JP2003053639A - Holding tool and workpiece joining and detaching method to/from the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To join a planar workpiece like a semiconductor wafer (8) to one side of a holding tool (2) without restraining air bubbles and to detach the workpiece part from the holding tool (2) without generating excessive stress in the workpiece, by improving the holding tool (2) itself and a workpiece joining and detaching method to/from the holding tool (2). SOLUTION: This holding tool (2) is formed of synthetic resin which becomes a rubber state when heated to above a glass transfer temperature and becomes a glass state when cooled to below the glass transfer temperature. When the workpiece is joined and detached to/from the holding tool (2), the holding tool (2) is heated to above the glass transfer temperature to make the tool (2) into the rubber state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-shaped holder used to hold a workpiece when processing a workpiece such as a semiconductor wafer, and a workpiece for the holder. The present invention relates to a joining and detaching method.

[0002]

As is well known to those skilled in the art, in the process of manufacturing a semiconductor chip, the semiconductor wafer is subjected to various machining processes, for example, the back surface is ground to reduce the thickness of the semiconductor wafer, which is caused by grinding. It is necessary to polish the back surface in order to remove the processing strain generated by the above, to cut the semiconductor wafer along the streets arranged in a grid, and to divide it into semiconductor chips. When a semiconductor wafer is subjected to required machining, the semiconductor wafer is held and handled on a holder. As a typical example of the holder, a plate-like holder made of glass, metal, synthetic resin or ceramics can be mentioned. The semiconductor wafer is bonded to one side of the holder via a suitable adhesive or adhesive.

[0003]

However, the conventional plate-shaped holder has the following problems to be decided. When bonding the semiconductor wafer to the one side of the holder, the one side of the holder and the one side of the semiconductor wafer cannot be sufficiently tightly adhered to each other across the whole, and small bubbles are bound between the two, resulting in such bubbles. Then, the semiconductor wafer may be damaged when the semiconductor wafer is machined. Further, when the semiconductor wafer is detached from one surface of the holder, excessive stress may be generated in the semiconductor wafer and the semiconductor wafer may be damaged.

The present invention has been made in view of the above facts, and its main technical problem is to improve the method of joining and releasing the holder itself and the workpieces to and from the holder so that a plate-shaped workpiece such as a semiconductor wafer can be obtained. To allow the work piece to be bonded on one side of the retainer without restraining air bubbles, and also to allow the work piece to be disengaged from the retainer without creating excessive stress on the work piece. Is.

[0005]

Means for Solving the Problems As a result of intensive studies, the present invention has been made from a synthetic resin that becomes a rubber state when heated to a glass transition temperature or higher and a glass state when cooled to a glass transition temperature or lower. In forming the tool, and when joining and releasing the workpiece with respect to the holder, the above-mentioned main technical problem can be achieved by heating the holder to a glass transition temperature or higher to bring it into a rubber state. I found that I could do it.

[0006] That is, according to one aspect of the present invention, a plate-shaped holder for holding a plate-shaped workpiece on one surface thereof is changed to a rubber state when it is heated to a temperature higher than the glass transition temperature. Provided is a holder characterized by being formed of a synthetic resin which becomes a glass state when it is chilled to a lower temperature.

The synthetic resin is preferably polynorbornene. In a preferred embodiment, a tack member made of a rubber sheet or film having tack property is joined to the one surface, and the work piece is joined to the one surface via the tack member. The term "tackiness" used in the present specification means a property (so-called item tackiness) that allows a work piece to be bonded to its surface by a rubber property without using an adhesive or an adhesive. When the tack member is heated to 40 to 250 ° C., the tack property is preferably lowered. The tack member may include a synthetic resin sheet or film laminated on the back surface of the rubber sheet or film. It is preferable that a plurality of concave portions are formed at intervals on the surface of the rubber sheet or film to which the workpiece is joined. Preferably, the surface of the rubber sheet or film to which the workpiece is joined is provided with the recesses in an area ratio of 20 to 50% in plan view, and is flat except for the recesses. It is convenient that a plurality of through holes are formed so as to penetrate in the thickness direction from the upper surface to the lower surface. The work piece may be a semiconductor wafer.

