JP2019197755A - Method for manufacturing semiconductor device - Google Patents

Abstract

To reduce peeling failure in a protective sheet peeling process.SOLUTION: A protective sheet peeling process comprises steps of: (S201) forming a separation starting point part for separating small pieces from a semiconductor wafer on the rear surface of the semiconductor wafer; (S202) sticking a release sheet on a protective sheet so as to overlap with the separation starting point part in a plan view; and (S203) peeling the release sheet and the protective sheet sticking the small pieces from the semiconductor wafer while separating the small pieces from the semiconductor wafer in the separation starting point part by applying peeling force to the release sheet.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a semiconductor device manufacturing technique, for example, a technique effective when applied to a semiconductor device manufacturing technique including a step of peeling a protective sheet attached to the surface of a semiconductor wafer.

  Japanese Patent Application Laid-Open No. 11-16862 (Patent Document 1) describes a technique relating to measures for preventing a peeling error in a step of peeling a protective sheet using a peeling tape attached on the protective sheet. Specifically, Patent Document 1 describes a technique for improving the adhesive force between a peeling tape and a protective sheet by performing pressure treatment or heat treatment when bonding the peeling tape to the protective sheet. Yes.

  Japanese Patent Application Laid-Open No. 11-163105 (Patent Document 2) describes a technique relating to measures for preventing a peeling error in a process of peeling a protective sheet using a peeling tape attached on the protective sheet. Specifically, in Patent Document 2, in order to reduce the adhesive force between the semiconductor wafer and the protective sheet, an ultraviolet curable adhesive is used as an adhesive for bonding the semiconductor wafer and the protective sheet. A technique for reducing the adhesive strength of an ultraviolet curable adhesive by irradiating ultraviolet rays when the protective sheet is peeled off is described.

Japanese Patent Laid-Open No. 11-16862 JP 11-163105 A

  For example, when processing is performed on the back surface of a semiconductor wafer, a protective sheet is attached on the surface of the semiconductor wafer in order to protect the surface of the semiconductor wafer. And after the process of the back surface of a semiconductor wafer is complete | finished, the protective sheet affixed on the surface of the semiconductor wafer is peeled off from a semiconductor wafer. Here, in the process of peeling the protective sheet from the surface of the semiconductor wafer, there may be a case where a protective sheet is peeled off. Therefore, a device for reducing the protective sheet peeling mistake as much as possible is desired.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  In the method for manufacturing a semiconductor device according to an embodiment, the protective sheet to which the small pieces are attached is peeled off from the wafer together with the release sheet while separating the small pieces from the wafer at the separation starting point.

  According to one embodiment, it is possible to reduce peeling mistakes in the protective sheet peeling step.

It is a flowchart which shows the flow of the manufacturing process of a semiconductor device. It is a figure explaining the room for improvement which exists in related technology. It is a figure explaining the room for improvement which exists in related technology. It is a figure explaining the room for improvement which exists in related technology. It is a flowchart explaining embodiment. It is a figure which shows the manufacturing process of the semiconductor device in embodiment. FIG. 7 is a diagram showing a manufacturing step of the semiconductor device following that of FIG. 6; FIG. 8 is a diagram showing a manufacturing step of the semiconductor device following that of FIG. 7; FIG. 9 is a diagram illustrating a manufacturing step of the semiconductor device following that of FIG. 8; FIG. 10 is a diagram illustrating a manufacturing step of the semiconductor device following that of FIG. 9; FIG. 11 is a diagram illustrating a manufacturing step of the semiconductor device following that of FIG. 10; In the peeling method in related technology, it is a figure explaining the mechanism which a peeling mistake tends to produce. In the peeling method in this Embodiment, it is a figure explaining the mechanism which becomes difficult to produce peeling mistake. It is a flowchart explaining a modification. It is a figure which shows the typical structure of the sheet | seat peeling apparatus in embodiment. It is a figure which shows an example of the separation origin part formed on the wafer by the separation origin formation part of a sheet peeling apparatus. It is a figure which shows another example of the separation origin part formed on the wafer by the separation origin formation part of a sheet peeling apparatus. It is a figure explaining attracting | sucking the area | region except the area | region used as a small piece of the back surface of a wafer with a chuck | zipper. It is a flowchart which shows operation | movement of the sheet | seat peeling apparatus in embodiment.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

  Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of components, etc., unless otherwise specified, and in principle, it is considered that this is not clearly the case, it is substantially the same. Including those that are approximate or similar to the shape. The same applies to the above numerical values and ranges.

