer 10 is suppressed, and the yield of the semiconductor device is improved.

  In the first embodiment, the case where the semiconductor wafer 10 is warped downward with respect to the stage 20 has been described as an example. Not only in this case, even when the semiconductor wafer 10 is warped upward, it is possible to determine whether the semiconductor wafer 10 can be transferred from the stage 20 in the same manner as in the first embodiment.

[Second Embodiment]
Next, a method for manufacturing the semiconductor device according to the second embodiment will be described.
First, a hardware configuration example of a semiconductor device manufacturing apparatus will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a hardware configuration example of the semiconductor device manufacturing apparatus according to the second embodiment. Note that a structural example in the case where a metal film such as an electrode or an insulating film is formed will be described below. More specifically, the back electrode is formed. However, the present invention is not limited to this, and the following can be similarly applied to processing such as etching.

  The manufacturing apparatus 1000 includes a control unit 1100, a display unit 1200 connected to the control unit 1100, an input detection unit 1300, and a film formation unit 1400.

  The control unit 1100 includes a CPU (Central Processing Unit) 1110, and the entire manufacturing apparatus 1000 is controlled by the CPU 1110. A RAM (Read Access Memory) 1120, an HDD (Hard Disk Drive) 1130, a graphic processing unit 1140, an input / output interface 1150, and a communication control unit 1160 are connected to the CPU 1110 via a bus 1170.

  The RAM 1120 temporarily stores at least a part of OS programs and application programs to be executed by the CPU 1110. The RAM 1120 stores various data necessary for processing by the CPU 1110 and various data obtained by executing each processing.

The HDD 1130 stores an OS and application programs.
A display unit 1200 is connected to the graphic processing unit 1140. The graphic processing unit 1140 displays an image on the screen of the display unit 1200 according to a command from the CPU 1110.

  An input detection unit 1300 and a film formation unit 1400 are connected to the input / output interface 1150. The input / output interface 1150 transmits signals sent from the input detection unit 1300 and the film forming unit 1400 to the CPU 1110 via the bus 1170.

The display unit 1200 is a display device such as a display, for example.
The input detection unit 1300 is, for example, a keyboard, a mouse, or a touch panel attached to the display unit 1200.

  The film formation unit 1400 forms a semiconductor element by performing processes such as impurity implantation, film formation of an electrode metal film, an insulating film, etc., etching, and the like on a semiconductor wafer. Such a film forming unit 1400 includes, for example, a film forming chamber 1410 having a distance sensor 1411, an electrostatic chuck 1412, and a static electricity removing unit 1418, and a transport unit 1420.

Next, details of the film forming unit 1400 will be described.
First, the film formation chamber 1410 provided in the film formation unit 1400 will be described with reference to FIG.

FIG. 3 is a diagram illustrating an example of a film forming chamber provided in the semiconductor device manufacturing apparatus according to the second embodiment.
3A is a perspective side view of the film formation chamber 1410, and FIG. 3B is a top view of the electrostatic chuck stage 1413. In FIG. 3B, the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 is indicated by a broken line. Further, a first center line passing through the center in the vertical direction in the drawing of the semiconductor wafer 2000 and a second center line passing through the center in the horizontal direction in the drawing are indicated by two-dot chain lines.

  As shown in FIG. 3A, the film formation chamber 1410 includes an electrostatic chuck stage 1413 on which the semiconductor wafer 2000 is placed, and a wafer stage 1414 on which the electrostatic chuck stage 1413 is placed. In FIG. 3A, the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 is supported by the wafer transfer susceptor 1421.

  The electrostatic chuck stage 1413 has a semiconductor wafer 2000 of 8 inches (in the case of a diameter of 200 mm) and a diameter of, for example, about 190 mm to 196 mm. The electrostatic chuck stage 1413 includes distance sensors 1411a to 1411e and electrostatic chucks 1412a and 1412b.

