JP2017087332A - Method for manufacturing template assembly, polishing method with use of template assembly, and template assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a template assembly by which a startup time for a template assembly can be shortened.SOLUTION: A method for manufacturing a template assembly for holding a wafer when polishing the wafer comprises: a process in which a guide material, which is bored in a doughnut shape from a resin plate, is prepared; a deburring process in which burrs of bored end faces on both of an inner periphery and an outer periphery of the guide material bored in a doughnut shape are removed; and a process in which the guide material is bonded and fixed to a backing pad. The deburring process is performed by multistage processing by use of deburring means having different yarn numbers.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a template assembly, a polishing method using the template assembly, and a template assembly.

  Polishing of a semiconductor wafer (hereinafter also simply referred to as a wafer) includes a surface plate with a polishing cloth (polishing cloth) attached thereto, a polishing slurry supply mechanism for supplying polishing slurry onto the polishing cloth, and a polishing head for holding the wafer. It is carried out using a polishing apparatus composed of, for example.

  The polishing head has a configuration in which a backing pad and a template assembly in which a guide material made of a resin such as a glass epoxy material or polycarbonate is integrally attached. When polishing the wafer, a load is applied to the polishing head while the wafer is held on the template assembly with water, and the polishing slurry is supplied onto the polishing cloth from the abrasive supply mechanism, and the surface plate and The wafer is polished by bringing the surface of the wafer into sliding contact with the polishing cloth while rotating the polishing head (see, for example, Patent Document 1).

  The guide material of the template assembly functions as a guide for preventing the deviation in the rotation direction because the wafer cannot be held by the backing pad alone.

  Such a guide material is, for example, a resin plate made of glass epoxy or the like is milled by a router or the like, the outer diameter is the diameter of the polishing head, and the inner diameter is a donut shape having an arbitrary size of wafer diameter + 0.5 to 5 mm. Produced.

  For the purpose of removing burrs generated during processing of such a guide material, grinding with a grindstone or buffing using abrasive grains is performed. And the template assembly is manufactured by adhering and fixing the guide material after removing the burr to the backing pad by heat-sensitive adhesion or the like.

  The template assembly manufactured in this manner is attached to the polishing head, and the wafer is held by the polishing head.

  Since the surface roughness of the punched end face immediately after removing the burrs is rough, fine dirt such as grinding debris during grinding may remain on the surface. Therefore, the polishing slurry at the time of polishing the wafer may remain on the surface and become fixed. In this case, if the wafer polishing is performed repeatedly, when the wafer end surface and the guide end surface come into contact, dust is generated or a fixed object is dropped during polishing, and the surface of the wafer is scratched or LPD (Light Point Defects). It becomes a problem that gets worse.

  Such deterioration of LPD is noticeable in the initial use of the template assembly. The roughness on the inner peripheral side of the end face that is penetrated into the donut shape of the guide material tends to improve the surface roughness due to contact with the end face of the wafer as the processing batch progresses. Reduced to a stable level. Further, the outer peripheral side of the end face that is penetrated into the donut shape of the guide material acts so that the polishing slurry is coated as the processing batch advances, and dust generation is suppressed.

  Therefore, after the template assembly is incorporated into the polishing head, the template assembly is started up for the purpose of maintaining the processed surface quality. For starting up the template assembly, the polishing head equipped with the template assembly is pressed against the surface plate on which the nonwoven fabric polishing cloth is attached, and the polishing head and the surface plate are rotated to polish the wafer while flowing the polishing slurry. Is. Then, after the start-up is completed, polishing of the wafer as a product is started.

JP 2008-93811 A

  Conventionally, the removal of burrs from the end face of the guide material as described above has been performed by, for example, one-step processing by grinding with a grindstone or buffing using abrasive grains. When burrs are removed by such one-step processing, the surface roughness of the punched end face is poor, and it takes a long time to start up the template assembly. For this reason, a loss time is generated, which causes a decrease in productivity.