  In all the drawings for explaining the embodiments, the same members are denoted by the same reference symbols in principle, and the repeated explanation thereof is omitted. In order to make the drawings easy to understand, even a plan view may be hatched.

<Manufacturing process of semiconductor device>
First, a manufacturing process of a semiconductor device will be described with reference to FIG.

  FIG. 1 is a flowchart showing a flow of a semiconductor device manufacturing process. For example, a wafer (semiconductor wafer) made of silicon single crystal is prepared (S101). Then, transistors are formed on this wafer by using a normal semiconductor manufacturing process (S102). Specifically, by using oxidation technology, photolithography technology, etching technology, ion implantation technology, film formation technology, heat treatment technology, etc., power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor) A representative power transistor is formed.

  Thereafter, a wiring layer is formed on the wafer by using a film forming technique, a photolithography technique, an etching technique, or the like. Subsequently, a pad is formed on the uppermost wiring layer by using a patterning technique. Next, after forming a passivation film (surface protective film) that covers the pad by using a film forming technique, an opening is formed in the passivation film by using a photolithography technique and an etching technique. At this time, the surface of the pad is exposed from the opening (S103).

  Subsequently, a protective sheet is affixed on the passivation film (S104). Then, the back surface of the wafer is ground (S105). Thereby, for example, a wafer having a thickness of about 750 μm is thinned, and a wafer having a thickness of about 400 μm or less can be formed. At this time, the protective sheet attached to the front surface of the wafer has a function of protecting the front surface of the wafer when the back surface of the wafer is ground. Furthermore, in the process of grinding the back surface of the wafer, depending on the product, it may be ground to a thickness of about 75 μm. When the back surface of the wafer is ground to such a thickness, the wafer tends to be warped. Therefore, the protective sheet attached to the front surface of the wafer also has a function of suppressing the warpage of the wafer.

  Next, a back electrode is formed on the back surface of the wafer (S106). This back electrode can be formed by sputtering, for example. The back electrode functions as a drain electrode of the power transistor. Furthermore, in order to reduce the on-resistance of the power transistor, the back electrode may be made thicker. In this case, for example, the thickness of the back electrode can be increased by using a plating method. Here, in the plating method, when a plating solution is used and this plating solution enters the front surface of the wafer, an unintended unnecessary plating film is formed not only on the back surface of the wafer but also on the front surface of the wafer. . For this reason, the protective sheet affixed to the surface of the wafer further has a function of suppressing the penetration of the plating solution into the surface of the wafer. As described above, the protective sheet attached to the surface of the wafer has a function of protecting the surface of the wafer as a basic function, a function of suppressing warpage of the thinned wafer, and a back surface including a plating film. It also has a function of suppressing the plating solution from entering the front surface of the wafer in the step of forming the electrode on the back surface of the wafer.

  Subsequently, the protective sheet attached to the surface of the wafer is peeled off (S107). Then, after a dicing tape is attached to the back surface of the wafer (S108), the wafer is diced (S109). As a result, a plurality of chip regions formed on the wafer are singulated, and a plurality of semiconductor chips can be obtained from one wafer. Next, for example, a semiconductor chip is mounted on a chip mounting portion (tab) formed on the lead frame via solder (S110). Then, the leads formed on the lead frame and the pads formed on the surface side of the semiconductor chip are connected by wires (wire bonding) (S111). Thereafter, a sealing body made of a resin for sealing the semiconductor chip and the wire is formed (mold) (S112). Next, for example, a semiconductor device can be manufactured through a lead cutting process, an exterior plating process on the surface of the lead, a lead molding process, and the like.

<Examination of improvement>
Next, the room for improvement found by the present inventors in the step of peeling the protective sheet from the wafer (S107 in FIG. 1) will be described with reference to the drawings.

  First, a related technique for removing the protective sheet from the wafer will be described.

  Here, the “related technology” in the present specification is a technology having a problem newly found by the inventor and is not a known conventional technology, but is a premise technology (unknown technology) of a new technical idea. ) Is a technique described with the intention of

  After the release sheet RS is attached to the protective sheet PS attached to the surface of the wafer WF, as shown in FIG. 2, while rotating the roller RL in close contact with the release sheet RS, in the direction of the arrow in FIG. Move. That is, as shown in FIG. 3, the rotating roller RL is moved in the direction of the arrow while pulling the release sheet RS obliquely upward. At this time, as shown in FIG. 4, for example, when the adhesive force between the release sheet RS and the protective sheet PS is weaker than the adhesive force between the wafer WF and the protective sheet PS, it is integrated with the release sheet RS. The protective sheet PS is not peeled off from the wafer WF, but the peeling sheet RS is peeled off from the protective sheet PS. As a result, in the related art, only the release sheet RS is peeled off from the protective sheet PS, and the protective sheet PS cannot be peeled off from the wafer WF integrally with the release sheet RS. That is, the present inventor has newly found that in the related technology, there is a high possibility that a protective sheet PS will be peeled off. In particular, the present inventor newly found that, for example, if there is a plating film forming step which is the back electrode forming step (S106) shown in FIG.

