JP2001291760A - Method and tape for peeling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a peeling method in which a substance can be prevented from breakage which is generated when the substance is peeled from a fixing tape for fixing the substance at such a machining duration as a back grind step or a dicing step for a semiconductor wafer. SOLUTION: This peeling method has a feature of suctioning (reducing a pressure) from other surface of a tape for peeling when a machining substance is attached with the tape for peeling, especially porous member is preferably used as the tape for peeling and the machining substance is attached, at the time of peeling the machining substance from a fixing tape for machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of peeling a processed article from a fixing tape for fixing an article to be processed at the time of processing, particularly when the processed article is thin and easily damaged. The present invention relates to a method of peeling a processed article exhibiting an effect.

[0002]

2. Description of the Related Art In recent years, the size of semiconductor wafers has been increasing in accordance with the increase in the size of devices. On the other hand, the thickness of semiconductor devices has been reduced to increase the number of layers and increase the density, or to accommodate thin products such as IC cards. Applications for reducing the thickness of a wafer are increasing. This increase in diameter and reduction in thickness reduces the strength of the wafer on which the semiconductor elements are formed, and tends to cause troubles such as cracks and chips in the manufacturing process. This measure is important.

[0003] As a process in which such troubles are likely to occur, there is a back grinding and dicing process.

[0004] In the back grinding step, a back grinding tape is affixed in a step of polishing a semiconductor wafer on which semiconductor elements are formed to a predetermined thickness, for the purpose of preventing contamination or damage of the surface on which the semiconductor elements are formed. However, when the wafer is peeled off from the back-grinding tape having a high adhesive strength after processing, a large distortion is generated in the wafer, and cracks and chips are easily generated.

On the other hand, the dicing step is a step of cutting and dividing the semiconductor wafer into individual semiconductor elements after the back grinding step. In this step, a semiconductor wafer is fixed on a dicing tape in which an adhesive is applied to a base tape such as vinyl chloride or polyester, and after cutting, each element is picked up by a suction jig called a collet and transported to the next step. This dicing tape needs to have sufficient adhesive strength so that each element is not scattered by the rotation of the dicing saw when cutting, while satisfying conflicting requirements such as low adhesive strength that does not apply a load to each element during pickup. is there.

[0006] For this reason, it is recently called a UV type, which has a high adhesive strength at the time of cutting, and has an ultraviolet (U)
Dicing tapes which meet the conflicting demands by irradiating V) to reduce the adhesive strength from a fraction to a tenth or less are widely used, but there is a variation in the adhesive strength due to UV irradiation or even if the adhesive strength is reduced. Since a few g of adhesive force remains, it is necessary to push up with a pin from below at the time of pickup. Therefore, even in the prior art, the element was not completely damaged by the push-up pin. Further, as the element becomes larger and thinner, the damage caused by the push-up pin becomes remarkable, and a countermeasure against the damage has become important.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to change from a fixing tape for fixing an article at the time of processing such as a back grinding process or a dicing process of a semiconductor wafer, to the article. An object of the present invention is to provide a peeling method capable of preventing breakage of an article which occurs when peeling off.

[0008]

The present invention relates to the following. 1. A peeling method, comprising: attaching a processed article to a peeling tape when peeling the processed article from the fixing tape during processing. 2. The release tape is a porous material, and is suctioned from another side of the release tape (decompression) when attaching a processed article.
Item 4. The peeling method according to Item 1. 3. Item 3. The peeling method according to Item 2, wherein the porous material comprises a porous polymer film. 4. Item 4. The peeling method according to Item 2 or 3, wherein a porous support is interposed between the porous material and an apparatus or jig for suctioning (reducing pressure). 5. Item 5. The peeling method according to any one of Items 2 to 4, which has an adhesive property to such an extent that the processed product adhered when the surface of the porous material returns to normal pressure can be prevented from dropping or shifting. 6. Item 6. The peeling tape and the peeling method according to items 1 to 5, wherein the processing is a back grinding or dicing step of the semiconductor wafer. 7. Peeling tape made of air-permeable porous material.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The processed article in the present invention is, for example, a semiconductor wafer, and the processing is, for example, back grinding or dicing of a semiconductor wafer. In such processing, in particular, when the back grinding tape is peeled off after the back grinding of the semiconductor wafer is completed, or after dicing, semiconductor elements such as a CPU, a memory, a diode, and a transistor are peeled off from the dicing tape. The above-mentioned back grinding tape and dicing tape are fixing tapes for processing.

