JP4476595B2 - Vacuum suction jig - Google Patents

Description

  The present invention relates to a vacuum chucking jig used for sucking and holding a semiconductor wafer, a glass substrate, or the like, which is a workpiece (a workpiece to be adsorbed), when performing wet processing such as lapping.

For example, when a semiconductor wafer is transported, processed, or inspected in the process of manufacturing a semiconductor device, a jig for holding the semiconductor wafer using a vacuum adsorption force is used. As such a vacuum suction jig, generally, a plurality of openings are formed on a suction surface on which a semiconductor wafer as an object to be sucked is placed, and a plurality of through holes continuing from each of the openings are formed inside. is there. During use, the inside of the through hole is evacuated by the action of a vacuum pump connected to the jig, and as a result, the semiconductor wafer placed so as to close the opening of the adsorption surface is adsorbed and held by the jig.

  However, this vacuum suction jig has the following problems. That is, the openings are formed on the jig suction surface at a certain interval, but the vacuum suction force actually works only locally, that is, only at the point where the opening exists. Therefore, the suction force is not uniform, and it is difficult to realize a stable suction holding state. Of course, in such a state, various problems such as a decrease in the processing accuracy of the semiconductor wafer are likely to occur.

In view of these problems, a jig is proposed in which a portion on which an adsorbent is placed is made of a porous body (see, for example, Patent Document 1). More specifically, the improved vacuum suction jig includes a mounting member made of a porous body having innumerable pores communicating with each other on the surface and inside, and a support member made of a non-porous body. As a main component. The support member has a recess that accommodates the entire mounting member. Therefore, both of the mounting member are fitted and accommodated in the support member with the glass sheet serving as a sealing layer or the glass sheet and the glass powder interposed therebetween. First, it is combined so that it will be in the state. The improved vacuum chuck is completed by further heat-treating at a predetermined temperature, joining the support member and the mounting member, and integrating them.
JP-A-53-90871

If the vacuum suction jig according to the above proposal is used, an object to be adsorbed such as a semiconductor wafer can be adsorbed with a uniform force over the entire adsorbing surface. That is, it is possible to easily realize a stable suction holding state, and problems such as a decrease in processing accuracy are unlikely to occur. However, on the other hand, it has the following problems. When processing the object to be adsorbed and held, for example, when grinding, contaminants such as grinding scraps and falling abrasive grains (abrasive grains dropped due to the self-generated action of the grinding wheel) are generated. Under such circumstances, when a vacuum suction jig having a mounting member made of a porous material is used, contaminants are inevitably sucked into the mounting member.

  If the vacuum suction jig is continuously used in a state where the contaminant has entered the inside of the mounting member (clogged state), the contaminant may be transferred to the back surface of the semiconductor wafer. For this reason, the vacuum suction jig, particularly its mounting member, must be cleaned periodically. By the way, the cleaning operation is performed by press-fitting the cleaning liquid into the jig from the suction port on the back surface of the support member. However, with the conventional vacuum chuck, the cleaning liquid leaks from the boundary between the mounting member and the support member even after such a cleaning process, completely eliminating clogging of the mounting member due to contaminants. There were many things I couldn't do.

  Therefore, the problem to be solved by the present invention is to prevent the cleaning liquid from leaking from the boundary portion between the mounting member and the support member during cleaning, and the contaminants that have entered the mounting member are transferred to the surface to be adsorbed. , To avoid the problem of contaminating it. Furthermore, the clogging of the mounting member is completely eliminated by the cleaning process so that the vacuum suction jig can withstand long-term use.

As a result of advancing earnest research to solve the above problems, the present invention has found the cause of the cleaning liquid leaking from the boundary portion between the mounting member and the support member during cleaning. In other words, as described above, a conventional vacuum suction jig is manufactured by storing a mounting member made of a porous body in a concave portion of a support member with a glass powder serving as an adhesive layer interposed therebetween, and further performing a heat treatment. ing. That is, the molten glass integrates the mounting member and the support member, and as a result, a vacuum suction jig is completed.