According to another aspect of the present invention, a method for joining a work piece to the holder is provided, the work piece is placed on the flat surface of the supporting means, and then the temperature is higher than the glass transition temperature. The holder that is heated to make it in a rubber state is gradually brought into a flat state from a curved state, so that one side of the holder is gradually brought into close contact with the workpiece from one side to the other side. A method is provided that is characterized by:
Further, the work piece joined to one side of the holder is separated from the one side of the holder, and the work piece is a lower layer and the holder is an upper layer on the flat surface of the supporting means. Placed in such a state, at the same time as or before or after such placement, the holder is heated to a temperature higher than the glass transition temperature to be in a rubber state, and then the holder is gradually curved from a flat state, Provided is a method characterized in that the one side of the holder is gradually separated from the work piece from one side thereof to the other side.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a holder constructed according to the present invention and a method of joining and releasing workpieces to and from the holder will be described below with reference to the accompanying drawings.
Detailed description.

1 and 2 illustrate a preferred embodiment of a retainer constructed in accordance with the present invention. The holder 2 includes a disc-shaped main body 4. It is important that the main body 4 is made of a synthetic resin that becomes a rubber state when it is heated to a temperature higher than the glass transition temperature and a glass state when it is heated to a temperature lower than the glass transition temperature. As such a synthetic resin, polynorbornene sold by Nippon Zeon Co., Ltd. under the trade name "No Solex" can be mentioned. Polynorbornene has an upper limit of glass transition temperature of about 40 ° C. and a lower limit of glass transition temperature of about 36 ° C. When it is heated to about 40 ° C. or higher, its elastic modulus decreases and becomes a rubber state, and it is cooled to about 36 ° C. or lower. And the elastic modulus increases and it becomes a glass state.

In the illustrated holder 2, a rubber sheet or film having tackiness on one surface (upper surface in FIG. 2) of the main body 4, that is, so-called self-adhesiveness for bonding a workpiece to the surface due to rubber characteristics. The tack member 6 formed of is joined. Such tack member 6
It is preferable that, in addition to the tackiness, the tackiness is softened when heated to, for example, about 40 to 250 ° C., and the tackiness is reduced or eliminated. Preferable examples of such a rubber sheet or film include silicone rubber sheets or films sold by Kureha Elastomer Co., Ltd. under the trade name “Perapera-kun”. The tack member 6 can be composed only of such a rubber sheet or film, but if desired, a polyethylene terephthalate sheet or film, a polyethylene sheet or film, or a polypropylene sheet or film may be appropriately provided on the back surface of the rubber sheet or film. The tack member 6 can also be formed by laminating the synthetic resin sheets or films described in 1 above by adhesion or heat fusion with an appropriate adhesive or adhesive. As shown in FIG. 2, a plurality of recesses 10 are formed at intervals on the surface (that is, the upper surface in FIG. 2) of the tack member 6 to which the workpiece, that is, the semiconductor wafer 8 (FIG. 3) is bonded. Is preferred. The recesses 10 may be, for example, circular recesses arranged at appropriate intervals or channel-like recesses extending in parallel at appropriate intervals. The proportion of the recesses 8 is preferably about 20 to 50% in terms of area in plan view. According to the experience of the present inventor, the recess 10
When the tack member 6 is formed, the tack property is effectively reduced or eliminated when the tack member 6 is heated, and the semiconductor wafer 10 is easily separated from the tack member 6. On the other hand, if the proportion of the recesses 10 is excessive, the tackiness of the tack member 6 at room temperature tends to be too small. The tack member 6 in the illustrated embodiment has a substantially same shape as the main body 4, and thus a circular shape having substantially the same diameter, and the tacking member 6 is bonded to one surface of the main body 4 by its tackiness itself or is formed by an appropriate adhesive or adhesive agent. 4 is joined on one side.

In the illustrated embodiment, the body 4 is further
Further, a plurality of through holes 12 extending through the tack member 6 in the thickness direction thereof (thus penetrating from the upper surface to the lower surface of the holder 2) are provided.

