JP2001196448A - Fixing implement for semiconductor wafer or semiconductor element and method for processing semiconductor wafer or semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for dicing a semiconductor wafer without damaging an element when the element is divided by a pickup without scattering the element at the wafer cutting time and a fixing implement. SOLUTION: The method for dicing the semiconductor wafer comprises the step of fixing the wafer and the element by pressure reduction of chucking in the case of dividing the wafer to the elements by dicing, a porous material which becomes the fixing implement for the wafer or chip is interposed between the pressure reduction or chucking device or jig and the wafer and the element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fixture for a semiconductor wafer or a semiconductor device and a method for processing a semiconductor wafer or a semiconductor device.

In the process of manufacturing semiconductor elements from a semiconductor wafer, there are processing steps such as back grinding, dicing and die bonding. Hereinafter, the dicing process will be described. In these processes, the semiconductor wafer needs to be fixed by some method. The semiconductor elements are collectively formed in a lattice pattern on a semiconductor wafer such as silicon, and a plurality of circuit patterns are cut by rotating teeth called dicing saws to be cut and divided into individual elements. At this time, the semiconductor wafer is fixed on a dicing tape in which an adhesive is applied to a base tape of vinyl chloride, polyester, or the like, and each element after cutting remains on the base tape because the base tape is not cut. Next, the semiconductor element is picked up by a suction jig called a collet and transported to the next step. This dicing tape must have sufficient adhesive power to prevent each element from being scattered by rotation by 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.

[0003] Therefore, in the case of a pressure-sensitive type dicing tape which has been conventionally used, the tolerance of the adhesive force is reduced, and various kinds of adhesive force suitable for the size of the element and the processing conditions are prepared in a wide variety of products. An operation such as switching is being performed. In recent years, it has been called a UV type, which has a high adhesive strength at the time of cutting, and irradiates ultraviolet rays (UV) before picking up to reduce the adhesive strength from a fraction to one-tenth or less, so as to meet the conflicting demands. Tape is also widely used. However, in the case of the pressure-sensitive type, a large number of varieties must be stocked, so that inventory management is required, and a switching operation is required for each process.

In recent years, the capacity of semiconductor devices, especially CPUs and memories, has been increasing, and as a result, the size of the devices has been increasing. Further, in products such as IC cards and memory cards, the memory used is becoming thinner. As these elements become larger and thinner, the pressure-sensitive type cannot satisfy the conflicting demands of fixing force (high adhesive force) during dicing and peelability (low adhesive force) during pickup. In addition, even in the UV type, there is variation in the decrease in the adhesive strength due to irradiation, or even if the adhesive strength is reduced, some adhesive strength remains. Therefore, it is necessary to push up with a pin from below when picking up. Was not nothing.

Further, as the size and thickness of the device have been increased and the push-up pins have been remarkably damaged, countermeasures have become important.

As a fixture for a semiconductor wafer during dicing, a porous member for fixing the semiconductor wafer by suction or reduced pressure has been proposed, but the study has been insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to prevent the elements from scattering when cutting a semiconductor wafer, and to damage the elements when the elements are divided by a pickup. An object of the present invention is to provide a fixture for a semiconductor wafer or a semiconductor element and a method for processing a semiconductor wafer or a semiconductor element.

[0008]

The present invention relates to the following. 1. It is made of a gas-permeable porous material, and has an adhesive strength of 5 × 10 ⁴ N / m ^{2 on the} surface of the porous material in contact with the semiconductor wafer or element.
The following semiconductor wafer or semiconductor device fixture. 2. A semiconductor wafer or a fixture for a semiconductor element, which is made of a gas-permeable porous material and has a gas permeability of 500 sec / 100 ml or less. 3. Item 3. The fixture for a semiconductor wafer or semiconductor element according to Item 2, wherein the adhesive strength of the surface of the porous material contacting the semiconductor wafer or element is 5 × 10 ⁴ N / m ² or less. 4. Item 4. The semiconductor wafer or semiconductor device fixture according to any one of Items 1 to 3, wherein the gas-permeable porous material is made of a gas-permeable porous polymer film. 5. Item 5. The semiconductor wafer or semiconductor device fixture according to Item 1, wherein the porous material is obtained by fixing a porous polymer film on a porous support. 6. When processing semiconductor wafers or semiconductor devices,
Item 6. A method for processing a semiconductor wafer or a semiconductor element, comprising fixing the semiconductor wafer or the semiconductor element by decompression or suction through the semiconductor wafer or the semiconductor element fixing tool according to any one of Items 1 to 5.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an example of a dicing device (part) capable of performing the present invention. In FIG. 1, a semiconductor wafer 1 is placed on a vacuum or suction stage 4 via a porous material composed of a polymer porous membrane 2 and a porous support 3. The decompression or suction stage is connected to a vacuum pump 6 via a decompression system intervening part 5 between a stage such as a pipe and the vacuum pump. FIG. 1 does not show a cutter device for dicing and a device for transporting semiconductor wafers and semiconductor elements.

