JP2859412B2 - Method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention [Table of Contents] ・ Overview ・ Industrial application fields ・ Prior art (FIG. 4) ・ Problems to be solved by the invention ・ Means for solving the problems ・ Function ・ Examples (No. (FIGS. 1 to 3) Effects of the Invention [Overview] The present invention relates to a method for manufacturing a semiconductor device, and more specifically, to a method for manufacturing a semiconductor device including a dicing step. An object of the present invention is to provide a method of manufacturing a semiconductor device capable of preventing the semiconductor device from adhering to a bonding pad, and after forming a processing film on an element formation surface of the wafer before dicing for separating the wafer into chips. And converting the surface of the electrode or the bonding pad formed on the element formation surface to water repellency by removing the treatment film.

[Industrial applications]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device including a dicing step.

[Conventional technology]

A conventional method of manufacturing a semiconductor device including a dicing step will be described with reference to FIGS. 3 and 4 (a) to (c).

FIG. 4 (a) is a cross-sectional view showing the wafer before dicing, and FIG. 3 shows an overall view. In FIG. 4 (a), 1
Is a wafer, 2 is a dicing region cut when the wafer is separated into chips, 3 is an element formation region (chip region) divided by the dicing region 2, 4 is an insulating film in the element formation region 3, and 5 is The bonding pad is made of gold (Au) on the insulating film 4.

When the wafer 1 is separated into chips, first, the holding adhesive tape 6 is attached to the back surface of the wafer 1 so that the chips separated by dicing do not fall apart, and then the surface on which the holding adhesive tape 6 is attached and the mounting table The wafer 1 is mounted on a mounting table of a dicer (not shown) such that the wafer 1 and the wafer 1 face each other.

Next, as shown in FIG.
The dicing blade 18 is moved along the dicing region 2 while spraying cleaning water on the contact surface between the dicing blade 18 and the dicing region 2 to cool the chip 18 and clean the chips, thereby cutting the dicing region 2. At this time, if static electricity is generated on the bonding pad 5 or the like on the wafer 1, a wafer piece generated by cutting the wafer 1 may adhere to the bonding pad 5. This is performed while removing static electricity from the bonding pad 5 and the like. In this way,
When the wafer 1 is separated into the chips 1a and 1b, the dicing step is completed.

When the dicing area 2 is half-cut,
After the dicing, cracking is performed to separate the wafer 1 into chips 1a and 1b.

[Problems to be solved by the invention]

By the way, when the bonding pad 5 is hydrophilic, the cleaning water containing the wafer pieces remains on the bonding pad 5. In particular, when the bonding pad 5 is made of gold (Au), this tendency is strong, and the remaining cleaning water 7a, 7b cannot be easily removed as shown in FIG. 4 (c). For this reason, a wafer piece remains on the bonding pad 5,
When wire bonding is performed later, there is a problem that the wires are not properly bonded, or if the wafer pieces are peeled off after assembling the chips 1a and 1b into a package or the like, a short circuit between the electrodes or the wirings is caused.

The present invention has been made in view of such a conventional problem, and provides a method of manufacturing a semiconductor device capable of preventing chips such as wafer pieces generated at the time of dicing from adhering to bonding pads 5 and the like. It is intended to do so.

[Means for solving the problem]

The above problem is firstly formed on an element formation surface by forming a processing film on an element formation surface of the wafer before dicing for separating the wafer into chips, and then removing the processing film. This is achieved by a method for manufacturing a semiconductor device, characterized in that the surface of an electrode or a bonding pad is converted to water-repellent. Second, the electrode or the bonding pad is an electrode or a bonding pad made of Au. Third, achieved by the method of manufacturing a semiconductor device according to the first or second invention, wherein the processing film is an adhesive tape. Fourth, the treatment film is an ultraviolet curable tape which is cured by irradiation of ultraviolet light, or a thermosetting tape which is cured by heating. Fifthly, the processing film is an ultraviolet-curable resin film or a thermosetting resin film formed by applying a solution. This is achieved by the method of manufacturing a semiconductor device according to the first or second invention.

