Manufacturing method for semiconductor device

Abstract

To provide a technique of suitably dividing a semiconductor substrate to which a holding tape is attached.SOLUTION: A manufacturing method for a semiconductor device includes the steps of: performing a process on a semiconductor substrate in which a holding tape is attached to a first surface; and dividing the semiconductor substrate by pressing a dividing member onto a second surface of the semiconductor substrate opposite to the first surface of the semiconductor substrate in which the holding tape is attached to the first surface. In the step of performing the process, the adhesive power of the holding tape to the first surface is higher than in the step of dividing the semiconductor substrate. In the manufacturing method described above, the adhesive power of the holding tape is high before the step of dividing the semiconductor substrate; however, the adhesive power is low in the step of dividing the semiconductor substrate. For this reason, the semiconductor substrate can be divided suitably in the step of dividing the semiconductor substrate.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a method for manufacturing a semiconductor device. [Background technology]

[0002] Patent Document 1 describes a technique for dividing a substrate by pressing a dividing member against the surface of the substrate opposite to the holding tape to which the holding tape is adhered. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-117290 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, if the adhesive strength of the holding tape is strong, the holding tape reinforces the substrate, making it less likely for cracks to occur in the substrate when the dividing member is pressed against it. This causes the problem of making it difficult to divide the substrate. Furthermore, if the adhesive strength of the holding tape is weak, there is a risk that the holding tape will peel off before the substrate dividing process. This specification proposes a technology for suitably dividing a semiconductor substrate to which a holding tape is adhered. [Means for solving the problem]

[0005] The method for manufacturing a semiconductor device of aspect 1 disclosed in the present specification comprises a step of processing a semiconductor substrate having a retaining tape adhered to a first surface thereof, and a step of dividing the semiconductor substrate by pressing a dividing member against a second surface of the semiconductor substrate having the retaining tape adhered to the first surface, the second surface being located opposite to the first surface thereof, wherein the adhesive force of the retaining tape to the first surface is stronger in the step of performing the processing than in the step of dividing the semiconductor substrate.

[0006] When a semiconductor device is manufactured using the above manufacturing method, the adhesive strength of the holding tape is strong before the step of dividing the semiconductor substrate, but is weak during the step of dividing the semiconductor substrate, so that the semiconductor substrate can be divided appropriately during the step of dividing the semiconductor substrate. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 2] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 3] 1 is a plan view of a semiconductor substrate according to an embodiment. [Figure 4] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 5] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 6] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 7] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 8] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 9] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 10] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 11] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 12] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 13] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 14] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 15] 1 is a method for manufacturing a semiconductor device according to an embodiment.

[0008] Following the above-mentioned first aspect, additional configurations of the method for manufacturing a semiconductor device disclosed in this specification will be described below. (Aspect 2) The manufacturing method according to aspect 1, further comprising the step of reducing adhesive strength of the holding tape after the step of performing the treatment and before the step of dividing the semiconductor substrate. (Aspect 3) 3. The manufacturing method according to aspect 1 or 2, wherein the step of performing the treatment is a step of peeling off an adhesive substance stuck to the second surface from the second surface. (Aspect 4) 4. The manufacturing method according to aspect 3, wherein in the step of performing the treatment, the adhesive strength of the holding tape to the first surface is higher than the adhesive strength of the adhesive substance to the second surface. (Aspect 5) The manufacturing method according to aspect 3 or 4, further comprising the steps of: attaching a support plate to the second surface via the adhesive; adhering the retention tape to the first surface after the step of attaching the support plate; and peeling the support plate from the adhesive after the step of adhering the retention tape to the first surface, wherein the step of peeling the adhesive from the second surface is performed after the step of peeling the support plate from the adhesive, and the step of dividing the semiconductor substrate is performed after the step of peeling the adhesive from the second surface. (Aspect 6) A manufacturing method according to aspect 5, further comprising the step of polishing the first surface after the step of attaching the support plate and before the step of adhering the holding tape. (Aspect 7) A manufacturing method according to any one of aspects 1 to 6, wherein in the step of dividing the semiconductor substrate, a protective tape is adhered to the second surface, and the dividing member is pressed against the second surface via the protective tape. (Aspect 8) The manufacturing method according to any one of aspects 1 to 7, further comprising, prior to the step of dividing the semiconductor substrate, a step of forming weakened portions distributed linearly in the lateral direction within the semiconductor substrate. (Aspect 9) Aspect 9. The manufacturing method according to aspect 8, wherein in the forming the fragile portion, a pressing member is pressed against the semiconductor substrate to form a crack in the semiconductor substrate. (Aspect 10) Aspect 9. The manufacturing method according to aspect 8, wherein in the step of forming the fragile portion, a modified layer is formed in the semiconductor substrate by irradiating the semiconductor substrate with a laser. (Aspect 11) 11. The manufacturing method according to any one of aspects 1 to 10, wherein in the step of dividing the semiconductor substrate, the dividing member is pressed against the second surface of the holding tape while supporting the surface of the holding tape opposite the semiconductor substrate with an elastic body.