  In the plating film forming process, a plating solution is used. However, if the adhesion between the wafer WF and the protective sheet PS attached to the surface of the wafer WF is weak, the plating solution enters between the wafer WF and the protective sheet PS. As a result, a plating film is also formed on the surface of the wafer WF. From this, when there is a plating film formation step, in order to prevent the formation of a plating film on the surface of the wafer WF due to the plating solution entering between the wafer WF and the protective sheet PS, The adhesion between the protective sheet PS and the protective sheet PS is increased. Thereby, it is possible to prevent the plating solution from entering between the wafer WF and the protective sheet PS.

  On the other hand, since the adhesive force between the wafer WF and the protective sheet PS is significantly stronger than the adhesive force between the release sheet RS and the protective sheet PS, the release sheet RS is used to remove the protective sheet PS from the wafer WF. When peeling off, only the release sheet RS is peeled off from the protective sheet PS, and the problem that the protective sheet PS cannot be peeled off from the wafer WF integrally with the release sheet RS becomes apparent.

  In this regard, for example, when an ultraviolet curable adhesive is used as an adhesive for bonding the wafer WF and the protective sheet PS and the protective sheet PS is peeled off from the wafer WF, first, the ultraviolet curable adhesive is used. It is conceivable that the adhesive force between the wafer WF and the protective sheet PS is weakened by irradiating the substrate with ultraviolet rays. However, in this case, since an expensive ultraviolet curable adhesive is used, the manufacturing cost of the semiconductor device increases.

  Therefore, there is a demand for a device that can prevent a peeling error that the protective sheet PS cannot be peeled off from the wafer WF integrally with the peeling sheet RS while suppressing an increase in the manufacturing cost of the semiconductor device. That is, there is a demand for a device that can prevent a peeling error without depending on the material change of the adhesive that causes an increase in manufacturing cost.

  Therefore, in the present embodiment, a device that can reduce peeling errors while suppressing an increase in manufacturing cost is provided. Below, the outline | summary of the peeling process of the protection sheet in this Embodiment which gave this device is demonstrated.

<Embodiment>
<< Overview of process for removing protective sheet >>
FIG. 5 is a flowchart for explaining the details of the protective sheet peeling step (S107) in the present embodiment.

  The process of attaching the protective sheet to the front surface of the wafer (S104) to the process of forming the back electrode (S106) are as described above.

  After the back electrode forming step, a separation starting point portion is formed on the back surface of the wafer (S201). The separation starting point portion is a starting point for separating small pieces from the wafer. Next, after attaching a release sheet on the protective sheet (S202), the protective sheet is peeled off together with the release sheet (S203). In the present embodiment, in the step of peeling off the release sheet, the wafer is cracked starting from the separation starting point formed on the back surface of the wafer, and the small pieces are separated from the wafer. Furthermore, in the present embodiment, in the step of peeling off the protective sheet, the protective sheet to which the small pieces separated from the wafer are attached is integrated with the release sheet and peeled off from the wafer.

  As described above, the protective sheet using the release sheet is peeled from the wafer.

<< Details of protective sheet peeling process >>
Below, the detail of the peeling process from the wafer of the protection sheet which specifically uses a peeling sheet is demonstrated, referring drawings.

  First, as shown in FIG. 6, a protective sheet PS is attached to the surface of a wafer WF having a front surface and a back surface located on the opposite side of the front surface. Then, after the back surface processing is performed on the back surface of the wafer WF, as shown in FIG. 7, a separation starting point SL for separating small pieces from the wafer WF is formed on the back surface of the wafer WF. Here, the separation starting point portion SL extends, for example, in a direction crossing the direction in which the protective sheet is peeled off from the wafer at the outer peripheral portion of the wafer. The separation starting point portion SL can be formed by, for example, a diamond cutter, or can be formed by laser processing. At this time, the depth of the separation starting point portion SL is deeper than the average surface roughness (Ra) on the back surface of the wafer WF, for example. For example, the depth of the separation starting point portion SL is deeper than 0.2 μm.

