Polishing treatment device

Abstract

To provide a polishing treatment device capable of coping with uniformization of a surface temperature of a platen pad, achieving further improvement of SFQR or the like on a wafer surface, and performing a large number of high-quality and stable polishing processes.SOLUTION: A polishing treatment device includes a polishing head having an annular body having an inner peripheral diameter that surrounds an outer periphery of a wafer to be subjected to polishing treatment, an elastic body that is covered at a lower-end side opening of the annular body and holds the wafer via a backing film adhered to a surface side thereof, a retainer ring that is formed in a shape that surrounds the outer periphery of the wafer held by the elastic body, and driving means that integrally rotates the annular body and the retainer ring horizontally. The device further includes: a first compensating heat source that is disposed on a surface side of a platen pad, is formed in a shape that surrounds a predetermined region of an outer periphery of the polishing head and adjusts a surface temperature of the platen pad; a second compensating heat source that is disposed on a rear surface side of the elastic body and adjusts temperatures of the wafer held by the elastic body and of the retainer ring; and a third compensating heat source that is disposed on a rear surface side of the platen and adjusts a temperature of the platen pad.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polishing processing apparatus used for polishing substrates such as semiconductor wafers or glass substrates. [Background technology]

[0002] In recent years, in the semiconductor device manufacturing process, with the increasing integration density of substrates such as semiconductor wafers and glass substrates (hereinafter referred to as wafers), wafer surface planarization technology has become increasingly important. Among these planarization technologies, the most important is chemical mechanical polishing (CMP). This chemical mechanical polishing is performed by using a polishing processing device (also called a polishing device) to supply a polishing solution containing abrasive grains such as silica (SiO2) onto a polishing surface such as a platen pad (polishing pad) while sliding the wafer against the polishing surface.

[0003] In a CMP system, the polishing removal rate (MRR (Material Removal Rate)) is significantly affected by the polishing surface temperature in an exponential manner (power function). Conventional technology was unable to control the temperature distribution within the wafer surface, which is the object to be polished, resulting in problems with the uniformity of the polishing rate within the surface. Furthermore, conventional methods used fluid temperature control, which resulted in problems with the response of the control and the accuracy of the heat source shape formation.

[0004] For example, the CMP device disclosed in Patent Document 1 is designed to equalize the temperature of the polishing table to which the platen pad (polishing pad) is attached. Specifically, this is a method of injecting steam or the like from a pipe into a low-temperature area, and aims to equalize the temperature of the platen pad by adjusting the curvature and position of the pipe.

[0005] In addition, the CMP devices disclosed in Patent Documents 2 and 3 control the temperature of the air pressure part of the membrane head, aiming to make the temperature uniform from the back surface of the wafer to the front surface of the wafer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-520834 [Patent Document 2] Japanese Patent Application Publication No. 2022-59759 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-166448 Summary of the Invention [Problem to be solved by the invention]

[0007] Uniform temperature on the platen pad is essential for uniform temperature across the wafer, but conventional technology has inadequate temperature control on the platen pad, resulting in uneven polishing. The main cause of this is inadequate formation of an external supplemental heat source. Conventional heat sources are 1) the wafer and retaining ring, and 2) external heat sources such as steam. In a typical CMP system, a circular workpiece is placed on the surface of a ring-shaped platen pad, held by a retainer ring with the same diameter as the surface width, but it is difficult to achieve a uniform temperature on the platen pad surface using only this circular heat source. Furthermore, an external supplemental heat source such as steam does not adequately shape the heat, making it difficult to achieve a uniform temperature on the platen pad.

[0008] The first objective of this invention is to form a fan-shaped heat source (fan-type heat source) using the circular heat source of the wafer and retainer ring and a supplemental heat source from an external source to achieve uniform temperature distribution on the platen pad. The second objective is to investigate a mechanism that can control the CMP reaction temperature. By solving these two problems, it is possible to achieve temperature uniformity of the platen pad, which has not been considered before, and further improve the SFQR (Site Front Least Square Range) of the wafer surface. The main objective is to provide a polishing processing device that can perform high-quality, stable polishing processing for multiple wafers. [Means for solving the problem]

[0009] The present invention relates to a polishing processing apparatus having a platen with a platen pad attached to its surface, and a polishing head that holds a wafer to be polished and slides the surface of the wafer to be polished against the surface of the platen pad, the polishing processing apparatus comprising: an annular body having an inner diameter large enough to surround the outer periphery of the wafer to be polished; an elastic body that covers the opening at the lower end of the annular body and holds the wafer via a backing film attached to the surface of the elastic body; a retainer ring formed in a shape that surrounds the outer periphery of the wafer held by the elastic body; and the retainer ring, and a driving means for rotating the retainer ring horizontally as a unit; a first supplemental heat source disposed on the front side of the platen pad and formed in a shape surrounding a predetermined region on the periphery of the polishing head, for adjusting the surface temperature of the platen pad; a second supplemental heat source disposed on the back side of the elastic body, for adjusting the temperatures of the wafer and the retainer ring held by the elastic body; and a third supplemental heat source disposed on the back side of the platen, for adjusting the temperature of the platen pad. [Effects of the Invention]

