JPH0578629A - Radiation-curable tacky tape - Google Patents

Abstract

PURPOSE:To obtain the subject tape, having a substrate laminated to a tacky agent layer having the surface in which prescribed regions are precured by selective exposure to radiation and further a laminated mold release film, prevented from unnecessary tack, excellent in operating efficiency and useful for fixing wafers, etc. CONSTITUTION:The objective tape is a radiation curing tacky tape provided with a substrate 13 having, e.g. 50-150mum thickness, a tacky agent layer 14, laminated to the surface of the substrate 13 and composed of a photopolymerizable oligomer, etc., curable by exposure to radiation and a mold release film 15 such as a polyester film, laminated to the surface of the tacky agent layer and having about 38mum thickness. Prescribed regions (14a) of the tacky agent layer 14 initiate polymerizing reaction to precure by selective exposure to the radiation and lose tackiness. In contrast, regions (14b) unexposed to the radiation have tackiness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-curable pressure-sensitive adhesive tape used for fixing a wafer during wafer dicing in a semiconductor device manufacturing process and protecting a pattern on a wafer surface during wafer back grinding.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device such as an IC and an LSI, a wafer after pattern formation is usually subjected to processing such as back grinding and etching in order to reduce its thickness. Further, the processed wafer is diced into chips. In these steps, an adhesive tape is usually used for various purposes. That is, at the time of back grinding or the like, an adhesive tape is attached to the pattern surface for the purpose of protecting the pattern on the wafer surface. Further, at the time of dicing, the wafer is fixed at the time of cutting the wafer, and the wafer is attached and held to an adhesive tape for the purpose of preventing scattering of formed chips.

The performance of the adhesive layer in this adhesive tape is such that it has a strong adhesive force for sufficiently fixing the wafer during use, and an adhesive force for easily peeling the wafer (chip) from the tape after use. It needs to be weakened.
Therefore, in recent years, a radiation-curable pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer that causes a polymerization reaction to be cured by irradiation of radiation and is cured is used as the pressure-sensitive adhesive tape.

The radiation-curable pressure-sensitive adhesive tape is usually used as follows. That is, first, the tape is attached to an article to be processed such as a wafer, and in this state, processing such as dicing and back grinding is performed on the article. Then, by irradiating the pressure-sensitive adhesive tape with radiation, the pressure-sensitive adhesive layer on the substrate is cured to lose the tackiness, and the processed article is peeled off from the pressure-sensitive adhesive tape.

As described above, in the radiation-curable pressure-sensitive adhesive tape, the pressure-sensitive adhesive layer is designed so that the adhesiveness on the surface is almost lost after the radiation-irradiated and cured, while the adhesive layer is adhered before the radiation-irradiated. It is designed to be very sticky to the body. Therefore, the adhesive tape achieves the desired adhesive strength before and after its use.

However, in the radiation-curable pressure-sensitive adhesive tape, tackiness is caused on the surface of the pressure-sensitive adhesive layer before irradiation with radiation due to high adhesiveness. Therefore, when the adhesive tape is accidentally attached to an object other than the intended adherend, if the adhesive tape is tried to be peeled off without irradiation with radiation, adhesive residue of the adhesive substance occurs on the object. In particular, when the pressure-sensitive adhesive tape is attached to an adherend such as a semiconductor wafer or ceramics, the surface area of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape is considerably larger than the area of the adhered portion of the adherend. The adhesive tape is stuck to a part of a jig used for sticking, for example, a tape holder, an adherend installation table, a rubber roller for sticking tape, an automated device of these, and an adhesive residue is generated at this part. Sometimes. Usually, the tape attaching jig and the device are designed so that the adherend is not contaminated by such adhesive residue. However, for example, when the adhesive tape is reattached to the adhesive residue portion, the adhesive tape is firmly adhered, so that it becomes gradually difficult to adhere the continuous adhesive tape.