  As shown in FIG. 3B, a distance sensor 1411a is disposed at the center of the electrostatic chuck stage 1413. A distance sensor 1411b is disposed above the distance sensor 1411a, and a distance sensor 1411c is disposed on the right side of the distance sensor 1411a. Further, a distance sensor 1411d is disposed below the distance sensor 1411a, and a distance sensor 1411e is disposed on the left side of the distance sensor 1411a. For example, eddy current sensors can be used as the distance sensors 1411a to 1411e. The distance values of the semiconductor wafer 2000 detected by the distance sensors 1411a to 1411e are represented as distances Ia to Ie. FIG. 3 illustrates a case where five distance sensors 1411a to 1411e are provided on the electrostatic chuck stage 1413. Not limited to this case, four or more distance sensors 1411 can be provided around the distance sensor 1411a with the distance sensor 1411a provided at the center of the electrostatic chuck stage 1413 as a center of point symmetry. Further, the installation positions of the distance sensors 1411b to 1411e provided around the distance sensor 1411a are preferably between the center of the semiconductor wafer 2000 and half of the radius of the semiconductor wafer 2000 to the outer periphery of the electrostatic chuck stage 1413. More preferably, it is between 6/10 and 8/10 of the radius of the semiconductor wafer 2000 from the center. If the distance sensors 1411b to 1411e are installed in the meantime, it is possible to accurately determine whether the semiconductor wafer 2000 is to be attracted from the electrostatic chuck stage 1413, which will be described later.

  Further, as compared with the electrostatic chuck stage 1413 provided with the distance sensors 1411a to 1411e in this way, the semiconductor wafer 2000 has a first center line whose distance sensors 1411a, 1411b, The orientation flat 2300 is disposed so as to be positioned on the distance sensor 1411d side so as to overlap with 1411d. The semiconductor wafer 2000 is arranged such that the second center line overlaps the distance sensors 1411a, 1411c, and 1411e. Details of the semiconductor wafer 2000 will be described later.

  Further, the film formation chamber 1410 includes a backing plate 1415 and a sputtering target 1416 supported by the backing plate 1415 in the case of a metal film forming process for electrodes, for example. Further, the film forming chamber 1410 includes a deposition preventing plate 1417 and a static electricity removing unit 1418. For example, the deposition preventing plate 1417 guides the process gas introduced for film formation to the upper side of the semiconductor wafer 2000 and prevents the film from being formed on other than the semiconductor wafer 2000. The static electricity removing unit 1418 is, for example, an ionizer, and removes static electricity by irradiating the charged semiconductor wafer 2000 on the electrostatic chuck stage 1413 after stopping the electrostatic chuck as described later.

Next, the transport unit 1420 included in the film formation unit 1400 will be described with reference to FIG.
FIG. 4 is a diagram illustrating an example of a transport mechanism included in the semiconductor device manufacturing apparatus according to the second embodiment.

In the film formation unit 1400, a plurality of film formation chambers 1410 (for example, film formation chambers 1410a and 1410b) are provided.
A transfer unit 1420 is used to transfer the semiconductor wafer 2000 between the film forming chambers 1401a and 1410b.

  The transfer unit 1420 includes a wafer transfer susceptor 1421 that supports the semiconductor wafer 2000, an arm 1422 that has the wafer transfer susceptor 1421 formed at one end thereof, and a rotation mechanism that is rotatable at the other end of the arm 1422. 1423.

Such a transfer unit 1420 transfers the semiconductor wafer 2000 based on the control signal from the control unit 1100 as follows.
When processing such as film formation on the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 of the film formation chamber 1410a is completed, the semiconductor wafer 2000 is supported by the wafer transfer susceptor 1421. The semiconductor wafer 2000 supported by the wafer transfer susceptor 1421 is transferred to the electrostatic chuck stage 1413 of the film forming chamber 1410b and placed on the electrostatic chuck stage 1413 by the rotational drive of the rotation mechanism 1423. The semiconductor wafer 2000 is subjected to a new process in the film forming chamber 1410b thus transported.

Next, the semiconductor wafer 2000 will be described with reference to FIG.
FIG. 5 is a diagram illustrating an example of a semiconductor wafer according to the second embodiment.
5A is a top view of the semiconductor wafer 2000, FIG. 5B is a side view of the semiconductor wafer 2000 from the arrow X in FIG. 5A, and FIG. It is a side view from arrow Y of Drawing 5 (A). In FIG. 5A, a first center line passing through the center in the vertical direction of the semiconductor wafer 2000 in the drawing and a second center line passing through the center in the horizontal direction in the drawing are indicated by two-dot chain lines. Further, the warping direction (left-right direction, up-down direction) of the semiconductor wafer 2000 is indicated by a broken line.

  The semiconductor wafer 2000 is made of, for example, silicon or silicon carbide, and has a diameter of 8 inches and a thickness of 30 μm to 150 μm. The semiconductor wafer 2000 has a semiconductor element structure 2100 formed on the main surface, and a scribe line 2200 is formed around the semiconductor element structure 2100 so as to be horizontal and orthogonal to the orientation flat 2300.