  Next, as illustrated in FIG. 8, for example, by moving the roller RL while rotating the wafer WF, the release sheet RS is pasted on the protective sheet PS so as to overlap the separation starting point portion SL in plan view. . After that, as shown in FIG. 9, the peeling force is applied to the release sheet RS by moving the roller RL in the reverse direction. At this time, as shown in FIG. 10, the peeling force applied to the release sheet RS is bonded to the front end portion of the protective sheet PS attached to the release sheet RS and the front end portion of the protective sheet PS. The front end portion of the wafer WF is pulled obliquely upward. As a result, as shown in FIG. 10, stress is applied to the separation starting point portion SL formed on the back surface of the wafer WF, which causes cracking of the wafer WF starting from the separation starting point portion SL. The small piece FG is separated from the wafer WF. That is, in this embodiment, by moving the roller RL while rotating in the reverse direction, the part of the release sheet RS that overlaps the small piece FG in a plan view is pulled obliquely upward, so that the small piece FG is separated from the wafer WF. Is done. After that, as shown in FIG. 11, when the roller RL is reversely rotated to move on the wafer WF and a peeling force is continuously applied to the release sheet RS, the protective sheet to which the small pieces FG are attached together with the release sheet RS. PS is peeled off from the wafer WF. As described above, according to the present embodiment, the protective sheet PS can be peeled from the surface of the wafer WF.

<< Features in Embodiment >>
For example, as shown in FIGS. 7 to 11, the feature point in the present embodiment is that a separation starting point SL for separating the small piece FG from the wafer WF to which the protective sheet PS is attached is formed on the back surface of the wafer WF. Thereafter, the release sheet RS is pasted on the protective sheet PS, and a peeling force is applied to the release sheet RS to separate the small piece FG from the wafer WF at the separation start point SL. Thereby, according to this Embodiment, the protection sheet PS to which small piece FG adhered can be easily peeled from the wafer WF with the peeling sheet RS.

  Below, according to the feature point in this Embodiment mentioned above, the mechanism which can prevent the peeling mistake at the time of peeling protective sheet PS from the surface of the wafer WF is demonstrated.

  For example, FIG. 12 is a diagram for explaining a mechanism in which a peeling error is likely to occur in the peeling method in the related art shown in FIGS. In FIG. 12, a release sheet RS is affixed on the protective sheet PS affixed to the wafer. In the related art, when the release sheet RS is peeled off, the protective sheet PS is also peeled off from the wafer. However, only the release sheet RS is actually peeled off and the protective sheet PS is attached to the wafer. A peeling error that maintains the state occurs. Specifically, in the related technique shown in FIG. 12, at the start of peeling of the protective sheet PS from the wafer by the peeling sheet RS, a point region 100 (pin point region) in the contact portion between the peeling sheet RS and the protective sheet PS. The peeling force is applied to At this time, since the area of the point region 100 is very small, the adhesive force between the release sheet RS and the protective sheet PS in the point region 100 is very weak. In this state, if a peeling force is continuously applied to the release sheet RS, the adhesive force between the release sheet RS and the protection sheet PS in the point region 100 is very weak. Before the adhesion is peeled off, peeling between the release sheet RS and the protective sheet PS in the point region 100 occurs. As a result, in the related art, only the peeling sheet RS is peeled off, and a peeling mistake occurs in which the state where the protective sheet PS is stuck to the wafer is maintained.

  On the other hand, FIG. 13 is a diagram for explaining a mechanism in which a peeling error is less likely to occur in the peeling method in the present embodiment shown in FIGS. In FIG. 13, a release sheet RS is affixed on the protective sheet PS affixed to the wafer. And in this Embodiment, when peeling off this peeling sheet RS, it becomes easy to peel off the protection sheet PS from a wafer as a result, and generation | occurrence | production of peeling mistake can be suppressed.

  Specifically, in the present embodiment shown in FIG. 13, at the start of peeling of the protective sheet PS from the wafer by the peeling sheet RS, the small pieces FG are separated from the separation starting point SL formed on the back surface of the wafer. Has occurred. As a result, the peeling force by the release sheet RS is applied to the linear region 200. That is, in the related art described above, at the time of starting the peeling of the protective sheet PS from the wafer by the release sheet RS, a peeling force by the release sheet RS is applied only to the point region 100 (pinpoint region). On the other hand, in the peeling method in the present embodiment, at the start of peeling of the protective sheet PS from the wafer by the peeling sheet RS, the peeling sheet RS is peeled to the linear area 200 larger than the point area 100 (pinpoint area). Power is applied (first advantage).