[0007] The radiation-curable pressure-sensitive adhesive tape may be adhered to an adherend by hand except for using an adherend installation base and rollers. In this case, you may work while holding the adhesive tape with the exposed adhesive layer with your gloved fingertips.
Adhesive tape adheres to the body, etc., reducing workability.

In addition, if an attempt is made to peel off a portion where the above-mentioned unnecessary sticking has occurred, a part of the adhesive tape may be peeled off from the intended adherend, or the adhesive tape may be distorted such as stretched. In some cases, the purpose of the pressure-sensitive adhesive tape cannot be achieved sufficiently.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to prevent unnecessary adhesion to other than the intended adherend and to adhere the adherend. Another object of the present invention is to provide a radiation-curable pressure-sensitive adhesive tape that improves the workability of processing after attachment.

[0010]

The radiation-curable pressure-sensitive adhesive tape of the present invention comprises a substrate, a pressure-sensitive adhesive layer laminated on the surface of the substrate and cured by irradiation with radiation, and laminated on the surface of the pressure-sensitive adhesive layer. A release film layer, and a predetermined region of the pressure-sensitive adhesive layer is previously cured by selective irradiation of radiation.

In the present invention, radiation means light rays such as ultraviolet rays or ionizing radiation such as electron beams.

The present invention will be described in detail below.

The base material in the radiation-curable pressure-sensitive adhesive tape of the present invention may be a radiation-permeable one-layer or multi-layer structure made of, for example, polyethylene, polyvinyl chloride, ethylene vinyl acetate, polyester or ethylene vinyl acetate copolymer. Good films can be used. The thickness of the substrate is usually set to about 50 to 150 μm.

In the radiation-curable pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer laminated on the surface of the substrate is, for example, a photopolymerizable oligomer, a photopolymerizable polyfunctional monomer, a photoinitiator,
A pressure-sensitive adhesive prepared by blending a sensitizer, other stabilizers and the like can be used. The pressure-sensitive adhesive has tackiness in an untreated state, but loses its tackiness by causing a polymerization reaction and curing upon irradiation with radiation. The thickness of the pressure-sensitive adhesive layer is usually set to about 5-40 μm.

The release film layer laminated on the surface of the pressure-sensitive adhesive layer in the radiation-curable pressure-sensitive adhesive tape of the present invention may be, for example, a film obtained by coating a surface of a polyester film with a silicone liquid and baking it. The release film is laminated with the silicone-coated side in contact with the pressure-sensitive adhesive layer, and is peeled off at the stage of using the pressure-sensitive adhesive tape with an article to be processed attached thereto. The thickness of the release film is usually set to about 38 μm in terms of economy and workability. As such a release film,
In general, release paper in which the surface of synthetic paper is treated with silicon is known. However, since the radiation-curable pressure-sensitive adhesive tape of the present invention is used in the process of manufacturing a semiconductor device, a release film using polyester as described above is preferable in terms of its clean level.

The radiation-curable pressure-sensitive adhesive tape of the present invention having the above-mentioned structure uses a light-shielding plate or the like to selectively irradiate only a predetermined region thereof with radiation. In this way, in the region selectively irradiated with radiation, the polymerization reaction proceeds and cures as described above, and the tackiness is lost. On the other hand, the tackiness is maintained in the area not irradiated with radiation. Here, the selective irradiation of the adhesive tape with radiation is preferably performed in a state where the release film is laminated.

The area where the radiation is selectively applied is appropriately adjusted according to the shape of the adherend adhered to the adhesive tape. That is, in the pressure-sensitive adhesive layer, at least the region (and its peripheral region) to which the adherend is attached on the surface must have adhesiveness, and therefore these regions must not be irradiated with radiation to be cured. The area is not irradiated. On the other hand, the region to which the adherend is not attached is a region that is selectively irradiated with radiation to be cured in advance.