[0010] According to the present invention, it is possible to achieve temperature uniformity on the platen pad by maintaining the shape of the heat source, which has not been possible until now. Based on this basic condition, temperature uniformity is achieved across the wafer surface, and uniformity in the MRR (Material Removal Rate) further improves SFQR and the like, thereby providing a polishing processing apparatus that can perform high-quality, stable polishing processing on a large number of wafers. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram for explaining the basic configuration of a polishing processing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view illustrating an example of a specific configuration on a platen of the polishing processing apparatus according to the embodiment. [Figure 3] FIG. 4 is a top view illustrating an example of a configuration on a platen. [Figure 4]10(a) and 10(b) are diagrams for explaining an example of the configuration of a second supplementary heat source. [Figure 5] FIG. 4 is a diagram illustrating an example of the configuration of a first supplementary heat source on a platen pad. [Figure 6] FIG. 10 is a diagram illustrating an example of the configuration of a third supplementary heat source below the platen. [Figure 7] FIG. 10 is a diagram showing an example of the configuration of a temperature sensor that acquires the temperature of a wafer in a pseudo manner during a polishing process. [Figure 8] 10(a) and 10(b) are diagrams for explaining another example of the configuration of the second supplementary heat source. [Figure 9] 10A and 10B are diagrams for explaining the temperature distribution of the wafer, the retainer heat source, and the platen pad at the supplementary heat source during polishing processing. [Figure 10] 10(a) and 10(b) are diagrams for explaining other examples of the shape and combination of the first supplementary heat source. [Figure 11] FIG. 10 is a diagram illustrating an example of a flow of conventional slurry supplied toward a platen pad. [Figure 12] FIG. 2 is a diagram for explaining an example of a heat transfer mechanism of a CMP system. [Figure 13] FIG. 1 is a schematic diagram illustrating an example of a thermal system configuration. [Figure 14] 10 is a flowchart illustrating an example of a main control procedure performed by a control unit when performing a polishing process. [Figure 15] 8 is a diagram showing an example of the configuration of a temperature sensor that acquires the temperature of a wafer during a polishing process in a pseudo manner, different from that shown in FIG. 7; [Figure 16] FIG. 4 is a diagram showing an example of the configuration of a first supplementary heat source, which is different from that shown in FIGS. 2 and 3. [Figure 17] FIG. 10 is a top view illustrating another example of the configuration of the first supplemental heat source when the first supplemental heat source is disposed on the rear side of the platen. [Figure 18] 10A and 10B are diagrams for explaining the formation of a substantially sector-shaped heat source region by a wire heater that is a first supplementary heat source. [Figure 19]19 is a diagram for explaining the formation of a substantially sector-shaped heat source region by a seat heater, which is a first supplementary heat source, different from FIG. 17 and FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0012] In CMP systems, the optimum chemical reaction temperature of the polishing fluid (slurry) on the platen pad is sometimes considered to be around 35°C. The heat source's heat quantity (Q) is determined by the formula Q = μPV / J [kcal / min], where μ is the pad friction coefficient, P is the polishing pressure, V is the relative velocity, and J is the frictional heat quantity per unit of motion (≒427 kgf·m / kcal). Therefore, any excess or deficiency in the amount of self-heating relative to the optimum chemical reaction temperature must be controlled using an external heat source.

[0013] Furthermore, the slurry flow also affects the in-plane temperature distribution of the platen pad and wafer, and must be treated as part of the heat source. For example, if the slurry temperature can be controlled to be the same as the platen pad temperature, Coriolis flow (a conventional flow method) would be sufficient. However, controlling the slurry temperature to be the same as the platen pad temperature is difficult in terms of responsiveness. For this reason, a fan-shaped slurry flow is ideal. Therefore, the slurry flow shape must also be fan-shaped, and the inventors have discovered that a "fan-shaped heat source" is optimal for temperature uniformity.

[0014] Furthermore, the temperature at any radius of the platen will depend on the time of contact with the heat source. Here, the platen temperatures at the wafer heat source and supplementary heat source during polishing processing will be described.

[0015] FIG. 9 is a diagram for explaining the temperature distribution of the wafer, the retainer heat source, and the platen pad at the supplementary heat source during polishing processing. Figure 9(a) is a diagram showing that the temperature distribution of the platen pad becomes uneven when the heat source is only a circular heat source (wafer and retaining ring), and Figure 9(b) is a diagram showing that the temperature distribution of the platen pad becomes uniform when a fan-shaped heat source is used, as in the polishing processing apparatus S of this embodiment.

[0016] As shown in Figure 9, when there is a circular heat source on the platen pad surface with an inner diameter of Ri and an outer diameter of Ro, and the circular heat source is in contact with the inner and outer diameters, the contact time ratio Ct between the platen radius R3 and the arc gh on the heat source disk due to platen rotation is Ct = R3 * θi / (2π * R3). The right diagram in Figure 9(a) shows the above-mentioned contact time ratio calculated over the entire radius of the platen, and as shown in the graph, it was found that the time ratio is not the same across the radius. At the platen surface width, the time ratio at the contact area between the inner and outer diameters of the platen is zero, and the peak point of the time ratio (temperature) is biased toward the center of the disk. The ideal time ratio is shown by the dashed line in the rectangle on the right.

[0017] In contrast, Figure 9(b) shows the contact time ratio for a fan-shaped heat source, and as shown in the graph on the right side of the figure, it was found that the contact time ratio was the same as for an ideal rectangular shape. This phenomenon makes it possible to uniformly distribute the temperature on the platen pad surface.

[0018] The present invention is characterized by forming a heat source shape on the surface of a rotating platen in a fan shape to achieve temperature uniformity within the surface, and at the same time controlling the CMP reaction temperature by supplementing the heat source from the backside of the wafer and platen.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The polishing processing apparatus of this embodiment is intended to polish substrates such as semiconductor wafers and glass substrates (hereinafter referred to as "wafers"). In this specification, one surface of the wafer is referred to as the circular or approximately circular polished surface. Furthermore, the surface of the platen pad that contacts the polished surface of the wafer is referred to as the polishing surface. [Example of implementation]

[0020] FIG. 1 is a diagram illustrating the basic configuration of a polishing processing apparatus S according to this embodiment. The polishing processing device S shown in FIG. 1 has a platen 51 which is a polishing table formed in a ring shape, and a platen pad 50 is adhered to the surface (front side) of the platen 51.

[0021] The polishing processing device S further includes a polishing head 100 that holds the wafer W and presses its surface to be polished against the surface of the platen pad 50, a nozzle N for supplying a polishing liquid (slurry) toward the platen pad 50, a motor (not shown) for horizontally rotating the platen 51 and the polishing head 100, a polishing liquid supply mechanism (not shown) connected to the nozzle N, and a control unit 20 that includes a computer for controlling each driving unit including the motor.

