JP2010062415A - Method of peeling protective tape, and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for peeling off a protective tape capable of peeling off the protective tape from a semiconductor substrate without leaving an adhesive residue on the surface of the semiconductor substrate.
A method for peeling off a protective tape (20) attached to a surface of a semiconductor substrate (10), wherein a foreign substance removing tape (30) is attached to the surface of the protective tape (20), and then the foreign substance removing tape is applied from the surface of the protective tape (20). After the foreign matter removing step for peeling 30 and the foreign matter removing step, the peeling tape 40 is attached to the surface of the protective tape 20, and then the peeling tape 40 and the protective tape 20 are integrally peeled from the semiconductor substrate 10 as a unit. ing.
[Selection] Figure 5

Description

  The present invention relates to a method for peeling a protective tape from a surface of a semiconductor substrate.

  In the manufacturing process of a semiconductor device, a protective tape may be attached to the surface of the semiconductor substrate. For example, in Patent Document 1, when one surface (hereinafter referred to as a second surface) of a semiconductor substrate is polished or etched, a protective tape is attached to the other surface (hereinafter referred to as a first surface) of the semiconductor substrate. It is described that it is attached.

  After the second surface is polished, a diffusion layer or an electrode may be formed on the second surface with the protective tape still attached to the first surface. The step of forming the diffusion layer and the electrode is performed in a vacuum or a reduced pressure atmosphere. Therefore, when air enters between the semiconductor substrate and the protective tape, the air expands. In order to prevent peeling due to the expansion of air, the protective tape requires a relatively strong adhesive force.

  After going through each step, the protective tape is peeled from the semiconductor substrate. When peeling off the protective tape, the release tape is attached to the surface of the protective tape. Then, the peeling tape and the protective tape are integrally peeled from the semiconductor substrate by pulling the peeling tape. However, since the protective tape has undergone each step, foreign matter is adhered to the surface of the protective tape. For this reason, a peeling tape cannot be affixed on a protective tape with strong adhesive force. Therefore, when peeling off the protective tape, the semiconductor substrate is heated from the second surface side. Thereby, the protective tape is heated, and the adhesive strength of the protective tape is reduced to less than the adhesive strength of the release tape. By pulling the peeling tape while heating the protective tape, the peeling tape and the protective tape can be integrally peeled from the semiconductor substrate.

JP 2007-31735 A

  As described above, in the conventional protective tape peeling method, the adhesive strength of the protective tape is reduced by heating. When the protective tape is peeled off while being heated, the adhesive of the protective tape causes cohesive failure, and thus the adhesive residue of the protective tape remains on the first surface of the semiconductor substrate after the protective tape is peeled off. Residues remaining on the surface of the semiconductor substrate cause various problems. For example, if a residue remains on an electrode formed on the surface of a semiconductor substrate, poor connection strength is caused when a semiconductor device manufactured from the semiconductor substrate is wire bonded. For this reason, in the conventional peeling method, it was necessary to remove the residue by washing the semiconductor substrate after peeling off the protective tape. When the residue removing step is performed, there arises a problem that the manufacturing efficiency of the semiconductor device is reduced and a problem that a cleaning liquid after use is required.

  The present invention was created in view of the above-described circumstances, and provides a method for peeling a protective tape that can peel a protective tape from a semiconductor substrate without leaving an adhesive residue on the surface of the semiconductor substrate. The purpose is to do.

In the protective tape peeling method of the present invention, the protective tape attached to the surface of the semiconductor substrate is peeled off. This method has a foreign matter removing step and a peeling step. In the foreign matter removing step, the foreign matter removing tape is attached to the surface of the protective tape, and then the foreign matter removing tape is peeled off from the surface of the protective tape. In the peeling step, after the foreign matter removing step, the peeling tape is attached to the surface of the protective tape, and then the peeling tape and the protective tape are integrally peeled from the semiconductor substrate.
In this peeling method, in the foreign matter removing step, the foreign matter removing tape is attached to the surface of the protective tape, and then the foreign matter removing tape is peeled off from the surface of the protective tape. Thereby, the foreign material adhering to the surface of the protective tape is adsorbed and removed by the foreign material removing tape. Therefore, after the foreign matter removing step, almost no foreign matter is present on the surface of the protective tape. In the peeling step after the foreign substance removing step, the peeling tape can be stuck to the protective tape with a strong adhesive force by sticking the peeling tape to the surface of the protective tape. Therefore, in the peeling step, the peeling tape and the protective tape can be peeled together from the semiconductor substrate without heating the protective tape. For this reason, it is possible to peel the protective tape from the semiconductor substrate without leaving an adhesive residue on the surface of the semiconductor substrate.

Moreover, this invention provides the manufacturing method of the semiconductor device which does not require the residue removal process after peeling of a protective tape. This manufacturing method includes a thinning process, a foreign matter removing process, and a peeling process. In the thinning process, the semiconductor substrate is thinned by polishing or etching the second surface of the semiconductor substrate with a protective tape attached to the first surface of the semiconductor substrate. In the foreign matter removing step, the foreign matter removing tape is attached to the surface of the protective tape after the thinning step, and then the foreign matter removing tape is peeled off from the surface of the protective tape. In the peeling step, after the foreign matter removing step, the peeling tape is attached to the surface of the protective tape, and then the peeling tape and the protective tape are integrally peeled from the semiconductor substrate.
According to this manufacturing method, it is not necessary to heat the protective tape in order to weaken the adhesive strength of the protective tape, so that no adhesive residue remains on the surface of the semiconductor substrate after the protective tape is peeled off. A semiconductor device can be manufactured without performing the residue removal process after peeling off the protective tape.

An embodiment of a semiconductor device manufacturing method to which the protective tape peeling method of the present invention is applied will be described. FIG. 1 shows a cross-sectional view of the semiconductor substrate 10. Although not shown, a semiconductor element structure such as a diffusion layer, an insulating film, and a metal wiring is already formed on the upper surface (first surface) 12 side of the semiconductor substrate 10. Since the semiconductor element structure on the upper surface 12 side is formed by a conventionally known method, a description thereof is omitted. A semiconductor element structure is not formed on the lower surface (second surface) 14 side of the semiconductor substrate 10. Note that reference numeral 20 in FIG. 1 indicates a protective tape attached to the upper surface 12 of the semiconductor substrate 10.
In this embodiment, the polishing process, the lower surface semiconductor element structure forming process, the foreign substance removing process, and the peeling process are performed on the semiconductor substrate 10 shown in FIG. 1 (the semiconductor substrate on which the upper surface side semiconductor element structure is formed). By carrying out, a semiconductor device is manufactured.

(Polishing process)
In the polishing step, the lower surface 14 of the semiconductor substrate 10 is polished. That is, first, as shown in FIG. 1, the protective tape 20 is attached to the entire upper surface 12 of the semiconductor substrate 10 (the upper surface 12 on which the semiconductor element structure is formed). As the protective tape 20, a tape having high rigidity and high adhesive strength is used. Then, the lower surface 14 of the semiconductor substrate 10 is polished with the protective tape 20 attached. Thereby, the semiconductor substrate 10 is thinned. For example, the semiconductor substrate 10 having a thickness of about 725 μm is thinned to a thickness of about 150 μm. FIG. 2 shows the semiconductor substrate 10 after the polishing process. As shown in FIG. 2, the semiconductor substrate 10 is thinned by the polishing process. Further, by performing the polishing process, polishing scraps (hereinafter referred to as foreign matter 90) of the semiconductor substrate 10 adhere to the surface of the protective tape 20.

(Lower side semiconductor element structure formation process)
In the lower surface side semiconductor element structure forming step, a semiconductor element structure is formed on the lower surface 14 side of the semiconductor substrate 10 after the polishing step. That is, first, impurities are implanted into the semiconductor substrate 10 from the lower surface 14. Thereafter, the semiconductor substrate 10 is heat-treated. In this heat treatment, since only the lower surface 14 of the semiconductor substrate 10 is locally heated by laser annealing or the like, the temperature of the protective tape 20 does not increase so much. By performing impurity implantation and heat treatment, an impurity diffusion layer 16 is formed in the vicinity of the lower surface 14 as shown in FIG. After the impurity diffusion layer 16 is formed, the metal electrode 18 is formed on the surface of the lower surface 14 by vapor deposition or the like. Since the impurity diffusion layer 16 and the metal electrode 18 are formed by a conventionally known method, the details of the formation method are omitted.
When forming the impurity diffusion layer 16 and when forming the metal electrode 18, the semiconductor substrate 10 is exposed to a substantially vacuum atmosphere. Therefore, a minute amount of air confined between the protective tape 20 and the upper surface 12 of the semiconductor substrate 10 expands. However, since the protective tape 20 has a high adhesive force, the protective tape 20 does not peel off.

(Foreign substance removal process)
In the foreign matter removing step, the foreign matter 90 attached to the surface of the protective tape 20 is removed after the lower surface side semiconductor element structure forming step. That is, first, as shown in FIG. 4, the foreign matter removing tape 30 is attached to the surface of the protective tape 20. The foreign matter removing tape 30 is attached so as to cover substantially half of the surface of the protective tape 20. In addition, the foreign material removal tape 30 uses the same kind of tape as a peeling tape 40 described later. Next, as shown in FIG. 5, the foreign matter removing tape 30 is peeled from the center side of the semiconductor substrate 10. Since the foreign matter 90 is interposed between the foreign matter removing tape 30 and the protective tape 20, the adhesive force of the foreign matter removing tape 30 to the protective tape 20 is weak. That is, the adhesive force of the foreign matter removing tape 30 to the protective tape 20 is weaker than the adhesive force of the protective tape 20 to the semiconductor substrate 10. Accordingly, the foreign matter removing tape 30 is peeled off from the protective tape 20. At this time, since the surface of the protective tape 20 does not have adhesiveness, the foreign matter 90 present on the surface of the protective tape 20 is adsorbed to the foreign matter removing tape 30. As a result, the foreign matter 90 is removed from the surface of the protective tape 20. When the foreign material 90 is removed from about half of the surface of the protective tape 20 as described above, the foreign material 90 is similarly removed from the remaining half region.

(Peeling process)
In the peeling step, the peeling tape 40 is attached to the entire surface of the protective tape 20 as shown in FIG. As described above, the same type of tape as the foreign matter removing tape 30 is used for the peeling tape 40. Since the foreign matter 90 is removed from the surface of the protective tape 20 in the foreign matter removing step, the peeling tape 40 can be attached to the protective tape 20 with a strong adhesive force. More specifically, the adhesive force of the peeling tape 40 to the protective tape 20 is stronger than the adhesive force of the protective tape 20 to the semiconductor substrate 10. When the release tape 40 is attached, the release tape 40 is pulled from the peripheral side of the semiconductor substrate 10 as shown in FIG. As described above, since the adhesive force of the peeling tape 40 to the protective tape 20 is strong, the peeling tape 40 does not peel from the protective tape 20. Therefore, the peeling tape 40 and the protective tape 20 are peeled from the semiconductor substrate 10 as a unit.

  When the protective tape 20 is peeled off, a dicing tape is attached to the semiconductor substrate 10. Then, the semiconductor substrate 10 is diced to divide the semiconductor substrate 10 into semiconductor devices having a predetermined chip size. Thereby, the semiconductor device is completed.

  As described above, in the method of manufacturing a semiconductor device according to the present embodiment, the foreign matter 90 on the surface of the protective tape 20 is adsorbed and removed by the foreign matter removing tape 30 and then the release tape 40 is attached to the surface of the protective tape 20. Then, by pulling the peeling tape 40, the peeling tape 40 and the protective tape 20 are integrally peeled from the semiconductor substrate 10. Since the protective tape 20 is not heated when the protective tape 20 is peeled off, the adhesive residue of the protective tape 20 does not remain on the upper surface 12 of the semiconductor substrate 10. For this reason, it is not necessary to wash the semiconductor substrate 10 after the peeling process. Therefore, a semiconductor device can be manufactured with high manufacturing efficiency, and the manufacturing cost of the semiconductor device can be reduced. In addition, since a cleaning step after the peeling step is not required, it is not necessary to process a waste liquid of the cleaning liquid used in the cleaning step. This also can reduce the manufacturing cost of the semiconductor device.

  Further, in the manufacturing method of the semiconductor device of this embodiment, the same kind of tape is used for the foreign matter removing tape 30 and the peeling tape 40. For this reason, it is not necessary to manage the foreign matter removing tape 30 and the peeling tape 40 separately. That is, since the peeling tape 40 used also in a prior art is used also as the foreign material removal tape 30, the kind of member used in a manufacturing process does not increase. For this reason, the burden which member management requires does not increase.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

FIG. 3 is a cross-sectional view of the semiconductor substrate 10 after the protective tape 20 is attached. Sectional drawing of the semiconductor substrate 10 after a grinding | polishing process. Sectional drawing of the semiconductor substrate 10 after a lower surface side semiconductor element structure formation process. FIG. 3 is a cross-sectional view of the semiconductor substrate 10 after the foreign matter removing tape 30 is attached. FIG. 3 is a cross-sectional view of the semiconductor substrate 10 during peeling of the foreign matter removing tape 30. FIG. 3 is a cross-sectional view of the semiconductor substrate 10 after the release tape 40 is attached. FIG. 3 is a cross-sectional view of the semiconductor substrate 10 during peeling of the protective tape 20.

Explanation of symbols

10: Semiconductor substrate 12: Upper surface 14: Lower surface 16: Impurity diffusion layer 18: Metal electrode 20: Protection tape 30: Foreign material removal tape 40: Release tape 90: Foreign material

Claims (2)

A method for peeling off a protective tape attached to a surface of a semiconductor substrate,
A foreign matter removing step of attaching a foreign matter removing tape to the surface of the protective tape, and then peeling the foreign matter removing tape from the surface of the protective tape;
After the foreign matter removing step, a peeling tape is applied to the surface of the protective tape, and then the peeling step of peeling the peeling tape and the protective tape together from the semiconductor substrate,
The peeling method of the protective tape characterized by having. A method for manufacturing a semiconductor device, comprising:
A thinning step of thinning the semiconductor substrate in a state where the protective tape is attached to the first surface of the semiconductor substrate;
After the thinning process, the foreign matter removing tape is attached to the surface of the protective tape, and then the foreign matter removing step of peeling the foreign matter removing tape from the surface of the protective tape;
After the foreign matter removing step, a peeling tape is applied to the surface of the protective tape, and then the peeling step of peeling the peeling tape and the protective tape together from the semiconductor substrate,
A method for manufacturing a semiconductor device, comprising:

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