JP2006082169A - Polishing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing method capable of highly accurately polishing a surface of a work without being affected by the thickness of the work and a retainer. <P>SOLUTION: This polishing method includes a process of setting a target shape of the work; a process of measuring the shape of the work before polishing; a process of calculating a target polishing amount distribution of the work on the basis of the target shape of the work and the shape of the work before polishing; a process of setting polishing conditions to the specific polishing conditions corresponding to the target polishing amount distribution on the basis of a relation between the polishing conditions of the work prepared in advance and the polishing amount distribution; and the process of polishing the work under the specific polishing conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polishing method and a polishing apparatus used for polishing a surface of a workpiece such as a wafer.

  The wafer manufacturing process includes a polishing process for finishing the surface of the wafer into a mirror surface. In this step, a wafer polishing apparatus is used that presses the wafer against the surface of the rotating polishing pad and polishes the surface of the wafer.

  This wafer polishing apparatus has a polishing table rotated by a drive shaft. A polishing pad is provided on the upper surface of the polishing table, and a polishing head that rotates while holding the wafer is disposed on the upper surface side of the polishing pad.

  FIG. 7 is a configuration diagram of a conventional polishing head. In addition, the code | symbol 105 in FIG. 7 has shown the said polishing pad.

  As shown in FIG. 7, the polishing head has a head body 100. The head body 100 is provided with a pressurizing chamber 101, and the lower surface opening 102 is closed by a rubber film 103. A wafer U is held on the lower surface of the rubber film 103, and the periphery thereof is surrounded by a ring-shaped retainer 104 fixed to the lower end surface of the head body 100. The retainer 104 protrudes inward in the radial direction of the head main body 100, and the outer peripheral portion of the rubber film 103 is supported on the upper surface thereof.

  When using the wafer polishing apparatus having the above-described configuration, the rotating polishing head is lowered, and the retainer 104 held on the lower end surface of the head body 100 is pressed against the surface of the polishing pad 105. At this time, when the gas is supplied to the pressurizing chamber 101 to expand the rubber film 103, the wafer U adhered and fixed to the lower surface of the rubber film 103 is pressed against the rotating polishing pad 105, and the surface is polished.

  By the way, in the wafer polishing apparatus having the above-described configuration, the outer peripheral portion of the rubber film 103 is held on the upper surface of the retainer 104. Therefore, depending on the thickness of the retainer 104 in the vertical direction, the entire surface of the wafer U cannot be polished at a uniform polishing rate.

  That is, as shown in FIG. 8A, when the thickness of the retainer 104 in the vertical direction is large, the supported height of the rubber film 103 is higher than the upper surface of the wafer U, and the desired peripheral edge of the wafer U is formed. Can't load power. Therefore, a required contact pressure cannot be applied between the peripheral portion of the wafer U and the polishing pad 105, and the peripheral portion of the wafer U is not polished much as compared with the central portion.

  Further, as shown in FIG. 8C, when the thickness of the retainer 104 in the vertical direction is small, the supported height of the rubber film 103 is lower than the upper surface of the wafer U, and is excessively large at the peripheral edge of the wafer U. Power is loaded. For this reason, the contact pressure between the peripheral edge of the wafer U and the polishing pad 105 is excessively increased, and so-called peripheral sag occurs in which the peripheral edge of the wafer U is polished more than the central portion.

  Therefore, in order to polish the entire surface of the wafer U at a uniform polishing rate, it is necessary to always set the thickness of the retainer 104 in the vertical direction appropriately as shown in FIG. 8B.

  However, since the retainer 104 is always in sliding contact with the polishing pad 105 when the wafer U is polished, the thickness in the vertical direction gradually decreases due to wear. Therefore, even if the thickness in the vertical direction of the retainer 104 is appropriately set in accordance with the thickness of the wafer U in the initial state, the position where the rubber film 103 is supported is lowered as shown in FIG. As a result, the outer peripheral sag occurs.

  Therefore, in order to polish the entire surface of the wafer U at a uniform polishing rate, it is necessary to select the retainer 104 according to the thickness of the wafer U, and it is necessary to constantly monitor the amount of wear of the retainer 104. There is. Therefore, the wafer polishing apparatus having the above-described configuration has a problem that the burden on the operator is large.