  Since the semiconductor wafer 2000 is sufficiently thin and has a reduced strength, the semiconductor wafer 2000 warps due to the stress (stress) caused by the formed semiconductor element structure 2100 and the scribe line 2200 and the residual stress of the heat treatment. Will occur. In particular, when forming an electrode on at least a passivation film on the surface of the semiconductor wafer 2000 and an electrode on the back surface of the semiconductor wafer 2000, a stress film is formed. After this film formation, the semiconductor wafer 2000 has a warp that is greater than the thickness of the semiconductor wafer 2000 because the stress is different between the front surface and the inside. Further, since the scribe line 2200 is formed so as to be horizontal and orthogonal to the orientation flat 2300, the semiconductor wafer 2000 is aligned along the direction of the scribe line 2200 as shown in FIG. It warps in the vertical direction (with the second center line as an axis) or in the left and right direction (with the first center line as an axis). For example, FIGS. 5B and 5C show a case where the semiconductor wafer 2000 is warped in the left-right direction in FIG. 5A (with the first center line as an axis). In this case, the main element side on which the semiconductor element structure 2100 and the scribe line 2200 are formed is warped so as to be on the outside. The semiconductor wafer 2000 may be warped so that the main surface side on which the semiconductor element structure 2100 and the scribe line 2200 are formed is on the inner side.

Next, a semiconductor device manufacturing method using the semiconductor device manufacturing apparatus 1000 having such a configuration will be described with reference to FIGS. 6, 7, and 8.
6 and 7 are flowcharts showing processes executed in the method for manufacturing a semiconductor device according to the second embodiment.

FIG. 8 is a diagram illustrating an example of a semiconductor wafer according to the presence or absence of an electrostatic chuck according to the second embodiment.
FIG. 8 is a side view of the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 as seen from the orientation flat 2300 side. Further, FIG. 8 shows a side view of an electrostatic chuck stage 1413 having distance sensors 1411c, 1411d, 1411e and electrostatic chucks 1412a, 1412b of the film forming chamber 1410. 8A shows a case where the semiconductor wafer 2000 is placed on the electrostatic chuck stage 1413, and FIG. 8B shows each side surface when the semiconductor wafer 2000 is electrostatically chucked on the electrostatic chuck stage 1413. The figure is shown. 8C shows the case where the suction is not released after the electrostatic chuck is stopped by the electrostatic chuck stage 1413. FIG. 8D is the case where the suction is stopped after the electrostatic chuck is stopped by the electrostatic chuck stage 1413. Each side view when is released is shown.

Each process described below is executed under the control of the control unit 1100.
[Step S <b> 110] The semiconductor wafer 2000 is transferred by the transfer unit 1420 and mounted on the electrostatic chuck stage 1413.

  For example, the semiconductor wafer 2000 in which the formation of the semiconductor element structure 2100, the scribe line 2200, and the like is completed is prepared in the manufacturing apparatus. Then, the semiconductor wafer 2000 supported by the wafer transfer susceptor 1421 is transferred and mounted on the electrostatic chuck stage 1413 in the film forming chamber 1410 according to the rotation of the rotation mechanism 1423 according to a transfer start command.

  Further, for example, as shown in FIGS. 5B and 5C, the semiconductor wafer 2000 is warped in the left-right direction with the first center line as an axis. Such a semiconductor wafer 2000 is placed as shown in FIG. 8A with the main surface on which the semiconductor element structure 2100 is formed in contact with the electrostatic chuck stage 1413. The positional relationship between the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 in this way and the distance sensors 1411a to 1411e is as shown in FIG. That is, the distance sensor 1411a is located at the center of the semiconductor wafer 2000, the distance sensor 1411b is located above the center, and the distance sensor 1411c is located on the right side from the center. Further, a distance sensor 1411d is positioned below the center of the semiconductor wafer 2000, and a distance sensor 1411e is positioned on the left side of the center.

  [Step S120] The distance sensors 1411a to 1411e measure each distance from the electrostatic chuck stage 1413 to the semiconductor wafer 2000. The control unit 1100 detects the warpage state (vertical direction or horizontal direction in FIG. 5) of the semiconductor wafer 2000 based on the distances measured by the distance sensors 1411a to 1411e.

