JP2009066717A - Gap filler for polishing pad and method for filling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gap filler which prevents corrosion on a polishing plate and contamination during polishing, also prevents a polishing pad from peeling when the divided polishing pad is attached onto the polishing plate, and is easy to control a hardening speed or a viscosity during filling. <P>SOLUTION: The polishing pad 2 is divided into a plurality of pieces, and a gap 8 on a joint of the divided polishing pad pieces 2 is filled with a gap filler 9. The gap filler 9 is a mixture of urethane resin and dimethylformamide, having a 5,000-20,000 cps viscosity, and a 15-30 wt.% percentage of the urethane resin in the filler. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gap filler for a polishing pad used in silicon wafers, semiconductor devices, glass, and other precision polishing applications, and a filling method thereof.

  A conventional silicon wafer polishing apparatus using CMP (Chemical Mechanical Polishing) will be described with reference to FIG.

  In FIG. 1, 1 is a surface plate, 2 is a polishing pad affixed to the surface of the surface plate 1 with an adhesive 7, 3 is a silicon wafer (object to be polished), and 4 is a polishing head. The surface plate 1 is rotationally driven in the direction of arrow 5 and the polishing head 4 is rotationally driven in the direction of arrow 6 opposite to the direction of arrow 5.

  Then, the wafer 3 held by the polishing head 4 is pressed against the polishing pad 2 installed on the surface plate 1, and the slurry is supplied from a nozzle (not shown) while the surface plate 1 and the polishing head 4 are moved to the arrows 5 and 6. The wafer 3 is polished by the polishing pad 2 by rotating in the direction.

  As the polishing pad 2 used for CMP, a single seamless polishing pad is usually used. However, with the recent increase in the size of the wafer 3, a large polishing pad 2 is required, and it is difficult to supply such a large polishing pad due to problems in manufacturing and transportation.

Therefore, a large polishing pad is manufactured by dividing it into a half circle, such as 1/2 or 1/4, and a plurality of these polishing pads are attached to the surface of the surface plate. .
JP-A-8-295866

  When the divided polishing pads are bonded to the surface of the surface plate, it is necessary to carefully bond the polishing pads without any gaps at the abutting portions of the polishing pads.

  This is because, when a gap occurs in the abutting portion of the polishing pad, the slurry directly touches the surface of the surface plate, so that the surface plate surface is corroded or contaminated by shavings during polishing (hereinafter referred to as contamination). It is a cause.

  In addition, there is a problem in that the adhesive material, which has adhered the polishing pad to the surface of the surface plate, is damaged by the slurry that has entered from the gap, and peeling occurs from the butt portion.

  In this way, it was necessary to apply the gap between the polishing pads without any gaps. However, if the gap was created, it would be necessary to re-paste the polishing pads themselves due to the non-uniformity of the adhesive material. This was not possible because the flatness of the glass was impaired.

  Furthermore, as disclosed in Patent Document 1, for example, a method of filling a gap with a filler of a type in which two organic solvents are mixed and cured is conceivable. However, the curing speed and viscosity can be adjusted during the filling operation. Because it is difficult and difficult to handle, problems arise if workability is poor.

  The gap filler for polishing pads of the present invention is a gap filler that fills the gaps between the butt portions of the divided polishing pads, and is a mixture of a urethane resin and a solvent, and the solvent is replaced with water. The urethane resin is cured.

  As the solvent, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, or N-methylpyrrolidone is used.

  The viscosity is 5000-20000 cps. Preferably, the viscosity is 9000-18000 cps.

  The ratio of the urethane resin in the filler is 15 to 30 wt%.

  The method for filling the gap filler for polishing pads of the present invention is a mixture of urethane resin and solvent in the gap between the butt portions of the divided polishing pads, and the solvent replaces water and cures the urethane resin. It includes a step of filling the gap filler, and a step of applying water to the surface of the gap filler to replace the solvent and curing the urethane resin.

  According to the gap filler for polishing pads and the filling method of the present invention, when a large polishing pad is divided and attached to the surface of the surface plate, the gap filler is filled in the gap generated at the abutting portion between the polishing pads. Therefore, the surface of the surface plate exposed on the bottom surface of the gap and the part where the polishing pad and the surface plate are attached are covered with a gap filler, preventing corrosion of the surface plate surface and contamination during polishing, and also peeling of the polishing pad. Can be prevented.

  Further, the gap filler is a mixture of a urethane resin and a solvent, and the solvent is substituted with water to cure the urethane resin. For example, compared to a type in which two organic solvents are mixed and cured, Since it is cured using, the workability is excellent because the curing speed and viscosity can be easily adjusted and handled easily.

  According to the gap filler for polishing pad and the filling method of the present invention, when a polishing pad divided on the surface plate surface is applied, corrosion of the surface plate surface and contamination during polishing are prevented, and the polishing pad is used. Can also be prevented. Further, at the time of filling, adjustment of the curing speed and viscosity is easy and easy to handle, so that workability is excellent.

  An embodiment of the present invention will be described with reference to FIGS.

  The polishing apparatus of this embodiment relates to a silicon wafer polishing apparatus by CMP shown in FIG.