[Action]

According to the investigation of the present inventor, if dicing is performed while spraying a cleaning liquid onto the wafer after the ultraviolet curable tape or the thermosetting tape is attached to and removed from the element forming surface of the wafer, the wafer piece is formed of the wafer after the dicing. It was found that the ratio remaining on the surface was significantly reduced.

This is considered to be due to the following reasons. That is, after patterning of the bonding pad, hydroxyl groups (OH groups) and carbonyl groups (COOH groups) contained in the used resist are particularly likely to remain on the Au surface, and a thin film of these functional groups is formed on the Au surface. Therefore, it is considered that the bonding pad becomes hydrophilic. Therefore, after attaching the ultraviolet curable tape or the thermosetting tape, the tape is peeled off, and the electrode or the bonding pad, especially the electrode made of Au or the hydrophilic film-shaped one formed on the surface of the bonding pad is removed. Because the adhesive force of the tape removed the tape along with the peeling of the tape and converted the surface of the electrodes and bonding pads to water repellency, the cleaning water contained in the wafer pieces generated during dicing no longer remained on the surfaces of the electrodes and bonding pads. It is considered to be.

Such functions and effects are present not only in ultraviolet-curable tapes and thermosetting tapes, but also in ordinary adhesive tapes and ultraviolet-curable resin films formed by applying a solution or thermosetting resin films.

Of these, in particular, UV-curable tapes or thermosetting tapes, UV-curable resin films, or thermosetting resin films are used to cure the resin as an adhesive with ultraviolet light or heat to easily remove the tape or film from the wafer. It is useful because you can do it.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1E are cross-sectional views illustrating a method for manufacturing a semiconductor device including a dicing step according to an embodiment of the present invention.

FIG. 3A shows the wafer 8 before dicing, and FIG. 3 shows the entire wafer 8 in a top view. In FIG. 1 (a), reference numeral 8 denotes a wafer, 9 denotes a dicing area cut when the wafer is separated into chips, 10a and 10b denote element forming areas (chip areas) divided by the dicing area 9, 11a , 11b are adjacent element forming regions 10a, 10b, respectively.
The insulating films 12a and 12b in the adjacent element forming regions 10
A bonding pad 13 made of gold (Au) on the insulating films 11a and 11b a and 10b, and a holding adhesive tape 13 attached to the back surface of the wafer 1 so that chips separated by dicing do not fall apart.

When such a wafer 8 is separated into chips, a hydroxyl group (OH group) or a carbonyl group (COOH) contained in a resist used for patterning the bonding pads 12a and 12b.
Group) tends to remain on the surface of Au in particular, and it is considered that the bonding pads 12a and 12b are hydrophilic because thin films of these functional groups and the like are formed on the surface of Au. As shown in FIG.
An ultraviolet-curing tape (treatment film) 14 having an acrylic resin film 14b as an adhesive which is cured by irradiation of ultraviolet light on the surface of a is attached to the element forming surface of such a wafer 8 to make good contact. Then, as shown in FIG.
When the entire ultraviolet curing tape 14 is irradiated with ultraviolet rays,
Since the acrylic resin film 14b of the ultraviolet-curable tape 14 is cured and can be easily separated from the wafer 8, the ultraviolet-curable tape 14 is separated from the wafer 8. As a result, the surfaces of the electrodes and the bonding pads are converted to water repellency. This is considered to be because the hydrophilic film-like material formed on the surfaces of the bonding pads 12a and 12b made of Au is removed together with the peeling of the ultraviolet-curable tape 14, but the clear reason is unknown. .