[0018]

Next, the operation of the radiation-curable pressure-sensitive adhesive tape of the present invention will be described according to its use process.

First, the release film layer is peeled from the pressure-sensitive adhesive layer (tape ejection operation). At this time, in the pressure-sensitive adhesive tape of the present invention, in the pressure-sensitive adhesive layer, a region having tackiness and a region having no tackiness coexist, so that the release film can be easily peeled off.

Next, an adherend (article to be processed) such as a wafer is attached to the surface of the non-irradiated portion of the pressure-sensitive adhesive layer, that is, the surface of the region having adhesiveness. In this case, in the pressure-sensitive adhesive tape of the present invention, in the pressure-sensitive adhesive layer, there are few regions having adhesiveness other than the region to which the adherend is attached. Therefore, the area other than the area where the adherend on the adhesive tape is adhered,
Unnecessary adhesion is less likely to occur even when a jig such as an adherend installation table is contacted, and workability of attaching the adherend is improved.

Next, in this state, the adherend is subjected to processing such as dicing, and then the adhesive tape (adhesive layer).
The whole adhesive layer is cured by irradiating it to lose its adhesiveness, and the adherend after processing is peeled off from the adhesive tape. In the pressure-sensitive adhesive tape of the present invention, it is not necessary to specifically irradiate and cure the surface of the pressure-sensitive adhesive layer that is exposed without the adherend being adhered. However, when disposing of the adhesive tape after use, if there are many areas where the adhesiveness remains on the surface of the adhesive layer,
Unnecessary adhesion occurs and workability deteriorates. Therefore, it is preferable to irradiate the entire area of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape with radiation to cure it after the above processing is completed.

By the way, it is known that the polymerization reaction of the pressure-sensitive adhesive used in the present invention by irradiation with radiation is generally inhibited by oxygen in the air. on the other hand,
When the adherend adhered on the pressure-sensitive adhesive layer is subjected to dicing, a metal frame is adhered on the pressure-sensitive adhesive tape, and the wafer is a workpiece within a range surrounded by the frame, Attach the ceramics etc. to the adhesive tape. At this time, since the pressure-sensitive adhesive layer in the region between the metal frame and the work piece is exposed to the air, when the work piece of the work piece is irradiated with radiation to cure the pressure-sensitive adhesive layer. Therefore, it becomes necessary to remove oxygen in the part exposed to this air.
Specifically, air purge is performed using nitrogen gas,
In this case, if a large amount of the uncured adhesive layer, that is, the adhesive layer that needs to be cured after processing remains, a large amount of nitrogen must be purged. Further, in this case, it takes a lot of time to replace the air with the nitrogen gas. However, in the pressure-sensitive adhesive tape of the present invention, since the predetermined region of the pressure-sensitive adhesive layer is previously cured by irradiation with radiation, the region requiring radiation curing after processing as described above is very limited around the adherend. It's just an area. Therefore, the amount of nitrogen purge used as described above can be reduced, and the radiation irradiation apparatus can be simplified.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. These examples are described for the purpose of facilitating the understanding of the present invention, and do not limit the present invention in particular. Further, each reference sign in the drawings has the same meaning throughout the drawings.

Example 1 An acrylic UV-curable pressure sensitive adhesive was applied to the surface of a transparent coextruded film having a total thickness of 100 μm and a three-layer structure, and a release film was laminated on the pressure sensitive adhesive to obtain the radiation of the present invention. A tape stock used for the curable adhesive tape was prepared.

The coextruded film having the three-layer structure has an intermediate layer of a high-density polyethylene layer having a thickness of 20 μm,
Both outer layers were formed as an ethylene vinyl acetate copolymer layer having a thickness of 40 μm, and each was molded by a multi-layer extruder using uncolored raw materials.