  The present invention has been made in view of the above-described problems, and provides a template assembly manufacturing method, a polishing method using the template assembly, and a template assembly that can shorten the startup time of the template assembly. The purpose is to do.

To achieve the above object, according to the present invention, there is provided a method of manufacturing a template assembly for holding a wafer when polishing the wafer,
A step of preparing a guide material that is penetrated into a donut shape from a resin plate; a burr removal step that removes burrs on both the inner and outer circumferences of the guide material that are penetrated into the donut shape; and A step of bonding and fixing the guide material to the backing pad,
The method for producing a template assembly is characterized in that the deburring step is performed in a multi-stage process by deburring means having different counts.

  In this way, the removal of burrs by multi-stage processing improves the surface roughness of both the inner and outer perforated end surfaces that are perforated in the donut shape of the guide material. A template assembly that can shorten the time required for start-up can be manufactured.

  At this time, the burr removing step is performed by grinding using a grindstone or buffing using abrasive grains as the burr removing means, and a rough grinding step and medium coarse grinding using a higher count than the rough grinding step. It is preferable to include a process and a finish grinding process using a higher count than the intermediate rough grinding process.

  In this way, it is possible to efficiently and reliably improve the surface roughness of the punched end face.

  Also, at this time, the rough grinding process uses a grindstone or abrasive grain with a count of # 240 or less, the intermediate coarse grinding process uses a grindstone or abrasive grain with a count of # 600 or less, and the finish grinding process has a count of # 1000. It is preferable to use the above grindstone or abrasive grains.

  In this way, it is possible to more reliably reduce the surface roughness of the punched end face sufficiently.

  Further, at this time, in the finish grinding step, it is preferable to perform grinding or polishing so that the surface roughness of both the inner and outer peripheral end surfaces of the guide material is 3 μm or less in terms of RMS value.

  Thus, if the surface roughness of the punched-through end face is 3 μm or less in terms of the RMS value, the surface roughness of the punched-through end face is sufficiently small.

At this time, the burr removing step
It is preferable to carry out such that the penetrating end faces of both the inner periphery and the outer periphery of the guide material are perpendicular to the surface of the guide material.

  As described above, it is preferable to perform the burr removing process so that both the inner and outer peripheral end surfaces of the guide material are perpendicular to the surface of the guide material.

Further, according to the present invention, while supplying the polishing slurry onto the polishing cloth attached to the surface plate, the surface of the wafer held by the template assembly attached to the polishing head is brought into sliding contact with the polishing cloth for polishing. A method for polishing a wafer,
A polishing method characterized by using a template assembly manufactured by the above-described method for manufacturing a template assembly of the present invention as the template assembly.

  As described above, since the wafer is polished by using the template assembly manufactured by the template assembly manufacturing method of the present invention, the time required to start up the template assembly can be shortened and productivity can be improved. it can.

According to the present invention, there is also provided a template assembly for holding the wafer when polishing the wafer,
A backing pad and a guide material that is penetrated into a donut shape that is bonded and fixed to the backing pad. There is provided a template assembly characterized by being perpendicular to the surface of the guide material and having a surface roughness of not more than 3 μm in RMS value on both inner and outer peripheral surfaces of the guide material.

  In such a case, since the value of the surface roughness of the punched end face is sufficiently small, the time required for starting up the template assembly at the time of polishing the wafer can be shortened.

  According to the template assembly manufacturing method of the present invention, by removing burrs by multi-stage processing, the surface roughness of both the inner and outer perforated end surfaces that are perforated in the donut shape of the guide material is improved. Therefore, it is possible to manufacture a template assembly that can shorten the time required to start up the template assembly.