  Furthermore, in the peeling method according to the present embodiment, as shown in FIG. 13, at the start of peeling of the protective sheet PS from the wafer by the peeling sheet RS, a small piece starting from the separation starting point SL formed on the back surface of the wafer. FG separation has occurred. Therefore, in this embodiment, even at the start of peeling, due to the separation of the small piece FG from the wafer, the peeling sheet RS and the protective sheet corresponding to the overlapping region 300 between the small piece FG and the peeling sheet RS. An adhesion area with PS is secured. This is because, in the present embodiment, as a result of securing the adhesive region between the release sheet RS and the protective sheet PS corresponding to the overlapping region 300, the release sheet RS and the protective sheet PS at the start of peeling are more effective than the related art. It means that the adhesive strength of can be secured. Therefore, in the present embodiment, if a peeling force is continuously applied to the release sheet RS, the adhesive force between the release sheet RS and the protection sheet PS in the overlapping region 300 is very strong, and thus the protection sheet PS and the wafer It is possible to effectively suppress the peeling between the release sheet RS and the protective sheet PS in the overlapping region 300 before the adhesion between the two is peeled off (second advantage). That is, in the peeling method in the present embodiment, the adhesion between the protective sheet PS and the wafer can be easily peeled while maintaining the adhesion between the peeling sheet RS and the protective sheet PS.

  From the above, the peeling method in the present embodiment has the above-described first and second advantages over the related art. From this, according to the peeling method in the present embodiment, due to the synergistic effect of the first and second advantages, only the peeling sheet RS is peeled off and the protective sheet PS is stuck to the wafer. The maintained peeling mistake can be easily prevented. Thereby, according to this Embodiment, in the manufacturing method of the semiconductor device which has the peeling process of protective sheet PS, improvement of a manufacturing yield can be aimed at.

  In particular, the present embodiment is a useful technical idea in that a device capable of preventing a peeling error is realized without relying on a material change of the adhesive that causes an increase in manufacturing cost. Thus, according to the present embodiment, it is possible to reduce a peeling error that occurs in the peeling process of the protective sheet PS while suppressing an increase in the manufacturing cost of the semiconductor device. Therefore, it can be seen that the present embodiment is an excellent technical idea in that both the manufacturing cost of the semiconductor device and the improvement of the manufacturing yield can be achieved.

<< Modification >>
In the embodiment, the configuration example in which the small piece FG is separated from the wafer WF at the separation starting point SL in the step of peeling the release sheet RS has been described. However, the present embodiment is not limited thereto, and for example, on the protective sheet PS In the step of attaching the release sheet RS to the substrate, it can be realized by a configuration in which the small piece FG is separated from the wafer WF at the separation starting point SL.

  Specifically, for example, by increasing the pressing force of the roller RL against the wafer WF, the wafer WF is cracked starting from the separation starting point SL, and a small piece separated from the wafer WF can be formed. .

  FIG. 14 is a flowchart for explaining the details of the protective sheet peeling step (S107) in this modification.

  The process of attaching the protective sheet to the front surface of the wafer (S104) to the process of forming the back electrode (S106) are as described above.

  After the back electrode forming step, a separation starting point portion is formed on the back surface of the wafer (S301). The separation starting point portion is a starting point for separating small pieces from the wafer. Here, the separation starting point portion SL extends, for example, in a direction crossing the direction in which the protective sheet is peeled off from the wafer at the outer peripheral portion of the wafer.

  Next, a release sheet is pasted on the protective sheet (S302). At this time, in this modification, the wafer is cracked starting from the separation starting point formed on the back surface of the wafer, and the small pieces are separated from the wafer. Thereafter, the protective sheet is peeled off together with the release sheet (S303). At this time, in this modification, in the step of peeling off the protective sheet, the protective sheet to which the small pieces separated from the wafer are attached is integrated with the release sheet and peeled off from the wafer. As described above, also in this modified example, the protection sheet using the release sheet is peeled from the wafer.

<Semiconductor Manufacturing Apparatus in Embodiment>
Next, a semiconductor manufacturing apparatus (sheet peeling apparatus) that embodies the basic idea of the present embodiment will be described with reference to the drawings.

<< Configuration of Semiconductor Manufacturing Equipment >>
FIG. 15 is a diagram showing a schematic configuration of the sheet peeling apparatus RA in the present embodiment. As shown in FIG. 15, the sheet peeling apparatus RA in the present embodiment includes a separation starting point forming unit 10, a peeling operation unit 20, and a conveyance unit 30.

