Protective film, method for forming protective film, and semiconductor device

Abstract

To provide a technique for reducing warpage of a semiconductor wafer.SOLUTION: The protective film for protecting the surface of the semiconductor wafer 10 includes a first resin film 20 and a second resin film 30. The semiconductor wafer 10 includes a main surface and a device pattern film provided on a surface layer of the main surface. The first resin film 20 covers the main surface of the semiconductor wafer 10. The second resin film 30 has the same film thickness as that of the first resin film 20 or has a film thickness within ± 10% thereof. The second film 30 includes a projection 31 provided on a part of the 20A of the first film 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a protective film that protects the surface of a semiconductor wafer, a method for forming the protective film, and a semiconductor device. [Background technology]

[0002] When a semiconductor wafer has a surface protection film formed thereon, heating and cooling the semiconductor wafer causes the surface protection film to shrink, causing the entire semiconductor wafer to warp. Patent Document 1 proposes a technology for reducing the warpage of the semiconductor wafer by using protrusions on a protective tape attached to the surface of the semiconductor wafer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5447296 Summary of the Invention [Problem to be solved by the invention]

[0004] Warpage of semiconductor wafers during the manufacturing process of semiconductor devices can cause transport errors, cracks, and other problems. In the manufacturing method described in Patent Document 1, when the surface of the semiconductor wafer is placed on a stage, the protective tape attached to the surface of the semiconductor wafer enters the grooves in the stage. This causes the protective tape in the area corresponding to the grooves in the stage to deform, forming convex portions. However, this method makes it difficult to form convex portions of sufficient size, and also requires the preparation of a new stage each time the layout of the convex portions is changed, making it difficult to operate flexibly. A technology that more effectively reduces warpage of semiconductor wafers is needed.

[0005] In order to solve the above-mentioned problems, an object of the present disclosure is to provide a technique for reducing warpage of semiconductor wafers. [Means for solving the problem]

[0006] The protective film according to the present disclosure is a protective film for protecting the surface of a semiconductor wafer, and includes a first resin film and a second resin film. The semiconductor wafer includes a main surface and a device pattern film provided on the surface layer of the main surface. The first resin film covers the main surface of the semiconductor wafer. The second resin film has the same thickness as the first resin film or a thickness within 10% of the first resin film. The second resin film includes a convex portion provided on a portion of the surface of the first resin film. [Effects of the Invention]

[0007] According to the present disclosure, a technique for reducing warpage of a semiconductor wafer is provided.

[0008] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view showing the configuration of a protective film in the first embodiment. [Figure 2] 2 is a cross-sectional view showing the configuration of a semiconductor wafer and a first resin film. FIG. [Figure 3] FIG. 10 is a cross-sectional view showing the configuration of a protective film in the second embodiment. [Figure 4] FIG. 10 is a diagram illustrating an example of a layout of convex portions. [Figure 5] FIG. 10 is a plan view showing the configuration of a semiconductor wafer in a fourth embodiment. [Figure 6] FIG. 2 is a plan view showing the configuration of one device pattern forming unit. [Figure 7] FIG. 2 is a cross-sectional view showing the configuration of one device pattern forming unit. [Figure 8] FIG. 13 is a cross-sectional view showing the configuration of a protective film in the fifth embodiment. [Figure 9] 1A and 1B are diagrams illustrating an outline of a manufacturing method in which a resin is applied onto a semiconductor wafer by a dispense method. [Figure 10] 13 is a flowchart showing a method for manufacturing a protective film in the seventh embodiment. [Figure 11] 5A to 5C are cross-sectional views showing the configuration of the protective film in each step. [Figure 12] 13 is a flowchart showing another method for manufacturing the protective film according to the seventh embodiment. [Figure 13] 10A and 10B are cross-sectional views showing the processing during back grinding in the subsequent step. [Figure 14] 13 is a flowchart showing a method for manufacturing a protective film in the eighth embodiment. [Figure 15] 5A to 5C are cross-sectional views showing the configuration of the protective film in each step. [Figure 16] 13 is a flowchart showing a method for manufacturing a protective film in the ninth embodiment. [Figure 17] 5A to 5C are cross-sectional views showing the configuration of the protective film in each step. [Figure 18] 20 is a flowchart showing a method for manufacturing a protective film in the tenth embodiment. [Figure 19] 5A to 5C are cross-sectional views showing the configuration of the protective film in each step. DETAILED DESCRIPTION OF THE INVENTION

[0010] <First Embodiment> Fig. 1 is a cross-sectional view showing the configuration of a protective film in embodiment 1. The protective film is a protective film that protects the surface of a semiconductor wafer 10, and includes a first resin film 20 and a second resin film 30. Fig. 2 is a cross-sectional view showing the configurations of the semiconductor wafer 10 and the first resin film 20.

[0011] The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film (not shown). The second main surface 12 is the surface opposite to the first main surface 11. For example, the first main surface 11 is the front surface of the semiconductor wafer 10, and the second main surface 12 is the back surface of the semiconductor wafer 10. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of, for example, silicon, silicon carbide, and gallium nitride.

[0012] The device pattern film is provided on the surface layer of the first main surface 11. A semiconductor element structure (not shown) such as a transistor is formed on the device pattern film.

