JP2013244574A - Grinding device and grinding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device and grinding method for efficiently grinding a workpiece to be processed.SOLUTION: A control part 21 of a grinding device 20 specifies a grinding area and executes first grinding processing. In this case, a first grinding pad with a large diameter is used. Next, the control part 21 executes mapping processing. Then, when a size of an unevenness distribution area is equal to or less than a first reference value, the grinding processing is completed. On the other hand, when the size of the unevenness distribution area exceeds the first reference value, regrinding is executed. When the size of the unevenness distribution area exceeds a second reference value, the first grinding processing is repeated. On the other hand, when the size of the unevenness distribution area is equal to or less than the second reference value, the control part 21 executes second grinding processing using a grinding pad with a small diameter.

Description

  The present invention relates to a polishing apparatus and a polishing method for polishing a workpiece to be processed.

  A polishing apparatus is used for manufacturing a semiconductor wafer or the like and for thinning the semiconductor wafer. In particular, a semiconductor wafer with a large diameter is desired to be extremely thin and flatness after processing is required. For this reason, a technique for achieving a necessary flatness accuracy range of the wafer by partially re-polishing the convex portion of the wafer in which irregularities are generated by polishing (see, for example, Patent Document 1). ). In the technique described in this document, a wafer that does not reach the standard of flatness is included in the standard by re-polishing. Specifically, an unevenness measuring apparatus that measures in-plane unevenness of a polished wafer, and partial polishing that determines partial polishing information including a polishing position, a polishing amount, and a polishing range that require re-polishing from the measured unevenness data. An information determining means and a partial polishing machine for partially polishing the wafer based on the partial polishing information are used.

JP-A-11-265860 (first page, FIG. 2)

  However, since the uneven state of the wafer differs depending on the substrate, the location where partial polishing is to be performed is different, and the amount of polishing is also different. In particular, when performing partial polishing on a wafer provided with a structure on the surface, it is necessary to perform polishing in consideration of this structure.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a polishing apparatus and a polishing method for efficiently polishing a workpiece to be processed.

  In order to solve the above problems, the invention described in claim 1 is a polishing apparatus including a control unit that controls the first and second polishing processes in order to polish a workpiece to be processed. The control unit identifies a first region to be polished on the workpiece surface, performs a first polishing process using a first polishing pad having a first area in the first region, and performs the first polishing process. After the polishing process, a second area in which the second polishing process is performed is specified using a second polishing pad having a second area smaller than the first area in the first area, The gist is to perform the second polishing process using the second polishing pad in the second region.

  According to a second aspect of the present invention, in the polishing apparatus according to the first aspect, after the first polishing process, the means for measuring the uneven distribution in the first region, and the uneven distribution, The gist is to specify the second region of the second polishing process.

  A third aspect of the present invention is the polishing apparatus according to the first aspect, wherein the second polishing process is performed on the uneven distribution generated after the first polishing process in the first area. A polishing condition storage unit that stores information on the second region that identifies the second region, and the control unit acquires information on the second polishing target region stored in the polishing condition storage unit, and The gist is to perform the polishing process.

  The invention according to claim 4 is a polishing method using a polishing apparatus including a control unit that controls the first and second polishing processes in order to polish a workpiece to be processed, wherein the control unit includes: A first region to be polished is specified on the workpiece surface, and a first polishing process is performed using a first polishing pad having a first area in the first region, and the first polishing process is performed. Later, in the first region, a second region to be subjected to a second polishing process is identified using a second polishing pad having a second area smaller than the first area. In the second region, The gist is to perform a second polishing process using the second polishing pad.

(Function)
According to the first and fourth aspects of the invention, the second polishing process is performed after the first polishing process. Accordingly, the polishing time can be shortened and the variation can be reduced by using the large-diameter pad and the small-diameter pad in combination and polishing in a plurality of stages.

  According to the invention described in claim 2, after the first polishing process, the second region of the second polishing process is specified based on the measurement result of the uneven distribution in the first region. The second polishing area can be specified.

  According to the third aspect of the present invention, since the polishing condition storage unit storing information related to the second region is provided, the second polishing process can be performed using this.

  According to the present invention, it is possible to provide a polishing apparatus and a polishing method for efficiently polishing a workpiece to be processed.

