JPH0734433B2 - Tape attaching method and tape peeling method for semiconductor wafer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is intended to attach a protective adhesive tape for pattern protection to a circuit pattern forming surface which is the front surface of a semiconductor wafer when polishing the back surface of the semiconductor wafer. And a method for peeling the protective adhesive tape from the semiconductor wafer after the polishing process.

<Prior Art> In a semiconductor wafer manufacturing process, usually, after a circuit pattern of an IC element or the like is formed, a back surface polishing step for polishing the back surface of the semiconductor wafer to a predetermined thickness is performed. Has been.

In the back surface polishing step, in order to prevent the circuit pattern forming surface from being contaminated or damaged by polishing dust or the like, protective means is provided in advance on the circuit pattern forming surface side of the semiconductor wafer.

Conventionally, as a protection means, a method using a protective pressure-sensitive adhesive tape provided with a layer made of an ordinary pressure-sensitive adhesive is known. That is, in this method, after the protective adhesive tape is attached to the circuit pattern formation surface side of the semiconductor wafer, the back surface of the semiconductor wafer is polished and the protective adhesive tape is peeled off after polishing.

The method using this protective adhesive tape solves the problem of insufficient protection capability for preventing damage to semiconductor wafers, which was present in the conventional method of applying a photosensitive resist material or the method of simply mounting spacers made of thin sheets. It has advantages such as excellent protection ability and polishing accuracy.

<Problems to be Solved by the Invention> However, when the protective adhesive tape is attached to the circuit pattern forming surface of the semiconductor wafer, if the protective adhesive tape is charged with static electricity, the circuit element may be broken due to a high voltage. there were.

When peeling the protective adhesive tape from the surface on which the circuit pattern is formed, another peeling tape having strong adhesive force is attached to the outer surface of the protective adhesive tape attached to the semiconductor wafer, and the peeling tape is pulled up to remove the protective adhesive tape. Is peeled from the semiconductor wafer. At this time, a high voltage is generated due to peeling electrification of the protective adhesive tape, which may break the circuit element.

Although not for protecting the surface of the semiconductor wafer, a conductive adhesive tape is used as the holding sheet to prevent static electricity generated in the wafer holding sheet used for holding the wafer when dicing the wafer. Some have been proposed (for example, Japanese Patent Laid-Open No. 61-80834).

However, since this type of conductive adhesive tape is formed by kneading a conductive substance such as metal powder or a surfactant into the base film or the adhesive layer, there is too much conductivity in view of film formability. It is not possible to mix organic substances and surfactants. Therefore, the surface resistance of the film cannot be sufficiently reduced, and the effect of suppressing static electricity generation is low. Further, if a conductive substance or a surfactant is mixed in the adhesive layer, the semiconductor wafer may be contaminated.

The present invention has been made in view of such circumstances, and prevents generation of static electricity when the protective adhesive tape is attached to the circuit pattern forming surface of the semiconductor wafer or when the protective adhesive tape is peeled from the semiconductor wafer. Therefore, it is an object of the present invention to provide a tape attaching method and a tape peeling method that can prevent the circuit element from being damaged and prevent the semiconductor wafer from being contaminated.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the method for tape-adhering a semiconductor wafer according to the present invention, in order to achieve the above-mentioned object, an insulating film is formed on a circuit pattern forming surface of a semiconductor wafer held on a grounded table. To the semiconductor wafer by supplying a strip-shaped protective adhesive tape comprising a conductive base film, a conductive thin layer, and an adhesive layer while electrically connecting the conductive thin layer to a grounded conductive roller. It is characterized in that the protective adhesive tape is attached.

And, in order to achieve the above-mentioned object, the tape peeling method for a semiconductor wafer according to the present invention, in order to achieve the above-mentioned object, a protective adhesive tape comprising an insulating base film, a conductive thin layer and an adhesive layer is attached to a circuit pattern forming surface The semiconductor wafer thus obtained is held on a grounded table, and an adhesive layer having an adhesive force stronger than that of the protective adhesive tape, a conductive thin layer,
A strip-shaped release tape with an insulating base film,
While electrically connecting the conductive thin layer to a grounded conductive roller, the conductive tape is attached to the outer surface of the protective adhesive tape on the semiconductor wafer, and the peeling tape is peeled and removed, so that the peeling tape is lowered. It is characterized in that the protective adhesive tape is peeled off from the semiconductor wafer.

<Operation> According to the semiconductor wafer tape sticking method of the present invention, the conductive thin layer of the protective adhesive tape is electrically connected to the grounded conductive roller to remove static electricity charged on the protective adhesive tape. The protective adhesive tape is supplied to the semiconductor wafer. Then, while the protective adhesive tape is grounded via the conductive roller and the semiconductor wafer is also grounded via the table, the protective adhesive tape is attached to the semiconductor wafer, so static electricity is suppressed when the protective adhesive tape is attached. To be

Then, according to the tape peeling method for a semiconductor wafer of the present invention, the conductive tape is electrically connected to the grounded conductive roller, the static electricity charged in the peeling tape is removed, and the peeling tape is removed. It is attached to the outer surface of the protective adhesive tape on the semiconductor wafer. Then, while the protective adhesive tape is grounded via the peeling tape and the semiconductor wafer is also grounded via the table, the peeling tape is peeled and removed, so that the occurrence of peeling charge is suppressed when the protective adhesive tape is peeled off. Since the high voltage is not generated, the element is not destroyed.