[0013] The first resin film 20 is provided so as to cover the entire first main surface 11 of the semiconductor wafer 10. The first resin film 20 has the function of protecting the device pattern film in the subsequent steps of the manufacturing process of the semiconductor device.

[0014] The second resin film 30 includes a protrusion 31 provided on a part of the surface 20A of the first resin film 20. The protrusion 31 protrudes from the surface 20A of the first resin film 20. In the first embodiment, the protrusion 31 may be provided at any position. In the first embodiment, a plurality of protrusions 31 are provided, and the distance between adjacent protrusions 31 is arbitrary. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, or a thickness within a range of 10% difference therebetween. The second resin film 30 is formed, for example, from the same material as the first resin film 20.

[0015] In subsequent steps in the manufacturing process of a semiconductor device, the semiconductor wafer 10 is subjected to a heat treatment of at least a certain level. If the convex portions 31 of the second resin film 30 are not provided, the first resin film 20 will shrink during cooling after the heat treatment, causing the semiconductor wafer 10 to warp downward. As a result, transport errors or cracks in the semiconductor wafer 10 will occur in the subsequent steps.

[0016] In the semiconductor device of the first embodiment, convex portions 31 of the second resin film 30 are formed. When cooling after heat treatment, the convex portions 31 of the second resin film 30 expand toward the surface of the semiconductor wafer 10, thereby absorbing the contraction of the first resin film 20. Compared to a structure in which the second resin film 30 is not provided, warpage of the semiconductor wafer 10 is reduced. As a result, transport errors and cracks in the semiconductor wafer 10 in subsequent processes are prevented, and the yield in the manufacturing process is improved.

[0017] It is preferable that the film thickness t2 of the second resin film 30 is the same as the film thickness t1 of the first resin film 20. If the film thickness t2 of the convex portions 31 of the second resin film 30 is thick, the effect of correcting the warpage of the semiconductor wafer 10 is greater. However, the convex portions 31 may come into contact with a transfer arm, a processing stage, etc. in subsequent processes, causing problems such as poor adhesion of the semiconductor wafer 10. On the other hand, if the film thickness t2 of the convex portions 31 of the second resin film 30 is thin, the effect of correcting the warpage of the semiconductor wafer 10 is reduced. It is effective to form thick convex portions 31 within a range that does not affect subsequent processes.

[0018] To summarize the above, the protective film in the first embodiment is a protective film that protects the surface of the semiconductor wafer 10, and includes a first resin film 20 and a second resin film 30. The semiconductor wafer 10 includes a first main surface 11 and a device pattern film provided on the surface layer of the first main surface 11. The first resin film 20 covers the first main surface 11 of the semiconductor wafer 10. The second resin film 30 has a film thickness that is the same as that of the first resin film 20 or within a 10% difference therebetween. The second resin film 30 includes a protrusion 31 provided on a part of the surface 20A of the first resin film 20.

[0019] Such a semiconductor device reduces warpage of the semiconductor wafer 10 during the manufacturing process. In addition, since the layout of the protrusions 31 can be flexibly changed, warpage of the semiconductor wafer 10 can be easily controlled.

[0020] <Embodiment 2> In the second embodiment, a description will be given of the differences from the first embodiment. Fig. 3 is a cross-sectional view showing the configuration of the protective film in the second embodiment.

[0021] The semiconductor wafer 10 has a crystal orientation based on the arrangement of atoms that make up the semiconductor wafer 10. The semiconductor wafer 10 of the second embodiment is warped downward so that the first main surface 11 is concave in accordance with the crystal plane orientation of the first main surface 11. That is, the semiconductor wafer 10 is warped downward in a U-shape. When warping occurs in the semiconductor wafer 10, warping is likely to occur in a specific direction based on the crystal orientation. In a silicon wafer with a (100) plane, warping is likely to occur in directions along two cleavage planes that are perpendicular to the main surface of the silicon wafer. The cleavage planes are (111) planes.

[0022] The convex portions 31 of the second resin film 30 in the second embodiment are provided on the first resin film 20 so as to follow the warpage direction of the semiconductor wafer 10. That is, the convex portions 31 of the second resin film 30 are provided along the direction in which the bottom of the U-shape extends. For example, the multiple convex portions 31 extend in a direction parallel to the direction in which the bottom of the U-shape extends. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20 or within a range of 10% difference therebetween.

[0023] This configuration provides a greater warpage reduction effect than the semiconductor device of embodiment 1. Since transfer errors and cracks in the semiconductor wafer 10 in subsequent processes are prevented, the yield in the manufacturing process is improved.

[0024] The semiconductor wafer 10 not only undergoes warpage due to the crystal plane orientation, but also warpage due to the device pattern film provided on the first main surface 11 of the semiconductor wafer 10. Depending on the configuration of the device pattern film, the device pattern film may have a greater influence on the direction of warpage than the crystal plane orientation of the semiconductor wafer 10. In particular, when multiple trenches are formed in the device pattern film along one direction parallel to the first main surface 11 of the semiconductor wafer 10, the warpage of the semiconductor wafer 10 due to the device pattern film becomes more pronounced.

[0025] In embodiment 2, when the semiconductor wafer 10 is warped downward in a U-shape according to the device pattern film, the convex portion 31 of the second resin film 30 is provided along the direction in which the bottom of the U-shape extends, as in the case of warping due to crystal plane orientation.