For example, the semiconductor wafer 2000 is detected to be warped in the left-right direction as described above.
Details of the processing in step S120 will be described later.

  [Step S130] The semiconductor wafer 2000 is chucked by the electrostatic chucks 1412a and 1412b, and the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413 as shown in FIG. It becomes a state.

  [Step S140] The distance sensors 1411a to 1411e measure each distance from the electrostatic chuck stage 1413 to the semiconductor wafer 2000 attracted to the electrostatic chuck stage 1413. The control unit 1100 detects that the semiconductor wafer 2000 is properly attracted to the electrostatic chuck stage 1413 based on the distances measured by the distance sensors 1411a to 1411e.

Details of the process in step S140 will be described later.
[Step S150] A process gas is supplied in the film forming chamber 1410 to form, for example, a back electrode on the horizontal semiconductor wafer 2000 adsorbed on the electrostatic chuck stage 1413. Execute the process.

[Step S160] The chucking of the semiconductor wafer 2000 to the electrostatic chuck stage 1413 by the electrostatic chucks 1412a and 1412b is stopped (dechucked).
The dechuck stops attracting the semiconductor wafer 2000 to the electrostatic chuck stage 1413 by various methods such as applying a voltage in the opposite direction to the applied voltage at the time of attracting or applying an oscillating voltage.

[Step S170] 1 is added to the number of times of dechucking.
[Step S180] The distance sensors 1411a to 1411e measure each distance from the electrostatic chuck stage 1413 to the semiconductor wafer 2000. The control unit 1100 determines whether or not the semiconductor wafer 2000 is warped based on the distances measured by the distance sensors 1411a to 1411e.

Details of the process in step S180 will be described later.
[Step S190] The control unit 1100 determines whether or not the semiconductor wafer 2000 is released from the chucking of the electrostatic chuck stage 1413, based on the determination result of step S180.

  For example, as shown in FIG. 8C, when the semiconductor wafer 2000 is not warped in the determination of step S180, the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413 (the attraction is released). And the processing of the next step S200 is executed.

  Even when the electrostatic chucks 1412a and 1412b are dechucked, the charging between the semiconductor wafer 2000 and the electrostatic chuck stage 1413 may be maintained. In this case, the state in which the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413 is maintained.

  As shown in FIG. 8D, when the semiconductor wafer 2000 is warped in the determination of step S180, the semiconductor wafer 2000 is not attracted to the electrostatic chuck stage 1413 (the attraction is released). The process of the next step S220 is executed.

[Step S200] The control unit 1100 determines whether or not the number of times of dechucking has reached a preset number of times (threshold number of times).
If the dechucking count has not reached the threshold count, the control unit 1100 executes the process of step S160 again. When the dechuck count reaches the threshold count, the control unit 1100 clears the previous dechuck count and executes the process of step S210.

[Step S210] The static electricity removing unit 1418 removes static electricity between the semiconductor wafer 2000 and the electrostatic chuck stage 1413.
After the removal, the control unit 1100 executes the process of step S180 again.

[Step S <b> 220] The transport unit 1420 transports the semiconductor wafer 2000 from the electrostatic chuck stage 1413 to, for example, another electrostatic chuck stage 1413.
A semiconductor device is manufactured according to the above steps.

Next, details of the process of step S120 executed in the method for manufacturing a semiconductor device will be described with reference to FIGS.
FIG. 9 is a flowchart showing a semiconductor wafer warpage state detection process executed in the semiconductor device manufacturing method according to the second embodiment.

FIG. 12 is a graph showing the distance of the semiconductor wafer from the electrostatic chuck stage according to the presence or absence of the electrostatic chuck of the second embodiment.
In FIG. 12, the X-axis represents a change with time, and the time when the electrostatic chuck is turned off, the time when the electrostatic chuck is turned on, the time when the dechuck and the electrostatic chuck are turned off are associated with each other. The Y axis is associated with the distance from the electrostatic chuck stage 1413 to the semiconductor wafer 2000 detected by the distance sensors 1411a to 1411e of the eddy current sensor.