Continuing the description with reference to FIG. 3 together with FIG. 1 and FIG. 2, when the semiconductor wafer 8 which is a plate-shaped workpiece is to be machined, one side of the holder 2 is used, in the illustrated embodiment. Joins the semiconductor wafer 8 on the surface where the tack member 6 is joined. At this time, as shown in FIG. 3, the semiconductor wafer 8 is placed on the supporting means 16 having the flat supporting surface 14. When grinding or polishing the back surface of the semiconductor wafer 8, the semiconductor wafer 8 is placed on the support surface 14 with the back surface facing downward and the surface exposed upward. When cutting from the surface of the semiconductor wafer 8 along the sleet, the semiconductor wafer 8 is placed on the support surface 14 with the front surface facing downward and the back surface exposed upward.
Next, for example, by holding the main body 4 in a rubber state by heating it to a temperature higher than the glass transition temperature (for example, 40 ° C.) by housing it in a heating chamber for a predetermined time, as shown by a chain double-dashed line 2A in FIG. One side of the one side (right side in FIG. 3) is brought into close contact with one side of the one side of the semiconductor wafer 8 in a curved state. Then, in FIG. 3, two-dot chain lines 2B and 2C are shown.
As shown in FIG. 3, the holding tool 2 is gradually flattened from the curved state, so that one side of the holding tool 2 is gradually brought into close contact with one side of the semiconductor wafer 8 from one side to the other side (left side in FIG. 3). Then, the state shown by the solid line in FIG. 3 is established. At this time, for example, a pressing roller (not shown) may be applied to the upper surface of the holder 2 to gradually press one surface of the holder 2 against one surface of the semiconductor wafer 8. By making the holder 2 in which the main body 4 is in the rubber state be gradually flat from the curved state,
Since one side of the holder 2 is gradually brought into close contact with one side of the semiconductor wafer 8 from one side to the other side, the semiconductor wafer 8 can be held without binding air bubbles between the one side of the holder 2 and the one side of the semiconductor wafer 8. The one side of the holding tool 2 can be brought into close contact with the entire one side.

After the state shown by the solid line in FIG. 3 is established, when the holder 2 is cooled to a temperature lower than the glass transition temperature (for example, 30 ° C.), the tackiness of the tack member 6 is restored, whereby the holder is held. The semiconductor wafer 8 is bonded to one surface of 2 sufficiently firmly. In addition, the main body of the holder 2 is in a glass state to increase the elastic modulus, which effectively reinforces the semiconductor wafer 8.

After the semiconductor wafer 8 is bonded to one surface of the holder 2 as described above, the back surface of the semiconductor wafer 8 bonded to one surface of the holder 2 is ground or polished or cut from the front surface. The required machining can be performed as described above. At this time, normally, the holder 2 is placed in a lower layer and the semiconductor wafer 8 is placed in an upper layer (hence, the state shown in FIG. 3 is turned upside down) and placed on the chuck means (not shown) of the processing machine. Deploy. The chuck means has a chuck plate formed of a porous material or formed with appropriate suction holes or grooves, and the holder 2 and the semiconductor wafer 8 are vacuum-adsorbed on the chuck means by connecting the chuck plate to a vacuum source. To be done. Illustrated holder 2
Since a plurality of through holes 12 are formed in
The vacuum suction action also acts directly on the semiconductor wafer 8 through the through holes 12, and thus the semiconductor wafer 8 is held sufficiently firmly on the chuck means.

After the semiconductor wafer 8 joined to the holder 2 has been subjected to the required machining, the semiconductor wafer 8 is
It is necessary to disengage the holder 2 from the. At this time, an operation similar to the above-described operation when joining the semiconductor wafer 8 to one surface of the holder 2 may be performed.
More specifically with reference to FIG. 3, the supporting surface 14 of the supporting means 16 is formed with the semiconductor wafer 8 in the lower layer and the holder 2 in the upper layer.
Place on top. Then, the holder 2 is heated to, for example, 40 ° C. or higher. An appropriate heating means (not shown) such as an electric resistance heating wire is provided in the support means 16, and the holder 2 can be heated as required by urging the heating means. When the holder 2 is heated, the tackiness of the tack member 6 is reduced or eliminated. Also,
The elastic modulus of the main body 4 is lowered and the main body 4 becomes a rubber state. Then, the semiconductor wafer 8 is made to rest on the support surface 14,
The holder 2 is gradually curved from the flat state shown by the solid line in FIG. 3 to the state shown by the chain double-dashed lines 2C, 2B and 2A in FIG. 3, and one side of the holder 2 is moved from one side (left side in FIG. 3) to the other side. The semiconductor wafer 8 is gradually separated from one side toward the side (right side in FIG. 3). In order to maintain the semiconductor wafer 8 in a stationary state, for example, at least a part of the support surface 14 is formed of a porous material or suction holes or grooves are formed in at least a part of the support surface 14 and the support surface 14 is used as a vacuum source. The semiconductor wafer 8 may be vacuum-adsorbed on the support surface 14 by communicating with each other. Excessive stress is generated in the semiconductor wafer 8 because the detachment of one side of the holder 2 from one side of the semiconductor wafer 8 is gradually advanced from one side to the other side by gradually bending the holder 2. Therefore, there is no risk that the semiconductor wafer 8 will be damaged.