  The separation starting point forming unit 10 is configured to form a separation starting point part for separating a small piece from a wafer having a protective sheet attached to the front surface in a portion of the back surface of the wafer that overlaps with the release sheet in plan view. Has been. For example, the separation starting point forming part 10 is configured to form the separation starting point part by diamond cutter or laser processing. For this reason, the separation starting point forming portion 10 is equipped with a diamond cutter or a laser.

  FIG. 16 is a diagram illustrating an example of the separation starting point SL formed on the wafer WF by the separation starting point forming unit 10 of the sheet peeling apparatus RA. In FIG. 16, the surface of the wafer WF is a (110) plane, and a plurality of chip regions CR are formed on the surface of the wafer WF. For example, a power transistor is formed in each of the plurality of chip regions CR. At this time, as shown in FIG. 16, the separation starting point SL is formed in a region that does not overlap with the plurality of chip regions CR in a plan view, that is, in the outer peripheral portion of the wafer.

Here, in the (110) plane, the extending direction of the separation starting point portion SL is parallel or orthogonal to the extending direction (y direction) of the center line connecting the center of the wafer WF and the notch NT formed in the wafer WF. It is desirable to be in the direction. In other words, when the surface of the wafer WF is the (110) plane, the extending direction of the separation starting point portion SL is a direction parallel to the extending direction (x direction or y direction) of the scribe regions that define the plurality of chip regions CR. It is desirable that This is because the wafer WF easily breaks in this direction on the (110) plane. In particular, in FIG.
An example in which the extending direction of the separation starting point portion SL is a direction orthogonal to the extending direction of the center line connecting the center of the wafer WF and the notch NT formed in the wafer WF is shown.

  FIG. 17 is a diagram illustrating another example of the separation starting point SL formed on the wafer WF by the separation starting point forming unit 10 of the sheet peeling apparatus RA. In FIG. 17, the surface of the wafer WF is a (100) plane, and a plurality of chip regions CR are formed on the surface of the wafer WF. For example, a power transistor is formed in each of the plurality of chip regions CR. At this time, as shown in FIG. 17, the separation starting point SL is formed in a region that does not overlap with the plurality of chip regions CR in plan view.

  Here, in the (100) plane, the angle formed by the extending direction of the separation starting point SL and the extending direction (y direction) of the center line connecting the center of the wafer WF and the notch NT formed in the wafer WF. Is preferably in the direction of + 45 ° or −45 °. In other words, when the surface of the wafer WF is the (100) plane, the angle formed by the extending direction of the separation starting point portion SL and the extending direction (x direction or y direction) of the scribe regions that define the plurality of chip regions CR. Is preferably in the direction of + 45 ° or −45 °. This is because the wafer WF easily breaks in this direction on the (100) plane.

  As described above, the extending direction of the separation starting point portion SL is different between the wafer WF having the (110) surface and the wafer WF having the (100) surface. Therefore, in order to make the sheet peeling apparatus RA in the present embodiment compatible with both wafers WF, for example, the separation starting point forming unit 10 has a separation starting point in a direction in which the wafer WF whose surface is (110) plane is easily broken. The direction of the wafer WF is adjusted so that the extending direction of the part SL can be aligned and the extending direction of the separation starting point SL can be aligned in a direction in which the surface of the wafer WF is easily cracked. It is desirable to have an alignment unit.

  For this reason, the separation starting point forming unit 10 in the present embodiment is configured to include an alignment unit that adjusts the orientation of the wafer WF in order to adjust the extending direction of the separation starting point SL formed on the wafer WF. ing.

  Next, the peeling operation unit 20 performs an operation of attaching the release sheet on the protective sheet attached to the wafer WF on which the separation start point SL is formed by the separation start point forming unit 10 and a peeling force on the release sheet. By adding, it is comprised so that the operation | movement which peels from the wafer WF the protective sheet with which the small piece adhered with the peeling sheet can be implement | achieved. Here, the peeling operation unit 20 may be configured to separate the small piece from the wafer WF at the separation starting point SL when applying a peeling force to the peeling sheet, or affixing the peeling sheet on the protective sheet. When attaching, the separation starting point SL may be configured to separate the small piece from the wafer WF.

  For example, as illustrated in FIG. 18, the peeling operation unit 20 includes a chuck CK that sucks the wafer WF. And the peeling operation | movement part 20 is comprised so that the area | region except the area | region used as the small piece of the back surface of the wafer WF may be adsorb | sucked with the chuck | zipper CK. This facilitates the formation of small pieces starting from the separation starting point SL formed on the back surface of the wafer WF.