The acrylic UV-curable pressure-sensitive adhesive is prepared by adding 100 parts by weight of an acrylic pressure-sensitive adhesive (a copolymer of 2-ethylhexyl acrylate and n-butyl acrylate) to a polyisocyanate compound (manufactured by Nippon Polyurethane Company, trade name:
3 parts by weight of coronate L), 60 parts by weight of tris-2-acryloxyethyl isocyanurate, and 1 part by weight of α-hydroxycycloxyl phenyl ketone as a photopolymerization initiator were measured and mixed, and prepared by a stirrer.

The release film layer has a thickness of 38 μm.
The silicone release agent is applied to one side of the polyester film and baked.

Next, selective irradiation of radiation was performed on the formed tape raw material. First, at a predetermined position on the surface of the release film of the original tape, a thickness of 0.1 mm, an outer diameter
A 100 nm circular stainless steel shading plate was placed closely. Subsequently, from the light-shielding plate side (release film side), ultraviolet rays are irradiated for 2 seconds at an emission wavelength of 375 nm and an irradiation density of 400 mW / cm ² using an ultraviolet ray irradiation device (UVL-4500M2-N1 manufactured by Ushio Inc.). did. Thus, the radiation-curable pressure-sensitive adhesive tape of the present invention was formed.

The structure of the radiation-curable pressure-sensitive adhesive tape according to Example 1 formed as described above will be described in detail below with reference to FIG.

FIG. 1A is a plan view of the adhesive tape. In (A), 11 is a radiation irradiation region and 12 is a radiation non-irradiation region. That is, the irradiation of radiation was performed after the stainless light shielding plate was placed at 12 positions.

FIG. 1B is a sectional view of the adhesive tape taken along the line cc 'in FIG. 1A. In (B), 13 is a base material, and the adhesive layer 14 is laminated on the base material 13, and the release film layer 15 is further laminated on the adhesive layer 14.

The pressure-sensitive adhesive layer 14 includes a cured region 14a corresponding to the radiation-irradiated region 11 and a radiation-unirradiated region 1.
2 and the adhesive area 14b corresponding to 2. In the cured region 14a, the adhesive is cured and loses its adhesiveness because it is irradiated with ultraviolet rays. On the other hand, in the adhesive area 14b, since the ultraviolet ray is not irradiated, the adhesive does not cure and the adhesiveness is maintained.

The characteristics of the adhesive tape of Example 1 were evaluated.

First, the cured area 14a and the adhesive area 14b were evaluated for adhesiveness by the test method of JISZ-0237. That is, the pressure-sensitive adhesive layer 14 is SUS-
When it was attached to a 304 stainless steel test plate and peeled in a 90 degree direction at a speed of 50 mm / min. With a tensile tester, it had an adhesive force of about 1000 g / 25 mm in the adhesive region 14b, but a test plate in the cured region 14a. Adhesiveness was lost so that it could not be attached to.

Then, a 4-inch silicon wafer having a pattern formed on the surface thereof was subjected to a jig such as a wafer setting table.
The adhesive tape of Example 1 was attached to the adhesive region 14b of the adhesive layer 14. In this case, the wafer installation table did not cause unnecessary adhesion to the adhesive layer 14, and its workability was improved.

Example 2 In the same manner as in Example 1, selective radiation of ultraviolet rays was performed using the above-mentioned tape raw material to prepare a radiation-curable pressure-sensitive adhesive tape having a structure shown in FIGS. 2 (A) and 2 (B). FIG. 3A is a plan view showing the outline of the radiation irradiation region of the adhesive tape, and FIG. 3B is a sectional view of the adhesive tape taken along the line cc ′ of FIG. It should be noted that, at the time of irradiating the ultraviolet rays, the position where the stainless steel shading plate is installed on the raw tape is shown in FIG.
It was set at a position corresponding to the unexposed region 12 (22a, 22b) in (A).

