Polishing head for chemical mechanical polishing of a square substrate

Abstract

The present invention relates to a polishing head for chemical mechanical polishing of a square substrate. According to one embodiment, a polishing head for chemical mechanical polishing (CMP) of a square substrate may be provided, comprising: a head body having a square shape; a square membrane structure disposed on the lower side of the head body and pressurizing at least a portion of the non-polishing surface of the square substrate through a pressure compartment structure; and a square retaining ring structure disposed on the lower periphery of the head body to surround the square membrane structure and forming a square inner space for accommodating the square substrate.

Description

Technology Field

[0001] The present invention relates to a polishing head for chemical mechanical polishing of a square substrate. Background Technology

[0002] Driven by the recent growth of the Artificial Intelligence (AI) and High Performance Computing (HPC) markets, semiconductor packaging technology is rapidly evolving toward heterogeneous integration. In this heterogeneous integration technology, interposers, which connect multiple chiplets into a single package, are used as core components.

[0003] Meanwhile, conventional silicon interposers and organic substrates have problems such as high cost, limitations on large-area fabrication, and warpage. Recently, glass interposers have been attracting attention as replacements, and these glass interposers have advantages such as excellent electrical properties, a low coefficient of thermal expansion, and the possibility of large-area panel processing.

[0004] The manufacturing of glass interposers necessarily involves a Through Glass Via (TGV) process to form via holes penetrating the glass, and a Chemical Mechanical Polishing (CMP) process is required to remove excess copper (overburden) remaining on the surface and to flatten the surface after the TGV process. At this time, the glass interposer is used in the form of a square panel to maximize productivity.

[0005] However, as shown in FIGS. 1 and 2, conventional CMP equipment and polishing heads are designed based on circular wafers, so the following problems occur when applied to square substrates.

[0006] When the square substrate rotates, the linear velocity at the corners is approximately 1.4 times faster than that at the center, causing pressure to concentrate in the corner areas and resulting in a corner effect that causes excessive polishing. Additionally, the corners of the square substrate act like wipers to expel the slurry outwards, causing a slurry starvation phenomenon in which the slurry supply to the center of the substrate becomes insufficient.

[0007] Therefore, there is a need for a polishing head with a new structure to solve the problems of corner pressure concentration and slurry starvation that may occur in the CMP process of square substrates. The problem to be solved

[0008] A polishing head for chemical mechanical polishing of a square substrate according to one embodiment of the present invention is proposed to solve the above-mentioned problem, and can resolve the imbalance in the amount of polishing between the corner area and the center area by applying a uniform polishing pressure across the entire surface of the substrate during the CMP process of the square substrate. means of solving the problem

[0009] According to one embodiment, a polishing head for chemical mechanical polishing (CMP) of a square substrate may be provided, comprising: a head body having a square shape; a square membrane structure disposed on the lower side of the head body and pressurizing at least a portion of the non-polishing surface of the square substrate through a pressure compartment structure; and a square retaining ring structure disposed on the lower periphery of the head body to surround the square membrane structure and forming a square inner space for accommodating the square substrate.

[0010] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the pressure section structure comprises: a central pressure zone corresponding to the central area of ​​the non-polishing surface of the square substrate; and a plurality of corner pressure zones corresponding to the corner areas of the non-polishing surface of the square substrate.

[0011] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the central pressure zone and the corner pressure zone expand as fluid is supplied to pressurize the central area of ​​the non-polishing surface and the corner area of ​​the non-polishing surface of the square substrate, respectively, with different fluid pressures, and the fluid pressure applied from the corner pressure zone is set lower than the fluid pressure applied from the central pressure zone.

[0012] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the central pressure zone is located at the center of the lower surface of the square membrane structure and has a shape among a disc shape; a shape in which a plurality of ring structures are arranged concentrically; and a combination thereof.

[0013] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the corner pressure zone is located at the corner of the lower surface of the square membrane structure and has a shape of a right triangle with a hypotenuse concave inward; and a shape formed by dividing the right triangle with a hypotenuse concave inward based on a virtual arc with the center of the square membrane structure as the center point.

[0014] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the above-described pressure section structure further comprises a plurality of side pressure zones corresponding to the side regions of the square substrate.

[0015] In addition, the above-mentioned pressure zone may be located at the lower edge of the square membrane structure, and a polishing head for chemical mechanical polishing of a square substrate may be provided, having a square shape with one side concave inward.

[0016] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the central pressure zone, the corner pressure zone, and the side pressure zone expand as fluid is supplied to pressurize the central area, the corner area, and the side area of ​​the non-polishing surface of the square substrate, respectively, with different fluid pressures.