It is process drawing which showed an example of the manufacturing method of the template assembly of this invention. It is the schematic for demonstrating the guide material pierced by the donut shape. 1 is a schematic view illustrating a template assembly of the present invention. It is the graph which showed the relationship between the starting preparation processing time of a template assembly and the number of LPD in an Example and a comparative example. It is the graph which showed the relationship with the number of LPD in the case where the starting preparation processing time of the template assembly of an Example and a comparative example is 30 minutes and 120 minutes.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
Conventionally, since the guide material is a resin, there has been a problem that dust generation from the guide material and solid matter may fall off during polishing, resulting in deterioration of scratches and LPD on the wafer surface. Further, when removing burrs by one-stage processing, there is a problem that it takes a long time to start up the template assembly because the surface roughness of the punched end face is poor.

  Therefore, the present inventors have intensively studied to solve such problems. As a result, it has been conceived that the burr removing step is performed by multi-stage processing using burr removing means having different counts. In this way, the removal of burrs in multi-stage processing improves the surface roughness of both the inner and outer perforated end surfaces that are perforated in the doughnut shape of the guide material. It has been found that a template assembly can be manufactured that can reduce the time it takes to complete. And the best form for implementing these was scrutinized and the present invention was completed.

  First, the manufacturing method of the template assembly of this invention is demonstrated. First, as shown in FIG. 2, a step of preparing a guide material 2 pierced from a resin plate 1 into a donut shape is performed (SP1 in FIG. 1).

  The resin plate 1 can be a plate material made of a conventionally used resin such as a glass epoxy material or polycarbonate. Then, the guide material 2 can be formed from such a resin plate 1 through a donut shape by milling using a router or the like, for example. At this time, for example, the outer diameter of the guide member 2 is the diameter of the polishing head, and the inner diameter can be an arbitrary size of about +0.5 to 5 mm of the diameter of the wafer to be held.

  Next, a burr removing step is performed to remove burrs on both the inner and outer peripheral end surfaces 3 of the guide material 2 that have been penetrated into the donut shape (SP2 in FIG. 1). The removal of burrs is performed by multi-stage processing using burrs removing means having different counts.

  At this time, as the burr removing means, grinding using a grindstone or buffing using abrasive grains can be performed. The burr removing means is not limited to this, and any burr removing means may be used as long as it can remove the burr on the end face 3 and improve the surface roughness.

  It is preferable that the burr removing step is performed so that the inner end surface and the outer peripheral end surface 3 of the guide material are perpendicular to the surface of the guide material 2. Specifically, for example, the burr removing means can be rolled and applied to the end surface 3 at a right angle.

  At this time, as shown in FIG. 1, the burr removing step includes a rough grinding step (SP3 in FIG. 1), a medium rough grinding step (SP4 in FIG. 1) using a higher count than the rough grinding step, and the medium rough grinding. It is preferable to have a finish grinding step (SP5 in FIG. 1) using a higher count than the step. In this way, the surface roughness of the punched end face 3 can be improved efficiently and reliably.

  At this time, the rough grinding step (SP3) uses a grindstone or abrasive grains with a count of # 240 or less, and the intermediate coarse grinding step (SP4) uses a grindstone or abrasive grains with a count of # 600 or less, and a finish grinding step (SP5). Is preferably performed using a grindstone or abrasive grain having a count of # 1000 or more.

  In this way, the removal of burrs is performed in three stages, and the number of rolls used in each stage is increased, so that the surface roughness of the punched end face 3 can be made sufficiently small and efficient. As a result, it is possible to improve scratches and LPD deterioration that have occurred remarkably in the initial use of the template assembly. Therefore, the time required for starting up the template assembly can be shortened.

  At this time, in the finish grinding step (SP5), it is preferable to perform grinding or polishing so that the surface roughness of both the inner and outer peripheral surfaces of the guide material 2 is 3 μm or less in terms of RMS value. Thus, if the surface roughness of the punched-through end face 3 is 3 μm or less in terms of the RMS value, the surface roughness of the punched-through end face 3 is sufficiently small.