[0022] The platen pad 50 is ring-shaped, and its radius is larger than the maximum diameter of the polishing surface of the wafer W. This mechanism allows the relative polishing speed within the wafer W surface to be adjusted by changing the rotation speed and direction of the platen 51 and the polishing head 100. The platen pad 50 itself has elasticity, and can be made of commercially available materials such as nonwoven fabric or urethane foam.

[0023] The polishing head 100 holds the wafer W so that its surface to be polished is in sliding contact with the surface of the platen pad 50, and has a pressing mechanism that applies a processing pressure P (see Figure 6) to the held wafer W from the back direction (back side) of the surface to be polished toward the platen pad 50.

[0024] The control unit 20 mainly performs the positioning of the nozzle N, control of starting or stopping the supply of polishing liquid from the nozzle N, control of the supply amount per unit time of the polishing liquid jetted from the nozzle N, and control of starting and stopping the motor. The rotational force of the motor controlled by the control unit 20 is transmitted to the platen 51 via a drive unit (not shown), causing the platen 51 to rotate horizontally or stop rotating. The rotational force (torque) of the motor is also transmitted via a drive unit (for example, a universal joint) not shown to the polishing head 100. This causes the polishing head 100 to rotate horizontally or stop rotating.

[0025] Generally, the rotation direction of the platen 51 and the polishing head 100 are the same. This is because if they are rotated in opposite directions, the relative polishing speed within the wafer surface will become uneven, which may make it impossible to polish an even amount. By rotating the platen 51 and the polishing head 100 in the same direction and adjusting the rotation speeds of both, the polishing precision can be improved.

[0026] The rotational force of a single motor may be transmitted to the platen 51 and the polishing head 100 via gears with different gear ratios, or may be transmitted to each via separate motors. Both can be designed arbitrarily. The control procedure by the control unit 20 will be described later.

[0027] The polishing liquid is supplied from the nozzle N to the platen pad 50 for a predetermined time under the control of the control unit 20 when the rotation speed of the platen 51 reaches a predetermined value.

[0028] FIG. 2 is a perspective view for explaining an example of a specific configuration on the platen 51 of the polishing processing apparatus S according to this embodiment. FIG. 3 is a top view for explaining an example of the configuration on the platen 51 of the polishing processing apparatus S according to this embodiment. 4A and 4B are diagrams illustrating an example of the configuration of the second supplementary heat source 200 in the polishing head 100 of the polishing processing apparatus S according to this embodiment. FIG. 4B is an enlarged view of part A shown in FIG. 4A. FIG. 5 is a diagram illustrating an example of the configuration of the first supplementary heat source (heater block) 300a (300b) on the platen in the polishing processing apparatus S according to this embodiment. FIG. 6 is a cross-sectional view taken along line AA in FIG. 3, illustrating an example of the configuration of a third supplementary heat source below the platen of the polishing processing apparatus S according to this embodiment. FIG. 7 is a diagram showing an example of the configuration of a temperature sensor 400 that acquires the temperature of the wafer W in a simulated manner during polishing processing. Hereinafter, the first, second, and third supplementary heat sources, which are one of the features of the polishing processing apparatus S according to this embodiment, will be described with reference to FIGS.

[0029] The polishing processing device S of this embodiment has a platen 51 with a platen pad 50 attached to its surface, and a polishing head 100 that holds the wafer W to be polished and slides the surface to be polished against the surface of the platen pad 50. The polishing processing device S also has supplementary heat sources (heater blocks) 300a, 300b, a temperature sensor 310 that acquires the temperature of the supplementary heat sources (shown in the figure as an example installed in the supplementary heat source 300a), a temperature sensor (wafer dummy sensor) 400, a slurry regulating frame 500, and a temperature sensor 600.

[0030] [Example of the first supplementary heat source / heater block configuration] 2 and 3, the supplementary heat sources 300a and 300b are heater blocks (heat sources, for example, electric heaters) disposed on the surface side of the platen 51 and formed in a shape that surrounds a predetermined region (predetermined range) on the periphery of the polishing head 100. Power is supplied to the supplementary heat sources 300a and 300b via wiring (not shown), and they generate heat in response to the supplied power. The supply and stop of power to the supplementary heat sources 300a and 300b is mainly controlled by the control unit 20. In addition, the supplementary heat sources 300a and 300b are first supplementary heat sources formed in an anchor shape with arc portions on both sides so that a portion of the source surrounds a predetermined area on the outer periphery of the polishing head 100, and are arranged on the surface side of the platen 51 so that one of the arc portions faces the outer periphery of the polishing head 100. The temperature sensor 310 is a temperature sensor that acquires the temperature of the supplementary heat source 300a.

[0031] In this way, the supplementary heat sources 300a and 300b are anchor-shaped heat sources that are identically shaped and arranged on a pair of back-to-back mirrors, and function as a first supplementary heat source that adjusts the surface temperature of the platen pad 50.

[0032] 5, the supplementary heat sources (heater blocks) 300a and 300b have a frame 301, a heat insulating material 302, a planar film heater 303, and a heat spreader plate 304 made of a resin-based or ceramic-based non-metallic material. The heat spreader plate 304 and the film heater 303 are attached together using, for example, double-sided tape with high thermal conductivity.

[0033] Further, the supplementary heat sources (heater blocks) 300a and 300b are held on the surface side of the platen 51 via a holding mechanism (not shown) that brings them into contact with the surface of the platen pad 50 with a light surface pressure. Further, supplementary heat sources (heater blocks) 300a, 300b may be arranged in a non-contact manner with the surface of the platen pad 50, and the surface temperature of the platen may be adjusted by radiant heat from the supplementary heat sources.

[0034] The timing of temperature detection by the temperature sensor 310 shown in FIGS. The temperature information acquired by the temperature sensor 310 is sent to the control unit 20, and the control unit 20 adjusts the temperatures generated in each of the first supplementary heat source, the second supplementary heat source, and the third supplementary heat source based on the acquired temperature information.

