JPH03167839A - Dicing method - Google Patents

Abstract

PURPOSE:To prevent chips or undefined parts from scattering by dicing a wafer held between two sheets of ultraviolet curing type adhesive tape. CONSTITUTION:Dicing is carried out with ultraviolet curing type adhesive tapes 7, 8 applied to both sides of a wafer 6. Then, after adhesion of the tape 7 is weakened through irradiation of ultraviolet rays, a third adhesive tape 12 is applied. When the tape 12 is peeled off, the tape 7 is also peeled off together with the tape 12, thereby realizing dicing method which prevents chips and undefined parts from scattering.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dicing method for dividing a semiconductor wafer into individual semiconductor pellets.

Conventionally, semiconductor devices such as commercially available transistors are manufactured by mounting semiconductor pellets on heat sinks or lead frames.

Here, the semiconductor pellet is obtained by forming a large number of semiconductor elements with the same pattern on one wafer at once, and dividing the semiconductor elements from adjacent parts.

A method for obtaining semiconductor pellets by dividing a wafer will be described below with reference to FIGS. 11 to 13. First, as shown in FIG. 11, an adhesive tape 2 is attached to a wafer 1. Then, as shown in FIG. 12, the wafer 1 is divided into grid shapes using a dicing saw 3 to form pellets 4. Thereafter, the pellet 4 is peeled off from the adhesive sheet 2 and mounted on a heat dissipation board (not shown) or the like.

By the way, if the adhesive sheet 2 has a high adhesive strength, it will be difficult to peel off the pellets 4, which will hinder the pellet supply operation, so an ultraviolet curing type adhesive sheet is used as the adhesive sheet 2.
After dicing, as shown in FIG.
The adhesive surface of the adhesive sheet 2 is irradiated with ultraviolet rays to reduce the adhesive strength and facilitate peeling.

However, in the conventional dicing method described above, cutting debris adheres to the pellet surface during dicing, and irregularly shaped parts of the wafer's outer circumferential surface scatter, which adheres to the pellet surface and interferes with normal pellet extraction, causing short circuits and other problems. There was a problem.

The second invention was proposed with the aim of solving the above problem, and involves attaching ultraviolet curing adhesive tape to both sides of the wafer, dicing from one side, and irradiating the dicing side with ultraviolet rays to reduce the adhesiveness. To provide a dicing method characterized in that the adhesive tape on one side is then peeled off.

Furthermore, according to the present invention, since the wafer is sandwiched between two ultraviolet-curable adhesive tapes during dicing, it is possible to prevent irregularly shaped parts from scattering when cutting debris scatters.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. In the figure, 6 is a wafer, 7 and 8 are a pair of ultraviolet curing tapes, 9 is a dicing plate, 10 is a pellet formed by dividing the wafer 6, and 11 is an ultraviolet irradiation lamp.

First, as shown in FIG. 1, first and second ultraviolet curing adhesive tapes 7 and 8 are attached to both sides of a wafer 6.

Next, as shown in FIG. 2, dicing is performed from the surface of the first adhesive tape 7 using a dicing saw 9 to form pellets 10. Thereby, it is possible to prevent irregularly shaped portions from scattering when cutting debris is scattered onto the wafer during dicing.

Next, as shown in FIG. 3, the dicing surface is irradiated with ultraviolet light from an ultraviolet irradiation lamp 11 to reduce the adhesive strength of the adhesive tape 7.

At this time, since the adhesive tape 7 is cut at the same time as the pellet, the adhesive tape of the same size is attached to the surface of the pellet. Therefore, by pasting the third adhesive tape 12 as shown in FIG. 4 and peeling off the third adhesive tape 12 as shown in FIG. 5, the adhesive tape 7 whose adhesive strength has decreased is peeled off from the pellet surface. can.

A second embodiment will be explained below with reference to FIGS. 6 to 10.

In the figure, lla and llb are ultraviolet irradiation lamps,
1 3 a and 1 3 b are used to selectively irradiate the first and second adhesive tapes 7 and 8 with ultraviolet rays using first and second masks, which have a positive and negative relationship with each other, and The mask 13a prevents irradiation of irregularly shaped portions around the wafer.

First, as shown in FIGS. 6 and 7, adhesive tapes 7 and 8 are attached to both sides of a wafer 6, and pellets 9 are formed by guising using a guising saw 9.

Next, as shown in FIG. 8, the first and second masks 13a, 13
b as the first and second adhesive tapes, and ultraviolet irradiation lamp l
Light of la and llb is irradiated through the first and second masks 13a and 13b. As a result, the adhesiveness of the irregularly shaped portion of the first adhesive tape 7 around the wafer remains, and the adhesiveness of the irregularly shaped portion of the second adhesive tape 8 around the wafer is reduced.

Next, as shown in FIGS. 9 and 10, the third adhesive tape 12 is pasted on the first adhesive tape 7, and when peeled off, the first adhesive tape 7 is separated from the pellet by removing the irregularly shaped part around the wafer. At the same time as the peeling, the irregularly shaped portion around the wafer can be peeled off from the second adhesive tape 8.

This prevents irregularly shaped parts from scattering on the wafer during dicing.

In both the first and second embodiments, the second adhesive tape 8 is irradiated with ultraviolet rays to facilitate the peeling of the pellets, as described in the prior art (FIG. 13).

As explained above, according to this invention, during dicing,
This prevents irregularly shaped parts from scattering on the wafer.

Additionally, irregularly shaped portions can be easily removed.

[Brief explanation of the drawing]

1 to 5 are side views showing a first embodiment of the present invention, FIGS. 6 to 10 are side sectional views showing a second embodiment of the invention, and FIGS. 11 to 13. The figure is a side cross-sectional view showing the dicing method that is the premise of the present invention. 6... Wafer, 7,8... Ultraviolet curing adhesive tape, 11,lla,
llb...ultraviolet irradiation lamp, 12...third adhesive tape.

Claims (1)

[Claims] Dicing characterized by pasting ultraviolet curing adhesive tape on both sides of the wafer, dicing from one side, irradiating the dicing side with ultraviolet rays to reduce adhesiveness, and then peeling off the adhesive tape on one side. Method.