Explanatory drawing of the functional block of the grinding | polishing apparatus of embodiment of this indication. It is explanatory drawing of the relationship between the workpiece | work and head of embodiment of this indication, Comprising: (a) is a side view of a 1st polishing pad, (b) is a top view of a 1st polishing pad, (c) is a 2nd polishing pad (D) is a top view of the second polishing pad. Explanatory drawing of the process sequence of embodiment of this indication.

Hereinafter, the polishing apparatus of the present disclosure will be described with reference to FIGS. In the present embodiment, it is assumed that partial polishing is performed to polish only a predetermined region of a semiconductor wafer (work).
FIG. 1 is a block diagram showing a schematic configuration of a polishing apparatus 20 according to an embodiment of the present invention. In this polishing apparatus 20, the surface of the workpiece 10 which is a wafer to be polished is polished. The polishing apparatus 20 includes a holding table 25 on which the workpiece 10 is placed and a polishing head 26 to which a polishing pad is attached.

The holding table 25 is provided with a fixing portion that sucks and fixes the placed work 10.
Further, the holding table 25 is rotated by the table rotation driving unit 274.
The polishing head 26 is supported by an arm (support), and a horizontal driving unit 271 is provided on the arm. The horizontal driving unit 271 can move the polishing head 26 in a horizontal plane with respect to the surface of the workpiece 10.

Further, a vertical drive unit 272 and a head rotation drive unit 273 are provided for the polishing head 26.
The vertical driving unit 272 adjusts the distance between the polishing pad of the polishing head 26 and the work 10 to separate the polishing head 26 from the work 10 or press the polishing pad against the work 10 based on predetermined polishing conditions. To adjust.
The head rotation drive unit 273 rotates the polishing pad holding the abrasive under predetermined polishing conditions.

  As shown in FIG. 2, in this embodiment, a first polishing pad 261 and a second polishing pad 262 are used as polishing pads. 2A is a side view of the first polishing pad, FIG. 2B is a top view of the first polishing pad, FIG. 2C is a side view of the second polishing pad, and FIG. It is a top view of a polishing pad. For this reason, the polishing head 26 to which the first polishing pad 261 is attached and the polishing head 26 to which the second polishing pad 262 is attached are provided independently. The first polishing pad 261 has a first area and is used when a large area is partially polished at high speed. In the present embodiment, the first polishing process is performed under the polishing conditions for flattening while performing stress release on the surface of the workpiece 10.

  On the other hand, the second polishing pad 262 has a second area smaller than the first area, and is used when partially polishing a small area. In the present embodiment, the second polishing process is performed under polishing conditions that flatten the uneven distribution remaining in the first polishing process.

In addition, the polishing apparatus 20 is provided with a slurry nozzle that drops the polishing slurry onto the polishing region of the workpiece 10.
Further, the polishing apparatus 20 includes a control unit 21, a process information storage unit 22, a mapping storage unit 23, and a sensor 28.

  The process information storage unit 22 functions as a polishing condition storage unit, and stores process data for controlling driving of the holding table 25 and the polishing head 26. Specifically, coordinate information for specifying a target region (first region) to be flattened is recorded on the surface of the workpiece 10. For example, when a structure is generated on the surface of the workpiece 10, an area excluding the structure is a flattening target area.

  Furthermore, the first and second polishing conditions (the head rotation speed, the head pressing pressure, the first polishing process using the first polishing pad 261, and the second polishing process using the second polishing pad 262) Data relating to table rotation speed, polishing time, etc.) are recorded.

Furthermore, data on conditions (first reference value and second reference value) for selectively using the first polishing pad 261 and the second polishing pad 262 are recorded. The first reference value is a reference value for determining the end of polishing. This first reference value is composed of a reference value of the unevenness height and unevenness area of the unevenness (unevenness) on the surface of the workpiece 10, and when larger than the first reference value, it is determined that polishing is continued.
The second reference value indicates a condition for properly using the first polishing pad 261 and the second polishing pad 262. Here, the second reference value is a reference value of the area of the unevenness area (area of the area to be polished), the first area of the first polishing pad 261, the second area of the second polishing pad 262. It is determined based on the area. That is, when unevenness is generated in an area larger than the first reference value, the first polishing pad 261 is used. On the other hand, the second polishing pad 262 is used when irregularities are generated in an area smaller than the second reference value.