[0009] According to the above-mentioned aspect 2, the adhesive strength of the holding tape is strong before the step of reducing the adhesive strength of the holding tape, so that the holding tape and the semiconductor substrate are not easily peeled off. After the step of reducing the adhesive strength of the holding tape, the adhesive strength of the holding tape is weak, so that the semiconductor substrate can be suitably divided when it is divided.

[0010] According to the above-mentioned aspects 3 and 4, when the adhesive material stuck to the second surface is peeled off from the second surface, the holding tape is difficult to peel off from the first surface.

[0011] The "lateral direction" in the above-mentioned eighth aspect is a direction parallel to the second surface of the semiconductor substrate.

[0012] The "modified layer" in the above-mentioned embodiment 10 is a layer that has been altered by a laser.

[0013] In the manufacturing method of the embodiment, a semiconductor device is manufactured from a semiconductor substrate 10 shown in Fig. 1. As shown in Fig. 1, the entire semiconductor substrate 10 before processing is composed of a semiconductor layer 12. The semiconductor layer 12 is composed of SiC or the like. The semiconductor layer 12 has an upper surface 12b and a lower surface 12a.

[0014] First, an element structure forming process is performed. In the element structure forming process, element structures (e.g., field-effect transistors, diodes, etc.) are formed in the semiconductor layer 12. Furthermore, as shown in FIGS. 2 and 3, a plurality of electrodes 14 are formed on the upper surface 12b of the semiconductor layer 12. In FIG. 3, the planned dividing lines 6 extending in a grid pattern are the locations where the semiconductor substrate 10 will be divided in a later dividing process. The planned dividing lines 6 are imaginary lines, not lines actually drawn on the semiconductor substrate 10. The planned dividing lines 6 extend in a grid pattern along the spaces between the electrodes 14. Hereinafter, the entire substrate including the semiconductor layer 12 and the electrodes provided on its surface will be referred to as the semiconductor substrate 10. Furthermore, the upper surface of the semiconductor substrate 10 (e.g., the surfaces of the electrodes 14 and the upper surface 12b of the semiconductor layer 12 in FIG. 2) will be referred to as the second surface 10b, and the lower surface of the semiconductor substrate 10 (e.g., the lower surface 12a of the semiconductor layer 12 in FIG. 2) will be referred to as the first surface 10a.

[0015] Next, a support plate attaching step is performed. As shown in FIG. 4, the support plate attaching step is a step of attaching a support plate 20 to the second surface 10b of the semiconductor substrate 10. Note that in FIGS. 4 to 7, the semiconductor substrate 10 is depicted with the second surface 10b facing downwards. The support plate 20 is attached to the second surface 10b via an adhesive 22. In other words, the adhesive 22 bonds the support plate 20 and the second surface 10b of the semiconductor substrate 10. The support plate 20 is made of, for example, a glass plate. The adhesive 22 is made of, for example, a silicone adhesive.

[0016] 5, the polishing step is a step of polishing the first surface 10a of the semiconductor substrate 10 (i.e., the lower surface 12a of the semiconductor layer 12) to thin the semiconductor layer 12.

[0017] Next, a fragile portion forming process is performed. As shown in FIG. 6, in the fragile portion forming process, a scribe wheel 32, which is a pressing member, is pressed against the first surface 10a of the semiconductor substrate 10. The scribe wheel 32 is a disk-shaped member and is axially supported by a support device (not shown). The scribe wheel 32 is rotatable. The scribe wheel 32 has a sharp outer periphery, but does not cut the semiconductor substrate 10. That is, the scribe wheel 32 is simply pressed against the first surface 10a. In the fragile portion forming process, the scribe wheel 32 is moved so as to roll while being pressed against the first surface 10a of the semiconductor substrate 10. As shown in FIG. 6, when the scribe wheel 32 is moved, a crack 34 extending in the thickness direction of the semiconductor substrate 10 is formed. The crack 34 is formed in a range near the surface layer of the first surface 10a. Here, a scribing wheel 32 is moved along each of the planned dividing lines 6 shown in FIG.

[0018] 7, in the electrode formation step, an electrode 40 is formed on the lower surface 12a of the semiconductor layer 12. The electrode 40 is made of a multilayer film in which, for example, titanium, nickel, and gold are stacked.