[0017] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, further comprising a vibration sensor disposed on one side of the square retaining ring structure and detecting frictional torque or vibration of the square substrate during the chemical mechanical polishing (CMP) process, wherein the fluid pressure applied from any one of the selected zones among the center pressure zone, the corner pressure zone, and the side pressure zone varies according to the detection signal of the vibration sensor.

[0018] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, further comprising a slurry supply pipe formed to penetrate the head body and the square retaining ring structure, and supplying a slurry to the contact surface between the square substrate and the polishing pad.

[0019] Additionally, a polishing head for chemical mechanical polishing of a square substrate may be provided, wherein the head body includes a retrofit interface structure formed to be coupled to the drive shaft of a chemical mechanical polishing (CMP) equipment for a circular substrate. Effects of the invention

[0020] A polishing head for chemical mechanical polishing of a square substrate according to one embodiment of the present invention has the effect of resolving the imbalance in polishing amount between the corner area and the center area by applying a uniform polishing pressure across the entire surface of the substrate during the CMP process of the square substrate. Brief explanation of the drawing

[0021] Figure 1 is a schematic diagram of a conventional circular CMP device. Figure 2 is a diagram illustrating the corner effect and slurry starvation phenomenon that occur during the CMP process of a square substrate. FIG. 3 is a drawing illustrating a polishing head for chemical mechanical polishing of a square substrate according to one embodiment of the present invention. FIG. 4 is a first exemplary diagram of a rectangular membrane structure according to one embodiment of the present invention. FIG. 5 is a second exemplary diagram of a rectangular membrane structure according to one embodiment of the present invention. FIG. 6 is a third exemplary diagram of a rectangular membrane structure according to one embodiment of the present invention. FIG. 7 is a fourth exemplary diagram of a rectangular membrane structure according to one embodiment of the present invention. FIG. 8 is a first exemplary diagram of a rectangular membrane structure according to another embodiment of the present invention. Specific details for implementing the invention

[0022] In order to fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0023] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications and changes. The description of the embodiments is provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In the attached drawings, the components are depicted enlarged from their actual size for convenience of explanation, and the proportions of each component may be exaggerated or reduced.

[0024] The terms used in this specification are for describing embodiments and are not intended to limit the invention. Furthermore, unless otherwise defined, the terms used in this specification may be interpreted in the sense commonly known to those skilled in the art. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, 'comprises' and / or 'comprising' do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0025] Where in this specification a layer is referred to as being 'on' another layer, it may be formed directly on the upper surface of the other layer, or a third layer may be interposed between them. Although terms such as first, second, etc., have been used in this specification to describe various regions, layers, etc., these regions and layers should not be limited by such terms. These terms are used merely to distinguish one specific region or layer from another region or layer. Accordingly, a part referred to as the first part in one embodiment may be referred to as the second part in another embodiment. The embodiments described and illustrated herein also include their complementary embodiments. Throughout the specification, parts indicated by the same reference numeral represent the same components.

[0026] In the present invention, a polishing head for a square substrate is provided that has the function of suppressing the corner effect occurring when polishing a square substrate using a CMP process by applying different fluid pressures to the center of the non-polishing surface and the corner of the non-polishing surface of the square substrate. Specifically, it is designed to enable uniform polishing across the entire surface of the substrate during the CMP process of a square substrate by utilizing a square membrane structure having a pressure compartment structure.

[0027] FIG. 3 is a drawing for explaining a polishing head for chemical mechanical polishing of a square substrate according to one embodiment of the present invention, FIG. 4 is a first exemplary diagram of a square membrane structure according to one embodiment of the present invention, FIG. 5 is a second exemplary diagram of a square membrane structure according to one embodiment of the present invention, FIG. 6 is a third exemplary diagram of a square membrane structure according to one embodiment of the present invention, FIG. 7 is a fourth exemplary diagram of a square membrane structure according to one embodiment of the present invention, and FIG. 8 is a first exemplary diagram of a square membrane structure according to another embodiment of the present invention.

[0028] FIG. 3a) is a front view of the polishing head, and FIG. 3b) is a cross-sectional view of the polishing head.

[0029] A polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention can chemically mechanical polish (CMP) a metal layer, such as an excess copper layer, on a square substrate (W) while the polishing pad (1) and the square substrate (W) are in contact. In this specification, the term polishing may be interpreted as a term including chemical mechanical polishing of the square substrate (W).

[0030] A polishing head (10) for chemical mechanical polishing of a square substrate can be placed on a polishing table (2) to which a polishing pad (1) to be used for polishing a square substrate (W) is attached. The polishing table (2) can be rotated by a first drive shaft (not shown), and accordingly, the polishing pad (1) can also be rotated. For example, the polishing table (2) can be rotated clockwise by the first drive shaft (not shown), and the polishing pad (1) can also be rotated clockwise.