  When the mounting member is bonded to the support member by such a technique, a fine gap is likely to be generated on the joint surface between them, more specifically, on the boundary surface between the mounting member and the adhesive layer. This is considered to be because a part of the molten glass penetrates into the surface layer portion of the mounting member. Now, when the cleaning liquid is press-fitted into the vacuum suction jig, it is ideal that the entire amount is discharged from the surface (suction surface) through the inside of the mounting member. However, in a vacuum suction jig in which a fine gap is generated in the boundary region between the mounting member and the adhesive layer, most of the cleaning liquid press-fitted into the gap passes through the gap, and the mounting member and the support member It will be discharged | emitted out of the space | gap between a boundary part and the aspect of a mounting member and the recessed part surrounding wall surface of a supporting member correctly. For these reasons, conventionally, the inside of the mounting member cannot be sufficiently cleaned.

  Therefore, the present inventor passes an unnecessary flow of the cleaning liquid toward the gap between the peripheral surface of the mounting member and the concave peripheral wall surface of the support member through the fine gap generated in the boundary region between the mounting member and the adhesive layer. We thought that the above problem could be solved by devising the internal structure of the jig so that it could be shut off. Based on these technical ideas. As a result of further research, on the bottom surface of the concave portion of the support member, at least organic on the surface of the annular plate glass or the annular plate glass so as to surround the boundary area between the mounting member and the adhesive layer along the peripheral wall surface of the concave portion. It has been found that an annular sealing layer obtained by melting and solidifying glass powder containing a system adhesive may be provided.

  That is, when a glass powder containing an organic adhesive applied to the surface of an annular plate glass or an annular plate glass is subjected to heat treatment, the plate glass partially melts and is further generated from the organic adhesive. The glass in which the gas is melted is foamed and finally becomes a closed pore layer having a sufficient liquid-tightness, that is, a sealing layer. Then, the sealing layer arranged as described above passes through a fine gap generated in the boundary region between the mounting member and the adhesive layer, and is formed into a gap between the peripheral surface of the mounting member and the concave peripheral wall surface of the support member. The direction of the flow of cleaning liquid is completely blocked by the presence of the annular sealing layer. Therefore, the entire amount of the cleaning liquid press-fitted into the vacuum suction jig is discharged from the surface (suction surface) through the inside of the mounting member.

  The present invention has been made on the basis of such new findings, and in order to solve the above-described problems, a placement member composed of a porous body on which an object to be adsorbed is placed, and a main surface side. A lower surface that is formed with a recess for accommodating the mounting member, and that supports a support member that supports the mounting member in a state in which the mounting member is accommodated in the recess, and an upper surface that contacts the object to be adsorbed on the mounting member. And an adhesive layer for joining the mounting member and the support member, interposed between the bottom surface of the concave portion in the support member, on the bottom surface of the concave portion in the support member. After installing the annular plate glass or the glass plate containing at least an organic adhesive on the surface of the annular plate glass so as to surround the boundary area between the mounting member and the adhesive layer along the peripheral wall surface of the recess Heat treated to melt and solidify It is not characterized by providing an annular sealing layer was obtained. Here, “surrounding the boundary area between the mounting member and the adhesive layer” means that the sealing layer extends over both the mounting member and the adhesive layer and exists in contact with them. To do.

  In addition, as a cyclic | annular plate glass which forms the said sealing layer, the commercially available normal plate glass which melt | dissolves partially at the temperature of about 900 degreeC can be used. Moreover, as a mixture which the mixture which forms the said sealing layer apply | coated to this cyclic | annular plate glass surface contains a commercially available organic adhesive, an epoxy resin, a silicone resin, an acrylic resin, a phenol resin etc. are mentioned, for example. In addition, alumina (Al2O3) powder or the like may be further mixed with the mixture forming the sealing layer, and in this case, the alumina powder functions as a filler.

In particular, when a mixture composed of three components of glass powder, epoxy resin, and alumina powder is used as the mixture applied to the surface of the annular plate glass forming the sealing layer, the ratio of the glass powder is 50 to 80% by weight, epoxy resin Is preferably set to 10 to 20% by weight, and the alumina powder is preferably set to 10 to 30% by weight. However, it goes without saying that the ratio α of the glass powder, the ratio β of the epoxy resin, and the ratio γ of the alumina powder are mutually adjusted so that the sum of these, that is, α + β + γ becomes 100%.

