JPH06209042A - Dicing tape for semiconductor wafer and separating method for chip - Google Patents

Abstract

PURPOSE:To obtain a dicing tape which can separate wafers into chips without using any conductive paste, etc., by making an electric current to flow to the wafers from a dicing blade. CONSTITUTION:This dicing tape used for holding semiconductor wafers stuck to the tape is constituted in such a way that a conductive high polymer layer 8a having conductivity in the direction of the sticking surface of the layer 8a is provided below a bonding agent layer 8b and, when semiconductor wafers are stuck to the tape, the wafers can be directly grounded through the high polymer layer 8a. Therefore, when the semiconductor wafers are cut by making an electric current flow to the wafers from a dicing blade, a discharging effect can be effectively obtained and the semiconductor wafers can be easily cut and, at the same time, the chip separating process can be simplified and the yield of chips can be improved, since no resistance exists other than that between the wafers and dicing blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer dicing tape which is used to hold a semiconductor wafer when the semiconductor wafer is separated into chips, and a chip separating method using the dicing tape.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a holding tape called a dicing tape used to hold a semiconductor wafer when the wafer is separated into chips. In FIG. 3, reference numeral 1 denotes a tape body, which has a structure in which an ultraviolet light photosensitive adhesive or a low-adhesive adhesive 1b is applied to the surface of a tape material 1a made of an insulating material. The adhesive 1b has a thickness of several μm and has sufficient adhesive force to hold the semiconductor wafer.

FIG. 4 is a top view showing a state of use of the dicing tape shown in FIG. 3, in which 1 is a dicing tape and 2 is a peripheral edge of the dicing tape 1 adhered to the peripheral edge of the dicing tape 1. Is a tape fixing ring for fixing. Reference numeral 3 is a semiconductor wafer adhered to the central portion of the dicing tape 1, and 4 is a conductive paste for drawing a ground from the periphery of the wafer 3 to the outside of the ring 2.

Next, the operation will be described. As shown in FIG. 5, together with the tape fixing ring 2, the semiconductor wafer 3 is adhered to the surface of the dicing tape 1 and the tape 1 is attracted to the table 5 of the dicing machine by vacuuming. The ring 2 is circulated from the surroundings to drop the ground on the table 5, and the dicing blade 6 connected to the (-) negative pole of the external pulse power source 7 applies a current to the wafer 3 to separate the chips.

[0005]

The conventional semiconductor wafer holding tape is constructed as described above, and when it is used in a chip separating method in which an electric current is applied to the wafer to cut it, the conductive paste 4 is used to draw out the ground. Therefore, there is a problem that the conductivity between the dicing blade and the ground is low and the wafer is difficult to be cut.

Further, since the conductive paste is applied to the peripheral portion of the surface of the wafer 3 to form the electrodes, the wafer 3 is contaminated, and the work of applying the conductive paste for each wafer is required, which is automated. There was a problem that it was difficult.

The present invention has been made to solve the above problems, and a semiconductor wafer adhered to the surface of a dicing tape is supplied with an electric current from a dicing blade to the wafer without using a conductive paste or the like. An object of the present invention is to provide a dicing tape that can be separated into individual chips, and a wafer separating method using the dicing tape.

[0008]

A dicing tape for a semiconductor wafer according to the present invention is a dicing tape for adhering and holding a semiconductor wafer, which is electrically conductive in a lower layer of an adhesive in a direction perpendicular to the adhering surface. It is provided with a conductive polymer.

Further, the dicing tape according to the present invention is an adhesive whose adhesive force is lowered by exposing the above adhesive to ultraviolet light.

Further, in the method of separating the chips of the semiconductor wafer, a semiconductor tape is adhered to a lower layer of the adhesive by using a holding tape having a conductive polymer having conductivity in a direction perpendicular to the bonding surface, and the holding tape is attached. With the ground as the ground, a current is passed from the dicing blade to the wafer to separate the chips.

[0011]

Since the dicing tape according to the present invention has conductivity in the direction perpendicular to the bonding surface, when a semiconductor wafer is cut by a method of passing a current from the dicing blade to the wafer, the dicing tape and the ground are separated from each other. Low conductivity makes wafers easy to cut,
Further, since it is not necessary to use the conductive paste, it is possible to prevent the wafer from being contaminated, and it is possible to easily automate the dicing process.

Further, in the dicing tape according to the present invention, since the adhesive is an adhesive whose adhesive strength is reduced by exposing it to ultraviolet light, the chips can be easily peeled off after the dicing step.