[0031] A slurry may be provided on the polishing table (2). The slurry may be a chemical solution containing an abrasive or abrasive particles.

[0032] A polishing head (10) for chemical mechanical polishing of a square substrate, on which a square substrate (W) to be polished is mounted, may be positioned on the polishing table (2). The polishing head (10) for chemical mechanical polishing of a square substrate may include a head body (100), a square membrane structure (200), a square retaining ring structure (300), a retrofit interface structure (500), and a fluid pressure regulator (600). A second drive shaft (not shown) may be connected to the retrofit interface structure (500), and accordingly, the polishing head (10) for chemical mechanical polishing of a square substrate may be rotated by the second drive shaft (not shown).

[0033] A polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention is intended to realize uniform polishing of a square substrate (W), which was difficult to achieve in a conventional chemical mechanical polishing (CMP) process for a circular substrate, and the differences from a polishing head used in a conventional CMP process will be explained in detail.

[0034] Referring to FIG. 3, a polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention may include a head body (100) having a square shape, a square membrane structure (200) disposed on the lower side of the head body (100) and pressurizing at least a portion of the non-polishing surface of the square substrate (W) through a pressure partition structure (210), and a square retaining ring structure (300) disposed on the lower periphery of the head body (100) to surround the square membrane structure (200) and forming a square inner space for accommodating the square substrate (W).

[0035] First, the external shape of the head body (100) may have a square shape corresponding to the shape of the square substrate (W). Here, the square shape is a concept that includes squares and rectangles, and the shape of the head body (100) may be determined according to the ratio of the width and height of the square substrate (W).

[0036] In this way, as the head body (100) has a shape corresponding to the shape of the square substrate (W), it can provide a structural basis for applying uniform pressure over the entire polished surface area of ​​the square substrate (W).

[0037] In one embodiment, the head body (100) may include a retrofit interface structure (500) formed to be connectable to the drive shaft of a chemical mechanical polishing (CMP) equipment for a circular substrate.

[0038] The retrofit interface structure (500) can be positioned on the upper side of the head body (100). Since the retrofit interface structure (500) is designed to be compatible with the drive shaft and rotary union of conventional chemical mechanical polishing (CMP) equipment for circular substrates, it enables the CMP process of a square substrate (W) to be performed by mounting the polishing head (10) for chemical mechanical polishing of a square substrate according to the present invention without modifying or replacing the conventional equipment. Accordingly, the cost and time associated with introducing dedicated equipment for polishing a square substrate (W) can be reduced, and the conventional chemical mechanical polishing infrastructure for circular substrates can be utilized as is.

[0039] Next, referring to FIGS. 3 to 8, the square membrane structure (200) is positioned on the lower side of the head body (100) and can expand by fluid supplied from the fluid pressure regulating device (600) to pressurize the non-polishing surface of the square substrate (W). Here, the non-polishing surface refers to the side opposite to the polishing surface that contacts the polishing pad (1) among the two sides of the square substrate (W), that is, the upper surface of the square substrate (W) facing the square membrane structure (200).

[0040] The above rectangular membrane structure (200) may include a pressurized compartment structure (210) and a non-pressurized structure (220).

[0041] The pressurized compartment structure (210) refers to two or more independent pressure zones in the square membrane structure (200), and can perform the function of applying different fluid pressures to each zone so that different pressures are applied to different areas of the non-polishing surface of the square substrate (W).

[0042] Specifically, the pressure section structure (210) may include a central pressure zone (211a, 211b, 211c) corresponding to the central area of ​​the non-polished surface of the square substrate (W); and a plurality of corner pressure zones (212a, 212b) corresponding to the corner areas of the non-polished surface of the square substrate (W).

[0043] Additionally, the central pressure zones (211a, 211b, 211c) and the corner pressure zones (212a, 212b) expand as fluid is supplied to pressurize the central area of ​​the non-polished surface and the corner area of ​​the non-polished surface of the square substrate (W) with different fluid pressures, and the fluid pressure applied from the corner pressure zones (212a, 212b) can be set lower than the fluid pressure applied from the central pressure zones (211a, 211b, 211c).

[0044] <중심 가압 존>

[0045] The central pressure zone (211a, 211b, 211c) can expand downward as fluid is supplied from the fluid pressure control device (600) to pressurize the central area of ​​the non-polished surface of the square substrate (W).

[0046] The central pressure zone (211a, 211b, 211c) is located at the center of the lower surface of the square membrane structure (200) and may have a shape of a disc, a shape in which a plurality of ring structures are arranged concentrically, and any one of the combinations thereof.