[0010] In the processing method of the present invention, decompression or suction can be performed using various vacuum pumps such as a water ring pump, a tool pump, and an oil rotary pump. The semiconductor wafer is fixed to the table on which the semiconductor wafer to be cut and divided is set by decompression or suction. At this time, if a porous material is interposed between the vacuum line and the semiconductor wafer, the installation surface is uniformly depressurized or suctioned. To be
This is preferable because a phenomenon such as breakage or jump of a semiconductor wafer or element can be prevented.

[0011] A porous material is used as the fixture in the present invention. As the porous material, as an inorganic compound, brick, ceramic, zeolite, carbon random,
Sintered foams of various metals, and organic substances include carbon products such as graphite and activated carbon; foams and sponges such as urethane and styrene; permeable membranes and separation membranes; and nonwoven fabrics. Further, a non-porous material formed by punching with a penetrating needle, a punching blade, a laser or the like may be used.

The air permeability of the above porous material (based on JIS P 8117)
Is 500 sec / 100 ml or less, preferably 50 sec.
c / 100 ml or less, more preferably 5 sec / 100
ml or less. If the air permeability is too large, the pressure loss at the time of suction increases, and there is a tendency that a sufficient fixing force of the semiconductor wafer or chip cannot be obtained. The air permeability may be 0 as long as it can be used as a support pair, but if it is too small, the strength as a support pair may be too low, and may be 0.001.
sec / 100 ml is preferred.

As the porous material, a polymer film produced based on a synthetic polymer is preferable from the viewpoint of handling properties and cost during dicing of a semiconductor wafer, and from the viewpoint of weak adhesion workability described later. 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, polycarbonate and polyester were irradiated with electron beam and etched to form a film, cellulose ester, polyamide,
Polysulfone etc. formed by phase inversion (micro phase separation) method, foam of thermoplastic polymer such as polystyrene, polyolefin, polyvinyl chloride, etc., thermosetting polymer such as polyurethane, phenol resin, melamine resin etc. Foam (foam). As the porous material, as described in JP-A-11-105141, a material obtained by mechanically perforating a non-porous polymer film such as polyolefin, polyester, or polyvinyl chloride with a penetrating needle is used. Is also good.

Most preferably, the porous material maintains a flat state even when reduced pressure or suction during dicing. If the strength of the porous polymer film alone is insufficient to support a semiconductor wafer, the film may be deformed into a concave shape when decompressed or sucked, and dicing may not be performed. For this reason, the porous material of the present invention may be constituted by using a reinforcing porous support having a strength that does not deform even when decompressed or sucked. As the porous support, a porous material of the above-mentioned inorganic compound, metal,
Non-porous materials such as ceramics and hard plastics are punched with a needle, drill, laser or the like.

Semiconductor devices (chips) generated by dicing not only at the time of transfer to a dicing apparatus but also at the time of transfer to a next process after dicing are fixed. It is necessary to keep. 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, the porous material is used to remove the semiconductor wafer or chip from the semiconductor wafer or chip so that the semiconductor wafer or chip is not displaced even at normal pressure during transport and does not hinder chip pickup. It is desirable that the mounting surface has a low tackiness.