  Therefore, in recent years, as a device that can polish the entire surface of the wafer U at a uniform polishing rate even if the retainer is worn, a separation type polishing head that holds the wafer U movably in the vertical direction with respect to the retainer has been disclosed. (For example, refer to Patent Document 1).

  FIG. 9 is a configuration diagram of a conventional separation type polishing head.

  As shown in FIG. 9, the polishing head has a head body 201 that is driven to rotate. The head main body 201 has a recess 201a on its lower surface, and a ring-shaped retainer 202 is fixed to the outer peripheral portion of the portion in contact with the polishing pad (not shown).

  A plate-like support plate 203 is provided substantially horizontally inside the recess of the head body 201. The support plate 203 is supported so as to be movable in the vertical direction inside the head main body 201, and an isolation film 204 is attached to the upper surface thereof. The isolation film 204 has flexibility, and the peripheral edge thereof is held by the head body 201.

  As a result, a first space 205 surrounded by the head main body 201 and the isolation film 204 is formed on the upper surface side of the support plate 203. A first gas supply pipe 206 is connected to the first space 205, and gas is supplied from the first gas supply pipe 206 to the first space 205, so that the first space 205 is interposed through the isolation film 204. The upper surface of the support plate 203 can be pressurized.

  A recess 207 is formed on the lower surface of the support plate 203. The recess 207 is closed by a rubber film 208, and a second space 209 is formed between the support plate 203 and the rubber film 208. A wafer U is held on the lower surface of the rubber film 208. A second gas supply pipe 210 is connected to the second space 209. By supplying gas from the second gas supply pipe 210 to the second space 209, the lower surface of the support plate 203 is added. It can be pressurized.

  When the wafer U is polished using the polishing head having the above-described configuration, the rotating head main body 201 is lowered, and the retainer 202 fixed to the lower end surface of the head main body 201 is rotated on the surface of the rotating polishing pad (not shown). Press on. Then, by supplying gas to the first space 205 and the second space 209 and controlling the pressure in the first and second spaces 205 and 209, the wafer U bonded and fixed to the lower surface of the rubber film 208 is removed. Press against a polishing pad (not shown).

Thus, the separation type polishing head is configured such that the head main body 201 and the support plate 203 are driven independently. Therefore, even if the retainer 202 is worn and its vertical thickness is reduced, the height at which the rubber film 208 is supported is not affected thereby. As a result, the peripheral portion of the wafer U is not excessively polished, and conversely, it is not excessively polished.
JP-T-2002-527893

  However, when the wafer U is polished using this polishing head, if the pressure in the first space 205 or the second space 209 varies, the height of the support plate 203 varies and the wafer U is polished well. Sometimes it was not done. This is because once the polishing is started, many wafers are polished with the same setting.

  For example, when the pressure in the first space 205 becomes lower than that in the second space 209, the support plate 203 rises due to the balance of pressures acting on the upper and lower surfaces thereof. At this time, the rubber film 208 that holds the wafer U swells in a downward arc due to the pressure in the second space 209, so that the contact pressure acting between the peripheral edge of the wafer U and the polishing pad is applied to the wafer U. As a result, the peripheral edge of the wafer U is hardly polished.

  Further, when the pressure in the first space 205 becomes higher than that in the second space 209, the support plate 203 descends due to the balance of pressures acting on the upper and lower surfaces. At this time, the rubber film 208 that holds the wafer U is somewhat shrunk so as to form an arc upward due to the pressure of the second space 209, so that the contact pressure acting between the central portion of the wafer U and the polishing pad is increased. As a result, the central portion of the wafer U is hardly polished.

  FIG. 10 is a simulation graph showing a change in contact pressure with respect to the radial direction of the wafer U when the pressure in the first space is changed. Here, the pressure applied to the second space is fixed at 200 [hPa], and the pressure applied to the first space is [1] 205 [hPa], [2] 200 [hPa], [3] 195 [hPa]. ] And fluctuate.

  As shown in FIG. 10, when the pressure in the first space is [1] 205 [hPa], the contact pressure between the wafer U and the polishing pad at the center of the wafer U is approximately 200 [hPa]. On the other hand, it can be seen that the contact pressure rapidly increases at the peripheral edge of the wafer U.