<< Operation of Semiconductor Manufacturing Equipment >>
The sheet peeling apparatus RA in the present embodiment is configured as described above, and the operation thereof will be described below with reference to the drawings.

  FIG. 19 is a flowchart for explaining the operation of the sheet peeling apparatus RA in the present embodiment. First, in the separation start point forming unit 10 of the sheet peeling apparatus RA, the orientation of the wafer WF is adjusted in order to adjust the extending direction of the separation start point portion SL formed on the wafer WF (S401). Next, the separation starting point forming part 10 forms the separation starting point part SL by, for example, diamond cutter or laser processing (S402). Thereafter, the wafer WF on which the separation starting point SL is formed is transferred from the separation starting point forming unit 10 to the peeling operation unit 20 by the transfer unit 30 (S403). Subsequently, the peeling operation unit 20 sucks a region of the back surface of the wafer WF excluding a region that becomes a small piece with a chuck (S404). Then, the peeling operation unit 20 attaches the release sheet on the protective sheet attached to the wafer WF (S405), and then applies the peeling force to the release sheet, so that the protective sheet is attached to the wafer WF together with the release sheet. (S406). Specifically, the peeling operation unit 20 moves the wafer WF in the first direction while rotating the roller so that the peeling sheet is attached to the protective sheet, and then the wafer WF is rotated backward while rotating the roller. By moving in a second direction opposite to the first direction, the release sheet and the protective sheet are integrally peeled from the wafer WF. At this time, in the present embodiment, when the peeling sheet is peeled off by the peeling operation unit 20, the wafer WF is cracked starting from the separation starting point SL formed on the back surface of the wafer WF, and a small piece is formed from the wafer WF. The protective sheet to which the small pieces separated from the wafer WF are attached is integrated with the release sheet and peeled off from the wafer WF. As described above, the sheet peeling apparatus RA can be operated.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The embodiment includes the following forms.

(Appendix 1)
A separation starting point for separating a small piece from a wafer having a front surface and a back surface opposite to the front surface, and having a protective sheet attached to the front surface; A separation starting point forming part to be formed in a portion overlapping the release sheet in view,
Affixing a release sheet on the protective sheet attached to the wafer on which the separation start point is formed by the separation start point forming unit, and then applying a peeling force to the release sheet, together with the release sheet A peeling operation unit for peeling off the protective sheet to which the small piece is attached from the wafer;
A semiconductor manufacturing apparatus comprising:

(Appendix 2)
In the semiconductor manufacturing apparatus according to attachment 1,
The peeling operation unit separates the small piece from the wafer at the separation starting point when applying a peeling force to the peeling sheet.

(Appendix 3)
In the semiconductor manufacturing apparatus according to attachment 1,
The peeling operation unit is a semiconductor manufacturing apparatus that separates the small piece from the wafer at the separation starting point when the peeling sheet is pasted on the protective sheet.

(Appendix 4)
In the semiconductor manufacturing apparatus according to attachment 1,
The separation starting point forming unit is a semiconductor manufacturing apparatus including an alignment unit that adjusts the orientation of the wafer in order to adjust the extending direction of the separation starting point portion formed on the wafer.

(Appendix 5)
In the semiconductor manufacturing apparatus according to attachment 1,
The separation start point forming unit includes a diamond cutter for forming the separation start point.

(Appendix 6)
In the semiconductor manufacturing apparatus according to attachment 1,
The separation start point forming unit includes a laser for forming the separation start point part.

(Appendix 7)
In the semiconductor manufacturing apparatus according to attachment 1,
The peeling operation unit has a chuck for sucking the wafer.

(Appendix 8)
In the semiconductor manufacturing apparatus described in appendix 7,
The said peeling operation | movement part is a semiconductor manufacturing apparatus which adsorb | sucks the area | region except the area | region used as the said small piece of the said back surface with the said chuck | zipper.

(Appendix 9)
In the semiconductor manufacturing apparatus according to attachment 1,
The peeling operation unit has a roller that is in close contact with the peeling sheet,
The peeling operation unit moves the surface of the wafer in the first direction while rotating the roller, and then attaches the peeling sheet on the protective sheet, and then rotates the roller on the wafer while rotating the roller in the reverse direction. The semiconductor manufacturing apparatus which peels the said peeling sheet and the said protective sheet integrally from the said wafer by moving to the 2nd direction opposite to the said 1st direction.