[0019] Next, a retention tape bonding step is performed. As shown in FIG. 8, in the retention tape bonding step, a retention tape 24 is bonded to the first surface 10a of the semiconductor substrate 10 (i.e., the surface of the electrode 40). Note that in FIG. 8 and subsequent figures, the semiconductor substrate 10 is depicted with the second surface 10b of the semiconductor substrate 10 facing up. The retention tape 24 is, for example, a dicing tape. The outer periphery of the retention tape 24 is fixed by a frame (not shown). The adhesive strength between the retention tape 24 and the first surface 10a of the semiconductor substrate 10 is higher than the adhesive strength between the adhesive material 22 and the second surface 10b of the semiconductor substrate 10.

[0020] Next, a support plate peeling step is carried out. In the support plate peeling step, the support plate 20 is peeled off from the adhesive material 22 as shown in FIG.

[0021] Next, an adhesive peeling step is carried out. As shown in Fig. 10, in the adhesive peeling step, the adhesive 22 is peeled off from the second surface 10b of the semiconductor substrate 10 by pulling it upward. The adhesive strength between the adhesive 22 and the second surface 10b of the semiconductor substrate 10 is lower than the adhesive strength between the holding tape 24 and the first surface 10a. Therefore, when the adhesive 22 is peeled off from the semiconductor substrate 10, the holding tape 24 does not peel off from the semiconductor substrate 10. In other words, the holding tape 24 remains attached to the semiconductor substrate 10.

[0022] 11, the protective tape bonding step is a step of attaching a protective tape 26 to the second surface 10b of the semiconductor substrate 10.

[0023] Next, an adhesive strength reducing step is carried out. As shown in Fig. 12, in the adhesive strength reducing step, UV light is irradiated from the underside of the holding tape 24 toward the holding tape 24. By irradiating UV light toward the holding tape 24, the adhesive strength between the holding tape 24 and the first surface 10a is reduced.

[0024] Next, the dividing step is performed. As shown in FIG. 13 , in the dividing step, the semiconductor substrate 10 is placed on the support base 28 so that the exposed surface of the holding tape 24 (i.e., the surface opposite to the semiconductor substrate 10) is in contact with the support base 28. The surface of the support base 28 is made of an elastic material (e.g., rubber). Next, a breaking bar 36, which is a dividing member, is pressed against the second surface 10b of the semiconductor substrate 10 via the protective tape 26. The breaking bar 36 is a plate-shaped member. The lower end of the breaking bar 36 has a sharp structure, but does not cut the semiconductor substrate 10. That is, the breaking bar 36 is simply pressed against the semiconductor substrate 10. Here, the breaking bar 36 is pressed against the second surface 10b along the planned dividing line 6. When the breaking bar 36 is pressed against the second surface 10b, a crack 34 extends in the thickness direction of the semiconductor substrate 10. As a result, the semiconductor substrate 10 is cleaved from the cracks 34 as starting points, and the semiconductor substrate 10 is divided.

[0025] 14, when the semiconductor substrate 10 is divided, the holding tape 24 stretches at the dividing position (i.e., below the break bar 36). In the part where the holding tape 24 stretches, the holding tape 24 slides against the first surface 10a of the semiconductor substrate 10.

[0026] If the adhesive strength of the holding tape 24 is too high, the holding tape 24 cannot slide against the first surface 10a, which suppresses the elongation of the holding tape 24. Therefore, if the adhesive strength of the holding tape 24 is too high, the semiconductor substrate 10 cannot be divided properly.

[0027] In contrast, in this embodiment, the adhesive strength reduction step is performed before the dividing step, so the adhesive strength between the holding tape 24 and the first surface 10a is low in the dividing step. Therefore, the holding tape 24 easily slides relative to the first surface 10a near the dividing position, and the holding tape 24 easily stretches at the dividing position. This facilitates cleavage of the semiconductor substrate 10, allowing the semiconductor substrate 10 to be divided appropriately. The chips divided from the semiconductor substrate 10 become semiconductor devices.

[0028] As described above, in this embodiment, the adhesive strength of the holding tape 24 is high at the stage of the adhesive peeling step, so the adhesive 22 can be properly peeled off from the semiconductor substrate 10 in the adhesive peeling step. In addition, since the adhesive strength reducing step is subsequently performed before the dividing step, the holding tape 24 can easily slide against the first surface 10a in the dividing step. Therefore, the semiconductor substrate 10 can be properly divided.