  The mapping storage unit 23 stores data related to the uneven distribution (uneven state map) measured by the sensor 28 for the polishing target region on the surface of the workpiece 10. By using this uneven distribution, the position where the unevenness is generated and the size of the unevenness can be specified.

The control unit 21 includes a region specifying unit 211 and a polishing control unit 212.
The area specifying unit 211 performs a process of specifying a polishing target area for partial polishing. In the present embodiment, the process information storage unit 22 identifies the first area and the sensor 28 identifies the second area.

The polishing control unit 212 executes processing for controlling polishing in the polishing target region.
The sensor 28 measures the state of unevenness on the surface of the workpiece 10. By scanning the sensor 28 on the horizontal plane of the workpiece 10, information regarding the uneven distribution on the surface of the workpiece 10 can be acquired.

(Operation of polishing apparatus 20)
Next, the operation of the polishing apparatus 20 will be described with reference to FIG.
First, the control unit 21 of the polishing apparatus 20 executes a polishing area specifying process (step S1-1). Specifically, the area specifying unit 211 of the control unit 21 acquires coordinate information of the flattening target area (first area) from the process information storage unit 22.

  Next, the control unit 21 of the polishing apparatus 20 performs a first polishing process (step S1-2). Specifically, the polishing control unit 212 of the control unit 21 acquires the first polishing condition recorded in the process information storage unit 22. Then, the polishing control unit 212 operates the table rotation driving unit 274 based on the first polishing condition to rotate the holding table 25 on which the workpiece 10 is placed.

  Further, the polishing control unit 212 uses the head rotation driving unit 273 to rotate the first polishing pad 261 for the head on which the first polishing pad 261 is mounted. Next, the polishing control unit 212 drives the vertical driving unit 272 so that the pressure is applied to the first polishing pad 261 against the workpiece 10 according to the first polishing condition recorded in the process information storage unit 22. Then, the polishing control unit 212 operates the horizontal driving unit 271 so as to polish the planarization target region.

  Then, the polishing control unit 212 performs polishing for the polishing time under the first polishing condition. When the polishing time has elapsed, the head 32 is separated from the workpiece 10 by the vertical driving unit 272, and the rotation of the holding table 25 and the polishing head 26 is stopped.

  Next, the control part 21 of the grinding | polishing apparatus 20 performs a mapping process (step S1-3). Specifically, the region specifying unit 211 of the control unit 21 drives the sensor 28 to measure the unevenness of the surface of the workpiece 10 to be flattened. Then, the area specifying unit 211 records the specified result (uneven state map) in the mapping storage unit 23.

  Next, the control unit 21 of the polishing apparatus 20 executes a polishing state evaluation process (step S1-4). Specifically, the polishing control unit 212 of the control unit 21 uses the uneven state map recorded in the mapping storage unit 23, so that planarization is not sufficient in the planarization target region where no structure is generated. An area where unevenness is generated (unevenness distribution area) is specified. And the grinding | polishing control part 212 specifies this uneven | corrugated distribution area | region as a new planarization object area | region (2nd area | region).

  Next, the control part 21 of the grinding | polishing apparatus 20 performs the determination process about whether it is below a 1st reference value (step S1-5). Specifically, the polishing control unit 212 of the control unit 21 compares the first reference value recorded in the process information storage unit 22 with the size of the uneven distribution region.

When the size of the uneven distribution region is equal to or smaller than the first reference value (“YES” in step S1-5), the control unit 21 of the polishing apparatus 20 ends the polishing process.
On the other hand, when the size of the uneven distribution region exceeds the first reference value (in the case of “NO” in step S1-5), the control unit 21 of the polishing apparatus 20 determines whether it is equal to or less than the second reference value. Processing is executed (step S1-6). Specifically, the polishing control unit 212 of the control unit 21 compares the second reference value recorded in the process information storage unit 22 with the size of the uneven distribution region.

  When the size of the uneven distribution region exceeds the second reference value (“NO” in step S1-6), the first polishing process (step S1-2) is repeated. In this case, the polishing conditions are changed according to the height of the unevenness and the size of the unevenness distribution region. Specifically, when the unevenness difference is small and the uneven distribution region is small, the polishing time is shortened or the pressure is decreased.