A mounting surface for a porous semiconductor wafer or chip.
To make the adhesive weak, apply an adhesive to the porous material.
It is preferable to keep it. Conventional adhesives
Are used for tapes.
It is not limited. Specifically, pressure-sensitive adhesive type
Used with acrylic or rubber adhesive or UV type
And the like are preferred. Its adhesive strength is 10mm square
The silicon chip was peeled vertically at 200 mm / min.
The maximum peeling force at the time is 5 × 10^FourN / m^TwoBelow, preferably 2
× 10^FourN / m^TwoHereinafter, more preferably 1 × 10^FourN /
m^TwoIt is adjusted to be as follows. 5 × 10 ^FourN / m^TwoTo
If it exceeds, the collet alone will peel off when picking up
Since it cannot be done, a push-up pin is required. Adhesive
Lower limit is 1 × 10^TwoN / m^TwoIt is preferred that this
If the adhesive strength is smaller than the lower limit, the peel resistance in the horizontal direction is not sufficient.
Tend to be in minutes. In addition, semiconductor wafers in the transport process
To prevent misalignment of chips or chips, use a 10 mm square
The chip was peeled off by applying force to the chip horizontally.
The maximum peeling resistance at the time is 1 × 10^ThreeN / m^TwoAbove, preferably
Is 1 × 10^FourN / m^TwoAbove, more preferably 5 × 10^FourN
/ M^TwoThat is all. If this peeling resistance is too small, it will be transported.
Sometimes semiconductor wafers and chips are misaligned and used
Can not. The upper limit of peel resistance is 2 × 10⁶N / m^Twoso
Preferably, there is. With a peel resistance greater than this upper limit
Has a tendency that the adhesive strength becomes too large.

The coating of the pressure-sensitive adhesive on a porous material or a non-porous material can be performed on a generally used entire surface such as a knife coater, a comma roll coater, a reverse roll coater, a kiss coater, a calendar coater, a gravure roll goter, a rod coater and the like. There is a coating method for uniformly applying the adhesive. Further, a method such as letterpress, planographic, gravure, screen printing, spraying, or dipping may be used. Also, there is no problem when drilling holes after applying the adhesive,
When applying to a porous material that already has holes, adjust the coating method, viscosity, wettability, concentration, etc. to prevent the adhesive solution from entering the holes, or prevent the holes from being blocked. It is necessary to make sure that the hole does not block,
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 employed. Further direct coating,
Alternatively, the transferred adhesive layer formed on a carrier film or the like is punched together with a porous substrate using a needle or a laser, or only the adhesive layer formed on the carrier film or the like is needled or a laser. Examples of the method include a method of forming a hole and transferring the image to a porous substrate. Further, a method of imparting porosity by giving the adhesive itself foaming properties may be employed.

[0018]

According to the present invention, when stress is applied to a semiconductor wafer or device by a dicing saw for cutting, a table or a jig for fixing a semiconductor or a device is depressurized or sucked, and the table or the jig is compressed by the atmospheric pressure. In order to prevent scattering by bringing the device into close contact with the tool and returning the element to normal pressure (atmospheric pressure) when picking up the element after cutting and splitting, the fixing force is reduced to an appropriate range. In addition, the device can be handled without using a push-up pin, and there is no fear of damaging the device. In addition, the interposition of a suitable air-permeable porous material uniformly reduces or sucks the surface on which the semiconductor wafer or element is placed, so that the phenomenon of breakage or jumping can be prevented.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Torayfan BO2575 (trade name, manufactured by Toray Industries, Inc., stretched polypropylene film, thickness: 40 μm) was coated with an acrylic pressure-sensitive adhesive having a glass transition point of minus 35 ° C. (butyl acrylate 63% by weight, ethyl acrylate 18% by weight, (A polymer obtained by polymerizing 15% by weight of acrylonitrile, 2% by weight of 2-hydroxyethyl acrylate and 2% by weight of methacrylic acid and having a weight average molecular weight of about 800,000)
An adhesive consisting of 2 parts by weight of a polyfunctional polyisocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) is applied to 0 part by weight so that the solid content becomes 0.1 g / m ² , and then 2
Holes were punched on the entire surface with a heated needle so as to have a hole diameter of 200 μm with an interval of mm, thereby producing a polymer porous membrane. Next, as shown in FIG. 1, a semiconductor wafer having a thickness of 50 μm was placed on a dicing apparatus (DAD341) manufactured by Disco Co., Ltd. in which the vacuum system was improved. That is, a SUS filter having an aperture of about 350 μm as a porous support on a decompression or suction stage of a dicing device equipped with a vacuum device, and further mounting the polymer porous membrane thereon,
Further, a semiconductor wafer was mounted thereon. Next, the vacuum device was operated, and the pressure was reduced or sucked until the absolute pressure became 10 mmHg, and the semiconductor wafer was fixed on the dicing device. The semiconductor wafer was diced and cut into 10 mm square semiconductor elements (chips). Then, the chip on the polymer porous membrane was picked up by a pickup device manufactured by Tokyo Electron Limited.