[0026] This configuration provides a greater warpage reduction effect than the semiconductor device of embodiment 1. Since transfer errors and cracks in the semiconductor wafer 10 in subsequent processes are prevented, the yield in the manufacturing process is improved.

[0027] The layout of the protrusions 31 is not limited to the above layout. FIG. 4 is a diagram showing an example of the layout of the protrusions 31. The protrusions 31 may be arranged in a lattice pattern (FIG. 4(a)), a concentric circle pattern (FIG. 4(b)), a stripe pattern (FIG. 4(c)), or a dot pattern (FIG. 4(d)). A layout that can achieve a higher warpage reduction effect is applied depending on the crystal plane orientation, diameter, thickness, etc. of the semiconductor wafer 10. Alternatively, a layout that can achieve a higher warpage reduction effect is applied depending on the configuration of the device pattern film.

[0028] <Third Embodiment> In the third embodiment, a description will be given of the differences from the first or second embodiment. The configurations of the semiconductor wafer 10, the device pattern film, and the first resin film 20 are the same as those in the first embodiment.

[0029] The second resin film 30 is made of a resin that is different from the resin of the first resin film 20. For example, the second resin film 30 is made of a thermal expansion resin.

[0030] The convex portions 31 of the second resin film 30, which is made of a thermally expandable resin, expand primarily toward the surface of the semiconductor wafer 10 during cooling after heat treatment. This expansion is more pronounced than the spread of the second resin film 30 toward the surface of the semiconductor wafer 10 in the first embodiment. The convex portions 31 of the second resin film 30 absorb a greater amount of contraction of the first resin film 20, resulting in a greater warpage reduction effect. As a result, transport errors and cracks in the semiconductor wafer 10 in subsequent processes are prevented, and the yield in the manufacturing process is improved.

[0031] <Fourth Embodiment> FIG. 5 is a plan view showing the configuration of a semiconductor wafer 10 in embodiment 4. The semiconductor wafer 10 is provided with a plurality of semiconductor chips, i.e., a plurality of device pattern formation units 13. FIG. 6 is a plan view showing the configuration of one device pattern formation unit 13A. FIG. 6 corresponds to an enlarged view of region R shown in FIG. 5. FIG. 7 is a cross-sectional view showing the configuration of one device pattern formation unit 13A. FIG. 7 corresponds to a cross-sectional view taken along line AA shown in FIG. 6.

[0032] The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film (not shown). The second main surface 12 is the surface opposite to the first main surface 11. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of, for example, silicon, silicon carbide, and gallium nitride.

[0033] The device pattern film is provided on the surface layer of the first main surface 11. Semiconductor element structures such as transistors are formed on the device pattern film.

[0034] Of the multiple device pattern formation portions 13 provided on the semiconductor wafer 10, one device pattern formation portion 13A corresponds to one semiconductor chip. A conductive portion 14 and a terminal portion 15 are provided in the device pattern film of one device pattern formation portion 13A. The terminal portion 15 is arranged around the conductive portion 14. The thickness of the semiconductor wafer 10 at the terminal portion 15 is thicker than the thickness of the semiconductor wafer 10 at the conductive portion 14.

[0035] There is a trade-off between the breakdown voltage and on-resistance of the semiconductor device and the thickness of the semiconductor wafer 10. The thicker the semiconductor wafer 10, the higher the breakdown voltage and the higher the on-resistance.

[0036] As shown in FIG. 7, in the fourth embodiment, only the thickness of the termination portion 15, which does not directly contribute to conduction but is provided to ensure voltage resistance, is thick. This improves the voltage resistance performance of the semiconductor device. Also, only the thickness of the conductive portion 14, which directly contributes to conduction, is thin. This reduces the on-resistance of the semiconductor device and improves the conduction performance. By configuring the thickness of the semiconductor wafer 10 as described above, desired electrical characteristics can be obtained.

[0037] If the thickness of termination 15 is large, the pressure resistance performance will improve, but it will require more process changes in the subsequent assembly process, etc. It is effective to provide a thick termination 15 within a range that takes into consideration the impact on the subsequent process.

[0038] <Fifth Embodiment> 8 is a cross-sectional view showing the configuration of the protective film in the fifth embodiment. The configurations of the semiconductor wafer 10, the device pattern film (not shown), and the first resin film 20 are the same as those in the first embodiment.

[0039] The second resin film 30 includes a recess 32 where a portion of the surface 20A of the first resin film 20 is exposed. In the fifth embodiment, the recess 32 may be provided at any position. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20 or within a range of 10% difference therebetween. The second resin film 30 is formed of the same material as the first resin film 20.

[0040] Due to the formation of the recesses 32 in the second resin film 30, the shrinkage of the first resin film 20 and the second resin film 30 occurs intermittently rather than continuously during cooling after the heat treatment performed in the subsequent process. The shrinking portions are dispersed, and the degree of shrinkage of the first resin film 20 and the second resin film 30 as a whole is reduced. This reduces warping of the semiconductor wafer 10. As a result, transport errors and cracks in the semiconductor wafer 10 in the subsequent process are prevented, and the yield in the manufacturing process is improved.