[Step S121] The distance sensors 1411a to 1411e measure the distances Ia to Ie from the electrostatic chuck stage 1413 to the semiconductor wafer 2000, respectively.
Eddy current sensors can be used for the distance sensors 1411a to 1411e. The eddy current sensor transmits a high-frequency signal to the semiconductor wafer 2000 and detects impedance due to the eddy current generated on the surface of the semiconductor wafer 2000. The impedance due to the eddy current depends on the distance of the semiconductor wafer 2000. Specifically, the impedance of the eddy current sensor increases as the distance between the eddy current sensor and the semiconductor wafer 2000 decreases, and the impedance of the eddy current sensor decreases as the distance between the eddy current sensor and the semiconductor wafer 2000 increases. . Therefore, the distances Ia to Ie to the semiconductor wafer 2000 can be calculated using the impedances ia to ie detected by the distance sensors 1411a to 1411e, which are eddy current sensors.

  Further, when the distance is measured by the eddy current sensor, the semiconductor wafer 2000 needs to have a conductive material. In a power semiconductor device having a vertical structure in which the thickness (wafer thickness) of the semiconductor wafer 2000 is 150 μm or less, the front surface and the back surface of the semiconductor wafer 2000 have an electrode structure. A metal film is always formed on the surface. In the manufacturing process of the semiconductor device, after the electrode film on the front surface is formed, the back surface of the semiconductor wafer 2000 is ground to reduce the thickness of the semiconductor wafer 2000. For this reason, a metal film is always formed on the semiconductor wafer 2000 during the manufacturing process of the thin semiconductor wafer 2000. For this reason, the distance from the electrostatic chuck stage 1413 to the semiconductor wafer 2000 can be detected using an eddy current sensor.

  The impedances ia to ie detected by the distance sensors 1411a to 1411e, which are eddy current sensors, indicate that the distance between the semiconductor wafer 2000 and the electrostatic chuck stage 1413 is in a state where the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413. Calibrate to 0 mm.

[Step S122] The control unit 1100 determines whether or not the distances Ia to Ie detected in step S121 satisfy the following expression (2).
The control unit 1100 executes the process of step S123 when the expression (2) is satisfied, and executes the process of step S124 when the expression (2) is not satisfied.

| Ic-Ia |> wafer thickness * 2 and
| Ie-Ia |> wafer thickness * 2 and
Ia≈Ib≈Id (2)
[Step S123] The control unit 1100 determines that the semiconductor wafer 2000 on the electrostatic chuck stage 1413 is warped in the left-right direction (with the first center line as an axis).

[Step S124] The control unit 1100 determines whether or not the distances Ia to Ie detected in step S121 satisfy the following expression (3).
If the following equation (3) is satisfied, the control unit 1100 executes the process of step S125. If not satisfied, the control unit 1100 ends the process of FIG.

| Ib-Ia |> wafer thickness * 2 and
| Id-Ia |> wafer thickness * 2 and
Ia≈Ic≈Ie (3)
[Step S <b> 125] The control unit 1100 determines that the semiconductor wafer 2000 on the electrostatic chuck stage 1413 is warped in the vertical direction (with the second center line as an axis).

In this manner, the warpage state of the semiconductor wafer 2000 mounted on the electrostatic chuck stage 1413 is detected in step S110.
For example, the distance sensors 1411a to 1411e measure the distances Ia to Ie (impedances ia to ie) for the semiconductor wafer 2000 shown in FIGS. 5B and 5C (step S121). The measured distances Ia to Ie satisfy the above formula (2) (step S122). That is, it corresponds to the case of “when electrostatic chuck is off (left end)” in FIG. 12, and the distances Ia, Ib, Id (impedances ia, ib, id) to the semiconductor wafer 2000 by the distance sensors 1411a, 1411b, 1411d are Almost the same equal. Furthermore, the distances Ic and Ie (impedance ic, ie) to the semiconductor wafer 2000 by the distance sensors 1411c and 1411e are longer (smaller) than the distances Ia, Ib and Id (impedances ia, ib and id). For this reason, it is determined that the semiconductor wafer 2000 is warped in the left-right direction (with the first center line as an axis) (step S123).

Next, details of the process of step S140 executed by the method for manufacturing a semiconductor device will be described with reference to FIGS.
FIG. 10 is a flowchart showing a semiconductor wafer suction detection process executed in the semiconductor device manufacturing method according to the second embodiment.

  [Step S141] The distance sensors 1411a to 1411e measure the distances Ia to Ie from the electrostatic chuck stage 1413 to the semiconductor wafer 2000 in the same manner as in Step S121.