  When the pressure in the first space is [3] 195 [hPa], the contact pressure between the wafer U and the polishing pad at the center of the wafer U is approximately 200 [hPa], whereas the wafer U It can be seen that the contact pressure is drastically reduced at the peripheral edge.

  As described above, when the wafer U is polished using the conventional polishing head, a large difference occurs in the polishing rate between the central portion and the peripheral portion of the wafer U with respect to the pressure fluctuation in the first and second spaces. End up.

  The present invention has been made in view of the above circumstances, and an object thereof is a polishing method capable of polishing the surface of a workpiece with high accuracy without being affected by the thickness of the workpiece or the retainer. And providing a polishing apparatus.

  In order to solve the problems and achieve the object, the polishing method and polishing apparatus of the present invention are configured as follows.

(1) A rotationally driven surface plate provided with a polishing pad, a rotationally driven head main body disposed opposite to the polishing pad, and provided with a first recess on a surface facing the polishing pad; A flexible first film-like member that is connected in the first depression and forms a first space with the head body, and the first depression is formed by the first film-like member. And a support plate that is supported so as to be movable in the axial direction of the head body and has a second recess on a surface facing the polishing pad, and a surface of the support plate facing the polishing pad. A second flexible space that holds the workpiece on a surface facing the polishing pad, and is stretched so as to close the concave portion of the two, forms a second space between the support plate and the support plate. A film-like member is provided on the surface of the head body facing the polishing pad. The retainer that surrounds the workpiece and is pressed by the polishing pad, and the pressure in the first space and the second space are adjusted, and held by the second film-shaped member In a polishing method for polishing a surface of the workpiece using a polishing apparatus including a pressure adjusting unit that presses the workpiece against the polishing pad, a step of setting a target shape of the workpiece; Based on the step of measuring the shape of the workpiece before polishing, the target shape of the workpiece, and the shape of the workpiece before polishing, the target polishing amount distribution of the workpiece is determined. A step of setting the polishing condition to a specific polishing condition corresponding to the target polishing amount distribution based on the relationship between the calculating step and the polishing condition and polishing amount distribution of the workpiece prepared in advance. And polishing the workpiece under the specific polishing conditions. Characterized by comprising the step of.

(2) In the polishing method described in (1), the polishing conditions are the pressure in the first and second spaces, the rotational speed of the surface plate, the rotational speed of the head body, and a retainer for the polishing pad. Among the pressures, at least one or more pressures are included.

(3) In the polishing method described in (1) or (2), obtained by measuring the shape of the workpiece after polishing and measuring the shape of the workpiece after polishing. The method further includes the step of correcting the relationship between the polishing condition of the workpiece and the polishing amount distribution using the measurement result.

(4) In a polishing apparatus that polishes the surface of the polishing pad using friction between the polishing pad and a workpiece, a rotationally driven surface plate provided with the polishing pad is disposed opposite to the polishing pad. The head main body having a first concave portion provided on the surface facing the polishing pad and being driven to rotate, is connected to the first concave portion, and forms a first space between the head main body and the head main body. A surface facing the polishing pad and supported by the flexible first film-like member and the first film-like member so as to be movable in the axial direction of the head body in the first recess. And a support plate provided with a second recess, and is stretched so as to close the second recess on a surface of the support plate facing the polishing pad, and a second space is formed between the support plate and the support plate. And forming the surface on the surface facing the polishing pad A flexible second film-like member for holding a workpiece, and a retainer provided on a surface of the head main body facing the polishing pad, surrounding the workpiece and pressed against the polishing pad; Adjusting the pressure in the first space and the second space, and pressure adjusting means for pressing the workpiece held by the second film-like member against the polishing pad; and Based on the target shape, the storage means for storing the relationship between the polishing condition and the polishing amount distribution of the workpiece, the shape of the workpiece before polishing, and the target shape of the workpiece, Based on the relationship between the calculation means for calculating the target polishing amount distribution of the workpiece and the polishing condition and the polishing amount distribution of the workpiece, the polishing condition is changed to the target polishing amount distribution of the workpiece. And setting means for setting corresponding specific polishing conditions. And butterflies.

(5) In the polishing apparatus described in (4), the polishing conditions include the pressures in the first and second spaces, the rotational speed of the head body, the rotational speed of the surface plate, and a retainer for the polishing pad. Among the pressures, at least one or more pressures are included.