[0035] [Configuration example of first temperature acquisition means] 2 and 3, the temperature sensor 600 is composed of, for example, three infrared cameras (IR cameras), and acquires the surface temperature of the platen pad 50 at a plurality of measurement positions (on the dashed dotted line shown in FIG. 2) at different distances from the center of the platen pad 50. In this way, the temperature distribution on the surface of the platen pad 50 is captured.

[0036] In this way, the temperature sensor 600 functions as a first temperature acquisition unit that acquires the surface temperatures of the platen pad 50 at a plurality of positions on the platen pad 50 . For example, the measurement positions of the temperature sensors 600 are arranged so as to be located on a straight line extending from the center of the platen pad 50 outward.

[0037] Furthermore, the timing of temperature detection by the temperature sensor 600 is mainly controlled by the control unit 20. The temperature information acquired by the temperature sensor 600 is sent to the control unit 20, and the control unit 20 adjusts the temperatures generated in each of the first supplementary heat source, the second supplementary heat source, and the third supplementary heat source based on the acquired temperature information.

[0038] [Configuration example of second temperature acquisition means] The temperature sensor 400 is a wafer dummy sensor that artificially acquires the surface temperature of the surface to be polished of the wafer W during the polishing process. To control the heating and temperature of the supplementary heat sources (heater blocks) 300a and 300b described above, it is necessary to acquire the surface temperature (temperature of the surface to be polished) of the polishing surface of the wafer W during the polishing process. However, it is difficult to measure the surface temperature of the surface to be polished of the wafer W during the polishing process. Therefore, a wafer dummy sensor is required to create an environment similar to that of the polishing surface of the wafer W during the polishing process and to acquire the temperature at the back surface, which is the shortest distance from the front surface, to measure the surface temperature (temperature of the surface to be polished) of the polishing surface of the wafer W.

[0039] As shown in FIG. 7, the temperature sensor 400 is made of the same material as the wafer W, and has a dummy wafer 401 (e.g., φ20×t0.075 [mm]) that is smaller than the wafer W. The temperature sensor 400 also has an annular body 405 having an inner diameter large enough to surround the outer periphery of the dummy wafer 401, and an elastic body 404 that covers the opening at the lower end of the annular body 405 and holds the dummy wafer 401 via a backing film 403 attached to the front surface of the annular body 405. The temperature sensor 400 also has a sensor 402 (e.g., a thermocouple) that detects the temperature of the dummy wafer 401.

[0040] The temperature sensor 400, which is made of the materials configured as described above, detects the temperature of the held dummy wafer 401 by bringing the surface to be polished of the dummy wafer 401 into sliding contact with the surface of the platen pad 50. In this way, the temperature sensor (wafer dummy sensor) 400 functions as a second temperature acquisition means for simulating the temperature of the wafer W during the polishing process.

[0041] The timing of temperature detection by temperature sensor 400 is mainly controlled by control unit 20. Temperature information acquired by temperature sensor 400 is sent to control unit 20, which adjusts the temperatures generated in the first supplemental heat source, second supplemental heat source, and third supplemental heat source based on the acquired temperature information. The temperature sensor 400 is preferably placed on the surface of the platen pad 50 at a position equidistant from the center of the wafer W radius.

[0042] The temperature sensor 400 is configured to hold a dummy wafer 401 so that its surface to be polished is in sliding contact with the surface of the platen pad 50, and to apply the same processing pressure P as that of the wafer to the held dummy wafer 401 from the back direction (back side) of its surface to be polished toward the platen pad 50.

[0043] [Example of slurry flow control / slurry regulation frame configuration] In the above process, it has been explained that the heat source must be fan-shaped, but the shape of the slurry flow also affects the temperature uniformity. The slurry control frame 500 is an L-shaped or approximately L-shaped frame body formed in a shape that surrounds a predetermined area on the outer periphery of the polishing head 100 at a position opposite the supplementary heat sources 300a and 300b, based on the polishing head 100, as shown in Figures 2 and 3.

[0044] The polishing liquid (slurry) supplied from the nozzle N toward the area surrounded by the polishing head 100 and the slurry regulating frame 500 can be shaped into a fan-like flow as shown by the two-dot chain line in Figure 3 by the slurry regulating frame 500. The slurry flow also includes the flow between the wafer and the pad. In this way, the slurry regulating frame 500 functions as a regulating means for forming the flow of the polishing liquid (slurry) supplied toward the platen pad 50 into a fan shape.

[0045] [Configuration Example of Polishing Head 100 and Second Supplementary Heat Source] As shown in Figures 4 and 6, the polishing head 100 of the polishing processing device S of this embodiment has an annular body 101 having an inner diameter large enough to surround the outer periphery of the wafer W to be polished, an elastic body 103 that covers the opening at the lower end of the annular body 101 and holds the wafer W via a backing film 102 attached to its surface side, and a retainer ring 104 formed in a shape that surrounds the outer periphery of the wafer W held by the elastic body 103.

[0046] 4(a), the polishing head 100 is provided with a circular supplementary heat source 200 on the rear surface side of the elastic body 103, and adjusts the temperature of the wafer W and the retainer ring 104 held by the elastic body 103. This supplementary heat source 200 functions as a second supplementary heat source.

[0047] The supplementary heat source 200 can be configured using, for example, a planar heater, as shown in Fig. 4. Electric power is supplied to the supplementary heat source 200 via wiring 200a, and the supplementary heat source 200 generates heat in response to the supplied power. The supply or stop of power to the supplementary heat source 200 is mainly controlled by the control unit 20.

[0048] [Example of a third supplemental heat source / fluid heat source under the platen] As shown in Figure 6, the polishing processing device S of this embodiment is composed of a platen 51, an upper base plate 55 formed in the same shape as the platen 51, a lower base plate 56, ring-shaped annular bodies 52, 53, and 54 of different diameter sizes, and a fluid pump 21.