[0047] When the central pressure zone (211a, 211b, 211c) has a disc shape, there is an advantage that the structure is relatively simple and easy to manufacture.

[0048] In addition, when the central pressure zone (211a, 211b, 211c) has a shape in which a plurality of ring structures are arranged concentrically, or a shape in which a disc shape and a plurality of ring structures are arranged concentrically are combined, the distribution of fluid pressure can be controlled, thereby allowing for more precise control of the polishing uniformity of the central area of ​​the non-polishing surface of the square substrate (W).

[0049] For example, when the central pressure zone (211a, 211b, 211c) has a shape in which a plurality of ring structures are arranged concentrically, the same fluid pressure can be applied to the plurality of ring structures, but unlike the disc shape, the pressure distribution applied to the central area of ​​the non-polished surface of the square substrate (W) can be changed by the ring pattern.

[0050] As another example, when the central pressure zones (211a, 211b, 211c) have a shape in which a plurality of ring structures are arranged concentrically, each of the plurality of ring structures may be a different central pressure sub-zone. That is, different fluid pressures may be applied from the fluid pressure control device (600) to each central pressure sub-zone, and the fluid pressure may be applied sequentially lower from the innermost ring structure to the outermost ring structure. In this way, the distribution of fluid pressure in the radial direction within the central pressure zones (211a, 211b, 211c) can be precisely controlled.

[0051] In the chemical mechanical polishing (CMP) process, the material removal rate (MRR) tends to be proportional to the product of the polishing pressure and the relative linear velocity. Since the relative linear velocity between the square substrate (W) and the polishing pad (1) is lowest at the center of the square substrate (W) and increases as it moves outward, it is desirable to apply a higher fluid pressure to the inner region where the linear velocity is low and to gradually decrease the fluid pressure as it moves toward the outer ring section in order to ensure polishing uniformity. In this way, by setting the fluid pressure to decrease stepwise from the innermost ring section to the outermost ring section within the central pressure zone (211a, 211b, 211c), the deviation of the radial MRR within the central pressure zone (211b) can be compensated. However, this corresponds to a basic embodiment, and it is also possible to finely control the polishing profile by selectively adjusting the fluid pressure of a specific ring section according to the polishing process conditions or the material characteristics of the square substrate (W). The embodiment in which independent fluid pressure is applied to each ring section in this way has the effect of more precisely correcting local polishing non-uniformity that may occur in the central region of the square substrate (W).

[0052] <모서리 가압 존>

[0053] The corner pressure zones (212a, 212b) can expand downward as fluid is supplied from the fluid pressure control device (600) to pressure the non-polished corner area of ​​the square substrate (W). That is, the corner pressure zones (212a, 212b) may be provided in multiple numbers to correspond to each of the four corners of the square substrate (W).

[0054] The corner pressure zones (212a, 212b) are located at the lower corners of the square membrane structure (200) and may have a shape of a right triangle with a hypotenuse concave inward, or a shape formed by dividing the right triangle with a hypotenuse concave inward based on a virtual arc with the center of the square membrane structure (200) as the center point.

[0055] When the corner pressure zone (212a, 212b) has the shape of a right triangle with the hypotenuse concave inward, the structure is relatively simple and easy to manufacture.

[0056] Here, "the hypotenuse is concave inward" refers to a shape where the hypotenuse of a right triangle is rounded and indented inward.

[0057] In addition, when the corner pressure zones (212a, 212b) have a shape in which a right-angled triangle with a hypotenuse concave inward is divided based on a virtual arc with the center of the square membrane structure (200) as the center point, the distribution of fluid pressure can be controlled, thereby allowing for more precise control of the polishing uniformity of the non-polishing corner area of ​​the square substrate (W).

[0058] For example, when the corner pressure zones (212a, 212b) have a shape in which a right triangle with an inwardly concave hypotenuse is divided based on a virtual arc with the center of the square membrane structure (200) as the center point, the same fluid pressure can be applied to the divided structure, but unlike the shape of a right triangle with an inwardly concave hypotenuse, the pressure distribution applied to the central area of ​​the non-polishing surface of the square substrate (W) can be changed.

[0059] In another example, when the corner pressure zones (212a, 212b) have a shape in which a right-angled triangle with an inwardly concave hypotenuse is divided based on a virtual arc with the center of the square membrane structure (200) as the center point, each divided structure may be a different corner pressure sub-zone. That is, different fluid pressures may be applied to each corner pressure sub-zone from the fluid pressure control device (600), and fluid pressure may be applied sequentially lower from the innermost divided structure to the outermost divided structure. Thus, the distribution of fluid pressure in the radial direction can be precisely controlled even within the corner pressure zones (212a, 212b).