<Example> FIG. 1 is a schematic configuration diagram of a first example of a tape attaching method according to the present invention.

The semiconductor wafer 1 on which the circuit pattern is formed is suction-held on the grounded conductive table 2 with its circuit pattern forming surface facing upward. A protective adhesive tape 3 for protecting a circuit pattern is supplied onto the semiconductor wafer 1 through a feeding guide roller 4, a movable guide roller 5 for attachment and a movable attachment roller 6, and the movable guide roller 5 and the movable attachment roller 6 are provided. The protective adhesive tape 3 is attached to the surface (circuit pattern forming surface) of the semiconductor wafer 1 by moving from the left side to the right side in the figure.

As shown in FIG. 2, the protective adhesive tape 3 is fed from a supply source (not shown) and separated from the separate film 7 at the feeding guide roller 4 section.
The insulating base film 3a having a thickness of about 130 μm and the adhesive layer 3b having a thickness of about 20 μm are provided with a conductive layer 3c as a conductive thin layer made of a thin metal layer (such as aluminum). As the conductive layer 3c, in addition to the metal layer, for example, a thin layer formed by applying an antistatic agent such as a conductive polymer or siloxane is used.

Then, as shown in FIG. 1 and FIG. 3, the protective adhesive tape 3 is provided with a grounded conductive roller 9 provided with a group of projections 8 that penetrate the adhesive layer 3b and come into contact with the conductive layer 3c. Is being acted upon. That is, the conductive layer 3c of the protective adhesive tape 3 is electrically connected to the grounded conductive roller 9 so that the static electricity charged on the protective adhesive tape 3 is released to the ground line. Further, the semiconductor wafer 1 itself is also grounded via the conductive table 2, so that the protective adhesive tape 3 and the semiconductor wafer 1 are set to the same potential (earth potential) to prevent the circuit elements from being destroyed by static electricity.

The surface resistances of the protective pressure-sensitive adhesive tape used in this example and the conventional protective pressure-sensitive adhesive tape will be compared and described below.

The protective pressure-sensitive adhesive tape 3 used in this example uses EVA (ethylene vinyl alcohol) of 130 μm as the base film 3a, and an acrylic adhesive of 20 μm as the adhesive layer 3b.
Apply the conductive layer between the base film 3a and the adhesive layer 3b.
As 3c, a 300Å aluminum vapor deposition layer is interposed. The surface resistance of this protective adhesive tape 3 was 1Ω.

On the other hand, as a conventional protective adhesive tape, 100 parts of EVA is mixed with 1 part of a nonionic surfactant as an antistatic agent to prepare a base film, and an acrylic resin is used as an adhesive layer on the base film. An adhesive coated with 20 μm was used. The surface resistance of this protective adhesive tape is 10 ¹² Ω
Met.

As is clear from the above comparative experiment, the protective adhesive tape 3 according to the present example, which includes the insulating base film 3a and the adhesive layer 3b and the independent conductive layer 3c, has a low surface resistance, and therefore, It can be understood that the effect of suppressing static electricity generation is extremely high.

FIG. 4 is an enlarged cross-sectional view of a main part showing a means for peeling the protective adhesive tape 3 attached as described above from the semiconductor wafer 1 after the polishing process.

In this case, the protective adhesive tape 3 is peeled from the semiconductor wafer 1 via the peeling tape 10 prepared separately.

The release tape 10 used here is provided with an adhesive layer 10b having an adhesive force stronger than that of the protective adhesive tape 3 on one surface of the insulating base film 10a, and a conductive layer 10c on the other surface of the insulating base film 10a. And the conductive layer 10c is connected to the grounded conductive roller 1
By being electrically connected to 1, the static electricity charged on the peeling tape 10 is released to the ground line, and the potential of static electricity between the peeling tape 10 and the semiconductor wafer 1 is prevented from increasing.

Second Embodiment FIG. 5 is a schematic configuration diagram showing a second embodiment of the tape attaching method according to the present invention.

The structure itself for attaching the protective adhesive tape 3 to the circuit pattern forming surface of the semiconductor wafer 1 is the same as that of the first embodiment, but here, the protective adhesive tape 3 is shown in an enlarged cross-sectional view of the main part of FIG. Things are used.

That is, as the protective adhesive tape 3, one having an adhesive layer 3b on one surface of the insulating base film 3a and a conductive layer 3c on the other surface is used, and the conductive layer 3c should be grounded via the conductive roller 12. The static electricity on the protective adhesive tape 3 is removed by.