(6) The polishing apparatus described in (4) is characterized by further comprising measurement means for measuring the shape of the workpiece after polishing.

(7) In the polishing apparatus described in (4), the polishing apparatus further includes a transfer device that receives the workpiece from the measurement unit and transfers the workpiece to the second film member.

  According to the present invention, the surface of the workpiece can be polished with high accuracy without being affected by the thickness of the workpiece and the thickness of the retainer.

  First, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view of a wafer polishing apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, this wafer polishing apparatus (polishing apparatus) has a cylindrical surface plate 1. The surface plate 1 is surrounded by a cup body 8, and a polishing pad 2 is stuck on the upper surface. The material of the polishing pad 2 is appropriately selected depending on the material of the polishing layer of the wafer U (workpiece). In addition, a drive shaft (not shown) of the surface plate driving device 3 is connected to the lower portion of the surface plate 1, and the surface plate 1 can be rotated in the direction of arrow A by rotating the drive shaft.

  Above the polishing pad 2 affixed to the surface plate 1, a polishing liquid supply pipe 4 is disposed to face the polishing pad 2. The polishing liquid supply pipe 4 is supported by a first swing arm 5 that swings on the polishing pad 2, and the polishing liquid L is supplied to the upper surface of the polishing pad 2 from the supply port. As the polishing liquid L, for example, an alkaline solution containing colloidal silica is used.

  In addition, a plurality of, in this embodiment, two polishing heads 6 are arranged opposite to each other above the polishing pad 2 attached to the surface plate 1. Each polishing head 6 is supported by a second swing arm 7 that swings on the polishing pad 2. The second swing arm 7 is supported by the vertical drive device 21, and the polishing head 6 can be pressed against the upper surface of the polishing pad 2 by lowering the second swing arm 7 by the vertical drive device 21. It has become. The second swing arm 7 has a cylindrical shape, and includes first and second gas supply pipes 14a and 14b (shown in FIG. 2), a connecting shaft 28 (shown in FIG. 2), and the like. Is arranged.

  A measuring device 22 (measuring means) for measuring the actual shape of the wafer U to be loaded, that is, the thickness distribution in the radial direction of the wafer U before polishing, is disposed on the side of the surface plate 1. A delivery device 23 for delivering the wafer U from the measurement device 22 to the polishing head 6 is disposed between the board 1 and the measurement device 22. In this embodiment, the wafer U is delivered from the measuring device 22 to the polishing head 6 using the delivery device 23. However, the present invention is not limited to this. For example, the wafer U is manually delivered from the measuring device 22. It may be delivered to the polishing head 6.

  FIG. 2 is a configuration diagram of the configuration of the polishing head 6 according to the embodiment.

  As shown in FIG. 2, the polishing head 6 has a head body 10, and a drive shaft 12 is connected to the top surface of the polishing head 6 substantially vertically. The drive shaft 12 is connected to a head drive device 24 via the connection shaft 28 disposed in the second swing arm 7, and by driving the head drive device 24, the head main body is driven. 10 can be rotated around its axis.

  In addition, a columnar first recess 11 is provided on the lower surface of the head body 10, and a disk-like support plate 13 is disposed substantially horizontally on the inner side. The support plate 13 is supported by the first film-like member 16 so as to be movable in the vertical direction with respect to the head body 10, and a cylindrical second recess 15 is provided on the lower surface.

  The first film-like member 16 is connected from the upper surface of the support plate 13 to the inner peripheral surface of the head main body 10, and is separated from the periphery between the first film-like member 16 and the head main body 10. The space 17 is formed. The first film member 16 is made of a flexible material such as resin.

  A second film-like member 18 for holding the wafer U is provided on the lower surface of the support plate 13. The second film-like member 18 is stretched on the lower end surface of the support plate 13 so as to close the second recess 15, and is isolated from the periphery between the second film-like member 18 and the support plate 13. A second space 19 is formed. The second film member 18 is made of a flexible material such as resin.

  At a substantially central portion in the radial direction of the head main body 10, a first gas supply pipe 14 a that supplies gas into the first space 17 and a second gas supply pipe 14 b that supplies gas into the second space 19. Is arranged. The first and second gas supply pipes 14a and 14b are connected to first and second gas supply apparatuses 9a and 9b (pressure adjusting means), respectively. By operating 9a and 9b, the insides of the first and second spaces 17 and 19 can be set to desired pressures, respectively.