In the back grinding and dicing of a semiconductor wafer, the semiconductor wafer is processed by attaching it to a fixing tape. Then, after the processing is completed, the article is peeled off from the fixing tape, and is provided to the next step. At the time of peeling, in the present invention, the article is attached to the peeling tape. Thereby, the semiconductor wafer and the elements formed thereon can be handled without damaging it.

In order to adhere the article to the peeling tape, it is preferable that the peeling tape is made of a porous material and the surface opposite to the side where the article is adhered is brought into contact with a reduced-pressure atmosphere or sucked.

Here, the pressure reduction or suction can be performed by using various vacuum pumps such as a water ring pump, a roots pump and an oil rotary pump.

(Specifically, how to use a suction jig and the like) At this time, a vacuum line is used to fix a table on which a semiconductor wafer to be cut / divided is to be mounted by decompression by a vacuum pump. When a porous material is interposed between the semiconductor wafers, the installation surface is uniformly depressurized or sucked, so that a phenomenon such as breakage or jump of the semiconductor wafer or element can be prevented.

Examples of the porous material include porous materials made of inorganic compounds such as brick, porcelain, zeolite, carbon random, and sintered forms of various metals; carbon products such as graphite and activated carbon; and plastic foams such as urethane and polystyrene. And sponges, permeable membranes and separation membranes, and nonwoven fabrics. Further, a non-porous material that has been mechanically punched with a needle or the like may be used.

As the porous material, a polymer film produced on the basis of a synthetic polymer is particularly preferable from the viewpoints of low tackiness, handling properties, cost and the like. Specifically, polymer powders such as polytetrafluoroethylene, polyethylene, and polypropylene are formed by sintering, and partially crystallized polymer films such as polytetrafluoroethylene, polyethylene, and polypropylene are formed by cold drawing and heat treatment. Filmed,
Films formed by irradiating polycarbonate, polyester, etc. with an electron beam and etched, cellulose esters, polyamides, polysulfones, etc., formed by phase inversion (microphase separation) method, thermoplastic polymers such as polystyrene, polyolefin, polyvinyl chloride, etc. And foams (foams) of thermosetting polymers such as polyurethane, phenolic resin and melamine resin. Further, as disclosed in JP-A-11-105141, a non-porous polymer film made of a non-porous polymer such as polyolefin, polyester, or polyvinyl chloride is mechanically punched with a penetrating needle.

Since these porous polymer films have low strength to support a semiconductor wafer or device under reduced pressure, a high-strength porous support is required. Examples of the porous support include a porous material of the above-mentioned inorganic compound and a non-porous material such as metal, ceramic, and hard plastic that are formed by drilling with a needle or a drill.

In this application, it is necessary to fix the semiconductor wafer and the chip not only at the time of peeling but also at the time of transportation in the apparatus and the next step. However, it is difficult to maintain the reduced pressure or the suction state in the transporting process due to constraints such as cost and space. Therefore, in order to prevent the semiconductor wafer or chip mounted thereon from being displaced even when transported even under normal pressure, it is desirable that the peeling tape has adhesiveness to such an extent as not to hinder chip pickup.

Adhesion can be achieved by applying an adhesive to the surface of the release tape.

Examples of the pressure-sensitive adhesive include, but are not limited to, those using a dicing tape. Specifically, a pressure-sensitive adhesive type acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, or a UV-type pressure-sensitive adhesive is preferred. The adhesive strength is preferably adjusted so that the maximum peeling force when peeling a 10 mm square silicon chip at 200 mm / min in the vertical direction is 50 gf or less, preferably 20 gf or less, and more preferably 10 gf or less. If it exceeds 50 gf, a large distortion is generated in the semiconductor wafer or the element at the time of pickup, so that cracks or chips are easily generated.