[0049] The upper base plate 55 and the lower base plate 56 are connected via ring-shaped annular bodies 52, 53, and 54 of different diameter sizes, and as shown in Figure 6, spaces are formed between the annular bodies 52 and 53, between the annular bodies 53 and 54, and on the inner diameter side of the annular body 54.

[0050] A fluid (e.g., water) is configured to circulate through the spaces between the annular bodies 52 and 53, between the annular bodies 53 and 54, and on the inner diameter side of the annular body 54, via piping 60 and a fluid pump 21. The fluid is supplied to the polishing processing device S after being adjusted to a predetermined temperature by a temperature adjustment device included in the fluid pump 21. The temperature regulation of the fluid by the fluid pump 21, the start or stop of the supply of the fluid, the amount of supply per predetermined time, etc. are mainly controlled by the control unit 20.

[0051] The fluid supplied via the fluid pump 21 serves as a supplementary heat source arranged on the back side of the platen 51, and the series of components including this fluid functions as a third supplementary heat source that adjusts the surface temperature of the platen pad 50.

[0052] Fig. 8 is a diagram for explaining another example of the configuration of the second supplementary heat source, and Fig. 8(b) is an enlarged view of part A shown in Fig. 8(a). The supplementary heat source (second supplementary heat source) shown in Figure 8 is a heat source arranged on the back side of the elastic body 103, and is composed of a circular supplementary heat source 201 that adjusts the temperature of the wafer W held by the elastic body 103, and a ring-shaped supplementary heat source 202 that adjusts the temperature of the retainer ring 104.

[0053] Supplementary heat sources 201 and 202 can be configured using, for example, planar heaters, as shown in Fig. 8. Supplementary heat source 201 is supplied with power via wiring 201a and generates heat in response to the supplied power. Supplementary heat source 202 is supplied with power via wiring 202a and generates heat in response to the supplied power. The supply or stop of power to the supplementary heat sources 201 and 202 is mainly controlled by the control unit 20.

[0054] By configuring the second supplementary heat source as supplementary heat source 201 (heater for the rear surface of the wafer) and supplementary heat source 202 (heater for the rear surface of the retaining ring) as described above, it becomes possible to adjust the temperature more accurately even when the surface pressures of the wafer and the retaining ring are different or when materials with different thermal conductivities are combined.

[0055] FIG. 10 is a diagram for explaining another example of the shape and combination of the first supplementary heat source different from those in FIGS. 2 and 3. In FIG. 10(a), two first supplementary heat sources 300a, 300b may be combined and disposed on the surface side of the platen pad 50. In other words, a substantially fan-shaped heat source region is formed on the surface of the platen pad 50 by the heat source of the first temperature adjustment mechanism and the heat sources of the two second temperature adjustment mechanisms surrounding the outer periphery of the polishing head. In this way, the shape and combination of the first supplementary heat source when forming a fan-shaped or approximately fan-shaped supplementary heat source area can be set to any shape as long as it has the same area and heat source capacity as the fan shape when combined with the second supplementary heat source (polishing head / circular heat source).

[0056] 10(b), it is also possible to use a single supplementary heat source (heater block). The first supplementary heat source shown in FIG. 10(b) is a supplementary heat source formed in a fan shape with an arc portion so as to surround a predetermined area on the outer periphery of the polishing head 100. In this case, the surface temperature of the supplementary heat source (heater block) will be twice as high as when there are two. In this way, the first supplementary heat source can be a single body or a divided body.

[0057] Furthermore, as in the polishing processing device S of this embodiment, it may be configured as an anchor-shaped supplementary heat source (heater block) arranged on the surface side of the platen 51 and formed in a shape that surrounds a predetermined area on the outer periphery of the polishing head 100. In this case, mirrors of the same shape may be arranged back to back to form an anchor or approximately anchor-shaped pair, or they may be integrally formed in an anchor or approximately anchor-shaped configuration.

[0058] FIG. 11 is a diagram for explaining an example of the flow of the polishing liquid (slurry) supplied toward the platen pad. As shown in Figure 11, conventional slurry flow paths result in Coriolis flow. However, as mentioned above, while Coriolis flow would be acceptable if the slurry temperature could be controlled to be the same as the platen temperature, this would be difficult in terms of responsiveness, so a fan-shaped slurry flow is ideal. Therefore, it is best to use the slurry regulating frame 500 to make the slurry flow also fan-shaped.

[0059] FIG. 12 is a diagram for explaining an example of a heat transfer mechanism of a CMP system. The initial heat source is frictional heat generated when the wafer and retainer ring rub against the pad. The surface temperatures of both the wafer side and the platen side rise in the initial state and reach a constant temperature after several tens of seconds, but the platen side has a lower temperature due to the difference in heat transfer volume between the two. The ideal state is one in which the temperature difference between the two is small. In other words, if the target surface temperature cannot be reached by CMP reaction heat alone, heat must be compensated for from the backside of each side.

[0060] FIG. 13 is a schematic diagram illustrating an example of a thermal system configuration. As mentioned above, CMP reaction heat flows in two directions: to the wafer side and to the platen side. Heat transfer to the wafer side is treated as heat conduction from a fixed heat source, while heat transfer to the platen side is treated as heat conduction from a moving heat source. In a CMP system, the polishing removal rate (MRR) is significantly affected by the polishing surface temperature in an exponential manner (power function). Therefore, the self-heating temperature must be controlled by an external heat source to avoid over or undershooting the optimum chemical reaction temperature.

[0061] [Polishing process control procedure] Next, the processing procedure by the polishing processing apparatus S of this embodiment will be described. Fig. 14 is a flowchart for explaining an example of the main control procedure by the control unit 20 when performing the polishing process. The processing procedure described below is for performing the polishing process (mass production) of wafers continuously based on the operating conditions described above.

[0062] The control unit 20 starts control when an input of a start instruction is received from an operator of the polishing processing device S (S100). After a predetermined initial processing, the control unit 20 starts holding the wafer W by the holding mechanism of the polishing head 100 (S101).