DESCRIPTION OF SYMBOLS 10 Separation start part 20 Separation operation part 30 Conveyance part CK Chuck FG Small piece NT Notch PS Protection sheet RA Sheet peeling device RL Roller RS Release sheet SL Separation origin part WF

Claims (19)

(A) a step of attaching a protective sheet to the front surface of a wafer having a front surface and a back surface located on the opposite side of the front surface;
(B) After the step (a), a step of performing processing on the back surface;
(C) After the step (b), a step of peeling the protective sheet from the surface,
A method for manufacturing a semiconductor device comprising:
The step (c)
(C1) forming a separation starting point portion on the back surface for separating small pieces from the wafer;
(C2) a step of affixing a release sheet on the protective sheet so as to overlap with the separation starting point in a plan view;
(C3) The process of peeling the said protection sheet to which the said small piece adhered together with the said peeling sheet from the said wafer by applying peeling force to the said peeling sheet,
Have
A method for manufacturing a semiconductor device, wherein in the step (c2) or the step (c3), the small piece is separated from the wafer at the separation starting point. In the manufacturing method of the semiconductor device according to claim 1,
The step (b) is a method for manufacturing a semiconductor device, including a step of grinding the back surface. In the manufacturing method of the semiconductor device according to claim 2,
The method for manufacturing a semiconductor device, wherein the thickness of the wafer after the step (b) is 400 μm or less. In the manufacturing method of the semiconductor device according to claim 3,
The method for manufacturing a semiconductor device, wherein the protective sheet suppresses warpage of the wafer. In the manufacturing method of the semiconductor device according to claim 1,
The step (b) is a method for manufacturing a semiconductor device, including a step of forming a plating film on the back surface. In the manufacturing method of the semiconductor device according to claim 5,
The said protection sheet is a manufacturing method of the semiconductor device which suppresses permeation of the plating solution to the said surface. In the manufacturing method of the semiconductor device according to claim 1,
The method for manufacturing a semiconductor device, wherein the separation starting point portion is formed of a diamond cutter. In the manufacturing method of the semiconductor device according to claim 1,
The method for manufacturing a semiconductor device, wherein the separation starting portion is formed by laser processing. In the manufacturing method of the semiconductor device according to claim 1,
The depth of the separation starting point is a method for manufacturing a semiconductor device, which is deeper than the average surface roughness of the back surface. In the manufacturing method of the semiconductor device according to claim 9,
The method of manufacturing a semiconductor device, wherein a depth of the separation starting point is deeper than 0.2 μm. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c3), the small piece is separated from the wafer by pulling upward the portion of the release sheet that overlaps the small piece in a planar manner. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c3), a method of manufacturing a semiconductor device, wherein a region of the back surface excluding the region that becomes the small piece is adsorbed by a chuck. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c1), in order to adjust the extending direction of the separation starting point portion, the orientation of the wafer is adjusted, and then the separation starting point portion is formed on the back surface. In the manufacturing method of the semiconductor device according to claim 13,
In the step (c1), when the surface is a (110) plane, the extending direction of the separation starting point portion is parallel to the extending direction of the center line connecting the center of the wafer and the notch formed in the wafer. Or the manufacturing method of the semiconductor device which adjusts direction of the wafer so that it may become a direction which intersects perpendicularly. In the manufacturing method of the semiconductor device according to claim 13,
The wafer has a scribe region that partitions a plurality of chip regions,
In the step (c1), when the surface is the (110) plane, the orientation of the wafer is adjusted so that the extending direction of the separation starting point portion is parallel to the extending direction of the scribe region. A method for manufacturing a semiconductor device. In the manufacturing method of the semiconductor device according to claim 13,
In the step (c1), when the surface is a (100) plane, the extension direction of the separation starting point portion is the extension direction of the center line connecting the center of the wafer and the notch formed in the wafer. A method of manufacturing a semiconductor device, wherein the orientation of the wafer is adjusted so that an angle formed is a direction of + 45 ° or −45 °. In the manufacturing method of the semiconductor device according to claim 13,
The wafer has a scribe region that partitions a plurality of chip regions,
In the step (c1), when the surface is a (100) plane, the extending direction of the separation starting point portion is in the direction of + 45 ° or −45 ° with the extending direction of the scribe region. And a method of manufacturing a semiconductor device, wherein the orientation of the wafer is adjusted. In the manufacturing method of the semiconductor device according to claim 1,
The wafer has a plurality of chip regions,
A method for manufacturing a semiconductor device, wherein a power transistor is formed in each of the plurality of chip regions. In the manufacturing method of the semiconductor device according to claim 1,
The wafer has a plurality of chip regions,
In the step (c1), the separation starting portion is formed in a region that does not overlap with the plurality of chip regions in plan view.

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