JPS634642A - Method for dividing wafer - Google Patents

Abstract

PURPOSE:To prevent a mistake on work by forming a photosensitive section, in which reflected beams are varied visually by the irradiation of beams, to an adhesive tape, cladding a wafer to the adhesive tape, conducting the irradiation of predetermined beams and picking up a pellet at a prescribed position. CONSTITUTION:A discriminating seal 4 is stuck to a section except the coating region of a wafer 1 on a surface on the side reverse to an adhesive surface, on which the wafer 1 is cladded, the rear side of a UV tape 3. With the discriminating seal 4, a substance such as a photosensitive material is applied onto the surface of the seal, and the rear of the seal has adhesive structure. A material having the large degree of visual alteration such as a material, a color of which changes to blue from red by the irradiation of ultraviolet rays, is preferable as the photosensitive material cladded to the discriminating seal 4 at that time. Since the color of a photosensitive surface in the discriminating seal 4 varies after the irradiation of ultraviolet-rays, a frame 2 is discriminated extremely easily after the irradiation of ultraviolet-rays 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a technique that is effective when used for dividing semiconductor wafers in the manufacture of semiconductor devices.

[Conventional technology]

A method for dividing a semiconductor wafer is described, for example, in RRC Mounting Techniques J, published by Kogyo Kenkyukai Co., Ltd., January 15, 1980, pages 100 to 101. Here, the wafer is adhered to a plastic adhesive tape attached to a frame with a predetermined tensile strength, the wafer is divided (diced) in this state, and then the pellets are separated from the back side of the tape using a push-up tool. A technique for pushing up and picking up is introduced.

The present inventor studied wafer dividing technology. The following are the techniques studied by the present inventor, and the outline thereof is as follows.

In the above-mentioned wafer dividing step, the tape to which the wafer is attached needs to have strong adhesive strength during dicing of the wafer. In other words, if the adhesive strength of the tape decreases during dicing, external force is applied to the wafer due to the operation of the dicing blade, causing the tape to separate from the frame and cause the wafer to become misaligned on the frame. be. On the other hand, after dicing, that is, when picking pellets (chips, gui), the adhesive strength of the tape to the wafer should be low.The reason is that the pellets can be easily removed from the tape by pressing the pick-up bin. This is to allow separation and smooth adsorption by the collet.

Therefore, a technology is needed to change the adhesive strength of the adhesive tape before and after dicing. As such a technique, it is conceivable to use an adhesive sheet having a structure in which a tape base is covered with an adhesive material whose adhesive strength decreases when irradiated with ultraviolet rays. That is, during dicing, dicing is performed with a blade while maintaining strong adhesive strength, and immediately after dicing, a predetermined portion of the tape is irradiated with ultraviolet rays for a predetermined period of time to reduce the adhesive strength of the tape, thereby reducing the adhesive strength of the tape. This makes it easy to pick up.

[Problem that the invention seeks to solve]

However, when the above technology is realized, it is difficult to judge whether or not the frame has already been irradiated with ultraviolet rays based only on the appearance of the frame to which the wafer is attached. Even though this has not been done, there is a possibility that a frame may be mistakenly transferred to the pick amplifier process because it has been irradiated with ultraviolet rays, making it difficult to pick up the pellets. many.

The present invention has been made focusing on the above problems,
The purpose is to prevent operational errors and provide highly reliable wafer dividing technology.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, the adhesive tape is equipped with a photosensitive part where the reflected light visually changes when irradiated with light, the adhesive tape is coated with sea urchin/%, and a predetermined light is irradiated to pick up pellets at a predetermined location. be.

[Effect]

According to the above-mentioned means, it is possible to very easily determine whether or not a predetermined light is irradiated based on a visual change in the photosensitive area of the adhesive tape, thereby preventing operational errors and realizing a highly reliable wafer dividing process. be able to.

〔Example〕

FIGS. 1 fal to +c+ are schematic explanatory diagrams sequentially showing a Ueno\ dividing method according to an embodiment of the present invention, and FIG. 2 is a plan view of a frame showing a state in which UNO/% is pasted.

The wafer dividing process of this embodiment includes a dicing process in which the wafer is diced, an irradiation process in which ultraviolet rays are irradiated,
It consists of a pick-up process to take out the pellets, and each of these processes is performed by a dicing mechanism A, an irradiation mechanism B,
and a pickup mechanism C.

The wafer 1 is provided in a frame 2 as shown in FIG.
Violet Tape), that is, a transparent plastic tape with an adhesive surface whose adhesive strength decreases when irradiated with ultraviolet rays is cut into a predetermined shape and stretched. The wafer 1 is attached with the formation surface facing upward.