    When the vacuum suction jig is configured as described above, first, the mounting member and the supporting member can be bonded (temporarily fixed) via an annular plate glass at room temperature due to the presence of the organic adhesive. As a result, the workability at the time of manufacturing the jig is greatly improved. Next, when the heat treatment is performed, as described above, a part of the annular plate glass and the glass powder containing the organic adhesive are foamed and melted to form an annular sealing layer, which is formed between the mounting member and the adhesive layer. The flow of the cleaning liquid toward the gap between the peripheral surface of the mounting member and the peripheral wall surface of the concave portion of the support member is completely blocked through the fine gap generated in the boundary region. Therefore, the cleaning liquid press-fitted into the vacuum suction jig does not leak out from the boundary portion between the mounting member and the support member, and all of it is discharged from the entire suction surface through the mounting member. Will come to be.

  Therefore, the vacuum suction jig according to the present invention can sufficiently clean the inside of the mounting member. That is, by continuously using the jig for a certain period of time, even if a contaminant enters the inside of the mounting member, it can be quickly removed by performing a cleaning operation. Further, by periodically performing the cleaning operation, the problem that the contaminants that have entered the inside of the mounting member are transferred to the surface to be adsorbed and contaminated is solved. Furthermore, since the vacuum suction jig according to the present invention can eliminate clogging of the mounting member by the cleaning process, it can sufficiently withstand long-term use while maintaining good suction performance. Therefore, the service life can be extended and the economy is excellent.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. Here, FIG. 1 is a plan view of a vacuum suction jig (hereinafter also referred to as this jig) according to the present embodiment, and FIG. 2 is a cross-sectional view of the jig taken along line XX in FIG. Now, this jig is used, for example, for sucking and holding a semiconductor wafer or the like. That is, an object to be adsorbed such as a semiconductor wafer is conveyed while being adsorbed and held by the jig, and processing and inspection are performed in the same state.

  The jig has a disk-like outer shape, and a semiconductor wafer (adsorbed object) F is adsorbed and held on the upper surface (adsorption surface) of the jig as indicated by a one-dot chain line in FIG. That is, when a vacuum pump (not shown) is operated, the internal space of the jig connected thereto is in a vacuum state, and the resulting vacuum suction force restrains the semiconductor wafer F on the suction surface.

  Now, the jig includes a mounting member 1 and a support member 2 as main components. Among these, the mounting member 1 is composed of a porous body, and a semiconductor wafer F as an adsorbed material is directly mounted thereon. More specifically, the mounting member 1 is made of ceramics such as alumina, and its upper surface (adsorption surface) is sufficiently flattened by polishing. Further, the peripheral surface of the mounting member 1 is sealed. That is, the opening of the pores was closed by coating the peripheral surface with glass so that suction was not performed from the peripheral surface. In addition, an annular notch is provided in the lower surface side peripheral portion of the mounting member 1. That is, the lower surface side peripheral portion of the mounting member 1 formed a step portion over the upper surface. This is to secure a space for arranging a sealing layer described later.

  In the present embodiment, first, a glass paste is applied to the peripheral surface of the mounting member 1, and then fired at about 1000 ° C. to form a glass coating layer (not shown). However, the sealing method is not limited to this. In addition, various methods such as resin coating, thermal spraying, and plating can be adopted in consideration of the material of the mounting member 1.

  Moreover, the material of the porous body which comprises the mounting member 1 is not limited to the thing of this embodiment. In addition, for example, the mounting member 1 can be obtained using a ceramic material such as zirconia, silicon carbide, or silicon nitride, a metal material such as copper, aluminum, or stainless steel, or a resin material such as fluororesin. Incidentally, the porous body constituting the mounting member 1 is preferably one having an average pore diameter of about 10 to 100 μm and a porosity of 20 to 40%.