The above adhesive is applied by a knife coater, comma roll coater, reverse roll coater, kiss coater,
A coating method in which a pressure-sensitive adhesive is uniformly applied to a generally used entire surface such as a calendar coater, a gravure roll coater, and a rod coater may be used. In addition, letterpress, planographic, gravure,
A method such as screen printing, a method such as spraying or dipping may be used.

There is no problem when holes are formed after the application of the pressure-sensitive adhesive, but when applying to a porous material that has already been formed, the coating method, viscosity, wettability, concentration, etc. are used so that the holes are not blocked. It is preferable that the pressure is adjusted so that the pressure-sensitive adhesive solution does not penetrate into the holes or that the holes do not close even if they do. Further, a method of removing the pressure-sensitive adhesive solution that has entered the holes with compressed air or the like after coating can also be adopted.

[0022]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 Acrylic adhesive (63% by weight of butyl acrylate, 18% by weight of ethyl acrylate, 18% by weight of acrylonitrile, acrylonitrile 15) having a glass transition point of minus 35 ° C. was applied to Trefane B02575 (25 μm, a drawn polypropylene film manufactured by Toray Industries, Inc.). % By weight, 2% by weight of 2-hydroxyethyl acrylate and 2% by weight of methacrylic acid, and 100 parts by weight of a polyfunctional polyisocyanate (Nippon Polyurethane ( Co., Ltd. Coronate L) An adhesive consisting of 2 parts by weight is applied so as to have a solid content of 0.1 g / m ² , and is then punched with a heated needle so as to have a hole diameter of about 200 μm at intervals of 2 mm. Then, a polymer porous membrane was produced.

Next, as shown in the conceptual diagram, a hole having a diameter of 160 to 250 as a porous support is placed on a stage of a dicing apparatus having a vacuum device on a stage on which a semiconductor wafer is mounted.
A glass filter having a thickness of 50 μm was further placed on the glass filter having a thickness of 50 μm.
m semiconductor wafers (elements) were mounted together with the dicing tape. Then, the vacuum device was activated, and the vacuum system was set to 70
The pressure was reduced until the pressure reached torr, the device was fixed, the dicing tape was peeled off, the element was transferred to a peeling tape, and the element was picked up at a normal pressure. The test results are summarized in a table.

Example 2 In the same manner as in Example 1, except that Nitto Denko Corporation SUNMAP (100 μm) was used as a base sheet for the polymer porous membrane of Example 1 without drilling. A polymer porous membrane was prepared. Next, a diameter of 200 μm was placed on a SUS plate as a porous support at 1.5 mm intervals.
The pickup was carried out in the same manner as in Example 1 except that k was used, which used a porous support having holes.

Example 3 A urethane foam Everlite Scott HR-5 manufactured by Bridgestone was used as a base sheet of the polymer porous membrane of Example 2.
0 (thickness 10 mm) was picked up in the same manner except that a material compressed to a thickness of 1 mm was used.

Comparative Example 1 As a dicing film, H manufactured by Hitachi Chemical Co., Ltd.
Normal dicing and pickup were performed using AE-1503.

Comparative Example 2 As a dicing film, D-Lintech Co., Ltd.
Using 675, UV irradiation was performed after normal dicing, and pickup was performed.

[0029]

[Table 1]

[0030]

According to the method of the present invention, when the article is peeled off from the fixing tape for fixing the article at the time of processing, the article can be prevented from being damaged.

Claims (7)

[Claims] 1. A peeling method, comprising: attaching a processed article to a peeling tape when peeling the processed article from the processing fixing tape. 2. The peeling method according to claim 1, wherein the peeling tape is a porous material, and is suctioned (depressurized) from another surface of the peeling tape when attaching a processed article. 3. The method according to claim 2, wherein the porous material comprises a porous polymer film. 4. The peeling method according to claim 2, wherein a porous support is interposed between the porous material and an apparatus or a jig for suction (pressure reduction). 5. The porous material according to claim 2, wherein the surface of the porous material has such an adhesive property as to prevent the adhered processed product from falling off or being displaced when the surface is returned to normal pressure. The stripping method as described. 6. The peeling tape and the peeling method according to claim 1, wherein the processing is a back grinding or dicing step of the semiconductor wafer. 7. A release tape made of a porous material having air permeability.