  A retainer ring 20 (retainer) for compressing the polishing pad 2 is provided at the lower end of the head body 10. The retainer ring 20 surrounds the wafer U held on the lower surface of the second film-like member 18 and prevents the wafer U from falling off the polishing head 6.

  The surface plate driving device 3, the vertical driving device 21, the head driving device 24, the measuring device 22, the delivery device 23, the first gas supply device 9a, and the second gas supply device 9b are for controlling these devices. The control device 25 is connected.

  FIG. 3 is a schematic diagram showing the configuration of the control device 25 according to the embodiment.

  As shown in FIG. 3, the control device 25 includes a control unit 25a (calculation unit, setting unit) and a storage unit 25b. The controller 25a is configured to rotate the surface plate 1, the number of revolutions of the polishing head 6, the pressure of the retainer ring 20 against the polishing pad 2 (hereinafter referred to as "retainer pressure"), and the pressure P1 in the first space 17 ( Hereinafter, the pressure P2 (hereinafter referred to as “second pressure”) in the second space 19 is controlled. An input device 26 is connected to the storage unit 25b. With this input device 26, the relationship between the first and second pressures P1 and P2 stored in the database and the polishing amount distribution and the wafer U obtained by the measurement are obtained. Various information such as a thickness distribution with respect to the radial direction is stored.

  The database showing the relationship between the first and second pressures P1 and P2 and the polishing amount distribution is obtained by actually polishing the wafer U while changing the first and second pressures P1 and P2 in various ways. By measuring the thickness distribution with respect to the radial direction of U, the amount of change in each radial direction is stored in advance.

  Next, a procedure for using the wafer polishing apparatus having the above configuration will be described with reference to FIG.

  FIG. 4 is a flowchart showing a process of polishing the wafer U according to the embodiment.

  As shown in FIG. 4, when using the wafer polishing apparatus having the above-described configuration, first, the target shape of the wafer U after polishing (hereinafter referred to as “target shape”), that is, the radial direction of the wafer U after polishing. A thickness distribution, for example, a center concave shape (concave shape of 2 μm in the central direction), a central convex shape (convex shape of 2 μm in the central direction), a flat shape (shape of ± 0 μm in the central direction), etc. is set by the input device 26 (step S11). When the setting of the target shape of the wafer U is completed, the wafer polishing apparatus is placed on the production line and the polishing of the wafer U is started.

  When polishing the wafer U, first, the actual shape of the wafer U before polishing, that is, the thickness distribution in the radial direction of the wafer U before polishing (hereinafter referred to as “actual shape”) is measured by the measuring device 22 ( Step S12).

  Then, based on the target shape of the wafer U after polishing and the actual shape of the wafer U before polishing, the control unit 25a calculates the polishing amount distribution that is the target of the wafer U (step S13).

  When the actual shape of the wafer U before polishing is measured, in parallel with the calculation of the polishing amount distribution of the wafer U, the second film-like member 18 provided on the head body 10 with the wafer U by the transfer device 23. Adhesive and fixed to the lower surface of the.

  When the polishing amount distribution of the wafer U is calculated, an optimum polishing condition for obtaining the calculated polishing amount distribution is selected with reference to the database stored in the storage unit 25b (step S14). Step S13 to step S14 will be described in more detail. In step S13, for example, the target shape of the wafer U after polishing is set as a “flat shape (center direction ± 0 μm shape)”, and the measured actual shape of the wafer U is “ In the case of “middle concave shape (4 μm concave shape in the central direction)”, the polishing amount distribution is calculated as “periphery direction + 4 μm polishing”. An optimum polishing condition (for example, P1> P2 etc.) for realizing the calculated polishing distribution is selected in step S14. In the present embodiment, the first and second pressures P1 and P2 are adopted as the polishing conditions.

  Then, the first and second spaces 17 and 19 are set to the first and second pressures P1 and P2 by the first and second gas supply devices (step 15), and the polishing pad 2 and the polishing head 6 are moved. While rotating, the second swing arm 7 is lowered.