[0041] <Sixth Embodiment> In the sixth embodiment, differences from the fifth embodiment will be described. As in the second embodiment, the semiconductor wafer 10 is warped downward so that the first main surface 11 is concave in accordance with the crystal plane orientation of the first main surface 11. That is, the semiconductor wafer 10 is warped downward in a U-shape.

[0042] The recesses 32 of the second resin film 30 of the sixth embodiment are provided so as to follow the warpage direction of the semiconductor wafer 10 (not shown). That is, the recesses 32 of the second resin film 30 are provided along the direction in which the bottom of the U-shape extends. For example, the multiple recesses 32 extend in a direction parallel to the direction in which the bottom of the U-shape extends.

[0043] With this configuration, a greater warpage reduction effect can be obtained than in the semiconductor device of embodiment 5. Since transfer errors in subsequent processes and cracks in the semiconductor wafer 10 are prevented, the yield in the manufacturing process is improved.

[0044] As in the second embodiment, the semiconductor wafer 10 also warps due to the device pattern film provided on the surface layer of the first main surface 11. Depending on the configuration of the device pattern film, the device pattern film may affect the direction of warpage more than the crystal plane orientation of the semiconductor wafer 10.

[0045] In embodiment 6, when the semiconductor wafer 10 is warped downward in a U-shape according to the device pattern film, the recess 32 of the second resin film 30 is provided along the direction in which the bottom of the U-shape extends, as in the case of warping due to crystal plane orientation.

[0046] With this configuration, a greater warpage reduction effect can be obtained than in the semiconductor device of embodiment 5. Since transfer errors in subsequent processes and cracks in the semiconductor wafer 10 are prevented, the yield in the manufacturing process is improved.

[0047] The layout of the recesses 32 is not limited to the above layout. The recesses 32 may be provided in a concentric, lattice, stripe, or dot pattern, similar to the protrusions 31 of the second embodiment. A layout that can achieve a higher warpage reduction effect is applied depending on the crystal plane orientation, diameter, thickness, etc. of the semiconductor wafer 10. Alternatively, a layout that can achieve a higher warpage reduction effect is applied depending on the configuration of the device pattern film.

[0048] <Seventh Embodiment> In the seventh embodiment, a method for manufacturing the protective film according to any one of the first to fourth embodiments will be described.

[0049] 9 is a diagram showing an outline of a manufacturing method for applying resin onto a semiconductor wafer 10 by a dispense method. In the dispense method, a dispense mechanism 40 pushes out a fixed amount of resin filled in a syringe 41 using gas pressure or the like, thereby applying the resin onto the semiconductor wafer 10, which is the object to be applied. The dispense mechanism 40 appropriately controls the pressure, such as the gas pressure, to form resin films with various thicknesses in different parts.

[0050] Fig. 10 is a flowchart showing a method for manufacturing a protective film according to Embodiment 7. Fig. 11 is a cross-sectional view showing the configuration of the protective film at each step.

[0051] In step S11, a semiconductor wafer 10 is prepared. FIG. 11(a) shows the configuration of the semiconductor wafer 10. The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film. The second main surface 12 is the surface opposite to the first main surface 11. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of silicon, silicon carbide, gallium nitride, etc. The device pattern film is provided on the surface layer of the first main surface 11. Semiconductor element structures such as transistors are formed on the device pattern film.

[0052] In step S12, a first resin film 20 is formed so as to cover the first main surface 11 of the semiconductor wafer 10 on which the device pattern film has been formed. FIG. 11(b) shows the configuration of the semiconductor wafer 10 on which the first resin film 20 has been formed. The first resin film 20 is formed by a dispense method. The first resin film 20 is formed by applying resin onto the first main surface 11 of the semiconductor wafer 10 using a syringe 41 that uses gas pressure.

[0053] In step S13, a second resin film 30 is formed, including protrusions 31 provided on a portion of the surface 20A of the first resin film 20. FIG. 11(c) shows the configuration of a semiconductor wafer 10 on which the second resin film 30 is formed. The second resin film 30 is formed by a dispense method. Resin is applied to a portion of the first resin film 20 using a syringe 41 that uses gas pressure. The resin is applied, for example, only to the position where the protrusions 31 are to be formed. This forms the protrusions 31 of the second resin film 30. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, or within a range of 10% difference.

[0054] In step S14, the semiconductor wafer 10 on which the first resin film 20 and the second resin film 30 are formed is subjected to a heat treatment. After the heat treatment, the semiconductor wafer 10 is cooled to room temperature. The cooling method is, for example, natural cooling, but other cooling means may also be used.

[0055] After steps S11 to S14, the subsequent steps are carried out. The above is the method for manufacturing the semiconductor device according to the seventh embodiment.

[0056] The semiconductor device manufactured by the manufacturing method of the seventh embodiment improves the yield because it prevents transfer errors in the subsequent steps and cracks in the semiconductor wafer 10.

[0057] When the protective film of the second embodiment is manufactured, the convex portions 31 of the second resin film 30 are formed so as to follow the U-shaped downward warpage due to the crystal plane orientation or the U-shaped downward warpage due to the device pattern film, thereby achieving a higher warpage reduction effect.

[0058] When the protective film of the third embodiment is manufactured, a thermal expansion resin is applied as the second resin film 30. This makes it possible to obtain a higher warpage reduction effect.