[0060] When polishing a square substrate (W) on a circular polishing pad (1), the corner portion of the square substrate (W) has a substantially higher relative linear velocity with respect to the polishing pad (1) compared to the center portion. Consequently, the material removal rate (MRR) per unit time becomes excessively high at the corner portion, and as a result, the corner portion of the square substrate (W) becomes over-polishing compared to other areas.

[0061] The corner pressure zones (212a, 212b) of the present invention may be configured to apply a fluid pressure different from that of the center pressure zones (211a, 211b, 211c) to solve this problem. Specifically, the fluid pressure applied from the corner pressure zones (212a, 212b) may be set lower than the fluid pressure applied from the center pressure zones (211a, 211b, 211c). By relatively reducing the pressure applied to the corner areas in this way, the increased relative linear velocity at the corners can be compensated, thereby improving the uniformity of polishing across the entire polishing surface of the square substrate (W).

[0062] <변 가압 존>

[0063] In another embodiment of the present invention, the pressure compartment structure (210) may further include a plurality of side pressure zones (213a) corresponding to the side regions of the square substrate (W).

[0064] Specifically, the pressure section structure (210) may include a central pressure zone (211a, 211b, 211c) corresponding to the central area of ​​the non-polished surface of the square substrate (W), a plurality of corner pressure zones (212a, 212b) and a side pressure zone (213a) corresponding to the corner area of ​​the non-polished surface of the square substrate (W).

[0065] Additionally, the central pressure zone (211a, 211b, 211c), the corner pressure zone (212a, 212b), and the side pressure zone (213a) expand as fluid is supplied to pressurize the central area, the corner area, and the side area of ​​the non-polished surface of the square substrate (W), respectively, with different fluid pressures, and the fluid pressure applied from the side pressure zone (213a) can be set to be higher than the fluid pressure applied from the corner pressure zone (212a, 212b) and lower than the fluid pressure applied from the central pressure zone (211a, 211b, 211c).

[0066] The side pressure zone (213a) can expand downward as fluid is supplied from the fluid pressure control device (600) to pressurize the side area of ​​the non-polishing surface of the square substrate (W). That is, multiple side pressure zones (213) may be provided to correspond to each of the four sides of the square substrate (W).

[0067] The side pressure zone (213a) is located on the lower side of the rectangular membrane structure (200) and may have a rectangular shape with one side concave inward.

[0068] When the side pressure zone (213a) has a rectangular shape with one side concave inward, the structure is relatively simple and easy to manufacture, which is an advantage.

[0069] Here, ‘one side is concave inward’ means that among the four sides of the rectangle, the side adjacent to the central pressure zone (211a, 211b, 211c) is rounded inward toward the inside of the figure.

[0070] <가압 존별 유체압>

[0071] In the polishing process, the relative linear velocity between the square substrate (W) and the polishing pad (1) has the characteristic of increasing as it moves further away from the center of the substrate. Since the faster speed area polishes more even when the same pressure is applied, if the center and the outer area are pressed with the same pressure, the outer area becomes over-polished. To prevent this, the key is to apply lower fluid pressure to the faster speed outer area so that the product of speed and pressure is evenly distributed across the entire surface. In particular, the corner area of ​​the square substrate (W) is located diagonally from the center, so the linear velocity is faster than that of the center of the side, and therefore the lowest fluid pressure among the three areas is required. For this reason, it is desirable to set the fluid pressure of each pressurized zone to decrease stepwise in the order of center pressurized zone (211a, 211b, 211c) > side pressurized zone (213a) > corner pressurized zone (212a, 212b).

[0072] In the chemical mechanical polishing (CMP) process, the material removal rate (MRR) is proportional to the product of the pressure and the relative linear velocity of the polishing pad (1) according to the Preston equation. In the case of a square substrate (W), the relative linear velocity of each region during the polishing process is proportional to the distance of that region from the center of the substrate, so there are different linear velocity distributions between the corner region, the edge region, and the center region.

[0073] Specifically, since each corner vertex of the square substrate (W) is located diagonally from the center of the substrate, the relative linear velocity (V_corner) of the corner region is geometrically approximately compared to the linear velocity (V_edge) of the center of each side. ship( 1.41 times higher, and the linear velocity (V_edge) at the center of the edge has an intermediate value between the edge and the center.

[0074] Therefore, in order to secure a uniform material removal rate (MRR), the fluid pressure (P_corner) applied to the corner pressurization zones (212a, 212b) is approximately 1 / 1 of the fluid pressure (P_center) applied to the center pressurization zones (211a, 211b, 211c). ship( It is theoretically desirable to set the fluid pressure (P_edge) applied to the side pressure zone (213a) to an intermediate value satisfying the relationship P_corner < P_edge < P_center, at a level of 0.71 times. In this way, by setting the fluid pressure between the three pressure zones stepwise in the order of center pressure zone (211a, 211b, 211c) > side pressure zone (213a) > corner pressure zone (212a, 212b), a more uniform material removal rate (MRR) can be realized across the entire surface of the square substrate (W).