  On the other hand, when the size of the uneven distribution region is equal to or smaller than the second reference value (“YES” in step S1-5), the control unit 21 of the polishing apparatus 20 executes the second polishing process (step S1-7). ). Specifically, the polishing control unit 212 of the control unit 21 acquires the second polishing condition recorded in the process information storage unit 22. Then, the polishing control unit 212 operates the table rotation driving unit 274 based on the second polishing condition to rotate the holding table 25 on which the workpiece 10 is placed.

  Further, the polishing control unit 212 uses the head rotation driving unit 273 to rotate the second polishing pad 262 attached to the polishing head 26. Next, the polishing control unit 212 drives the vertical driving unit 272 so as to have a pressure for pressing the second polishing pad 262 against the workpiece 10 according to the second polishing condition recorded in the process information storage unit 22. Then, the polishing control unit 212 operates the horizontal driving unit 271 so as to polish the uneven distribution region recorded in the mapping storage unit 23.

Then, the polishing control unit 212 performs polishing for the polishing time recorded in the second polishing condition. When the polishing time has elapsed, the vertical drive unit 272 separates the polishing head 26 from the workpiece 10 and stops the rotation of the holding table 25 and the polishing head 26.
And the control part 21 of the grinding | polishing apparatus 20 returns to a mapping process (step S1-3).

According to this embodiment, the following effects can be obtained.
(1) In this embodiment, the control part 21 of the grinding | polishing apparatus 20 performs the specific process of a grinding | polishing area | region (step S1-1). Thereby, only the predetermined area | region in the workpiece | work 10 can be grind | polished. Therefore, when it is not necessary to polish the entire surface of the workpiece 10, polishing can be performed efficiently.

  (2) In this embodiment, the control part 21 of the grinding | polishing apparatus 20 performs a mapping process after execution of a 1st grinding | polishing process (step S1-2) (step S1-3). Here, when the size of the uneven distribution region exceeds the second reference value (in the case of “NO” in step S1-6), the control unit 21 of the polishing apparatus 20 performs the first polishing process (step S1-2). )repeat. Thereby, it is possible to efficiently polish a wide area by using the large-diameter polishing pad (first polishing pad 261).

  (3) In the present embodiment, when the size of the uneven distribution region is equal to or smaller than the second reference value (“YES” in step S1-6), the control unit 21 of the polishing apparatus 20 executes the second polishing process. (Step S1-7). Thereby, in the first polishing, the region that cannot be polished can be polished by the second polishing using the second polishing pad 262. Therefore, by properly using the first polishing pad 261 and the second polishing pad 262, the target region can be efficiently polished.

Moreover, you may change the said embodiment as follows.
In the above embodiment, the control unit 21 of the polishing apparatus 20 executes the polishing area specifying process (step S1-1) and the first polishing process (step S1-2). Here, the mapping process (step S1-3) may be executed first to specify the polishing target region. In this case, when the size of the uneven distribution region is equal to or smaller than the first reference value and exceeds the second reference value, the control unit 21 of the polishing apparatus 20 executes the second polishing process (step S1). -7).

  Furthermore, in the above-described embodiment, the process information storage unit 22 records coordinate information for specifying a target area (a flattening target area) to be flattened. Instead of this, a condition (target area specifying condition) for specifying the flattening target area may be recorded. For example, before the first polishing process, mapping is performed by the sensor 28 to detect a structure having a reference height or more. Then, the control unit 21 of the polishing apparatus 20 compares the mapping result with the target region specifying condition and specifies the flattening target region. Thereby, according to the condition of the workpiece | work 10, an appropriate planarization object area | region can be specified.

  In the above embodiment, the control unit 21 of the polishing apparatus 20 executes the mapping process (step S1-3) and the polishing state evaluation process (step S1-4). Instead, information on the uneven distribution region after the first polishing process may be recorded in the process information storage unit 22 in advance, and the second polishing process may be executed based on this information.