[0059] The step of forming the second resin film 30 in step S13 does not need to be performed consecutively after the step of forming the first resin film 20 in step S12. Fig. 12 is a flowchart showing another method for manufacturing a protective film in embodiment 7. The step of preparing a semiconductor wafer in step S21 and the step of forming the first resin film 20 in step S22 are the same as steps S11 and S12, respectively, shown in Fig. 10.

[0060] In step S23, a heating process and a cooling process are performed. In step S24, other processes are performed. In step S25, a second resin film 30 is formed. For example, resin is applied only to positions on the first resin film 20 where the convex portions 31 are to be formed. In step S26, a heating process and a cooling process are performed.

[0061] If the protrusions 31 of the second resin film 30 cause abnormalities in the subsequent process, the abnormalities can be avoided by changing the timing of forming the second resin film 30.

[0062] If there is a region in the semiconductor wafer 10 where the thickness should be reduced, such as the conductive portion 14 described in the fourth embodiment, a convex portion 31 of the second resin film 30 is formed in that region. During backside grinding in a subsequent process, a semiconductor device is manufactured in which the thickness of the semiconductor wafer 10 at the terminal portion 15 is greater than the thickness of the semiconductor wafer 10 at the conductive portion 14. FIG. 13 is a cross-sectional view illustrating the processing during backside grinding in a subsequent process. FIG. 13(a) shows the configuration of the semiconductor wafer 10 on which the second resin film 30 is formed. The semiconductor wafer 10 is inverted, and the first main surface 11 on which the first resin film 20 and the second resin film 30 are formed is adsorbed to a grinding stage (not shown). This adsorption eliminates any steps between the first resin film 20 and the second resin film 30, and unevenness is formed on the second main surface 12 of the semiconductor wafer 10 that corresponds to the steps formed on the first main surface 11. FIG. 13(b) shows the configuration of the semiconductor wafer 10 on which unevenness is formed on the second main surface 12. In this state, the second main surface 12 is ground to reduce the thickness of the semiconductor wafer 10 to a height 12A. Thereafter, when the suction of the grinding stage is released, a semiconductor device is manufactured in which the portions where the second resin film 30 is formed have the thickness of the conductive portion 14, and the portions where the second resin film 30 is not formed have the thickness of the termination portion 15. In other words, a semiconductor device is manufactured in which the thickness of the semiconductor wafer 10 at the termination portion 15 is thicker than the thickness of the semiconductor wafer 10 at the conductive portion 14. FIG. 13(c) shows the configuration of a semiconductor wafer 10 formed so that the thickness of the termination portion 15 is thicker than the thickness of the conductive portion 14. In such a semiconductor device, the breakdown voltage performance and conductivity performance are improved.

[0063] <Embodiment 8> In the eighth embodiment, a method for manufacturing the protective film according to any one of the first to third embodiments will be described. Fig. 14 is a flowchart showing the method for manufacturing the protective film according to the eighth embodiment. Fig. 15 is a cross-sectional view showing the configuration of the protective film in each step.

[0064] In step S31, a semiconductor wafer 10 is prepared. FIG. 15(a) shows the configuration of the semiconductor wafer 10. The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film. The second main surface 12 is the surface opposite to the first main surface 11. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of silicon, silicon carbide, gallium nitride, etc. The device pattern film is provided on the surface layer of the first main surface 11. Semiconductor element structures such as transistors are formed on the device pattern film.

[0065] In step S32, a resin film including the first resin film 20 and the convex portions 31 of the second resin film 30 is formed. FIG. 15(b) shows the configuration of a semiconductor wafer 10 on which the first resin film 20 and the convex portions 31 of the second resin film 30 are formed. The resin film is formed by a dispense method. A syringe 41 using a first gas pressure applies resin to the first main surface 11 of the semiconductor wafer 10, thereby forming the first resin film 20. The dispense mechanism 40 then controls the pressure, such as the gas pressure, to be high only when the convex portions 31 are applied. Here, the syringe 41 uses a second gas pressure that is higher than the first gas pressure used to form the first resin film 20, to apply the resin to a portion of the first main surface 11. As a result, the first resin film 20 and the convex portions 31 of the second resin film 30 are formed in a single application. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20 or within a 10% difference therebetween.

[0066] In step S33, the semiconductor wafer 10 on which the first resin film 20 and the second resin film 30 are formed is subjected to a heat treatment. After the heat treatment, the semiconductor wafer 10 is cooled to room temperature. The cooling method is, for example, natural cooling, but other cooling means may also be used.

[0067] After steps S31 to S33, the subsequent steps are carried out. The above is the method for manufacturing the semiconductor device according to the eighth embodiment.

[0068] The semiconductor device manufactured by the manufacturing method of the eighth embodiment improves the yield by preventing transfer errors in subsequent processes and cracking of the semiconductor wafer 10. Furthermore, the manufacturing method of the eighth embodiment reduces the processing time compared to the seventh embodiment because the first resin film 20 and the convex portions 31 of the second resin film 30 are formed by a single coating.

[0069] When the semiconductor device of the second embodiment is manufactured, the convex portions 31 of the second resin film 30 are formed so as to follow the U-shaped downward warpage due to the crystal plane orientation or the U-shaped downward warpage due to the device pattern film, thereby achieving a higher warpage reduction effect.