  Thereafter, as shown in FIG. 3, a step of bonding and fixing the guide material 2 to the backing pad 4 is performed (SP6 in FIG. 1), and the template assembly is manufactured.

  Specifically, for example, the heat-sensitive tape 5 can be attached to one side of the guide material 2 and then bonded and fixed to the backing pad 4 by thermocompression bonding.

  In this way, by removing burrs by multi-stage processing, the surface roughness of both the inner and outer perforated end surfaces 3 that are perforated into the donut shape of the guide material 2 is improved. Since there is less dust generation, the template assembly 6 that can shorten the time required for starting up the template assembly 6 can be manufactured.

  And a wafer can be grind | polished using the template assembly manufactured by the manufacturing method of such a template assembly of this invention.

  That is, while supplying the polishing slurry onto the polishing cloth attached to the surface plate, the surface of the wafer held by the template assembly manufactured by the manufacturing method of the present invention attached to the polishing head is brought into sliding contact with the polishing cloth. Then, the wafer is polished.

  As described above, the template assembly manufactured by the method for manufacturing a template assembly of the present invention has improved surface roughness of the punched-through end face. Therefore, by performing polishing using such a template assembly, the time required for starting up the template assembly can be shortened, and productivity can be improved.

Here, the template assembly of the present invention will be described.
As shown in FIG. 3, the template assembly 6 of the present invention has a backing pad 4 and a guide material 2 that is penetrated in a donut shape that is fixedly bonded to the backing pad 4. The inner and outer perforated end faces 3 that are perforated in the shape of a donut are perpendicular to the surface of the guide member 2, and the surface roughness of both the inner perimeter and the outer perimeter of the guide member 2 is the surface roughness. The RMS value is 3 μm or less. In such a case, since the surface roughness value of the punched-through end face 3 is sufficiently small, dust generation is small from the beginning, so that the time required for starting up the template assembly 6 when polishing the wafer is shortened. Will be able to.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.

(Example)
The template assembly was manufactured according to the template assembly manufacturing method of the present invention. First, using a router, a guide material was prepared which was cut into a donut shape from a glass epoxy plate. The deburring process is a three-stage process comprising a rough grinding process using a # 240 grinding wheel, a medium rough grinding process using a # 600 grinding wheel, and a finish grinding process using a # 1000 grinding wheel. The punching end face was made to be perpendicular to the surface of the guide material.

  When the surface roughness of the punched through end face of the guide material after the finish grinding step was measured, the RMS value was 2.9 μm.

  Thereafter, a heat-sensitive tape was attached to one side of the guide material, and then bonded and fixed to the backing pad by thermocompression bonding to produce a template assembly.

  The template assembly manufactured in this way was mounted on a polishing head. The polishing head equipped with the template assembly was cleaned with a brush and water on the backing pad and guide material, and then the template assembly was prepared for startup.

The template assembly start-up preparation process uses a solution containing KOH-based colloidal silica as the polishing slurry, recycling with a polishing head rotation of 20 rpm, a platen rotation of 19 rpm, a load of 150 g / cm ² and a polishing slurry flow rate of 2.5 L / min. This was performed by polishing a silicon wafer having a diameter of 450 mm.

  After the template assembly start-up preparation process was performed for 30 minutes, 25 silicon wafers were polished by a normal polishing process. At this time, the number of LPDs in the polished wafer was evaluated (LPD is the number of detected 24 nm UP). The number of LPDs was evaluated with a particle counter (SP3 manufactured by KLA).

  The polishing apparatus was a SRED polishing machine manufactured by Fujikoshi Kikai Co., Ltd. The above normal polishing was performed by secondary polishing + finish polishing. The polishing conditions were as shown in Table 1 below.