  Next, as for the support member 2, this support member 2 is also made of ceramics such as alumina. However, unlike the mounting member 1, the ceramic constituting the supporting member 2 is a dense non-porous body. The material of the support member 2 is not limited to that of the present embodiment, and other than that, for example, a ceramic material such as zirconia, silicon carbide, or silicon nitride, or a metal material such as aluminum is used. Can be configured.

  On the upper surface side (one main surface side) of the support member 2, a circular recess (large-diameter recess) 2 a having almost the same size as the outer shape of the mounting member 1 is formed. It is integrated with the support member 2 in a state of being completely accommodated. In other words, the support member 2 has a recess 2a for accommodating the mounting member 1, and plays a role of supporting the mounting member 1 in a state of being fitted and accommodated in the recess 2a. A recess (small-diameter recess) 2b having an inner diameter smaller than the recess 2a in which the mounting member 1 is accommodated is further formed inside the support member 2. The open surface of the recess 2 b is at the same height as the bottom surface of the recess 2 a, and the bottom surface is connected to the intake port 2 c provided on the lower surface of the support member 2. Therefore, when the mounting member 1 and the supporting member 2 are integrated, that is, in a state where the opening surface of the recess 2b is closed by the mounting member 1, the vacuum pump connected to the air inlet 2c is operated. The inside of 2b becomes a vacuum.

  Next, the structure of the joint portion between the mounting member 1 and the support member 2 will be described in more detail. The jig includes an adhesive layer 3 that joins the placement member 1 and the support member 2. That is, the adhesive layer 3 having a small thickness is interposed between the lower surface facing the upper surface of the mounting member 1 that contacts the semiconductor wafer F and the bottom surface of the recess 2 a of the support member 2. The adhesive layer 3 is obtained by melting and solidifying glass powder (for example, one having a softening temperature lower than that of the glass used for the sealing treatment) by heat treatment.

  The jig further includes an annular sealing layer 4 in addition to the adhesive layer 3. The sealing layer 4 is provided on the bottom surface of the concave portion 2a in the support member 2 so as to surround the boundary area between the mounting member 1 and the adhesive layer 3 along the peripheral wall surface of the concave portion 2a. In other words, in this embodiment, the boundary surface between the mounting member 1 and the adhesive layer 3 is in a state of being completely contained in an open space surrounded by the annular sealing layer 4. The sealing layer 4 is obtained by melting and solidifying an annular plate glass or a glass plate containing glass powder containing at least an organic adhesive on the surface of the annular plate glass after installation.

  The approximate manufacturing procedure of this jig (joining procedure of the mounting member 1 and the support member 2) is as follows. In order to obtain this jig, first, on the bottom surface of the recess 2a in the support member 2, especially along the peripheral wall surface thereof, an annular plate glass, or a glass powder containing at least an organic adhesive on the surface of the annular plate glass The one coated with (hereinafter referred to as a mixture forming a sealing layer) is installed in an annular shape. However, the mixture forming the sealing layer may be disposed on the mounting member 1 side, particularly on the stepped portion. In addition to this, an appropriate amount of glass powder to be the adhesive layer 3 is dispersed on the bottom surface of the recess 2a in the support member 2.

  When the preparation for joining is thus completed, the mounting member 1 whose peripheral surface has been sealed is then housed in the recess 2 a of the support member 2. At this time, due to the adhesive action of the mixture forming the sealing layer, the mounting member 1 is simply temporarily fixed to the support member 2 regardless of the room temperature. After the mounting member 1 is assembled to the support member 2, heat treatment is performed at about 900 ° C., for example, and the two are completely integrated by the action of the adhesive layer 3 and the sealing layer 4 formed thereby. Finally, if the surface (suction surface) on which the semiconductor wafer F is placed is polished using a diamond grindstone or the like, a vacuum suction jig having a cross section as shown in FIG. 2 is completed.

  When the vacuum suction jig is configured as described above, a glass powder containing a part of the annular plate glass and the organic adhesive is foamed and melted to form the annular sealing layer 4 when heat treatment is performed. And this is the flow of the cleaning liquid toward the gap between the peripheral surface of the mounting member 1 and the peripheral wall surface of the recess 2a in the support member 2 through a fine gap generated in the boundary region between the mounting member 1 and the adhesive layer 3. Is completely shut off. Therefore, a part of the cleaning liquid press-fitted into the vacuum suction jig does not leak out from the boundary portion between the mounting member 1 and the supporting member 2, and the entire amount passes through the mounting member 1. , Discharged from the entire adsorption surface.