[0070] When the semiconductor wafer 10 has an area where the thickness of the semiconductor wafer 10 should be reduced, such as the conductive portion 14 described in the fourth embodiment, a convex portion 31 of the second resin film 30 is formed in that area. During the subsequent backside grinding process, a semiconductor device is manufactured in which the thickness of the semiconductor wafer 10 at the terminal end portion 15 is greater than the thickness of the semiconductor wafer 10 at the conductive portion 14. The semiconductor wafer 10 is inverted, and the first main surface 11 on which the first resin film 20 and the second resin film 30 are formed is adsorbed to a grinding stage (not shown). This adsorption eliminates any steps between the first resin film 20 and the second resin film 30, and unevenness is formed on the second main surface 12 of the semiconductor wafer 10 that corresponds to the steps formed on the first main surface 11 ( FIG. 13( b) ). In this state, the second main surface 12 is ground to reduce the thickness of the semiconductor wafer 10 to a height 12A. Thereafter, when the suction of the grinding stage is released, a semiconductor device is manufactured in which the area where the second resin film 30 is formed has the thickness of the conductive section 14, and the area where the second resin film 30 is not formed has the thickness of the termination section 15 (FIG. 13(c)). That is, a semiconductor device is manufactured in which the thickness of the semiconductor wafer 10 at the termination section 15 is thicker than the thickness of the semiconductor wafer 10 at the conductive section 14. In such a semiconductor device, the withstand voltage performance and conductivity performance are improved.

[0071] <Ninth Embodiment> In the ninth embodiment, a method for manufacturing the protective film described in the fifth or sixth embodiment will be described. Fig. 16 is a flowchart showing the method for manufacturing the protective film in the ninth embodiment. Fig. 17 is a cross-sectional view showing the configuration of the protective film in each step.

[0072] In step S41, a semiconductor wafer 10 is prepared. FIG. 17(a) shows the configuration of the semiconductor wafer 10. The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film. The second main surface 12 is the surface opposite to the first main surface 11. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of silicon, silicon carbide, gallium nitride, etc. The device pattern film is provided on the surface layer of the first main surface 11. Semiconductor element structures such as transistors are formed on the device pattern film.

[0073] In step S42, a first resin film 20 is formed so as to cover the first main surface 11 of the semiconductor wafer 10 on which the device pattern film has been formed. FIG. 17(b) shows the configuration of the semiconductor wafer 10 on which the first resin film 20 has been formed. The first resin film 20 is formed by a dispense method. The first resin film 20 is formed by applying resin onto the first main surface 11 of the semiconductor wafer 10 using a syringe 41 that uses gas pressure.

[0074] In step S43, a second resin film 30 is formed, including a recess 32 provided in a portion of the surface 20A of the first resin film 20. FIG. 17(c) shows the configuration of a semiconductor wafer 10 on which the second resin film 30 is formed. The second resin film 30 is formed by a dispense method. Resin is applied to a portion of the first resin film 20 using a syringe 41 that uses gas pressure. For example, the resin is not applied only to the position where the recess 32 is to be formed. This forms the recess 32 in the second resin film 30. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, or within a range of 10% difference.

[0075] In step S44, the semiconductor wafer 10 on which the first resin film 20 and the second resin film 30 are formed is subjected to a heat treatment. After the heat treatment, the semiconductor wafer 10 is cooled to room temperature. The cooling method is, for example, natural cooling, but other cooling means may also be used.

[0076] After steps S41 to S44, the subsequent steps are carried out. This completes the method for manufacturing the semiconductor device according to the ninth embodiment.

[0077] The semiconductor device manufactured by the manufacturing method of the ninth embodiment improves the yield by preventing transfer errors in the subsequent steps and cracking of the semiconductor wafer 10.

[0078] When the semiconductor device of the sixth embodiment is manufactured, the recesses 32 of the second resin film 30 are formed so as to follow the U-shaped downward warpage due to the crystal plane orientation or the U-shaped downward warpage due to the device pattern film, thereby achieving a higher warpage reduction effect.

[0079] <Tenth Embodiment> In the tenth embodiment, a method for manufacturing the protective film described in the fifth or sixth embodiment will be described. Fig. 18 is a flowchart showing the method for manufacturing the protective film in the tenth embodiment. Fig. 19 is a cross-sectional view showing the configuration of the protective film in each step.

[0080] In step S51, a semiconductor wafer 10 is prepared. FIG. 19(a) shows the configuration of the semiconductor wafer 10. The semiconductor wafer 10 includes a first main surface 11, a second main surface 12, and a device pattern film. The second main surface 12 is the surface opposite to the first main surface 11. The semiconductor wafer 10 is formed of one or more materials selected from the group consisting of silicon, silicon carbide, gallium nitride, etc. The device pattern film is provided on the surface layer of the first main surface 11. Semiconductor element structures such as transistors are formed on the device pattern film.

[0081] In step S52, a resin film including the first resin film 20 and the recesses 32 in the second resin film 30 is formed. FIG. 19(b) shows the configuration of a semiconductor wafer 10 on which the first resin film 20 and the recesses 32 in the second resin film 30 are formed. The resin film is formed by a dispense method. A syringe 41 using two types of gas pressure applies resin to the first main surface 11 of the semiconductor wafer 10, thereby forming the first resin film 20 and the second resin film 30 in a single application. At this time, the dispense mechanism 40 controls the pressure, such as the gas pressure, to be lower only when the recesses 32 are applied. Here, the syringe 41 uses a first gas pressure that is lower than the second gas pressure used to form the second resin film 30, to apply resin to a portion of the first main surface 11. As a result, the first resin film 20 and the recesses 32 in the second resin film 30 are formed in a single application. The thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20, and specifically, the thickness t2 of the second resin film 30 is the same as the thickness t1 of the first resin film 20 or within a 10% difference therebetween.