Further, according to the semiconductor wafer chip separating method of the present invention, the semiconductor wafer is bonded by using the holding tape having the conductive polymer having conductivity in the direction perpendicular to the bonding surface as the lower layer of the adhesive. Then, by using the holding tape as a ground, an electric current is passed from the dicing blade to the wafer to separate the chips, so that the wafer is easily cut, and an electric current is passed from the dicing blade to the wafer to separate the semiconductor wafer. The yield of the chip separation process using the cutting method can be improved.

[0014]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a dicing tape according to a first embodiment of the present invention. Reference numeral 8 denotes a holding tape body, which is a lower layer of the adhesive 8a and which has conductivity in a direction perpendicular to the bonding surface. It has a structure using a conductive polymer 8b such as polythiophene, poly-3-methylthiophene, and polyacetylene.

Next, the operation will be described. As shown in FIG. 2, together with the tape fixing ring 2, the semiconductor wafer 3 is adhered to the surface of the dicing tape 8 and the tape is attracted to the table 5 of the dicing machine which has been dropped to the ground by vacuuming.

Next, chip separation is performed while applying a pulse current to the wafer 3 by the dicing blade 6 which is connected to the (-) negative electrode of the external pulse power source 7 and which is made of, for example, Ni as a main material.

Here, the adhesive 8b has a thickness of several .mu.m and has sufficient adhesive force to hold the semiconductor wafer. Usually, the adhesive 8b does not completely cover the tape material but has unevenness. Therefore, the back surface of the semiconductor wafer 3 adhered on the tape should be in direct contact with the conductive polymer 8b at the uneven portion. Becomes Since an electrode is formed on the back surface of the semiconductor wafer 3 by gold plating or the like, this electrode is grounded to the dicing table 5 by the conductive polymer 8b. Therefore, in this embodiment, the conductivity between the dicing blade and the ground is lower than in the conventional case where the conductive paste is used to ground the periphery, and the semiconductor wafer is efficiently cut.

As described above, according to this embodiment, since the lower layer of the adhesive has a structure having conductivity perpendicular to the bonding surface, the pulse current during dicing has resistance only between the wafer and the dicing blade, The discharge effect can be effectively obtained, and the process yield can be significantly improved. Further, since it is not necessary to apply electrodes from the periphery of the wafer surface by using a conductive paste or the like for each wafer, the wafer is not contaminated, and the process of performing the contamination prevention process on the wafer can be reduced. Also, automation of the dicing process can be easily realized because there is no conductive paste application work.

Example 2. In addition, in the dicing tape 8 shown in FIG. 1, when an adhesive whose adhesive strength is reduced by being exposed to ultraviolet light is used as the adhesive 8a,
By irradiating with ultraviolet light after the completion of the dicing process, the separated chips can be easily peeled off from the dicing tape, and the workability can be improved.

[0020]

As described above, according to the present invention, since the dicing tape has a structure in which the adhesive lower layer has conductivity perpendicular to the adhesive surface, a method of cutting by applying an electric current from the dicing blade to the wafer is used. When cutting a semiconductor wafer with, there is no resistance other than between the wafer and the dicing blade, effective discharge effect can be obtained, the semiconductor wafer can be easily cut, and it is necessary to perform contamination prevention processing etc. on the wafer. As a result, the chip separation process can be simplified, automation can be easily realized, and the yield of the chip separation process can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conductive dicing tape.

FIG. 2 is a cutting state diagram using a conductive dicing tape.

FIG. 3 is a sectional view of a dicing tape.

FIG. 4 is a diagram showing a state in which a ground is drawn using a conductive paste.

FIG. 5 is a cutting state diagram using a conductive paste.

[Explanation of symbols]

 1 Dicing Tape 1a Tape Material 1b Adhesive 2 Tape Fixing Ring 3 Semiconductor Wafer 4 Conductive Paste 5 Dicing Table 6 Dicing Blade 7 External Pulse Power Supply 8 Conductive Dicing Tape 8a Conductive Polymer 8b Adhesive

Claims (3)

[Claims] 1. A dicing tape of a semiconductor wafer for adhering a semiconductor wafer to a surface and cutting the semiconductor wafer, wherein the dicing tape comprises an adhesive for holding the semiconductor wafer, and a lower layer of the adhesive. A dicing tape for a semiconductor wafer, comprising: a conductive polymer, which is provided on the adhesive surface and has a conductive polymer in a direction perpendicular to the adhesive surface. 2. The semiconductor wafer holding tape according to claim 1, wherein the adhesive is an adhesive whose adhesive strength is reduced by exposure to ultraviolet light. 3. A chip separating method for separating a semiconductor wafer into chips, wherein a dicing tape having an adhesive lower layer and a conductive polymer for giving conductivity in a direction perpendicular to the adhesive surface is used. And a step of applying a current from a dicing blade to the semiconductor wafer to separate the wafer into chips by using the dicing tape as a ground potential.