JP2001200234A - Adhesive for fixation of semiconductor wafer and processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive for fixation of a semiconductor wafer likely to be fixed with strong adhesiveness when processing and likely to be detached with weak adhesiveness after split-processing, when fixing and split-processing a semiconductor wafer using an adhesive. SOLUTION: A semiconductor makes it detach readily from an adhesive generating a gas decomposed with ultraviolet ray irradiation by containing a compound having an azide group in the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for fixing a semiconductor wafer when dicing a wafer after completion of a wafer process in a process of manufacturing various semiconductors, and an adhesive for fixing the semiconductor wafer. The present invention relates to a method for processing a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, to perform a dicing process for cutting and dividing a semiconductor wafer into element pieces, the semiconductor wafer is pasted and fixed on an adhesive tape (dicing tape) in advance, and the wafer is formed into an element shape by a rotating round blade. A so-called direct pick-up method is adopted, in which each element is cut along the line, and then each element is picked up from an adhesive tape and mounted on a die. When using the above method, the fixing force (adhesive force) when fixing the wafer
Is required to be strong, and conversely, when picking up, it is required to have a low adhesive strength (easy peeling property). Conventionally, in order to respond to such a demand, an ultraviolet-curing adhesive tape which reduces the adhesive strength by curing the adhesive layer by irradiation with ultraviolet (UV), ionizing radiation, electron beam or the like (Japanese Patent Laid-Open No. 1-227213) ) And a type of pressure-sensitive adhesive tape that elutes with warm water after dicing using a water-soluble polymer as the pressure-sensitive adhesive component.

[0003]

At present, semiconductor wafers are becoming larger and thinner on a worldwide scale, and many of the latest wafers are easily damaged by external forces.
Therefore, how to reduce the load applied to the wafer at the time of dicing or pick-up is a new problem of the dicing tape. For example, the ultimate goal is to develop a pressure-sensitive adhesive that completely eliminates the adhesive force during pickup ("Adhesion", Vol. 43, No. 1, p. 22-25, Polymer Publishing Association, 1999).

[0004] The present invention largely solves the above-mentioned problems. That is, an object of the present invention is to provide a pressure-sensitive adhesive for fixing a semiconductor, which has greatly improved the releasability at the time of pickup after dicing. Another object of the present invention is to provide a method for processing a semiconductor wafer using the adhesive.

[0005]

The pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive for fixing a semiconductor wafer at the time of processing the wafer, and is characterized by containing a gas generating agent. Further, the method for processing a semiconductor wafer of the present invention includes fixing the wafer with an adhesive containing a gas generating agent, dicing the wafer, and generating a gas generating agent by an electromagnetic wave or an electron beam such as visible light, ultraviolet light, X-ray, or the like. Gas is generated from the wafer to peel off the wafer.

[0006] The gas generating agent is provided with visible light, ultraviolet light,
It is desirable to generate gas by electromagnetic waves such as X-rays or electron beams. As such a gas generating agent, those containing a compound having an azide group are preferable. The azide group is decomposed and absorbs relatively stable nitrogen molecules as a gas when absorbing an electromagnetic wave such as a light beam, particularly an ultraviolet ray. In other words, when a compound having an azide group is contained as an adhesive, it is decomposed by ultraviolet irradiation and releases nitrogen gas, and the nitrogen gas released between the wafer and the adhesive reduces the contact area between the wafer and the adhesive. In addition, by facilitating interfacial peeling by gas pressure, the peelability of the pressure-sensitive adhesive can be greatly improved.

[0007] As compounds having an azide group, for example, sodium azide and AM Helmy et al., 20th Joint Propulsion Confere
nce (Ohio, 1984), titled `` Investigation of
New Energetic Ingredientfor Minimum Signature Prop
Azide group-containing compounds described in the bulletin of "ellants" are known. In particular, a compound having a methylazido group is preferable from the viewpoint of ease of synthesis and handling (safety). For example, GAP (Glycidyl AzidoPolyme
r), AMMO (3-azidomethyl-3 methyloxetane), BAMO
(3,3-bis azidomethyl oxetane) and the like. Even in the state of a monomer, it may be polymerized and used. The mechanism of decomposition of a compound having a methyl azide group by ultraviolet light is as follows.
The present inventors have published the results of studies on handling safety ("Industrial Explosives", Vol. 51, No. 4, p. 240-24.
5, 1990).

The pressure-sensitive adhesive of the present invention desirably contains a UV-curable pressure-sensitive adhesive in which the pressure-sensitive adhesive layer is cured by irradiation with ultraviolet rays, ionizing radiation, electron beams or the like. As previously mentioned,
This is because an ultraviolet curable adhesive generally has a high adhesive strength and can be cured by irradiation with ultraviolet light after dicing to reduce the adhesive strength between the wafer and the adhesive tape. That is, in one embodiment of the present invention, the ultraviolet curable pressure-sensitive adhesive further contains a gas generating agent that generates a gas by ultraviolet irradiation, thereby generating a decomposition gas from the inside when irradiated with ultraviolet light. Thus, the contact area between the wafer and the pressure-sensitive adhesive is reduced, or the peelability is dramatically improved by gas pressure.