  As a result, the wafer U held on the lower surface of the second film-like member 18 is pressed against the surface of the polishing pad 2 with an optimum load for obtaining a target polishing amount distribution, that is, a calculated polishing amount distribution. As a result, after a predetermined time has elapsed, the surface of the wafer U is polished by the target polishing amount distribution, and a wafer U having a shape substantially the same as the target shape is manufactured (step S16).

  According to the wafer polishing apparatus having the above configuration, the actual shape of the wafer U before polishing is measured for each wafer, and the polishing amount distribution of the target wafer U is calculated based on the input target shape of the wafer U. . Then, by comparing and referring to the target polishing amount distribution and the database stored in the storage unit 25b, the optimum first and second pressures P1 and P2 for obtaining the target polishing amount distribution are selected.

  Therefore, the wafer U can be easily obtained without being influenced by the thickness of the wafer U or the retainer ring 20 only by creating an accurate correspondence relationship between the first and second pressures P1 and P2 and the polishing amount distribution. Can be made the target shape. Naturally, the occurrence of so-called outer periphery sag or the like in which the thickness of the outer peripheral portion of the wafer U becomes thinner than the central portion of the wafer U is suppressed.

  Moreover, by using the measuring device 22 and the transfer device 23, the measurement of the actual shape of the wafer U and the bonding and fixing of the wafer U to the second film-shaped member 18 are automated. Can be reduced.

  In the present embodiment, the gas is supplied into the first and second spaces 17 and 19, but the present invention is not limited to the gas, and the inside of the first and second spaces 17 and 19 is added. For example, a liquid may be used as long as it can be pressurized. Moreover, although the wafer U is used as a workpiece, it is not limited to this.

  Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to the said embodiment here, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 5 is a flowchart showing a process of polishing the wafer U according to the second embodiment of the present invention.

  In the present embodiment, the first pressure P1, the second pressure P2, the rotational speed R1 of the surface plate 1, the rotational speed R2 of the polishing head 6, and the retainer pressure Pr are adopted as the polishing conditions. An optimum polishing condition is selected from the correspondence relationship with the distribution in order to obtain a target polishing amount distribution. That is, in the present embodiment, the first pressure P1, the second pressure P2, the rotation speed R1 of the surface plate 1, the rotation speed R2 of the polishing head 6, the retainer pressure Pr, and the polishing amount distribution, which are stored in a database, are stored. The correspondence relationship is stored in the storage unit 25b.

  That is, as shown in FIG. 5, first, a target shape after polishing is set by the input device 26 (step S21). When the setting of the target shape of the wafer U is completed, the wafer polishing apparatus is placed on the production line and the polishing of the wafer U is started.

  When polishing the wafer U, first, the actual shape of the wafer U before polishing is measured by the measuring device 22 (step S22). Then, based on the target shape of the wafer U after polishing and the actual shape of the wafer U before polishing, the control unit 25a calculates the polishing amount distribution that is the target of the wafer U (step S23).

  When the actual shape of the wafer U before polishing is measured, in parallel with the calculation of the polishing amount distribution of the wafer U, the second film-like member 18 provided on the head body 10 with the wafer U by the transfer device 23. Adhesive and fixed to the lower surface of the.

  When the polishing amount distribution of the wafer U is calculated, referring to a database stored in the storage unit 25b, the optimum polishing conditions for obtaining the calculated polishing amount distribution, that is, the first pressure P1 and the second pressure. P2, the rotation speed R1 of the surface plate 1, the rotation speed R2 of the polishing head 6, and the retainer pressure Pr are selected (step S24).

  Then, the first pressure P1, the second pressure P2, the rotational speed R1 of the surface plate 1, the rotational speed R2 of the polishing head 6, and the retainer pressure Pr are set to optimum values (step S25), and the second oscillation is performed. The arm 7 is lowered. As a result, the wafer U held on the lower surface of the second film-like member 18 is pressed against the surface of the polishing pad 2 under optimum conditions for obtaining the calculated polishing amount distribution. As a result, after a predetermined time, the surface of the wafer U is polished with the calculated polishing amount distribution, and the wafer U having the same shape as the target shape is manufactured (step S26).

  According to the wafer polishing apparatus having the above configuration, in addition to the correspondence relationship between the first and second pressures P1 and P2 and the polishing amount distribution, the number of rotations of the surface plate 1, the number of rotations of the polishing head 6, the retainer pressure and polishing. By creating a correspondence relationship with the quantity distribution in a database, the wafer U can be polished under better conditions to obtain the calculated polishing quantity distribution, so that the shape of the wafer U is made closer to the target shape. Can do.