[Step S142] The control unit 1100 determines whether or not the distances Ia to Ie detected in step S141 satisfy the following expression (4).
The control unit 1100 executes the process of step S143 when the following expression (4) is satisfied, and ends the process when the expression (4) is not satisfied.

| Ib-Ia | <wafer thickness * 2 and,
| Ic-Ia | <wafer thickness * 2 and,
| Id-Ia | <wafer thickness * 2 and,
| Ie-Ia | <Wafer Thickness * 2 (4)
When the semiconductor wafer 2000 is mounted on the electrostatic chuck stage 1413 and electrostatically chucked, the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413. Since the semiconductor wafer 2000 is sufficiently thin as described above, when the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413, the distance between the electrostatic chuck stage 1413 and the semiconductor wafer 2000 is almost all within the plane of the semiconductor wafer 2000. Be the same. In other words, if the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413, the distance sensors 1411a to 1411e all have substantially the same value, and therefore can be determined to be in the attracted state.

[Step S143] The control unit 1100 determines that the semiconductor wafer 2000 on the electrostatic chuck stage 1413 is properly sucked.
For example, the distance sensors 1411a to 1411e measure the distances Ia to Ie with respect to the semiconductor wafer 2000 electrostatically chucked on the electrostatic chuck stage 1413 (step S141). The measured distances Ia to Ie satisfy the above formula (4) (step S142). That is, this corresponds to the case of “when electrostatic chuck is on” in FIG. 12, and the distances Ia to Ie (impedances ia to ie) to the semiconductor wafer 2000 by the distance sensors 1411a to 1411e are substantially the same. Therefore, the semiconductor wafer 2000 is electrostatically chucked (adsorbed) to the electrostatic chuck stage 1413 and is detected to be in a horizontal state (step S143).

Next, details of the process of step S180 executed in the method for manufacturing a semiconductor device will be described with reference to FIGS.
FIG. 11 is a flowchart showing a semiconductor wafer warpage determination process executed in the method for manufacturing a semiconductor device of the second embodiment.

  [Step S181] The distance sensors 1411a to 1411e measure the distances Ia to Ie from the electrostatic chuck stage 1413 to the semiconductor wafer 2000, similarly to step S121.

[Step S182] The control unit 1100 determines the direction of warpage of the semiconductor wafer 2000 detected in step S120.
The control unit 1100 executes the next step S183 when the warp of the semiconductor wafer 2000 is in the horizontal direction, and executes the next step S184 when the warp of the semiconductor wafer 2000 is in the vertical direction.

[Step S183] The control unit 1100 determines whether or not the distances Ia to Ie detected in step S181 satisfy the above formula (2).
If the following equation (2) is satisfied, the control unit 1100 executes the process of step S185, and if not, the process ends. This is a state in which the suction is not released in step S190, and then step S200 is executed.

[Step S184] The control unit 1100 determines whether or not the distances Ia to Ie detected in step S181 satisfy the above formula (3).
The control unit 1100 executes the process of step S185 when the expression (3) is satisfied, and ends the process when the expression (3) is not satisfied. This is a state in which the suction is not released in step S190, and then step S200 is executed.

[Step S185] The control unit 1100 determines that the dechucked semiconductor wafer 2000 on the electrostatic chuck stage 1413 is warped.
For example, after the electrostatic chuck stage 1413 is turned off, the distance sensors 1411a to 1411e measure the distances Ia to Ie (impedances ia to ie) with respect to the semiconductor wafer 2000 (step S181). The semiconductor wafer 2000 is warped in the left-right direction (step S182), and the measured distances Ia to Ie satisfy equation (2) even after the electrostatic chuck is turned off (step S183). That is, this corresponds to the case of “dechuck” to “when electrostatic chuck is off (right end)” in FIG. 12, and distances Ia, Ib, Id (impedances ia, ib, id) again becomes approximately the same and equal. Further, the distances Ic, Ie (impedance ic, ie) to the semiconductor wafer 2000 by the distance sensors 1411c, 1411e are again longer (smaller) than the distances Ia, Ib, Id (impedances ia, ib, id). For this reason, it is determined that the semiconductor wafer 2000 is warped in the left-right direction (with the first center line as an axis) (step S185).

  As described above, in the semiconductor device manufacturing method, the semiconductor element structure 2100 and the scribe line 2200 are formed on the main surface, and the semiconductor wafer 2000 warped by the semiconductor element structure 2100 and the scribe line 2200 is separated from the distance sensors 1411a to 1411e and the static electricity. The electrostatic chuck stages 1413 provided with the electric chucks 1412a and 1412b are attached by suction. The adsorption of the electrostatic chucks 1412a and 1412b is stopped, and the distance sensors 1411a to 1411e measure the distances Ia to Ie between the semiconductor wafer 2000 and the electrostatic chuck stage 1413, and the semiconductor wafer 2000 is statically moved according to the distances Ia to Ie. It is determined whether or not conveyance from the electric chuck stage 1413 is possible.