  In the above embodiment, the control unit 21 of the polishing apparatus 20 executes the second polishing process based on the second polishing condition recorded in the process information storage unit 22 (step S1-7). Instead, the second polishing condition may be changed according to the polishing state. Here, the polishing conditions are changed according to the height of the unevenness and the size of the uneven distribution region. Specifically, when the unevenness difference is small and the uneven distribution region is small, the polishing time is shortened or the pressure is decreased.

  In the above embodiment, the table rotation driving unit 274 is operated to rotate the holding table 25 on which the workpiece 10 is placed. Here, the rotation of the holding table may be controlled in accordance with the size of the uneven distribution region. For example, when the uneven distribution region extends over the entire workpiece 10, the table is rotated. On the other hand, when the uneven distribution region is biased, only the uneven distribution region may be polished without rotating the holding table 25.

  In the above embodiment, the polishing apparatus 20 includes a slurry nozzle that drops the polishing slurry onto the polishing region of the workpiece 10. Here, when performing partial polishing, the dripping region and flow of the polishing slurry may be controlled. For example, it is made to flow so as to be blown away by a jet or the like so that the polishing slurry does not stay in a region not to be polished.

  In the above embodiment, the polishing apparatus 20 is provided with the polishing head 26 to which the first polishing pad 261 is attached and the polishing head 26 to which the second polishing pad 262 is attached independently. Instead, in the polishing head 26, the first polishing pad 261 and the second polishing pad 262 may be replaced. In this case, when switching between the first polishing process and the second polishing process, the polishing apparatus 20 outputs an exchange instruction.

  Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.

(A) A polishing apparatus characterized by specifying an arrangement of a structure provided on a workpiece and specifying a first region excluding the structure.
Thus, even when the arrangement of the structure differs depending on the workpiece, the structure can be avoided and polished.

(B) A polishing apparatus characterized by specifying an arrangement of a structure provided on a workpiece, specifying a position where the slurry is dropped according to the arrangement of the structure, and moving a slurry nozzle.
Thereby, even when the arrangement of the structures differs depending on the workpiece, the slurry can be dropped at an appropriate position and polished efficiently.

(C) A polishing apparatus characterized by specifying an arrangement of a structure provided on a workpiece and causing the slurry to flow in the vicinity of the structure according to the arrangement of the structure so as not to remain.
Thereby, the influence of the slurry with respect to a structure can be suppressed.

  DESCRIPTION OF SYMBOLS 10 ... Work, 20 ... Polishing apparatus, 21 ... Control part, 22 ... Process information storage part, 23 ... Mapping storage part, 211 ... Area | region identification part, 212 ... Polishing control part, 25 ... Holding table, 26 ... Polishing head, 261 DESCRIPTION OF SYMBOLS 1st polishing pad, 262 ... 2nd polishing pad, 271 ... Horizontal drive part, 272 ... Vertical drive part, 273 ... Head rotation drive part, 274 ... Table rotation drive part, 28 ... Sensor.

Claims (4)

A polishing apparatus including a control unit that controls the first and second polishing processes in order to polish a workpiece to be processed,
The control unit is
Identify the first area to be polished on the workpiece surface,
In the first region, a first polishing process is performed using a first polishing pad having a first area,
After the first polishing process, a second region in which the second polishing process is performed is specified by using a second polishing pad having a second area smaller than the first area in the first area. And
A polishing apparatus that performs a second polishing process using the second polishing pad in the second region. Means for measuring the uneven distribution in the first region after the first polishing treatment;
The polishing apparatus according to claim 1, wherein the second region of the second polishing process is specified based on the uneven distribution. In the first region, a polishing condition storage unit that stores information related to the second region that specifies the target region for performing the second polishing process, with respect to the uneven distribution generated after the first polishing process,
2. The polishing apparatus according to claim 1, wherein the control unit acquires information related to a second polishing target area stored in the polishing condition storage unit, and executes a polishing process for the second region. In order to polish a workpiece to be processed, a polishing method using a polishing apparatus having a control unit for controlling the first and second polishing processes,
The control unit is
Identify the first area to be polished on the workpiece surface,
In the first region, a first polishing process is performed using a first polishing pad having a first area,
After the first polishing process, a second region in which the second polishing process is performed is specified by using a second polishing pad having a second area smaller than the first area in the first area. And
In the second region, a second polishing process is performed using the second polishing pad.

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