  In the present embodiment, the first pressure P1, the second pressure P2, the rotation speed R1 of the surface plate 1, the rotation speed R2 of the polishing head 6, the retainer pressure Pr, and the like are employed as the polishing conditions. Various other conditions can be considered. It goes without saying that if this polishing condition is increased, more accurate polishing can be performed.

  Next, a third embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to the said embodiment here, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 6 is a flowchart showing a process of polishing a wafer U according to the third embodiment of the present invention.

  In the present embodiment, after the polishing of the wafer U is completed, the shape of the wafer U is measured again, and the measurement result is fed back to the database, so that the database is constantly updated to the latest one.

  That is, as shown in FIG. 6, first, a target shape after polishing is set by the input device 26 (step S31). When the setting of the target shape of the wafer U is completed, the wafer polishing apparatus is placed on the production line and the polishing of the wafer U is started.

  When polishing the wafer U, first, the actual shape of the wafer U before polishing is measured by the measuring device 22 (step S32). Then, based on the target shape of the wafer U after polishing and the actual shape of the wafer U before polishing, the control unit 25a calculates the polishing amount distribution that is the target of the wafer U (step S33).

  When the actual shape of the wafer U before polishing is measured, in parallel with the calculation of the polishing amount distribution of the wafer U, the wafer 23 is placed on the lower surface of the second film-like member 18 provided on the head body 10 by the transfer device 23. Adhering and fixing U.

  When the polishing amount distribution of the wafer U is calculated, the optimum condition for obtaining the calculated polishing amount distribution, that is, the first pressure P1 and the second pressure P2 is referred to the database stored in the storage unit 25b. Then, the rotational speed R1 of the surface plate 1, the rotational speed R2 of the polishing head 6, and the retainer pressure Pr are selected (step S34).

  Then, the first pressure P1, the second pressure P2, the rotational speed R1 of the surface plate 1, the rotational speed R2 of the polishing head 6, and the retainer pressure Pr are set to optimum values (step S35), and the second oscillation is performed. The arm 7 is lowered. As a result, the wafer U held on the lower surface of the second film-like member 18 is pressed against the surface of the polishing pad 2 under optimum conditions for obtaining the calculated polishing amount distribution. As a result, after a predetermined time, the surface of the wafer U is polished with the calculated polishing amount distribution, and the wafer U having the same shape as the target shape is manufactured (step S36).

  When the polishing of the wafer U is completed, the measurement device 22 measures the actual shape of the wafer U after polishing, that is, the thickness distribution in the radial direction of the wafer U after polishing (step S37), and feeds back the measurement result to the database. (Step S38). That is, the actual polishing amount obtained under the conditions set in step S35 (first pressure P1, second pressure P2, rotation speed R1 of the surface plate 1, rotation speed R2 of the polishing head 6, retainer pressure Pr). The distribution is measured and fed back to the database.

  As a result, the deterioration of the polishing pad 2, clogging, temperature change, change in polishing agent, etc. are immediately reflected in the database, and the database is constantly updated to the latest correspondence relationship. A situation in which the shape greatly fluctuates from the target shape is unlikely to occur.

  Furthermore, by accumulating the database, it is possible to predict the machining accuracy that changes with time and automatically set more appropriate polishing conditions.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a perspective view of a wafer polishing apparatus according to a first embodiment of the present invention. The block diagram of the structure of the grinding | polishing head which concerns on the embodiment. Schematic which shows the structure of the control apparatus which concerns on the same embodiment. The flowchart which shows the process of grind | polishing the wafer which concerns on the embodiment. 9 is a flowchart showing a process for polishing a wafer according to a second embodiment of the present invention. 9 is a flowchart showing a process for polishing a wafer according to a third embodiment of the present invention. The block diagram of the conventional grinding | polishing head. Schematic which shows the relationship between the conventional retainer and a rubber film. The block diagram of the conventional separate type | mold polishing head. The simulation graph which shows the change of the contact pressure with respect to the radial direction of the wafer U at the time of changing the pressure in 1st space.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Surface plate, 2 ... Polishing pad, 10 ... Head main body, 11 ... 1st recessed part, 13 ... Support plate, 15 ... 2nd recessed part, 16 ... 1st film-shaped member, 17 ... 1st space, DESCRIPTION OF SYMBOLS 18 ... 2nd film-like member, 19 ... 2nd space, 20 ... Retainer ring (retainer), 22 ... Measuring apparatus (measuring means), 25a ... Control part (calculation means, setting means), 25b ... Memory | storage part ( Storage means), 9a ... first gas supply device (pressure adjustment means), 9b ... second gas supply device (pressure adjustment means), U ... wafer (workpiece).