FIG. 7 is a cross-sectional view of a main part showing a second embodiment of the tape peeling method according to the present invention, in which the peeling tape 10 has a conductive film between the insulating base film 10a and the strong adhesive layer 10b. Layer 10
What has c and is configured such that a part of the conductive layer 10c is exposed on the surface of the adhesive layer 10b is used. By attaching this peeling tape 10 to the protective adhesive tape 3,
Conductive layer 3c of protective adhesive tape 3 and conductive layer 10 of peeling tape 10
The conductive layer 10c of the peeling tape 10 is grounded through the conductive roller 11 as well as the electric conduction of c, so that the static electricity of the protective adhesive tape 3 as well as the static electricity charged on the peeling tape 10 is removed. The circuit element is surely prevented from being damaged by static electricity.

The following table shows the grounding effect at the time of sticking and peeling when the two types of adhesive protection tapes A and B used in the above-mentioned examples and the peeling tapes C and D are used in combination, and the mechanism is easy. It shows the result of evaluation of the reliability and the certainty of movement.

The protective adhesive tape A is the adhesive tape used in Example 1 and has a structure of base film / conductive layer / adhesive layer. The protective pressure-sensitive adhesive tape B is the pressure-sensitive adhesive tape used in Example 2 and has a structure of conductive layer / base film / adhesive layer. The peeling tape C is the peeling tape used in Example 1 and has a structure of conductive layer / base film / adhesive layer. The release tape D is the release tape used in Example 2 and has a structure of base film / conductive layer / adhesive layer, and a part of the conductive layer is exposed on the surface of the adhesive layer.

The combination 1 to be evaluated is a combination of the protective tape A and the peeling tape C and corresponds to that of the first embodiment. Combination 2
Is a combination of the protective tape A and the peeling tape D. The combination 3 is a combination of the protective tape B and the peeling tape D and corresponds to that of the second embodiment. The combination 4 is a combination of the protective tape B and the peeling tape C.

In the table, ◯ indicates that the evaluation result is excellent, and Δ indicates that it is slightly inferior to the evaluation result of ◯.

<Effects of the Invention> As described above, according to the method for tape-adhering a semiconductor wafer according to the present invention, a protective adhesive tape provided with an insulating base film, a conductive thin layer, and an adhesive layer is used as the conductive thin film. Since the protective adhesive tape is attached to the semiconductor wafer while the layer is grounded via the conductive roller and the semiconductor wafer is also grounded via the table, discharge occurs on the circuit pattern forming surface due to charging of the protective adhesive tape. It is possible to reliably prevent the circuit element of the semiconductor wafer from being damaged by static electricity when the tape is attached.

Also, according to the method for tape-adhering a semiconductor wafer according to the present invention, it is not necessary to mix a conductive substance or a surfactant into the adhesive layer that contacts the wafer surface, and therefore contamination of the semiconductor wafer can be avoided.

Then, according to the tape peeling method for a semiconductor wafer according to the present invention, a peeling tape provided with an insulating base film, a conductive thin layer, and an adhesive layer is grounded through the conductive roller. However, since the semiconductor wafer is also grounded via the table and the peeling table is attached to the protective adhesive tape on the semiconductor wafer to peel off the tape, there is no discharge due to the charging of the peeling tape. It is possible to prevent the circuit element of the semiconductor wafer from being broken by static electricity at the time of peeling.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a semiconductor wafer tape sticking method according to the present invention, FIG. 2 is an enlarged sectional view of a protective adhesive tape used in this method, and FIG. 3 is a tape sticking portion. FIG. 4 is an enlarged cross-sectional view of an essential part showing a first embodiment of a semiconductor wafer tape peeling method according to the present invention, and FIG. 5 is a semiconductor wafer tape sticking method according to the present invention. FIG. 6 is a schematic configuration diagram showing a second embodiment, FIG. 6 is an enlarged sectional view of a protective pressure-sensitive adhesive tape used in this method, and FIG. 7 is a second method of peeling a semiconductor wafer tape according to the present invention.
It is an expanded sectional view of the important section showing an example. 1 ... Semiconductor wafer, 2 ... Table 3 ... Protective adhesive tape, 3c ... Conductive layer 10 ... Release tape

Claims (2)

[Claims] 1. A belt-shaped protective adhesive tape comprising an insulating base film, a conductive thin layer, and an adhesive layer on the circuit pattern forming surface of a semiconductor wafer held on a grounded table, and a grounded conductive roller. A method for tape-adhering a semiconductor wafer, comprising: applying the conductive thin layer to the semiconductor wafer while electrically connecting the protective adhesive tape to the semiconductor wafer. 2. A semiconductor wafer having a protective adhesive tape having an insulating base film, a conductive thin layer, and an adhesive layer attached to a circuit pattern forming surface is held on a grounded table, and the protective adhesive tape An adhesive layer having a stronger adhesive force than the adhesive force, a conductive thin layer, and a strip-shaped release tape having an insulating base film, electrically connecting the conductive thin layer to a grounded conductive roller While sticking to the outer surface of the protective adhesive tape on the semiconductor wafer and peeling off the peeling tape, the protective adhesive tape is peeled from the semiconductor wafer via the peeling tape. Tape peeling method.