Then, a silicon wafer was attached to the adhesive tape of Example 2. First, the release film layer 15 was peeled off from the adhesive tape. continue,
The silicon wafer was placed on a smooth silicon wafer installation base, and the installation base was attached to the adhesive layer corresponding to the specific radiation-unirradiated region 22a of the adhesive tape. In this state,
The silicon wafer on the installation table was attached by pressing it with a hand roller onto the adhesive layer corresponding to the specific unirradiated region 22b of the adhesive tape.

Further, as a comparison, the same wafer sticking operation as described above was performed using a conventional adhesive tape which is not selectively irradiated with ultraviolet rays (tape having adhesiveness on the entire surface).

As a result, when the adhesive tape of Example 2 was used, the workability was improved because the wafer installation table did not cause unnecessary adhesion to the adhesive layer 14. However, in the case of using the conventional adhesive tape, the wafer installation table adheres to the area of the adhesive layer where the wafer is not adhered,
Peeling work was required and workability declined.

Example 3 In the same manner as in Example 1, selective radiation of ultraviolet rays was carried out using the above-mentioned tape raw material to prepare a radiation-curable pressure-sensitive adhesive tape having a structure shown in FIGS. 3 (A) and 3 (B). FIG. 3A is a plan view showing the outline of the radiation irradiation region of the adhesive tape, and FIG. 3B is a sectional view of the adhesive tape taken along the line cc ′ of FIG. It should be noted that, at the time of irradiating the ultraviolet rays, the position where the stainless steel shading plate is installed on the original tape is shown in FIG.
It was set at a position corresponding to the unexposed region 12 in (A).

In the pressure-sensitive adhesive tape of Example 3, the release film 15 could be easily peeled from the pressure-sensitive adhesive layer 14. In particular, in the adhesive tape, since the radiation irradiation area 11 exists at a predetermined width on both side edge portions of the tape as shown in FIG. 3A, the adhesive does not adhere even if gloves or the like is used.

Example 4 The tape raw material used in Example 1 was punched into a label,
Similarly, by selectively irradiating ultraviolet rays, a radiation-curable pressure-sensitive adhesive tape having a structure shown in FIGS. 4 (A) and 4 (B) was produced. The same figure (A) is a plan view showing the outline of the radiation irradiation region of the adhesive tape, and the figure (B) is cc 'of the same figure (A).
It is sectional drawing of the adhesive tape which followed the line. Incidentally, the position where the stainless steel shading plate was set on the tape raw material at the time of the ultraviolet irradiation was set to a position corresponding to the radiation non-irradiated region 12 of FIG. 4 (A). Further, this ultraviolet irradiation was carried out by inserting a filter in the ultraviolet light emitting part and slightly lowering the illuminance. As a result, in the cured area 14a in FIG. 4 (B), the polymerization reaction of the adhesive did not proceed sufficiently, and the adhesive strength of about 30 to 50% of the adhesive area 14b remained.

Then, using the pressure-sensitive adhesive tape of Example 4, a silicon wafer, particularly a wafer in which the peripheral portion is more likely to react with the UV-curable pressure-sensitive adhesive than the central portion, was attached. First, the release film layer 15 is removed from the adhesive tape.
Was peeled off, and then the silicon wafer as described above was attached to the pressure-sensitive adhesive layer corresponding to the radiation-unirradiated region 12 of the pressure-sensitive adhesive tape. In this state, back-grinding was performed on the silicon wafer on the pressure-sensitive adhesive layer, and ultraviolet rays were further irradiated to cure the pressure-sensitive adhesive layer 14 as a whole, and the wafer was peeled from the pressure-sensitive adhesive tape.

For comparison, a conventional adhesive tape (adhesive tape on the entire surface) which has not been selectively irradiated with ultraviolet rays is used to perform the same wafer adhering work and back grinding as described above. Processed.