[0075] For example, if the fluid pressure (P_center) of the center pressurization zone (211a, 211b, 211c) is set to approximately 5 psi, the fluid pressure (P_corner) of the corner pressurization zone (212a, 212b) is approximately 3.5 psi ( The fluid pressure (P_edge) of the variable pressure zone (213a) can be set to approximately 4 psi, at a level of 5 Х 1 / √v2). This is merely an exemplary value based on theoretical standards, and since the optimal fluid pressure ratio may vary depending on various process variables such as the elastic properties of the polishing pad (1), slurry viscosity, material properties of the square substrate (W), and driving conditions in the actual process, the above value is used as a theoretical standard value for the initial process setting and can be adjusted according to actual process conditions.

[0076] Next, referring again to FIGS. 3 to 8, the square retaining ring structure (300) is positioned on the lower periphery of the head body (100) to surround the square membrane structure (200) and can serve to form a square inner space for accommodating a square substrate (W).

[0077] A square retaining ring structure (300) can be installed to support a square substrate (W) within a square inner space to prevent the square substrate (W) from detaching during a chemical mechanical polishing (CMP) process and to supply slurry uniformly during polishing.

[0078] The square retaining ring structure (300) may have a square ring shape, and a slurry supply pipe (310), which will be described later, may be disposed inside. Accordingly, the square retaining ring structure (300) can supply slurry onto the polishing pad (1) through the slurry supply pipe (310).

[0079] Next, referring again to FIGS. 3 to 8, a polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention may further include a vibration sensor (400) that detects frictional torque or vibration of the square substrate (W) during the chemical mechanical polishing (CMP) process, and is disposed on one side of the square retaining ring structure (300).

[0080] Additionally, the fluid pressure applied from any one of the selected zones among the center pressure zone (211a, 211b, 211c), the corner pressure zone (212a, 212b), and the side pressure zone (213a) can be varied according to the detection signal of the vibration sensor (400).

[0081] For example, as the square retaining ring structure (300) supports the square substrate (W), friction torque or vibration generated during the polishing process of the square substrate (W) can be transmitted through the square retaining ring structure (300).

[0082] The vibration sensor (400) may be connected to a control unit (not shown) of the CMP equipment via wired or wireless connection, and the control unit (not shown) may compare the detection signal received from the vibration sensor (400) with a preset reference value and output a control signal to a fluid pressure regulating device (600) so that the fluid pressure applied from at least one of the central pressure zone (211a, 211b, 211c), corner pressure zone (212a, 212b), and variable pressure zone (213a) varies according to the deviation.

[0083] In other words, if the friction torque or vibration in a specific area during the polishing process deviates from the reference value, the fluid pressure control device (600) can optimize the polishing pressure distribution by adjusting the fluid pressure of the pressurized zone corresponding to that area in real time.

[0084] Next, referring again to FIGS. 3 to 8, a polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention may further include a slurry supply pipe (310) that is formed to penetrate the head body (100) and the square retaining ring structure (300) and supplies a slurry to the contact surface between the square substrate (W) and the polishing pad (1).

[0085] In conventional chemical mechanical polishing (CMP) equipment for circular substrates, a method of supplying slurry to the center or outer part of the polishing pad (1) is applied, but when polishing a square substrate (W), there is a problem that it is difficult to uniformly supply slurry to the entire contact surface between the square substrate (W) and the polishing pad (1) using this method.

[0086] In particular, when the square substrate (W) is in close contact with the polishing pad (1), the corners of the square substrate (W) act like car wipers to bounce the polishing slurry outward or generate turbulence, thereby destroying the slurry film. Consequently, a slurry starvation region can be formed at the center of the square substrate (W) where the slurry cannot reach.

[0087] The slurry supply pipe (310) is configured to solve this problem by forming a flow path that penetrates the head body (100) and the square retaining ring structure (300) in the vertical direction, so that the slurry can be directly supplied to the contact surface between the square substrate (W) and the polishing pad (1). By configuring it in this way, the slurry is evenly supplied to the entire contact surface between the square substrate (W) and the polishing pad (1), thereby improving the uniformity of polishing.