[0029] In the weakened portion forming step of the above-described embodiment, cracks 34 (i.e., weakened portions) are formed using a scribing wheel 32. However, as shown in FIG. 15 , in the weakened portion forming step, a modified layer 38 may be formed in the semiconductor substrate 10 by irradiating the semiconductor substrate 10 with a laser. In FIG. 15 , the laser is focused inside the semiconductor substrate 10. In the portion where the laser is focused, a modified layer 38 is formed by the laser light, which has been altered. The modified layer 38 is a weakened portion that is weaker in strength than the surrounding semiconductor layer 12. In the dividing step, cleavage occurs starting from the modified layer 38.

[0030] In the above-described embodiment, the fragile portion forming step was performed after the polishing step and before the electrode forming step. However, the fragile portion forming step may be performed at any time before the dividing step.

[0031] In the above-described embodiment, the adhesive material 22 is, for example, a silicon adhesive. However, the adhesive material 22 may be configured as a double-sided tape that bonds the support plate 20 and the semiconductor substrate 10 together.

[0032] In the above-described embodiment, the polishing step was performed after the support plate attaching step and before the fragile portion forming step. However, the polishing step may be performed at any time after the support plate attaching step and before the holding tape adhering step.

[0033] In the above-described embodiment, the adhesive strength reducing step is a step of reducing the adhesive strength between the holding tape 24 and the first surface 10a by UV irradiation. However, in the adhesive strength reducing step, the adhesive strength may be reduced by applying heat to the holding tape 24.

[0034] In the above-described embodiment, the step of peeling off the adhesive material 22 was carried out as the step of processing the semiconductor substrate 10 (hereinafter referred to as the processing step). However, other steps (e.g., electrode plating, electrical testing of semiconductor elements) may also be carried out as the processing step. Even in such processing steps, the high adhesive strength of the holding tape 24 can prevent the holding tape 24 from peeling off during processing.

[0035] In the above-described embodiment, the dividing step is carried out after the treating step, but the treating step may be carried out after the dividing step.

[0036] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0037] 6: Planned division line 10: Semiconductor substrate 12: Semiconductor layer 14: Electrode 20: Support plate 22: Sticky 24: Retaining tape 26: Protective tape 28: Support stand 32: Scribe wheel 34: Crack 36: Break Bar 40: Electrode

Claims

1. A method for manufacturing a semiconductor device, comprising: A step of performing a process on a semiconductor substrate (10) having a support tape (24) adhered to a first surface (10a); a step of dividing the semiconductor substrate by pressing a dividing member (36) against a second surface (10b) located opposite to the first surface of the semiconductor substrate to which the holding tape is adhered; Equipped with The method for manufacturing a semiconductor device, wherein the adhesive force of the holding tape to the first surface is higher in the step of performing the treatment than in the step of dividing the semiconductor substrate.

2. The manufacturing method according to claim 1 , further comprising the step of reducing adhesive strength of the holding tape after the step of performing the processing and before the step of dividing the semiconductor substrate.

3. The manufacturing method according to claim 1 or 2, wherein the step of performing the treatment is a step of peeling off the adhesive substance (22) adhering to the second surface from the second surface.

4. The manufacturing method according to claim 3 , wherein in the step of performing the treatment, the adhesive strength of the holding tape to the first surface is higher than the adhesive strength of the adhesive material to the second surface.

5. a step of attaching a support plate (20) to the second surface via the adhesive; a step of adhering the holding tape to the first surface after the step of attaching the support plate; a step of peeling the support plate from the adhesive material after the step of adhering the holding tape to the first surface; and the step of peeling the adhesive material from the second surface is carried out after the step of peeling the support plate from the adhesive material, the step of separating the semiconductor substrate is performed after the step of peeling the adhesive material from the second surface. The method of claim 3.

6. The manufacturing method according to claim 5 , further comprising the step of polishing the first surface after the step of attaching the support plate and before the step of adhering the holding tape.

7. 3. The manufacturing method according to claim 1, wherein in the step of dividing the semiconductor substrate, a protective tape (26) is adhered to the second surface, and the dividing member is pressed against the second surface via the protective tape.

8. The manufacturing method according to claim 1 , further comprising the step of forming weakened portions distributed linearly in a lateral direction in the semiconductor substrate prior to the step of dividing the semiconductor substrate.

9. The manufacturing method according to claim 8, wherein in the step of forming the fragile portion, a pressing member (32) is pressed against the semiconductor substrate to form a crack (34) in the semiconductor substrate.

10. The manufacturing method according to claim 8, wherein in the step of forming the fragile portion, a modified layer (38) is formed in the semiconductor substrate by irradiating the semiconductor substrate with a laser.

11. 3. The manufacturing method according to claim 1, wherein in the step of dividing the semiconductor substrate, the dividing member is pressed against the second surface of the holding tape while the surface of the holding tape opposite the semiconductor substrate is supported by an elastic body.

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