[0063] The control unit 20 holds the wafer W from the wafer transfer table (not shown) and moves the polishing head 100 to the starting position of the polishing process (S102). The control unit 20 supplies a predetermined amount of pressure fluid to adjust the processing pressure P (S103).

[0064] If the control unit 20 confirms that the pressures corresponding to the supply amounts of pressure fluid are appropriate (S104: Yes), it issues an instruction to a motor (not shown) to start rotating the platen 51 and the polishing head 100 (S105). As a result, the platen 51 and the polishing head 100 start rotating horizontally.

[0065] After issuing an instruction to start rotating the platen 51 and polishing head 100, the control unit 20 instructs the positioning of the nozzle N and issues an instruction to the polishing liquid supply mechanism to start supplying the polishing liquid (S106). As a result, the polishing liquid is supplied from the nozzle N toward the surface of the platen pad 50. In this way, the control unit 20 starts polishing (S107).

[0066] The control unit 20 adjusts the temperatures generated by the first supplementary heat source, the second supplementary heat source, and the third supplementary heat source based on the detection results of the temperature sensors (S108).

[0067] Thereafter, the control unit 20 determines whether polishing is completed (S109). This determination is made based on, for example, the detection result of a sensor, and polishing is completed when it is determined that the wafer W has been polished to the desired thickness. If not (S109: No), the process returns to step S108.

[0068] When the control unit 20 determines that polishing has been completed (S109: Yes), it instructs the polishing liquid supply mechanism to stop supplying the polishing liquid (S110).

[0069] Thereafter, the control unit 20 issues a stop command to the motor to stop the rotation of the platen 51 and the polishing head 100 (S111). Thereafter, the polishing head 100 is moved to a table on which the polished wafer W is placed (S112). This completes the series of polishing processes.

[0070] The determination of whether the wafer W has been released can be made by using, for example, various sensors (not shown). The supplied pressure fluid may be recovered after the rotation of the platen 51 and the polishing head 100 has stopped. By controlling in this manner, it is possible to prevent the polished wafer W from accidentally dropping off during transportation.

[0071] Here, an example of the process of step S108 in which the temperatures generated by the first, second, and third supplementary heat sources are adjusted based on the detection results of the respective temperature sensors will be described.

[0072] In the control procedure by the control unit 20 in the process of step S108, the temperature sensor 400 and the temperature sensor 310 control the amount of supplementary heat from the first supplementary heat source. As a control example, the control unit 20 predicts the temperature value Tw of the wafer polishing surface after 40 seconds based on 30-second data from the temperature sensor 400 (only the wafer reaches the temperature due to rubbing). If the temperature is different from the CMP target temperature: Tc, the control unit 20 controls the amount of supplementary heat from the second supplementary heat source to set "Tc-Tw" to zero (aiming for the CMP target temperature). The control unit 20 predicts the temperature value Tp of the platen pad 50 after 40 seconds from the data of the temperature sensor 600 for 30 seconds (the temperature reached by only the amount of heat generated by rubbing the wafer). If the CMP target temperature is different from Tc, the control unit 20 controls the amount of supplementary heat from the third supplementary heat source to reduce "Tc-Tp" (control of the circulating water temperature).

[0073] In this way, the polishing processing device S of this embodiment makes it possible to achieve uniform temperature on the platen pad surface, further improving the SFQR of the wafer surface, etc., and enabling high-quality, stable polishing processing for multiple wafers.

[0074] [Modification of the second temperature acquisition means] FIG. 15 is a diagram showing an example of the configuration of a temperature sensor that acquires the temperature of a wafer during polishing processing in a pseudo manner, which is different from that shown in FIG. The following description will focus on the differences from the temperature sensor 400 shown in FIG.

[0075] The temperature sensor 420 shown in FIG. 15 is a wafer dummy sensor that artificially acquires the surface temperature of the surface to be polished of the wafer W during the polishing process. The temperature sensor 420 is made of the same material as the wafer W, as shown in FIG. 15, and has a dummy wafer 401 (e.g., φ20×t0.075 [mm]) that is smaller than the wafer W. The temperature sensor 420 also has an annular body 405 having an inner diameter large enough to surround the outer periphery of the dummy wafer 401, and an elastic body 404 that covers the opening at the lower end of the annular body 405 and holds the dummy wafer 401 via a backing film 403 attached to the front surface of the annular body 405. The temperature sensor 400 also has a sensor 402 (e.g., a thermocouple) that detects the temperature of the dummy wafer 401. The temperature sensor 420 has a circular heater (supplementary heat source) 410 disposed on the rear surface side of the elastic body 404 , and adjusts the temperature of the dummy wafer 401 to the elastic body 404 .

[0076] By configuring the temperature sensor 420 in this manner and setting the supplementary heat source 200 (second supplementary heat source) and the heater (supplementary heat source) 410 to the same temperature, it becomes possible to more accurately reproduce an environment that is similar to the polishing surface of the wafer W. The temperature sensor 420, which is made of the materials configured as described above, detects the temperature of the held dummy wafer 401 by bringing the surface to be polished of the dummy wafer 401 into sliding contact with the surface of the platen pad 50. In this way, the temperature sensor (wafer dummy sensor) 420 functions as a second temperature acquisition means for simulating the temperature of the wafer W during the polishing process.

[0077] The timing of temperature detection by temperature sensor 420 is mainly controlled by control unit 20. Temperature information acquired by temperature sensor 420 is sent to control unit 20, and control unit 20 adjusts the temperatures generated in the first supplemental heat source, second supplemental heat source, and third supplemental heat source based on the acquired temperature information. The supply or stop of power to the heater (supplementary heat source) 410 is mainly controlled by the control unit 20. The temperature sensor 420 is preferably placed on the surface of the platen pad 50 at a position equidistant from the radial center of the wafer W.