The wafer l of this embodiment has a plurality of regions of pellets 1a formed with a predetermined circuit formed on a silicon substrate in the vertical and horizontal directions, and each pellet 1a is configured as an element having a memory capacity of, for example, 1 megabit. has been done.

In addition, in this embodiment, an identification sticker as shown in FIG. 4
is attached. This discrimination seal 4 has, for example, a photosensitive material adhered to the surface of the seal, and the back surface of the seal has an adhesive structure. Here, the photosensitive material adhered to this identification sticker 4 is one that visually changes in response to a predetermined wavelength of ultraviolet rays, and specifically, a material that changes color from red to blue when irradiated with ultraviolet rays. It is preferable that the degree of visual change is large.

In addition, as for the UV wavelength that reacts with UV tape 3 described below,
It is desirable that the UV wavelength be the same as or similar to the wavelength of the ultraviolet light used to change the adhesive strength of the UV light.

Specifically, for example, when the ultraviolet wavelength that changes the adhesive strength of the UV tape 3 is about 365 nm, the discrimination sticker 4 coated with a photosensitive material that changes color when irradiated with ultraviolet wavelengths close to this is used. be able to.

When the frame 2 is placed at a predetermined position on the dicing stage 5 of the dicing mechanism A by a transfer means (not shown), the disc-shaped dicing blade 6 is lowered to a predetermined position on the wafer 1 while rotating at high speed. The dicing operation of the wafer l is performed by moving in the horizontal direction (Fig. 1 (
at).

Here, the dicing of this embodiment is not so-called full dicing in which the front surface of the wafer 1 is completely separated from the back surface of the wafer 1. Instead, each pellet 1a is formed into a block shape by leaving a thickness of, for example, about 20 μm near the back surface of the wafer 1. This is so-called semi-dicing, in which cuts are formed so that the parts are connected to each other.

Furthermore, although the above dicing is performed along the boundaries of each pellet 1a, TEG (Testing Element
On a wafer (not shown) in which an extra region such as a loop (roup) section is formed at t, dicing is performed along this 720 section.

After the dicing is completed, the frame 2 is moved to the irradiation mechanism B.
sent to.

The irradiation mechanism B has an irradiation stage 7 that holds the frame 2 with the element forming surface of the wafer 1 facing upward.
With the frame 2 placed on this irradiation stage 7,
The structure is such that ultraviolet light 9 is irradiated from below by an irradiation lamp 8 through an irradiation window 7a provided on the irradiation stage 7.

Here, the irradiation window 7a allows the irradiation lamp 8 to cover a slightly wider area than the adhered portion of the wafer 1 on the back side of the UV tape 3.
Similarly, the photosensitive surface of the discrimination sticker 4 is also exposed to the irradiation lamp 8 (FIG. 1(bl)).

Therefore, in this state, the ultraviolet light 9 is
When irradiation is performed, the adhesive force of the adhesive surface of the UV tape 3 is reduced over a slightly wider area than the wafer 1, and the color of the photosensitive surface of the discrimination sticker 4 also changes due to the influence of the irradiation with the ultraviolet rays 9. - On the other hand, the adhesive portion of the UV tape 3 with the frame 2 is blocked by the irradiation stage 7 and is not directly irradiated with the ultraviolet rays 9, so that a strong adhesive force is maintained.

Here, the frame 2 taken out from above the irradiation stage 7
There is no difference in appearance from the one before irradiation with ultraviolet rays 9. Therefore, it becomes difficult to distinguish between frame 2 before irradiation and frame 2 after irradiation, and they may be confused and transferred to the next process. However, according to this embodiment, the color of the photosensitive surface of the identification sticker 4 changes after irradiation with the ultraviolet rays 9 as described above, so it is extremely easy to identify the frame 2 after the irradiation with the ultraviolet rays 9. be.

In this way, the frame 2 that has been confirmed to have been irradiated with the ultraviolet rays 9 is transferred to the pickup mechanism C.

In the pick amplifier mechanism C, a push-up jig 11 provided with a vacuum suction hole 11a is located below the frame 2 fixed by the fixing means 10.
1 is located at a predetermined position, vacuum suction is performed from the vacuum suction hole 11a, and a predetermined pellet 1a is suctioned from the back side of the UV tape 3. This vacuum suction is performed using the push-up jig 1.
This is done in order to prevent positional deviation between 1 and 1a, and the pin 12 is pushed up inside the vacuum suction hole 11a while maintaining this vacuum suction state, and the pin 12 is raised to a predetermined position of 1a. Push up the back.