[0088] Meanwhile, a polishing head (10) for chemical mechanical polishing of a square substrate according to one embodiment of the present invention may include a fluid pressure regulating device (600), and the fluid pressure regulating device (600) may perform the function of expanding each zone by supplying fluid to each pressurized zone, namely the central pressurized zone (211a, 211b, 211c), the corner pressurized zone (212a, 212b), and the side pressurized zone (213a), which constitute the pressurized section structure (210) of the square membrane structure (200). The fluid pressure regulating device (600) may be located on the upper part of the head body (100) and may be connected to an individual fluid supply path (not shown) through which fluid can flow to each pressurized zone.

[0089] Here, the fluid may include gases such as air and nitrogen, but is not limited thereto, and a hydraulic liquid fluid may also be used. The fluid pressure control device (600) can individually control the fluid pressure for each zone through an independent fluid supply path for each pressurized zone.

[0090] Hereinafter, as illustrated in FIGS. 4 to 8, various embodiments of the pressurized compartment structure (210) according to an embodiment of the present invention will be described.

[0091] First, as illustrated in FIG. 4, a first example of a square membrane structure (200) according to one embodiment of the present invention may include a pressure section structure (210) of the square membrane structure (200) that includes a central pressure zone (211a) corresponding to a central area of ​​the non-polishing surface of the square substrate (W) and a plurality of corner pressure zones (212a) corresponding to corner areas of the non-polishing surface of the square substrate (W).

[0092] In the first example according to one embodiment, the center pressure zone (211a) has a disc shape, and the corner pressure zone (212a) may have a right triangle shape with the hypotenuse concave inward.

[0093] The central pressure zone (211a) and the corner pressure zone (212a) expand as fluid is supplied, so that they can each pressurize the central area of ​​the non-polished surface and the corner area of ​​the non-polished surface of the square substrate (W) with different fluid pressures.

[0094] Additionally, the fluid pressure applied from the corner pressure zone (212a) is set lower than the fluid pressure applied from the center pressure zone (211a).

[0095] Next, looking at a second example of a square membrane structure (200) according to one embodiment of the present invention as illustrated in FIG. 5, the central pressure zone (211b) of the pressure compartment structure (210) may have a shape in which a plurality of ring structures are arranged concentrically. In the second example according to one embodiment, each of the concentrically arranged ring structures functions as a different sub-zone, and the same fluid pressure may be applied to each sub-zone or different fluid pressures may be applied from the fluid pressure regulating device (600).

[0096] Here, when different fluid pressures are applied to each sub-zone, the fluid pressure is set to gradually decrease from the inner ring structure adjacent to the center to the outer ring structure, and the deviation in material removal rate (MRR) within the central pressurization zone (211b) can be compensated.

[0097] Additionally, the fluid pressure applied from the corner pressure zone (212a) is set lower than the fluid pressure applied from the center pressure zone (211b).

[0098] Next, looking at a third example of a rectangular membrane structure (200) according to one embodiment of the present invention as illustrated in FIG. 6, the central pressure zone (211c) of the pressure compartment structure (210) may have a shape that combines a disc shape and a shape in which a plurality of ring structures are arranged concentrically. In the third example according to one embodiment, a disc at the center and a plurality of concentric ring structures surrounding the outside are combined, thereby enabling the structural simplicity of the disc shape and the precise pressure control characteristics of the concentric ring shape (211b) to be realized together.

[0099] Next, looking at a fourth example of a square membrane structure (200) according to one embodiment of the present invention as illustrated in FIG. 7, the corner pressure zone (212b) of the pressure compartment structure (210) may have a shape that is divided based on a virtual arc with the center of the square membrane structure (200) as the center point, in the shape of a right triangle with the hypotenuse concave inward. In the fourth example according to one embodiment, each divided structure functions as a different corner pressure sub-zone, and the same fluid pressure may be applied to each corner pressure sub-zone or different fluid pressures may be applied from the fluid pressure control device (600).

[0100] Through this, the fluid pressure distribution within the corner pressure zone (212b) can be precisely controlled stepwise to more effectively correct local polishing non-uniformity in the corner area.

[0101] Finally, as illustrated in FIG. 8, looking at a first example of a rectangular membrane structure (200) according to another embodiment of the present invention, the pressure compartment structure (210) may include a central pressure zone (211a), a corner pressure zone (212a), and a side pressure zone (213a). In the first example according to another embodiment, the side pressure zone (213a) has a rectangular shape with one side concave inward, and may be provided in multiple numbers to correspond to each of the four sides of the rectangular substrate (W).

[0102] The above central pressure zone (211a), the above corner pressure zone (212a), and the above side pressure zone (213a) may each have different fluid pressures applied individually from the fluid pressure control device (600). Accordingly, the pressure applied to the central area, corner area, and side area of ​​the non-polishing surface of the square substrate (W) can be controlled individually, and the polishing state in each area can be controlled more precisely.