  FIG. 2 is a plan view showing a state where a polishing pad divided on the surface of the surface plate is attached, FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIG. Show.

  2 and 3, polishing pads 2 and 2 divided in half are arranged and pasted on the surface of a surface plate 1 made of a metal material such as stainless steel. When affixing the polishing pads 2, 2, it is preferable not to create a gap at the abutting portion between the polishing pads 2, 2. However, it is difficult to accurately position the polishing pads 2 and 2 so that no gap is generated, and a gap 8 is generated at the abutting portion as shown in the figure. The gap 8 is filled with a gap filler 9.

  Examples of the polishing pad 2 include a polishing pad having a structure in which a nonwoven fabric is impregnated with resin, a polishing pad having a bulk structure including bubbles, or a polishing pad having a bulk structure not including bubbles.

  On the back surface of the polishing pad 2, an adhesive tape 7 serving as an adhesive material for attaching the polishing pad 2 to the surface of the surface plate 1 is attached. The thickness of the adhesive tape 7 is preferably about 50 to 200 μm. In place of the adhesive tape 7, an adhesive may be used for bonding.

  Next, the gap filler 9 that fills the gap 8 will be described.

  The gap filler 9 is a mixture of a urethane resin and a solvent, and the solvent substitutes water to cure the urethane resin.

  Examples of the solvent include dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), or N-methylpyrrolidone (NMP).

  The gap filler 9 is in a liquid state, and the solvent elutes when blended with water, and the urethane resin is cured while the volume is reduced. That is, the urethane resin is cured by replacing the solvent with water, and the volume is reduced at this time.

  Table 1 shows the results of comparing the ease of handling when filling the gap 8 with the gap filler 9 according to the viscosity of the gap filler 9.

なお、隙間充填剤９としては、大日本インキ製のＬＱ−４５０にＤＭＦでもって分散エマルジョンウレタンにしたものを用いた。なお、大日本インキ製のＬＱ−６６０にＤＭＦでもって分散エマルジョンウレタンにしたものにおいても同様の結果が得られた。

As the gap filler 9, LQ-450 made by Dainippon Ink and made into dispersed emulsion urethane with DMF was used. The same result was obtained when LQ-660 made by Dainippon Ink was made into dispersed emulsion urethane with DMF.

  In Table 1, the urethane content in the filler is weight (wt)%, and indicates the ratio of the urethane resin in the filler, and the viscosity changes according to the urethane content. That is, the viscosity increases as the proportion of the urethane resin increases, and conversely, the viscosity decreases as the proportion of the urethane resin decreases.

  From Table 1, the ease of handling of the gap filler 9 was good when the viscosity was 5000-20000 cps, preferably 9000-18000 cps. In this range, the gap filler 9 can be filled into the gap 8.

  When the viscosity was 50000 cps and the urethane content was 50%, the viscosity was too high, so when filling the gap 8 with the syringe, the gap filler 9 did not pass through the needle hole of the syringe and injection was not possible.

  Further, when the viscosity was 1000 cps and the urethane content was 10%, the viscosity was too low and the liquid flowed out from the gap 8. Specifically, in the case where the polishing pad is attached to the surface plate from below, the gap filling material 9 is similarly filled from below with the syringe in the gap between the polishing pads, and the viscosity is low. Therefore, the gap filler 9 hangs down from the gap and cannot be filled.

  Next, filling of the gap filler 9 will be described with reference to FIG.

  On the surface of the surface plate 1, the polishing pads 2 and 2 divided into ½ are arranged and pasted. A gap filler 9 is filled with a syringe or the like into the gap 8 generated at the abutting portion between the polishing pads 2 and 2. The gap filler 9 is as described above. As an example, a mixture of urethane resin and DMF having a viscosity in a range in which the handleability shown in Table 1 is good is used.

  For example, the gap filler 9 is filled up to a portion that is substantially flush with the polishing surface 2b of the polishing pad 2 so that the gap 8 is completely filled (see FIG. 4A). Note that the filling amount can be appropriately changed depending on the thickness of the polishing pad 2 and the like, and may be filled up to the middle portion of the gap 8 in the depth direction.

  Next, water (pure water) is poured onto the surface of the gap filler 9 filled in the gap 8 by hand or using a machine. On the surface side of the gap filler 9, the urethane resin is cured by replacing DMF with water (primary curing). At this time, the volume of the gap filler 9 decreases from the surface side familiar with water (see FIG. 4B).

  Next, when the surface of the polishing pad 2 is washed with pure water in a dressing operation at the start of polishing, water is also applied to the surface of the gap filler 9 filled in the gap 8, and the surface side of the gap filler 9 , The urethane resin is further cured by substituting DMF with water (secondary curing). At this time, the volume of the gap filler 9 further decreases from the surface side familiar with water (see FIG. 4C).

  For polishing the wafer 3, the polishing pads 2 and 2 are attached to the surface plate 1 and the gap filling operation is performed, and then the wafer 3 held by the polishing head 4 is pressed against the polishing surface 2 b of the polishing pads 2 and 2. By rotating the surface plate 1 and the polishing head 4 in the opposite directions while supplying the slurry, the wafer 3 is polished by the polishing pads 2 and 2 and the surface is flattened.