  Therefore, this jig can sufficiently clean the inside of the mounting member 1. That is, by continuously using this jig for a certain period of time, even if a contaminant enters the inside of the mounting member 1, it can be quickly removed by performing a cleaning operation. Further, the problem that the contaminants that have entered the inside of the mounting member 1 are transferred to the back surface of the semiconductor wafer F and contaminate it does not occur. Further, the jig can easily remove the clogging of the mounting member 1 by the cleaning process, and thus can sufficiently withstand long-term use while maintaining good adsorption performance. Therefore, the service life can be extended and the economy is excellent.

  As a mixture for applying the vacuum suction jig according to the present embodiment to an annular plate glass and its surface to form a sealing layer, an annular plate glass (product name: float plate glass manufactured by Asahi Glass Co., Ltd.), glass powder (product name: ASF-100 manufactured by Asahi Glass Co., Ltd., epoxy resin (product name: XNR-3305 manufactured by Three Bond Co.), and alumina powder (WA # 200) were used to produce a total of four types. Hereinafter, Examples 1 to 5 are different from each other in the mixing ratio of the above three components expressed in mass%. That is, Example 1 is composed only of an annular plate glass. In Example 2, the distribution ratio of glass powder, epoxy resin, and alumina powder is 60:20:20. The blending ratio of Example 3 is 80:10:10, and the blending ratios of Example 4 and Example 5 are 50:30:20 and 40:40:20, respectively. For comparison, a conventional vacuum suction jig having no annular sealing layer was also prepared (hereinafter referred to as a comparative example. Other conditions are the same as those in Examples 1 to 5).

  A cleaning test was conducted on Examples 1 to 5 and Comparative Example, and the presence or absence of leakage of the cleaning liquid was examined. The pressure of the cleaning liquid is 400 kPa (about 4 atm). The results were as shown in Table 1 below. Next, with respect to Examples 1 to 5 and the comparative example, the adsorption performance at the start of use and the adsorption performance after alternately repeating the use and the washing treatment 100 times (after 100 cycles) were examined. That is, a semiconductor wafer was used as an object to be adsorbed, and the adsorption ability of each jig was evaluated in three stages: ◎ (very good), ○ (good), and × (insufficient adsorption power). The results are also shown in Table 1.

From the results of Table 1, the vacuum adsorption jig of the present invention did not leak the cleaning liquid, and the adsorption performance after 100 times of repeated use and cleaning treatment (after 100 cycles) was good.
On the other hand, in the comparative example, leakage of the cleaning liquid was observed, and the decrease in adsorption performance was significant. Furthermore, the degree of contamination of the adsorbents has increased significantly.

It is a top view of the jig for vacuum suction concerning the embodiment of the present invention. It is sectional drawing of the jig | tool for vacuum suction which concerns on embodiment of this invention in the XX line in FIG.

Explanation of symbols

1 Mounting member 2 Support member
2a Recess of support member (large diameter recess)
2b Support member recess (small-diameter recess)
2c Support member air inlet 3 Adhesive layer 4 Sealing layer F Semiconductor wafer (adsorbent)

Claims (1)

A placing member made of a porous body on which an object to be adsorbed is placed, and a concave portion for accommodating the placing member is formed on one main surface side. A mounting member and a supporting member that are interposed between a supporting member that is supported in a state of being accommodated in the housing, a lower surface that opposes the upper surface that contacts the object to be adsorbed in the mounting member, and a bottom surface of the recess in the supporting member A vacuum suction jig comprising a bonding layer to be joined, and on the bottom surface of the concave portion of the support member, so as to surround the boundary region between the mounting member and the adhesive layer along the peripheral wall surface of the concave portion, A vacuum suction jig comprising an annular sealing layer obtained by heat-treating a glass plate containing at least an organic adhesive coated on an annular plate glass surface after installation.

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