In the above-described embodiment, the tack member 6 is bonded to one surface of the holder 2 in order to bond the semiconductor wafer 8 to one surface of the holder 2. However, if desired, the tack member 6 may be replaced with a semiconductor. One side of wafer 8 and / or holder 2
It is also possible to apply an appropriate pressure sensitive adhesive or adhesive to one side of and to bond the semiconductor wafer 8 to one side of the holder 2 by means of the pressure sensitive adhesive or adhesive. In this case, an adhesive or adhesive whose bonding strength is reduced or eliminated by heating or UV irradiation is used, and when the semiconductor wafer 8 is detached from one surface of the holder 2, the adhesive or adhesive is heated or UV. It is convenient to irradiate.

[0018]

According to the present invention, a plate-like work piece such as a semiconductor wafer can be bonded on one side of a holder without restraining air bubbles, and excessive stress is generated in the work piece. It is possible to disengage the processed portion from the holder without pressing.

[Brief description of drawings]

FIG. 1 is a perspective view of a preferred embodiment of a holder constructed in accordance with the present invention.

FIG. 2 is a sectional view of the holder shown in FIG.

FIG. 3 is a cross-sectional view for explaining a method of joining and releasing a semiconductor wafer, which is a workpiece, with respect to the holder shown in FIG.

[Explanation of symbols]

2: Holder 4: Main body of holder 6: Tack member 8: Semiconductor wafer 10: Recess 12: Through hole 14: Support surface 16: Supporting means

Claims (11)

[Claims] 1. A plate-shaped holder for holding a plate-shaped work piece on one surface, which becomes a rubber state when heated to a temperature higher than the glass transition temperature, and a glass state when pressed to a temperature lower than the glass transition temperature. The holder is made of a synthetic resin. 2. The synthetic resin is polynorbornene,
The holder according to claim 1. 3. A tack member composed of a rubber sheet or film having tackiness is joined to the one surface, and a work piece is joined to the one surface through the tack member. The holder according to 1 or 2. 4. The holder according to claim 4, wherein the tacking property of the tacking member deteriorates when heated to 40 to 250 ° C. 5. The holder according to claim 3, wherein the tack member includes a synthetic resin sheet or film laminated on the back surface of the rubber sheet or film. 6. The holding according to any one of claims 3 to 5, wherein a plurality of recesses are formed at intervals on a surface of the rubber sheet or film to which a workpiece is joined. Ingredient 7. The surface of the rubber sheet or film to which the workpiece is bonded is 20 to 50% in plan view.
7. The holder according to claim 6, wherein the concave portion is formed in an area ratio of, and is flat except for the concave portion. 8. The holder according to any one of claims 1 to 7, wherein a plurality of through holes are formed so as to penetrate in the thickness direction from the upper surface to the lower surface. 9. The holder according to claim 1, wherein the work piece is a semiconductor wafer. 10. A method for joining a work piece to the holder according to claim 1, wherein the work piece is placed on a flat surface of the supporting means, and then the glass transition temperature is set. The holding tool, which is heated to a higher temperature than that and made to be in a rubber state, is gradually made flat from a curved state, so that one surface of the holding tool gradually becomes a work piece from one side to the other side. A method characterized by being intimate. 11. A flat surface of a support means, comprising a method of separating a workpiece joined to one surface of a holder according to any one of claims 1 to 9 from the one surface of the holder. The work piece is placed on the lower layer in a state in which the holder is in the upper layer, and at the same time as or before or after such placing, the holder is heated to a temperature higher than the glass transition temperature to be in a rubber state, and then, A method of gradually bending the holder from a flat state to gradually separate the one surface of the holder from one side of the holder to the other side of the work piece.