Claims (7)

A rotationally driven surface plate with a polishing pad;
A head body that is rotationally driven and is disposed opposite to the polishing pad and includes a first recess on a surface facing the polishing pad;
A flexible first film-like member that is connected in the first recess and forms a first space with the head body;
A support plate that is supported by the first film member so as to be movable in the axial direction of the head body in the first recess, and has a second recess on a surface facing the polishing pad;
A surface of the support plate facing the polishing pad is stretched so as to close the second recess, and a second space is formed between the support plate and the surface facing the polishing pad. A flexible second film-like member holding the workpiece;
A retainer that is provided on a surface of the head body that faces the polishing pad, surrounds the workpiece, and is pressed against the polishing pad;
Pressure adjusting means for adjusting the pressure in the first space and the second space, and pressing the workpiece held by the second film-like member against the polishing pad;
In a polishing method for polishing the surface of the workpiece using a polishing apparatus comprising:
Setting a target shape of the workpiece;
Measuring the shape of the workpiece before polishing;
Calculating a target polishing amount distribution of the workpiece based on a target shape of the workpiece and a shape of the workpiece before polishing;
A step of setting the polishing condition to a specific polishing condition corresponding to the target polishing amount distribution based on the relationship between the polishing condition and the polishing amount distribution of the workpiece prepared in advance;
Polishing the workpiece under the specific polishing conditions;
A polishing method comprising:   The polishing conditions include at least one of the pressures in the first and second spaces, the rotation speed of the surface plate, the rotation speed of the head body, and the pressure of the retainer against the polishing pad. The polishing method according to claim 1. Measuring the shape of the workpiece after polishing;
Using the measurement result obtained by measuring the shape of the workpiece after polishing, correcting the relationship between the polishing condition of the workpiece and the polishing amount distribution;
The polishing method according to claim 1, further comprising: In a polishing apparatus for polishing the surface of the polishing pad using friction between the polishing pad and a workpiece,
A rotationally driven surface plate comprising the polishing pad;
A head body that is rotationally driven and is disposed opposite to the polishing pad, and includes a first recess on a surface facing the polishing pad;
A flexible first film-like member that is connected in the first recess and forms a first space with the head body;
A support plate that is supported by the first film-like member so as to be movable in the axial direction of the head body in the first recess, and has a second recess on a surface facing the polishing pad;
A surface of the support plate facing the polishing pad is stretched so as to close the second recess, and a second space is formed between the support plate and the surface facing the polishing pad. A flexible second membrane member holding the workpiece;
A retainer that is provided on a surface of the head body that faces the polishing pad, surrounds the workpiece, and is pressed against the polishing pad;
Pressure adjusting means for adjusting the pressure in the first space and the second space, and pressing the workpiece held by the second film-like member against the polishing pad;
Storage means for storing a target shape of the workpiece and a relationship between a polishing condition and a polishing amount distribution of the workpiece;
Calculation means for calculating a target polishing amount distribution of the workpiece based on a shape of the workpiece before polishing and a target shape of the workpiece;
Based on the relationship between the polishing condition of the workpiece and the polishing amount distribution, setting means for setting the polishing condition to a specific polishing condition corresponding to the target polishing amount distribution of the workpiece;
A polishing apparatus comprising:   The polishing conditions include at least one of the pressures in the first and second spaces, the rotational speed of the head body, the rotational speed of the surface plate, and the pressure of the retainer against the polishing pad. The polishing apparatus according to claim 4.   The polishing apparatus according to claim 4, further comprising a measuring unit that measures a shape of the workpiece after polishing.   The polishing apparatus according to claim 4, further comprising a transfer device that receives the workpiece from the measuring unit and transfers the workpiece to the second film member.

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