[0104] Although a polishing head for chemical mechanical polishing of a square substrate according to an embodiment of the present invention has been described above as a specific embodiment, this is merely illustrative and the present invention is not limited thereto, and should be interpreted as having the broadest scope in accordance with the basic concept disclosed in this specification. Those skilled in the art may implement unspecified embodiments by combining or substituting the disclosed embodiments, and this also does not deviate from the scope of the present invention. Furthermore, those skilled in the art may easily modify or alter the embodiments disclosed based on this specification, and it is evident that such modifications or alterations also fall within the scope of the present invention. Explanation of the symbols

[0105] 1: Polishing pad 10: Polishing head for chemical mechanical polishing of square substrates 100 : Head body 2 : Grinding Table 200 : Rectangular membrane structure 210: Pressurized compartment structure 211a, 211b, 211c: Central pressurization zone 212a, 212b: Corner pressure zone 213a : Variable pressure zone 220 : Non-pressurized structure 300 : Square retaining ring structure 310: Slurry supply pipe 400: Vibration sensor 500: Retrofit Interface Structure 600: Fluid pressure regulator W : Square substrate

Claims

Claim 1 A polishing head for chemical mechanical polishing (CMP) of a square substrate comprises: a head body having a square shape; a square membrane structure disposed on the lower side of the head body and pressurizing at least a portion of the non-polishing surface of the square substrate through a pressure compartment structure; and a square retaining ring structure disposed on the lower periphery of the head body to surround the square membrane structure and forming a square inner space for accommodating the square substrate; wherein the pressure compartment structure comprises a central pressure zone corresponding to the central area of ​​the non-polishing surface of the square substrate; A polishing head for chemical mechanical polishing of a square substrate, comprising: a plurality of corner pressure zones corresponding to the non-polishing surface corner areas of the square substrate; wherein the corner pressure zones are located at the lower surface corner portion of the square membrane structure and have a shape formed by dividing a right-angled triangle with a hypotenuse concave inwardly based on a virtual arc with the center of the square membrane structure as the center point, each divided structure is a different corner pressure sub-zone, each corner pressure sub-zone expands as fluid is supplied to pressurize the non-polishing surface corner areas of the square substrate with different fluid pressures, and the fluid pressure applied from the corner pressure sub-zone corresponding to the outermost divided structure among the divided structures is set lower than the fluid pressure applied from the corner pressure sub-zone corresponding to the innermost divided structure among the divided structures. Claim 2 delete Claim 3 A polishing head for chemical mechanical polishing of a square substrate according to claim 1, wherein the central pressure zone and the corner pressure zone expand as fluid is supplied to pressurize the central area of ​​the non-polishing surface and the corner area of ​​the non-polishing surface of the square substrate, respectively, with different fluid pressures, and the fluid pressure applied from the corner pressure zone is set lower than the fluid pressure applied from the central pressure zone. Claim 4 A polishing head for chemical mechanical polishing of a square substrate, wherein the central pressure zone is located at the center of the lower surface of the square membrane structure and has any one of the following shapes: a disc shape; a shape in which a plurality of ring structures are arranged concentrically; and a combination thereof. Claim 5 delete Claim 6 In claim 4, the polishing head for chemical mechanical polishing of a square substrate, wherein the pressure section structure further comprises a plurality of side pressure zones corresponding to the side regions of the square substrate. Claim 7 In claim 6, the side pressure zone is located on the lower surface edge of the square membrane structure and has a square shape with one side concave inward, a polishing head for chemical mechanical polishing of a square substrate. Claim 8 A polishing head for chemical mechanical polishing of a square substrate according to claim 7, wherein the central pressure zone, the corner pressure zone, and the side pressure zone expand as fluid is supplied to pressurize the central area, the corner area, and the side area of ​​the non-polishing surface of the square substrate, respectively, with different fluid pressures. Claim 9 A polishing head for chemical mechanical polishing of a square substrate according to claim 8, further comprising a vibration sensor disposed on one side of the square retaining ring structure and detecting frictional torque or vibration of the square substrate during the chemical mechanical polishing (CMP) process, wherein the fluid pressure applied from any one of the selected zones among the center pressure zone, the corner pressure zone, and the side pressure zone varies according to the detection signal of the vibration sensor. Claim 10 A polishing head for chemical mechanical polishing of a square substrate according to claim 1, further comprising a slurry supply pipe formed to penetrate the head body and the square retaining ring structure, for supplying a slurry to the contact surface between the square substrate and the polishing pad. Claim 11 A polishing head for chemical mechanical polishing of a square substrate according to claim 1, wherein the head body comprises a retrofit interface structure formed to be connectable to the drive shaft of a chemical mechanical polishing (CMP) equipment for a circular substrate.

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