[0078] [Modification of the first supplemental heat source / heater block] FIG. 16 is a diagram showing another example of the first supplementary heat source (supplementary heat sources 300a, 300b) shown in FIGS. Here, when the wafer dummy sensor is configured as the above-mentioned temperature sensor 420, this temperature sensor 420 also functions as a heat source and therefore affects the surface temperature of the platen pad 50. Therefore, the following describes how the shape of the first supplementary heat source is configured like the first supplementary heat source (supplementary heat sources 320a, 320b) shown in FIG. 16 to cancel out the effect of the temperature sensor 420 on the surface temperature of the platen pad 50. The following description will focus on the differences in configuration from the first supplementary heat source (supplementary heat sources 300a, 300b) shown in FIGS.

[0079] 16 are heater blocks (heat sources) disposed on the surface side of the platen 51 and formed in a shape that surrounds a predetermined area on the periphery of the polishing head 100. The temperature sensor 310 is a temperature sensor that acquires the temperature of the supplementary heat source 320a. The supplementary heat sources 320a and 320b are first supplementary heat sources formed in an anchor shape with arc portions on both sides that surround a predetermined area on the outer periphery of the polishing head 100, and one of the arc portions is arranged on the surface side of the platen 51 facing the outer periphery of the polishing head 100.

[0080] Supplementary heat sources 320a and 320b are anchor-shaped heat sources of the same shape arranged on a pair of mirrors back to back. Supplementary heat sources 320a and 320b also have semicircular recesses 321a and 321b, respectively, at their back-to-back locations. The total area of ​​the hole (circle) obtained by adding up the areas of the semicircular recesses is set to be the same as the area of ​​dummy wafer 401 (e.g., φ20 [mm]) of temperature sensor 420. By configuring the supplementary heat sources 320a and 320b, it is possible to cancel out the effect of the temperature sensor 420 on the surface temperature of the platen pad 50, allowing for more precise temperature adjustment of the surface temperature of the platen pad 50. The supplementary heat sources 320a and 320b are supplied with power via wiring (not shown) and generate heat in response to the power supplied. The supply and stop of power to the supplementary heat sources 320a and 320b is mainly controlled by the control unit 20.

[0081] The selection of the wafer dummy sensor configuration and the provision of a semicircular depression in the first supplementary heat source can be arbitrarily selected depending on the degree of temperature accuracy to be set after the CMP target temperature is reached, or the processing temperature range during the polishing process corresponding to the type of wafer to be polished. Furthermore, a wafer dummy sensor with a supplementary heat source may be arranged at the position of the hole formed in the first supplementary heat source.

[0082] [Example of configuration using a wire heater as the first supplementary heat source] FIG. 17 is a top view illustrating another example of the configuration of the first supplemental heat source when the first supplemental heat source is disposed on the rear surface side of the platen 51. In FIG. 17, a linear wire heater 350 is disposed as a first supplementary heat source on the rear surface of the platen 51. The wire heater 350 is shown by a dashed line because it is disposed in contact with the rear surface of the platen 51.

[0083] Electric power is supplied to the wire heater 350 via wiring (not shown), and the wire heater 350 generates heat in response to the supplied electric power. The supply of electric power to the wire heater 350 or its stop is mainly controlled by the control unit 20.

[0084] 17, the wire heater 350 is configured by arranging, for example, a plurality of ring-shaped wire heaters concentrically on the back surface of the platen 50. Alternatively, the wire heater 350 may be configured by arranging a so-called spirally wound wire heater on the back surface of the platen 50. Hereinafter, the formation of a substantially sector-shaped heat source region by the wire heater 350 will be described with reference to FIG.

[0085] FIG. 18 is a diagram for explaining the formation of a substantially sector-shaped heat source region by the wire heater 350. In FIG. As mentioned above, when forming a fan-shaped or approximately fan-shaped supplementary heat source area, the shape and combination of the first supplementary heat source can be set arbitrarily as long as it has the same area and heat source capacity as the fan shape when combined with the second supplementary heat source (polishing head / circular heat source).

[0086] The wire heater 350 shown in FIG. 18 has its heating element density adjusted so that it has the same area and heat source capacity as the supplementary heat sources (heater blocks) 300a and 300b. Specifically, the wire heaters 350 are arranged spirally or concentrically, and the spacing (gap) between adjacent wire heaters 350 on the rear surface of the platen 51 is divided into areas where the spacing (gap) is sparse (areas with low heating element density) and areas where the spacing (gap) is dense (areas with high heating element density), thereby making it possible to adjust the heating element density.

[0087] This density relationship can be calculated by, for example, letting the pitch of each line be Pi, where Pi is the proportional length of the platen width B and the line length ratio (Xi / ΣXi). In areas where the line length ratio (Xi / ΣXi) is large, the pitch Pi becomes small, and in areas where the line length ratio (Xi / ΣXi) is small, the pitch Pi becomes large.

[0088] In this way, by arranging the wire heater 350 so that it has the same area and heat source capacity as the supplementary heat sources (heater blocks) 300a and 300b, it is possible to secure the same area and heat source capacity as the fan-shaped one when combined with the second supplementary heat source (polishing head / circular heat source). This increases the degree of freedom in the configuration of the front surface side of the platen pad 50.

[0089] [Example of configuration using a first supplementary heat source / plane seat heater] FIG. 19 is a top view illustrating another example of the configuration of the first supplemental heat source when the first supplemental heat source is disposed on the rear surface side of the platen 51, which is different from those in FIGS. 19, a planar seat heater 360 is disposed as a first supplementary heat source on the rear side of the platen 51. Since the seat heater 360 is disposed on the rear side of the platen 51, it is indicated by a dashed line.

[0090] 19, a fan-shaped or approximately fan-shaped supplementary heat source area is formed by combining a sheet heater 360 arranged on the rear surface of the platen 51 as a first supplementary heat source with a second supplementary heat source (polishing head / circular heat source). Therefore, the supplementary heat source area formed by the second supplementary heat source (polishing head / circular heat source) is formed as a hole in the sheet heater 360. In other words, the area where the first supplementary heat source and the second supplementary heat source do not overlap is provided as a hole, and the sheet heater 360 is formed so that a fan-shaped or approximately fan-shaped supplementary heat source area is formed by combining the first supplementary heat source and the second supplementary heat source.