In general, an ultraviolet-curable pressure-sensitive adhesive is prepared by blending an acrylic pressure-sensitive adhesive having adhesive strength, a photopolymerizable oligomer and a photoinitiator, and a gas such as an azide group-containing compound is added to the ultraviolet-curable pressure-sensitive adhesive. In the case where a generator is included, the compounding ratio may be determined in consideration of the adhesive strength and the degree of easy peeling as necessary. The pressure-sensitive adhesive of the present invention is preferably provided in a sheet shape using a flat plate or a film or in a tape shape so as to be easily wound up. When the pressure-sensitive adhesive generates gas by electromagnetic waves such as ultraviolet rays, it is preferable that the flat plate or the film is made of an ultraviolet-transparent substrate.

The method of processing a semiconductor wafer using the pressure-sensitive adhesive of the present invention is to generate a gas by electromagnetic waves or the like to peel off the wafer as described above. There are many advantages, for example, it can be carried out using the used apparatus as it is. less than,
The present invention will be described more specifically with reference to examples. In order to demonstrate the effect of the present invention, the following three simulation experiments were performed. That is, the gas generation characteristics by ultraviolet irradiation when the azide group-containing compound was used alone as a gas generating agent and when used together with another ultraviolet curable resin were demonstrated.

[0011]

EXAMPLE 1 GAP according to the disclosure of US Pat. No. 4,268,450
The polymer was synthesized. Spread this polymer thinly (approximately 3 mm), and place a microscope cover glass plate (18 × 18 m
m), and irradiate ultraviolet rays (115V, 60H) from above.
z, 0.16 A). As a result, it was confirmed that many bubbles estimated to be nitrogen gas were generated between the glass plate and the polymer.

[0012]

Example 2 100 g of a GAP polymer (molecular weight: about 2500, containing OH groups at both terminals) synthesized by the same method as in Example 1
3.6 g of DI (isophorone diisocyanate), TPA-1
8.7 g of 00 (an adduct of hexamethylene diisocyanate; manufactured by Asahi Kasei Kogyo Co., Ltd.) was added, uniformly mixed, and then spread thinly. In this state, ultraviolet rays were irradiated in the same manner as in Example 1, and as a result of observing the state, a few minutes later, the contact surface was peeled off by the gas generated from the inside, and became partially lifted.

[0013]

Example 3 The above polymer was converted to APR manufactured by Asahi Kasei Corporation
The mixture was mixed with a resin (photosensitive resin, carboxylic acid-modified polyurethane resin) at a ratio of 1: 1 and spread thinly in the same manner as described above, a glass plate was placed, and ultraviolet rays were irradiated. As a result, gas generation was observed during and after the curing of the polymer. Then, as a result of being exposed to sunlight for about 30 minutes, partial exfoliation of the glass plate and the polymer was observed, and it could be easily removed by applying force by hand.

[0014]

[Comparative Example 1] A polymer was converted to PPG by the same method as in Example 3.
(Polypropylene glycol). The glass plate and the polymer were cured while keeping them in close contact with each other, and it was almost impossible to remove them by hand without breaking the glass plate.

[0015]

As described above, the present invention provides a pressure-sensitive adhesive for fixing a semiconductor wafer and a method for processing a semiconductor wafer using the pressure-sensitive adhesive by including a gas generating agent in the pressure-sensitive adhesive. After the semiconductor wafer is fixed and diced, it is very easy to peel off the wafer. In particular, by including a compound having an azide group as a gas generating agent, when irradiating with ultraviolet rays or the like, a gas is released even in a single state, a cured state, or a state used in combination with other substances, and the wafer is peeled off. Is made easier.

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Claims (6)

[Claims] 1. An adhesive for fixing a semiconductor wafer during processing of the semiconductor wafer, the adhesive comprising a gas generating agent. 2. The pressure-sensitive adhesive according to claim 1, wherein the gas generating agent generates a gas by an electromagnetic wave such as visible light or ultraviolet light or an electron beam. 3. A compound containing a compound having an azide group.
The pressure-sensitive adhesive described. 4. The pressure-sensitive adhesive according to claim 1, comprising an ultraviolet-curable pressure-sensitive adhesive. 5. The pressure-sensitive adhesive according to claim 1, which is formed into a sheet or a tape using a film. 6. A method for processing a semiconductor wafer, comprising fixing a wafer with an adhesive containing a gas generating agent, dicing the wafer, and generating a gas from the gas generating agent by an electromagnetic wave or an electron beam. A processing method comprising peeling a wafer.