[0082] In step S53, the semiconductor wafer 10 on which the first resin film 20 and the second resin film 30 are formed is subjected to a heat treatment. After the heat treatment, the semiconductor wafer 10 is cooled to room temperature. The cooling method is, for example, natural cooling, but other cooling means may also be used.

[0083] After steps S51 to S53, the subsequent steps are carried out. This completes the method for manufacturing the semiconductor device according to the tenth embodiment.

[0084] The semiconductor device manufactured by the manufacturing method of the tenth embodiment improves the yield by preventing transfer errors in subsequent processes and cracking of the semiconductor wafer 10. Furthermore, the manufacturing method of the tenth embodiment reduces the processing time compared to the ninth embodiment because the first resin film 20 and the second resin film 30 are formed by a single coating.

[0085] When the semiconductor device of the sixth embodiment is manufactured, the recesses 32 of the second resin film 30 are formed so as to follow the U-shaped downward warpage due to the crystal plane orientation or the U-shaped downward warpage due to the device pattern film, thereby achieving a higher warpage reduction effect.

[0086] In the present disclosure, the embodiments can be freely combined, and the embodiments can be modified or omitted as appropriate.

[0087] Various aspects of the present disclosure are summarized below as appendices.

[0088] (Appendix 1) A protective film for protecting a surface of a semiconductor wafer including a main surface and a device pattern film provided on a surface layer of the main surface, a first resin film covering the main surface of the semiconductor wafer; a second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including a convex portion provided on a part of the surface of the first resin film;

[0089] (Appendix 2) the semiconductor wafer is warped downward in a U-shape according to the crystal plane orientation of the main surface, 2. The protective film according to claim 1, wherein the convex portion of the second resin film is provided along a direction in which the bottom of the U-shape extends.

[0090] (Appendix 3) the semiconductor wafer is warped downward in a U-shape in response to the device pattern film, 2. The protective film according to claim 1, wherein the convex portion of the second resin film is provided along a direction in which the bottom of the U-shape extends.

[0091] (Appendix 4) 4. The protective film according to claim 1, wherein the second resin film is made of the same material as the first resin film or a thermal expansion resin.

[0092] (Appendix 5) a semiconductor wafer including a main surface; a device pattern film provided on a surface layer of the main surface of the semiconductor wafer, the device pattern film includes a conductive portion and a termination portion provided around the conductive portion, A semiconductor device, wherein the thickness of the semiconductor wafer at the termination portion is greater than the thickness of the semiconductor wafer at the conductive portion.

[0093] (Appendix 6) A protective film for protecting a surface of a semiconductor wafer including a main surface and a device pattern film provided on a surface layer of the main surface, a first resin film covering the main surface of the semiconductor wafer; a second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including a recess in which a part of the surface of the first resin film is exposed;

[0094] (Appendix 7) the semiconductor wafer is warped downward in a U-shape according to the crystal plane orientation of the main surface, 7. The protective film according to claim 6, wherein the recess in the second resin film is provided along a direction in which the bottom of the U-shape extends.

[0095] (Appendix 8) the semiconductor wafer is warped downward in a U-shape in response to the device pattern film, 7. The protective film according to claim 6, wherein the recess in the second resin film is provided along a direction in which the bottom of the U-shape extends.

[0096] (Appendix 9) A method for forming a protective film according to any one of Supplementary Note 1 to Supplementary Note 4, preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming the first resin film to cover the main surface of the semiconductor wafer; forming the second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including the convex portion provided on a part of the surface of the first resin film; The step of forming the first resin film includes: forming the first resin film by applying a resin onto the main surface of the semiconductor wafer using a syringe under gas pressure; The step of forming the second resin film includes: a method for forming a protective film, the method comprising: applying resin to a portion of the first resin film using the syringe under the gas pressure, thereby forming the convex portion of the second resin film.

[0097] (Appendix 10) A method for forming a protective film according to any one of Supplementary Note 1 to Supplementary Note 3, preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming a resin film including the first resin film covering the main surface of the semiconductor wafer, and the second resin film having the same film thickness as the first resin film or a thickness within a range of 10% increase or decrease, and including the convex portion provided on a part of the surface of the first resin film; The step of forming the resin film includes: A method for forming a protective film, comprising: applying a resin onto the main surface of the semiconductor wafer using a syringe with a first gas pressure; and applying the resin onto the main surface with the syringe with a second gas pressure higher than the first gas pressure, thereby forming the first resin film and the convex portions of the second resin film in a single application.

[0098] (Appendix 11) A method for forming a protective film according to any one of Supplementary Notes 6 to 8, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming the first resin film to cover the main surface of the semiconductor wafer; forming the second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including the recessed portion where a part of the surface of the first resin film is exposed; The step of forming the first resin film includes: forming the first resin film by applying a resin onto the main surface of the semiconductor wafer using a syringe under gas pressure; The step of forming the second resin film includes: a method for forming a protective film, the method comprising: applying resin to a portion of the first resin film using the syringe under the gas pressure, thereby forming the recess in the second resin film.