As a result, when the pressure-sensitive adhesive tape of Example 4 was used, the wafer after back grinding did not react with the pressure-sensitive adhesive layer 14 in both the central portion and the peripheral portion thereof, and the pressure-sensitive adhesive layer 14 as a whole. It was easily peeled off by curing. However, when the conventional adhesive tape is used, the wafer after back grinding reacts strongly with the adhesive layer 14 in the peripheral portion thereof and strongly adheres, and even if the entire adhesive layer 14 is cured. It could not be peeled off easily.

Example 5 In the same manner as in Example 1, selective irradiation of ultraviolet rays was carried out using the above tape raw material to prepare a radiation curable pressure sensitive adhesive tape having a structure shown in FIGS. 5 (A) and 5 (B). FIG. 3A is a plan view showing the outline of the radiation irradiation region of the adhesive tape, and FIG. 3B is a sectional view of the adhesive tape taken along the line cc ′ of FIG. It should be noted that, at the time of irradiating the ultraviolet rays, the position where the stainless steel shading plate is installed on the original tape is shown in FIG.
The position corresponding to the radiation non-irradiation region 12 (52a, 52b) in (A) is set.

Next, using the adhesive tape of Example 5, a silicon wafer was attached. First, the release film layer 15 was peeled off from the adhesive tape. continue,
The dicing frame is used as an adhesive layer corresponding to the specific non-irradiated area 52a of the adhesive tape, and the semiconductor wafer placed on the wafer installation table is used as an adhesive layer corresponding to the specific non-irradiated area 52b of the adhesive tape. I stuck each one.

As a comparison, the same sticking operation as above was performed using a conventional adhesive tape which was not selectively irradiated with ultraviolet rays (tape having the entire surface adhesive).

As a result, when the adhesive tape of Example 5 was used, the workability was improved because the wafer mounting table did not cause unnecessary adhesion to the adhesive layer 14. However, in the case of using the conventional adhesive tape, in the adhesive layer between the portion where the semiconductor wafer is attached and the portion where the dicing frame is attached, the wafer installation table causes unnecessary adhesion, The work etc. became necessary and the workability fell.

[0050]

As described in detail above, the radiation-curable pressure-sensitive adhesive tape of the present invention can be used for wafer dicing, back-grinding, etc. when a workpiece is adhered to the pressure-sensitive adhesive layer except for the intended adherend. The unnecessary adhesion to is reduced, and it has a remarkable effect in improving the workability of sticking and processing after sticking.

[Brief description of drawings]

FIG. 1A is a plan view showing a radiation curable pressure-sensitive adhesive tape according to Example 1 of the present invention. (B): A sectional view taken along the line cc ′ of FIG.

FIG. 2A is a plan view showing a radiation curable pressure-sensitive adhesive tape according to Example 2 of the present invention. (B): A sectional view taken along the line cc ′ of FIG.

FIG. 3A is a plan view showing a radiation curable pressure-sensitive adhesive tape according to Example 3 of the present invention. (B): A sectional view taken along the line cc ′ of FIG.

FIG. 4A is a plan view showing a radiation curable pressure-sensitive adhesive tape according to Example 4 of the present invention. (B): A sectional view taken along the line cc ′ of FIG.

FIG. 5A is a plan view showing a radiation curable pressure-sensitive adhesive tape according to Example 5 of the invention. (B): A sectional view taken along the line cc ′ of FIG.

[Explanation of symbols]

11 ... Radiation irradiation area, 12, 22a, 22b, 52
a, 52b ... Radiation non-irradiated area, 13 ... Base material, 14 ... Adhesive layer, 14a ... Cured area, 14b ... Adhesive area, 15 ...
Release film layer

Claims (1)

[Claims] 1. A radiation-curable pressure-sensitive adhesive tape comprising a substrate, a pressure-sensitive adhesive layer laminated on the surface of the substrate and cured by irradiation with radiation, and a release film layer laminated on the surface of the pressure-sensitive adhesive layer. A radiation-curable pressure-sensitive adhesive tape, wherein a predetermined region of the pressure-sensitive adhesive layer is previously cured by selective irradiation of radiation.