[0091] Furthermore, since the seat heater 360 rotates together with the platen 51, Figure 20 shows the seat heater 360 having six holes formed therein so that, when combined with the second supplemental heat source (polishing head / circular heat source) described above, a fan-shaped or approximately fan-shaped supplemental heat source area is formed. This increases the degree of freedom in the configuration of the front surface side of the platen pad 50.

[0092] The above-described embodiments are intended to more specifically explain the present invention, and the scope of the present invention is not limited to these examples. [Explanation of symbols]

[0093] 50...platen pad, 51...platen, 100...polishing head, 200, 201, 202...second supplementary heat source, 300a, 300b, 320a, 320b...first supplementary heat source (heater block), 350...first supplementary heat source (wire heater), 360...first supplementary heat source (sheet heater), 310, 600...temperature sensor, 400, 420...temperature sensor (wafer dummy sensor), 410...heater, 500...slurry control frame, S...polishing processing device, N...nozzle, W...wafer.

Claims

1. A polishing processing apparatus having a platen having a platen pad attached to its surface, and a polishing head that holds a wafer to be polished and brings the surface of the wafer to be polished into sliding contact with the surface of the platen pad, an annular body having an inner diameter large enough to surround the outer periphery of the wafer to be polished; an elastic body that covers the opening at the lower end of the annular body and holds the wafer via a backing film that is attached to the surface side of the elastic body; a retainer ring formed in a shape surrounding the outer periphery of the wafer held by the elastic body; the polishing head having a driving means for horizontally rotating the annular body and the retaining ring together; a first supplemental heat source disposed on the surface side of the platen pad and formed in a shape surrounding a predetermined region on the outer periphery of the polishing head, for adjusting the surface temperature of the platen pad; a second supplemental heat source disposed on the rear surface side of the elastic body and configured to adjust the temperature of the wafer and the retainer ring held by the elastic body; a third supplemental heat source disposed on the rear side of the platen and configured to adjust the temperature of the platen pad, Polishing processing equipment.

2. The first supplementary heat source is a supplementary heat source formed in a fan shape having an arc portion surrounding a predetermined area on the outer periphery of the polishing head. The polishing processing device according to claim 1 .

3. the first supplemental heat source is a supplemental heat source formed in an anchor shape having arc portions on both sides, a part of which surrounds a predetermined region on the outer periphery of the polishing head, and one of the arc portions is disposed on the surface side of the platen pad, facing the outer periphery of the polishing head. The polishing processing device according to claim 1 .

4. the second supplemental heat source and the two first supplemental heat sources surrounding the outer periphery of the polishing head form a fan-shaped or approximately fan-shaped supplemental heat source region on the surface of the platen pad. The polishing processing device according to claim 1 .

5. a first temperature acquisition means for acquiring the surface temperature of the platen pad at a plurality of measurement positions at different distances from the center of the platen, the first temperature acquisition means being a reference point for the platen pad; 5. The polishing processing device according to claim 1, 2, 3 or 4.

6. the first temperature acquisition means is composed of a plurality of infrared cameras, and the measurement positions of the infrared cameras are arranged on a straight line extending outward from the center of the platen, and the surface temperature of the platen pad is acquired at each position. The polishing processing device according to claim 5 .

7. the first supplemental heat source is in contact with the surface of the platen pad with a light surface pressure, and at least a surface in contact with the surface of the platen pad is formed using a non-metallic material.

5. The polishing processing device according to claim 1, 2, 3 or 4.

8. the first supplementary heat source is disposed in a non-contact state with the surface of the platen pad, and adjusts the surface temperature of the platen pad by radiant heat from the supplementary heat source.

5. The polishing processing device according to claim 1, 2, 3 or 4.

9. the polishing processing device has a second temperature acquisition means for acquiring a simulated surface temperature of the polished surface of the wafer during the polishing processing, The second temperature acquisition means a dummy wafer that is made of the same material as the wafer and is smaller than the wafer; an annular body having an inner diameter large enough to surround the outer periphery of the dummy wafer; an elastic body that covers the opening at the lower end of the annular body and holds the dummy wafer via a backing film that is attached to the surface side of the elastic body; a sensor for detecting the temperature of the dummy wafer, the surface to be polished of the held dummy wafer is brought into sliding contact with the surface of the platen pad to acquire the temperature of the dummy wafer.

5. The polishing processing device according to claim 1, 2, 3 or 4.

10. a restricting means having an L-shape or a substantially L-shape formed in a shape surrounding a predetermined region on the outer periphery of the polishing head at a position facing the first supplementary heat source with respect to the polishing head; The regulating means forms a flow of the polishing liquid supplied toward the platen pad in a fan shape. The polishing processing device according to claim 1, 2 or 3.

11. the second supplementary heat source is a heat source disposed on the rear surface side of the elastic body, and is characterized in that it is composed of a circular supplementary heat source that adjusts the temperature of the wafer held in the elastic body and a ring-shaped supplementary heat source that adjusts the temperature of the retainer ring.

5. The polishing processing device according to claim 1, 2, 3 or 4.

12. the first supplementary heat source is a plurality of ring-shaped wire heaters arranged concentrically on the rear surface of the platen, The polishing processing device according to claim 1 .

13. the first supplemental heat source is a spirally wound wire heater disposed on the back surface of the platen; The polishing processing device according to claim 1 .

14. The wire heaters arranged on the rear surface of the platen are characterized in that the heating element density is adjusted by providing areas on the rear surface of the platen where the spacing between adjacent wire heaters is sparse and areas where the spacing is dense. The polishing processing device according to claim 12 or 13.

15. the first supplementary heat source is a seat heater disposed on the rear surface of the platen, and the seat heater has a plurality of holes. The polishing processing device according to claim 1 .

Images