[0099] (Appendix 12) A method for forming a protective film according to any one of Supplementary Notes 6 to 8, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming a resin film including the first resin film covering the main surface of the semiconductor wafer, and the second resin film having the same thickness as the first resin film or a thickness within a range of 10% increase or decrease, and including the recess in which a part of the surface of the first resin film is exposed; The step of forming the resin film includes: A method for forming a protective film, comprising: applying a resin onto the main surface of the semiconductor wafer using a syringe with a first gas pressure; and applying the resin onto the main surface with the syringe with a second gas pressure lower than the first gas pressure, thereby forming the first resin film and the recesses of the second resin film in a single application. [Explanation of symbols]

[0100] 10 semiconductor wafer, 11 first main surface, 12 second main surface, 13 device pattern forming portion, 13A device pattern forming portion, 14 conductive portion, 15 termination portion, 20 first resin film, 20A surface, 30 second resin film, 31 convex portion, 32 concave portion, 40 dispensing mechanism, 41 syringe.

Claims

1. A protective film for protecting a surface of a semiconductor wafer including a main surface and a device pattern film provided on a surface layer of the main surface, a first resin film covering the main surface of the semiconductor wafer; a second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including a convex portion provided on a portion of the surface of the first resin film;

2. the semiconductor wafer is warped downward in a U-shape according to the crystal plane orientation of the main surface, The protective film according to claim 1 , wherein the convex portion of the second resin film is provided along a direction in which the bottom of the U-shape extends.

3. the semiconductor wafer is warped downward in a U-shape in response to the device pattern film, The protective film according to claim 1 , wherein the convex portion of the second resin film is provided along a direction in which the bottom of the U-shape extends.

4. The protective film according to claim 1 , wherein the second resin film is made of the same material as the first resin film or a thermal expansion resin.

5. a semiconductor wafer including a main surface; a device pattern film provided on a surface layer of the main surface of the semiconductor wafer, the device pattern film includes a conductive portion and a termination portion provided around the conductive portion, A semiconductor device, wherein the thickness of the semiconductor wafer at the termination portion is greater than the thickness of the semiconductor wafer at the conductive portion.

6. A protective film for protecting a surface of a semiconductor wafer including a main surface and a device pattern film provided on a surface layer of the main surface, a first resin film covering the main surface of the semiconductor wafer; a second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including a recess in which a portion of the surface of the first resin film is exposed.

7. the semiconductor wafer is warped downward in a U-shape according to the crystal plane orientation of the main surface, The protective film according to claim 6 , wherein the recess in the second resin film is provided along a direction in which the bottom of the U-shape extends.

8. the semiconductor wafer is warped downward in a U-shape in response to the device pattern film, The protective film according to claim 6 , wherein the recess in the second resin film is provided along a direction in which the bottom of the U-shape extends.

9. 5. A method for forming a protective film according to claim 1, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming the first resin film to cover the main surface of the semiconductor wafer; forming the second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including the convex portion provided on a part of the surface of the first resin film; The step of forming the first resin film includes: forming the first resin film by applying a resin onto the main surface of the semiconductor wafer using a syringe under gas pressure; The step of forming the second resin film includes: a second resin film formed on the second surface of the first resin film by applying resin to a portion of the first resin film using the syringe under gas pressure;

10. 4. A method for forming a protective film according to claim 1, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming a resin film including the first resin film covering the main surface of the semiconductor wafer, and the second resin film having the same film thickness as the first resin film or a thickness within a range of 10% increase or decrease, and including the convex portion provided on a part of the surface of the first resin film; The step of forming the resin film includes: A method for forming a protective film, comprising: applying a resin onto the main surface of the semiconductor wafer using a syringe with a first gas pressure; and applying the resin onto the main surface with the syringe with a second gas pressure higher than the first gas pressure, thereby forming the first resin film and the convex portion of the second resin film in a single application.

11. 9. A method for forming a protective film according to claim 6, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming the first resin film to cover the main surface of the semiconductor wafer; forming the second resin film having the same thickness as the first resin film or a thickness within 10% of the first resin film, the second resin film including the recessed portion where a part of the surface of the first resin film is exposed; The step of forming the first resin film includes: forming the first resin film by applying a resin onto the main surface of the semiconductor wafer using a syringe under gas pressure; The step of forming the second resin film includes: a syringe that applies a resin to a portion of the first resin film using the gas pressure, thereby forming the recess in the second resin film.

12. 9. A method for forming a protective film according to claim 6, comprising: preparing the semiconductor wafer including the main surface and the device pattern film provided on the surface layer of the main surface; forming a resin film including the first resin film covering the main surface of the semiconductor wafer, and the second resin film having the same thickness as the first resin film or a thickness within a range of 10% increase or decrease, and including the recess in which a part of the surface of the first resin film is exposed; The step of forming the resin film includes: A method for forming a protective film, comprising: applying a resin onto the main surface of the semiconductor wafer using a syringe with a first gas pressure; and applying the resin onto the main surface with the syringe with a second gas pressure lower than the first gas pressure, thereby forming the first resin film and the recesses of the second resin film in a single application.

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