  Thereby, it is possible to specify whether or not the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413 after the suction is stopped. When not attracted, the semiconductor wafer 2000 is transported from the electrostatic chuck stage 1413, and when attracted, the semiconductor wafer 2000 is not transported from the electrostatic chuck stage 1413. For this reason, an excessive force is not applied to the semiconductor wafer 2000, the occurrence of damage to the semiconductor wafer 2000 is suppressed, and the yield of the semiconductor device is improved.

[Third Embodiment]
Next, a method for manufacturing the semiconductor device of the third embodiment will be described.
In the third embodiment, the manufacturing apparatus 1000 (FIGS. 2 to 4) and the semiconductor wafer 2000 (FIG. 5) of the second embodiment are used.

In the third embodiment, the semiconductor device manufacturing method (FIGS. 6 and 7) of the second embodiment is executed to form the semiconductor device.
However, in the third embodiment, the process of step S180 of the method for manufacturing the semiconductor device of FIGS. 6 and 7 is different from the process of the second embodiment.

Therefore, in the third embodiment, details of the processing in step S180 of the method for manufacturing the semiconductor device of FIGS. 6 and 7 will be described with reference to FIG.
FIG. 13 is a flowchart showing a semiconductor wafer warpage determination process executed in the method for manufacturing a semiconductor device of the third embodiment.

The following processing is executed by the control unit 1100 after the processing in step S170 in the flowcharts shown in FIGS.
[Step S281] The control unit 1100 specifies the distances Ia to Ie measured in step S120 in the longest order.

  Note that the semiconductor wafer 2000 placed on the electrostatic chuck stage 1413 warps in either the left-right direction or the up-down direction as described with reference to FIG. When the semiconductor wafer 2000 warps in the left-right direction, the distances Ic, Ie measured by the distance sensors 1411c, 1411e are the longest among the distances Ia-Ie, and when the semiconductor wafer 2000 warps in the vertical direction, the distances Ia-Ie Of these, the distances Ib and Id measured by the distance sensors 1411b and 1411d are the longest.

  [Step S282] The distance sensors 1411a to 1411e measure the distances Ia to Ie from the electrostatic chuck stage 1413 to the semiconductor wafer 2000, similarly to step S121.

  [Step S283] In the control unit 1100, the longest distance In (measured in step S120) specified in step S281 and the distance In measured by the distance sensors 1411a to 1411e that measured the distance In after dechucking are expressed by the following equations. It is determined whether or not (5) is satisfied.

If the following equation (5) is satisfied, the control unit 1100 executes the process of step S284, and if not, the process ends.
Note that if a plurality of longest distances are specified in step S281, it is determined whether or not Expression (5) is satisfied for all longest distances.

In> In (step S120) * 0.5> wafer thickness (5)
That is, in the equation (5), it is determined whether the most warped (longest distance) portion of the semiconductor wafer 2000 before suction is warped in the same manner as before suction after dechucking. .

For example, the semiconductor wafer 2000 that has warped in the left-right direction before being attracted by the electrostatic chucks 1412a, 1412b returns to the warp in the left-right direction after dechucking.
In the semiconductor wafer 2000 before suction, the longest distances Ic and Ie from the electrostatic chuck stage 1413 are measured by distance sensors 1411c and 1411e that are line-symmetric with respect to the first center line. Therefore, the distance sensors 1411c and 1411e measure again how far the longest distances Ic and Ie before the chucking of the semiconductor wafer 2000 after dechucking have been performed.

  Thus, the semiconductor wafer 2000 after dechucking is sucked by using the following expressions for the distances Ic, Ie (step S120) before sucking measured by the distance sensors 1411c, 1411e and the distances Ic, Ie after dechucking. It is determined whether it has warped as before.

Ic> Ic (step S120) * 0.5> wafer thickness and
Ie> Ie (Step S120) * 0.5> Wafer Thickness The semiconductor wafer 2000 warped in the vertical direction before being attracted by the electrostatic chucks 1412a and 1412b returns to the vertical warpage after dechucking.