Example 2 The pressure-sensitive adhesive layer of Example 1 was formed on a polyethylene film and further laminated with a polyethylene film.
Drilling was performed in the same manner as in Example 1 to obtain a porous adhesive layer. Next, this adhesive layer was laminated and transferred to SUNMAP (trade name, Nitto Denko Corporation, 100 μm thickness), which was a corona discharge treated substrate sheet of a polymer porous membrane, to produce a polymer porous membrane. Next, a semiconductor wafer was diced and chips were picked up in the same manner as in Example 1 except that a porous support having holes of 1 mm in diameter and 2 mm apart in an aluminum plate was used as a porous support.

Example 3 A urethane foam Everlight Scott H manufactured by Bridgestone Corporation was used as a substrate sheet for the polymer porous membrane of Example 2.
A semiconductor wafer was diced and chips were picked up in the same manner as in Example 2, except that R-50 (thickness 10 mm) was compressed to a thickness of 1 mm.

Comparative Example 1 The same procedure as in Example 1 was carried out except that dicing and picking up were performed at normal pressure without using reduced pressure or suction, using HAE-1503 manufactured by Hitachi Chemical Co., Ltd. as a film for dicing as a fixture. I went.

Comparative Example 2 The procedure of Example 1 was repeated except that the dicing was performed at normal pressure without reducing or sucking the pressure.

Table 1 summarizes the evaluation results for the results of the examples and comparative examples.

[Table 1] In Table 1, the fixing force is a device according to FIG.
The maximum peeling force when a 10 mm square silicon chip is peeled vertically at 200 mm / min at 10 ³ Pa. Also, the peeling force is normal pressure (absolute pressure 1.013 × 10 ⁵
It shows the maximum peeling force when a 10 mm square silicon chip was peeled at 200 mm / min in the vertical direction at (Pa).

[0026]

According to the present invention, dicing of a semiconductor wafer can be performed efficiently and safely without breakage or scattering of the semiconductor wafer and elements (chips). In addition, semiconductor wafers and chips can be transported efficiently and safely without breakage or scattering.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a dicing apparatus (part) that can perform the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor wafer 2 polymer porous film 3 porous support 4 decompression or suction stage 5 decompression system interposed part 6 vacuum pump

Claims (6)

[Claims] 1. An air-permeable porous material having an adhesive strength of 5 × 10 on a surface of a porous material in contact with a semiconductor wafer or element.
^A fixture for semiconductor wafers or semiconductor elements having a density of ⁴ N / m ² or less. 2. A fixture for a semiconductor wafer or a semiconductor element comprising a gas permeable porous material, wherein the gas permeability of the porous material is 500 sec / 100 ml or less. 3. The adhesive strength of a surface of a porous material to which a semiconductor wafer or an element is in contact is 5 × 10 ⁴ N / m ² or less.
The fixture for semiconductor wafers or semiconductor elements according to the above. 4. The fixture for a semiconductor wafer or a semiconductor element according to claim 1, wherein the gas-permeable porous material comprises a gas-permeable porous polymer film. 5. The semiconductor wafer or semiconductor device fixture according to claim 1, wherein the porous material is obtained by fixing a porous polymer film on a porous support. 6. When processing a semiconductor wafer or a semiconductor element, fixing the semiconductor wafer or the semiconductor element by depressurization or suction through the fixture for the semiconductor wafer or the semiconductor element according to claim 1. A method for processing a semiconductor wafer or a semiconductor device, comprising: