Process for producing semiconductor chip

Details Process for producing semiconductor chip Process for producing semiconductor chip

2001-02-06

2002-08-20

Nelms, David (Department: 2818)

Semiconductor device manufacturing: process

Semiconductor substrate dicing

Reexamination Certificate

active

06436795

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for producing semiconductor chips. More particularly, the present invention relates to a process for producing semiconductor chips with high yield without damaging the semiconductor chips.
BACKGROUND OF THE INVENTION
In recent years, the spread of IC cards has been promoted, and accordingly the reduction of the thickness thereof is increasingly demanded. Thus, it is now needed to reduce the thickness of semiconductor chips from the conventional about 350 &mgr;m to 50-100 &mgr;m or less.
In the production of the above semiconductor chips, it is common practice to first fix a semiconductor wafer on a pressure sensitive adhesive sheet known as a dicing tape, subsequently perform required processing (dicing, etc.) to thereby form semiconductor chips and thereafter pick up the semiconductor chips while thrusting them up by applying a thrust pin to the back (base side) of the dicing tape. However, the semiconductor chips of reduced thickness are so brittle that they are occasionally damaged by the impact of the thrusting.
The applicant, in Japanese Patent Application No. 11(1999)-109806, has proposed a technique utilizing a pressure sensitive adhesive double coated sheet including a heat shrink base. In this technique, first a semiconductor wafer is fixed on a hard plate by means of the pressure sensitive adhesive double coated sheet, and subsequently required processing is performed to thereby form the semiconductor wafer into semiconductor chips. Thereafter, the pressure sensitive adhesive double coated sheet is heated to thereby effect a heat shrink of the base of the double coated sheet with the result that the pressure sensitive adhesive layer of the double coated sheet is deformed. The deformation of the pressure sensitive adhesive layer reduces the area of contact of the semiconductor chips with the pressure sensitive adhesive layer to thereby result in reduction of adherence. This facilitates the pickup of the semiconductor chips. However, in this process, it is requisite to dice the semiconductor wafer from the back thereof. In the event of chip cracking, it is likely to occur at the circuit surface thereof to thereby invite the danger of lowering the yield of semiconductor chips.
The present invention has been made in view of the above state of the prior art. Thus, it is an object of the present invention to provide a process for producing semiconductor chips with high yield while avoiding the damage to the semiconductor chips, such as chip splitting or cracking, while working a semiconductor wafer having extremely reduced thickness.
SUMMARY OF THE INVENTION
The process for producing semiconductor chips according to the present invention comprises the steps of:
providing a semiconductor wafer having a surface overlaid with circuits;
forming an arrangement wherein a back of the semiconductor wafer is fixed on a dicing tape and wherein a pressure sensitive adhesive double coated sheet is stuck to a circuit surface of the semiconductor wafer, this pressure sensitive adhesive double coated sheet comprising a shrinkable base having its both sides overlaid with pressure sensitive adhesive layers, at least one of these pressure sensitive adhesive layers composed of an energy radiation curable pressure sensitive adhesive;
dicing the semiconductor wafer together with the pressure sensitive adhesive double coated sheet by each circuit to thereby form semiconductor chips;
fixing the semiconductor chips on a transparent hard plate by adherence of the pressure sensitive adhesive layer of the pressure sensitive adhesive double coated sheet remote from the semiconductor chips;
stripping the dicing tape from the semiconductor chips;
irradiating the pressure sensitive adhesive double coated sheet, from the transparent hard plate side, with energy radiation;
shrinking the shrinkable base of the pressure sensitive adhesive double coated sheet; and
picking the semiconductor chips up.
In the present invention, it is preferred that both the pressure sensitive adhesive layers of the pressure sensitive adhesive double coated sheet be composed of an energy radiation curable pressure sensitive adhesive. Further, in the present invention, it is preferred that, after the stripping of the dicing tape from the semiconductor chips but before the irradiating of the pressure sensitive adhesive double coated sheet, from the transparent hard plate side, with energy radiation, backs of the semiconductor chips exposed by the stripping of the dicing tape are ground.
The above present invention enables producing semiconductor chips of extremely reduced thickness in high production efficiency while minimizing the damaging thereof.


REFERENCES:
patent: 5705016 (1998-01-01), Senoo et al.
patent: 5714029 (1998-02-01), Uemura et al.
patent: 6007920 (1999-12-01), Umehara et al.
patent: 6140151 (2000-10-01), Akram
patent: 6176966 (2001-01-01), Tsujimoto et al.
patent: 2 340 772 (2000-03-01), None
patent: 60(1985)-196956 (1985-10-01), None
patent: 60(1985)-223139 (1985-11-01), None
patent: 5(1993)-32946 (1993-02-01), None
patent: 8(1996)-27239 (1996-01-01), None
patent: 11(1999)-109806 (1999-04-01), None

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