  In addition, in order to investigate the case where the time for the preparation for the start-up of the template assembly is changed, the time for the preparation for the start-up for the template assembly is changed, and then the same LPD is measured as described above. This is shown in FIG. 4 together with the result of a comparative example described later. In FIG. 5, the case where the template assembly start-up preparation processing time is 30 minutes and the case of 120 minutes are extracted and described.

(Comparative example)
The template assembly was manufactured in the same manner as in the example except that the intermediate rough grinding step and the finish grinding step in manufacturing the template assembly in the example were not performed.

  When the surface roughness of the piercing end face of the guide material after removing the burr in the comparative example was measured, the RMS value was 24.2 μm.

  Thereafter, the manufactured template assembly was mounted on a polishing head, and the template assembly was prepared for startup and the silicon wafer was polished in the same manner as in the example. The measurement results of the number of LPDs of the polished wafer are shown in FIGS.

  As a result, as shown in FIGS. 4 and 5, in the comparative example, the number of LPDs was very large when the startup preparation time of the template assembly was short. In particular, in order to reduce the LPD to 100 pcs / wf or less, in the comparative example, it took about 120 minutes to prepare for starting the template assembly. On the other hand, in the example, the time required for LPD to be 100 pcs / wf or less could be shortened to 30 minutes.

  That is, it is confirmed that the polishing head mounted with the template assembly that has undergone the 30-minute template preparation process in the example is at the same level as the 120-minute startup process in the comparative example. did it.

  As described above, in the example, the time required to start up the template assembly could be shortened by 90 minutes from the comparative example. As a result, the polishing apparatus can be directed to product processing for 90 minutes, leading to an improvement in productivity.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

DESCRIPTION OF SYMBOLS 1 ... Resin board, 2 ... Guide material, 3 ... Perforated end face, 4 ... Backing pad,
5 ... thermal tape, 6 ... template assembly.

Claims (7)

A method of manufacturing a template assembly for holding a wafer when polishing the wafer, comprising:
A step of preparing a guide material that is penetrated into a donut shape from a resin plate; a burr removal step that removes burrs on both the inner and outer circumferences of the guide material that are penetrated into the donut shape; and A step of bonding and fixing the guide material to the backing pad,
The method for producing a template assembly, wherein the deburring step is performed by multi-stage processing by deburring means having different counts.   The burr removing step is performed by grinding using a grindstone or buffing using abrasive grains as the burr removing means, a rough grinding step, and a medium rough grinding step using a higher count than the rough grinding step, The template assembly manufacturing method according to claim 1, further comprising a finish grinding step using a higher count than the intermediate rough grinding step.   In the rough grinding step, a grindstone or abrasive grain having a count of # 240 or less is used, in the intermediate coarse grinding step, a grindstone or abrasive grain having a count of # 600 or less is used, and in the finish grinding step, a grindstone having a count of # 1000 or more is used. The method for producing a template assembly according to claim 2, wherein the method is performed using abrasive grains.   4. The finish grinding step, wherein grinding or polishing is performed such that the surface roughness of both end surfaces of the inner periphery and outer periphery of the guide material is an RMS value of 3 μm or less. A method for producing a template assembly according to claim 1. The burr removing step includes
5. The template assembly according to claim 1, wherein both end surfaces of the inner periphery and the outer periphery of the guide member are perpendicular to the surface of the guide member. 6. Production method. A method for polishing a wafer, wherein a polishing slurry is supplied onto a polishing cloth affixed to a surface plate, and the surface of the wafer held by a template assembly affixed to a polishing head is slid in contact with the polishing cloth and polished. ,
A polishing method using a template assembly manufactured by the method for manufacturing a template assembly according to claim 1, as the template assembly. A template assembly for holding the wafer when polishing the wafer,
A backing pad and a guide material that is penetrated into a donut shape that is bonded and fixed to the backing pad. A template assembly characterized by being perpendicular to the surface of the guide material and having a surface roughness of 3 μm or less in terms of RMS value on both inner and outer peripheral surfaces of the guide material.

Images