  In the semiconductor wafer 2000 before suction, the longest distances Ib and Id from the electrostatic chuck stage 1413 are measured by distance sensors 1411b and 1411d that are line-symmetric with respect to the second center line. Therefore, the distance sensors 1411b and 1411d again measure how far the longest distances Ib and Id before the chucking in the semiconductor wafer 2000 after dechucking are measured.

  Thus, the semiconductor wafer 2000 after dechucking is sucked by using the following expressions for the distances Ib and Id before sucking measured by the distance sensors 1411b and 1411d (step S120) and the distances Ib and Id after dechucking. It is determined whether it has warped as before.

Ib> Ib (step S120) * 0.5> wafer thickness and
Id> Id (Step S120) * 0.5> Wafer Thickness [Step S284] The control unit 1100 determines that the dechucked semiconductor wafer 2000 on the electrostatic chuck stage 1413 is warped.

  The control unit 1100 determines whether or not the semiconductor wafer 2000 is attracted from the electrostatic chuck stage 1413 according to the determination of whether or not the semiconductor wafer 2000 is warped by the processing of the flowchart (FIG. 13). It is determined whether it has been released (step S190 (FIG. 7)).

  In this way, it is determined how much the position where the distance from the electrostatic chuck stage 1413 before the suction to the semiconductor wafer 2000 is the longest after the dechucking is displaced. Depending on the determination result, it can be determined whether or not the semiconductor wafer 2000 is attracted to the electrostatic chuck stage 1413 after dechucking. The semiconductor wafer 2000 is transported from the electrostatic chuck stage 1413 only when it is not attracted, and when it is attracted, the semiconductor wafer 2000 is not transported from the electrostatic chuck stage 1413. For this reason, an excessive force is not applied to the semiconductor wafer 2000, the occurrence of damage to the semiconductor wafer 2000 is suppressed, and the yield of the semiconductor device is improved.

DESCRIPTION OF SYMBOLS 10 Semiconductor wafer 11 Main surface 20 Stage 21a, 21b, 21c Distance sensor 22a, 22b Adsorption device 23 Mounting surface 30 Wafer conveyance susceptor

Claims (8)

An element structure is formed on the main surface, and a step of adhering a semiconductor wafer warped by the element structure to the mounting surface of the stage provided with a distance sensor by suction;
Stopping the suction and measuring a first distance between the mounting surface and the semiconductor wafer by the distance sensor;
Determining whether the semiconductor wafer is transportable from the stage based on the first distance;
I have a,
The measurement location of the semiconductor wafer where the first distance is measured is:
Before the suction, the location where the second distance between the placement surface measured by the distance sensor and the semiconductor wafer is maximum,
One half of the second distance is equal to or greater than the thickness of the semiconductor wafer.
A method for manufacturing a semiconductor device. Scribe lines are formed in a lattice pattern on the main surface across the element structure.
The method of manufacturing a semiconductor device according to claim 1. Determining that the semiconductor wafer is transportable from the stage when the first distance is one half or more of the second distance;
The method for manufacturing a semiconductor device according to claim 1 , wherein: Another distance sensor is provided point-symmetrically with respect to the point where the second distance measured by the distance sensor is maximum with respect to the center point of the semiconductor wafer.
4. A method of manufacturing a semiconductor device according to claim 1 , wherein the method is a semiconductor device manufacturing method. The distance sensor measures the center distance from the mounting surface to the center of the semiconductor wafer, and the center measurement point of the center of the mounting surface, and the first measurement of the mounting surface that measures the first distance. And a second measurement location of the mounting surface provided in the second direction perpendicular to the first direction from the center portion with respect to the first direction from the first measurement location to the center portion. Each provided,
The method of manufacturing a semiconductor device according to claim 2. The first direction and the second direction are respectively parallel to the scribe line;
6. A method of manufacturing a semiconductor device according to claim 5 , wherein: A second difference between a first difference between the center distance and the first distance or a third distance between the placement surface and the semiconductor wafer measured by the distance sensor from the center distance and the second measurement location. Based on the difference, it is determined that the semiconductor wafer can be transferred from the stage.
A method for manufacturing a semiconductor device according to claim 5 or 6 . When the semiconductor wafer is warped about the first direction,
The first difference is not more than twice the thickness of the semiconductor wafer;
The second difference is greater than twice the thickness of the semiconductor wafer;
8. A method of manufacturing a semiconductor device according to claim 7 , wherein:

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