Next, such a wafer 8 is mounted on a mounting table of a dicer (not shown) such that the surface on which the holding adhesive tape 13 is adhered and the mounting table face each other. Next, the dicing blade 16 is moved along the dicing region 9 while spraying cleaning water composed of water on the contact surface between the dicing blade 16 and the dicing region 9 for cooling the dicing plate 16 and cleaning chips. Then, the dicing region 9 is cut off (FIG. 4D). At this time, the cleaning water containing the cut wafer pieces flows on the surface of the wafer 8, but the surfaces of the bonding pads 12a and 12b are also water-repellent. Bonding pad 12
a, 12b immediately flows off from above, and the bonding pad 12
It does not remain long on a, 12b. Note that bonding pad 1
In order to remove static electricity generated in 2a, 12b, etc., usually, a washing water having a specific resistance as low as possible is used.

When the wafer 8 is separated into the chips 8a and 8b in this way, the dicing process is completed (FIG. 4E). In addition,
When the dicing region 9 is half-cut, after the dicing is completed, cracking is performed so that the wafer 8 is
Separate into b.

In the chips 8a and 8b thus separated, the wafer pieces included in the cleaning water flow away from the wafer 8 together with the cleaning water during dicing, so that the wafer pieces are subjected to the dicing on the surface of the wafer, particularly the bonding pads 12a. , 12b, etc., can be greatly reduced.
This prevents wire bonding defects from occurring,
Since a short circuit between wirings or the like can be prevented, the yield of a semiconductor device is improved.

In the above embodiment, an ultraviolet curable tape is used as a treatment film for converting hydrophilicity to water repellency, but a normal pressure-sensitive adhesive tape or thermosetting tape, or a second film formed by applying a solution. UV curable resin film 1 shown in Fig. 2
7, or a thermosetting resin film can be used. Among them, particularly, an ultraviolet-curable tape or a thermosetting tape, an ultraviolet-curable resin film, or a thermosetting resin film can be easily removed from the wafer by curing the tape or the film with ultraviolet light or heat. So useful.

〔The invention's effect〕

As described above, according to the method for manufacturing a semiconductor device of the present invention, an ultraviolet-curable tape or a thermosetting tape, an ultraviolet-curable resin film or a thermosetting resin film, or a normal adhesive tape, After bonding or forming on the surface,
Since this is removed, the surface of the wafer, particularly the surface of the bonding pad made of Au, is converted to water repellency. Therefore, after dicing, the wafer pieces and the like are washed out of the wafer together with the cleaning liquid, and can be prevented from remaining and adhering on the bonding pads and the like.

As a result, it is possible to prevent the occurrence of wire bonding defects and to prevent short-circuiting between wirings and the like.
It contributes to improvement in the yield of semiconductor devices.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a dicing step according to an embodiment of the present invention, FIG. 2 is a cross-sectional view illustrating another embodiment of the present invention, FIG. 3 is a top view of a wafer to be diced, FIG. 4 is a cross-sectional view illustrating a dicing process of a conventional example. [Description of symbols] 1,8 ... wafer, 2,9 ... dicing area, 3a, 3b, 10a, 10b ...
Element formation area (chip area), 4a, 4b, 11a, 11b ... insulating film, 5a, 5b, 12a, 12b ... bonding pad, 6, 13 ... holding adhesive tape, 7, 7a, 7b, 15 ... cleaning water, 14: UV curable tape (treatment film), 14a: Polyethylene film, 14b: Acrylic resin film, 16, 18: Dicing blade, 17: UV curable resin film (treatment film).

Claims (5)

(57) [Claims] An electrode or a bonding formed on an element formation surface by forming a processing film on an element formation surface of the wafer before dicing for separating the wafer into chips, and removing the processing film. A method for manufacturing a semiconductor device, comprising converting a surface of a pad to water repellency. 2. The method according to claim 1, wherein the electrode or the bonding pad is an electrode or a bonding pad made of Au. 3. The method according to claim 1, wherein the processing film is an adhesive tape. 4. The method for manufacturing a semiconductor device according to claim 1, wherein said treatment film is an ultraviolet curable tape which is cured by irradiation of ultraviolet rays, or a thermosetting tape which is cured by heating. . 5. The method for manufacturing a semiconductor device according to claim 1, wherein said processing film is an ultraviolet curable resin film or a thermosetting resin film formed by applying a solution.