  According to the gap filler for the polishing pad and the filling method thus configured, the gap filler 9 is filled in the gap 8 generated at the abutting portion between the polishing pads 2 and 2, and is exposed to the bottom surface of the gap 8. The adhesive tape 7 exposed on the surface of the board 1 and the end faces 2 a and 2 a of the polishing pads 2 and 2 is covered with a gap filler 9.

  Thus, even if the polishing pad 2 and 2 divided | segmented on the surface of the surface plate 1 are roughly positioned and affixed and the clearance gap 8 arises in the butt | matching part of the polishing pads 2 and 2, the clearance gap 8 is filled with clearance gap By filling the surface of the surface plate 1 by filling the agent 9, corrosion of the surface plate surface and contamination during polishing can be prevented, and the adhesive tape exposed on the end surface 2 a of the polishing pad 2 7 is also covered, so that peeling of the polishing pad 2 can be prevented.

  In addition, urethane resin is cured by replacing DMF with water, and compared with a type in which two organic solvents are mixed and cured, there is no damage to the polishing pad 2 because it is cured using water. Moreover, since it is easy to handle, it is excellent in filling workability.

  Further, as shown in FIG. 4C, a groove 10 surrounded by the surface of the gap filler 9 and the end surfaces 2a and 2a of the polishing pads 2 and 2 is produced. The generated object to be polished, polishing pad shavings, polishing agent, and the like can be discharged from the end face of the groove 10, and polishing can be performed efficiently. In addition, the groove 10 is automatically formed when DMF is replaced with water and the volume is reduced, and a process for forming the groove 10 is not required. In addition, it is not necessary to actively form the groove 10 for discharging the shavings and the like, and the gap filler 9 is originally intended to be filled with the gap 8 in order to eliminate the step at the butt portion. If it is.

  In the above embodiment, the polishing pads 2 and 2 divided into two halves are attached to the surface of the surface plate 1, but the present invention is not limited to this, and as shown in FIG. In this case, a gap filler 9 is filled in the gap 8 at the abutting portion between the polishing pads 2 and 2.

  Moreover, in the said embodiment, although the turntable type polishing apparatus was used, this invention is not limited to this, It can be used also for the conveyor type polishing apparatus provided with the endless belt.

  Further, as shown in FIGS. 6 and 7, grooves 11 are formed on the polishing surface 2 b of the polishing pad 2 in a lattice shape for discharging an object to be polished, polishing pad shavings, abrasives, and the like generated during polishing. A polishing pad 2 may be used. When filling the gap filler 9, the gap 8 is filled with a thickness that does not block the opening end of the groove 11 on the gap 8 side, and covers the surface of the surface plate 1 and the end face of the adhesive tape 7. The portion filled with the gap filler 9 exists in a state similar to the groove 11 of the polishing surface 2b of the polishing pad 2, and does not affect the polishing. Accordingly, corrosion of the surface of the surface plate and contamination during polishing can be prevented, and the polishing pad can be prevented from being peeled off. Also, an object to be polished, polishing pad shavings, polishing agent, etc. generated during polishing can be removed in the groove 11. Through the groove 10.

  INDUSTRIAL APPLICABILITY The present invention is useful as a polishing pad gap filler used in a silicon wafer polishing apparatus in planarization CMP and a filling method thereof.

Schematic diagram of polishing equipment for silicon wafer by CMP OLE_LINK5 plan view of a state in which the divided polishing pad is bonded to the surface of the surface plate in the embodiment of the present invention III-III sectional view of Fig. 2 The partial expanded sectional view which shows the mode of the filling of the gap filler in embodiment of this invention The top view of the state which bonded the polishing pad divided | segmented on the surface plate surface in the modification of this invention The top view of the state which bonded the polishing pad divided | segmented on the surface plate surface in the further another modified example of this invention VII-VII sectional view of FIG.

Explanation of symbols

1 Surface plate 2 Polishing pad 3 Silicon wafer (object to be polished)
4 Polishing head 7 Adhesive tape (adhesive material)
8 Gap 9 Gap filler

Claims (6)

A gap filler that fills the gaps between the butted parts of the divided polishing pads,
A gap filler for a polishing pad, which is a mixture of a urethane resin and a solvent, and the solvent replaces water to cure the urethane resin.   The gap filler for a polishing pad according to claim 1, wherein the solvent is dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, or N-methylpyrrolidone.   The gap filler for polishing pads according to claim 2, having a viscosity of 5000 to 20000 cps.   The gap filler for polishing pads according to claim 2, which has a viscosity of 9000 to 18000 cps.   The gap filler for polishing pads according to claim 2, wherein the proportion of the urethane resin in the filler is 15 to 30 wt%. Filling the gap between the butt portions of the divided polishing pads with a gap filler that is a mixture of a urethane resin and a solvent and that cures the urethane resin by replacing the solvent with water;
A method of filling a gap filler for a polishing pad, comprising a step of applying water to the surface of the gap filler to replace the solvent and curing the urethane resin.

Images