With this operation of the push-up pin 12, UV
The pellet 1a pushed up from the adhesive surface of the tape 3 is
A collet 13 located above the frame 2 is lowered and held by vacuum suction. At this time, in this embodiment, the adhesive surface of the pellet 1a and the UV tape 3 is irradiated with ultraviolet rays 9, so that the adhesive force of the pellet 1a is increased.
The condition has fallen to a level suitable for withdrawal.

Therefore, the pellets la are easily separated from the adhesive surface of the UV tape 3 by the operation of the push-up bottle 12 and collet 13.

Therefore, it is possible to prevent mistakes in picking up the pellets la due to strong adhesion.

The pellets 1a picked up as described above are sent to a non-oral storage jig or a bonding position of a pellet bonder to complete the wafer dividing process.

As described above, according to this embodiment, the following effects can be obtained.

(1) By installing a photosensitive part on the tape whose adhesive strength changes when irradiated with a predetermined light, along with the wafer, whose reflected light changes visually when the predetermined light is irradiated, it is possible to easily determine whether or not the predetermined light has been irradiated. This prevents work errors.

(2) The existing wafer dividing process using UV tape 3 is almost changed by using ultraviolet 9 as the predetermined light and using identification sticker 4 whose surface is coated with a photosensitive material that reacts to ultraviolet 9 as a photosensitive part. It is possible to prevent work errors due to misrecognition of ultraviolet irradiation without having to do so.

(3) Highly efficient wafer division can be realized by the above (11 and (2)).

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. No, for example, identification sticker 4
The description has been made for the case where the UV tape is attached to the back side of the adhesive side of the UV tape 3, but it may also be attached to the adhesive side. In this case, the adhesive side of the UV tape 3 and the photosensitive identification sticker 4 The discrimination sticker 4 is pasted so that the surface is in contact with the surface.

In addition, as a photosensitive part, an identification sticker 4 coated with a photosensitive material is used.
Although a case has been described in which a UV tape is used, a photosensitive material may be applied directly to the front or back side of the UV tape. Alternatively, the adhesive material may be mixed with a photosensitive material, or the tape base itself may be mixed with a photosensitive material.

In the above description, the invention made by the present inventor was mainly applied to wafers used in the field of application, that is, manufacturing so-called semiconductor devices, but the invention is not limited to this, for example, transistors, etc.
It can also be applied to wafers used for manufacturing other electronic components such as diodes.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, a wafer is adhered to the adhesive surface of a translucent tape whose adhesive strength decreases when irradiated with a predetermined light, and the predetermined light is applied to the adhesive surface of the tape or its back side in the direction of irradiation of the predetermined light. A photosensitive area is provided in which the reflected light visually changes when irradiated, and after irradiating the tape with a predetermined light from the back side of the adhesive surface of the tape, the pellet at a predetermined area is picked up. It becomes possible to very easily determine whether or not the predetermined light is irradiated by a visual change in the wafer, thereby preventing operational errors and realizing a highly reliable wafer dividing process.

[Brief explanation of drawings]

Fig. 1 (al~(C1 is a schematic explanatory diagram sequentially showing a wafer dividing method according to an embodiment of the present invention, and Fig. 2 is a plan view of a frame showing a state in which wafers are attached. 1. ... Wafer, 2... Frame, 2a... Frame member, 3... UV tape, 4... Identification sticker, 5
... Dicing stage, 6... Dicing blade, 7... Irradiation stage, 7a... Irradiation window, 8...
・Irradiation lamp, 9...ultraviolet light, 10...fixing means,
11... Push-up jig, lla... Vacuum suction hole, 1
2... Push-up pin, 13... Collet, A...
Dicing mechanism, B...irradiation mechanism, C...pick amplifier mechanism. Figure 1 (c) Ku 1st potato

Claims (1)

[Claims] 1. A wafer is adhered to the adhesive surface of a translucent tape whose adhesive strength decreases when irradiated with a predetermined light, and a wafer is attached to the adhesive surface of the tape or its back side in the direction of irradiation of the predetermined light. A photosensitive part is provided in which reflected light visually changes when irradiated with the predetermined light, and after irradiating the tape and the photosensitive part with the predetermined light from the back side of the adhesive surface of the tape, the predetermined part is Wafer splitting method to pick up pellets. 2. The wafer dividing method according to claim 1, wherein the photosensitive portion is provided by pasting a sticker coated with a photosensitive material. 3. The wafer dividing method according to claim 1, wherein the irradiated light is ultraviolet light.