TW380075B - Polishing apparatus - Google Patents

Abstract

A compact polishing apparatus can produce a high degree of flatness and cleanliness in the polished object. The polishing apparatus comprises a polishing table having an abrading plate, a pressing device for forcing a work surface of a workpiece against an abrading surface of the abrading plate. A driving device is provided for making the abrading surface and the work surface undergo a relative circulative translation motion tracing a given pattern.

Description

V. Description of the invention (1), --- Field of the invention The present invention relates to a polishing device, especially to a work piece whose surface requires high flatness, such as semiconductor wafers, glass wafers, and liquid crystal display panels. (Iiquid crystal display panels). Description of Conventional Technology In recent years, owing to the significant progress in integration density of integrated circuit devices, there has been a demand for a narrower interval between lines. The circuit system that uses optical lithographic reproduction to make highly integrated devices uses a stepper printing process. This method requires a shallow depth of focus, so the surface of the wafer must be very flat. . At the same time, if a particle with a size larger than the gap between the lines remains on the finished product, it may cause a short circuit and cause the device to malfunction. Therefore, it is obvious that the method of manufacturing the work piece must achieve the purpose of making the work piece flat and clean. And, the device and method can also be applied to other general work pieces, for example, glass sheets or liquid crystal display panels used as photo-masking. FIG. 4 illustrates a conventional grinding device, which includes a grinding unit 10, a loading / unloading unit 21, an automatic conveying machine 22, and two washing machines 23a, 23b. FIG. 5 illustrates the structure of the polishing unit 10, including a turntable 12 provided with a polishing cloth l1, and a fixed work piece (wafer) 1 and a pressing work piece 1 to the rotation. The upper washer of the table 12 (t〇 p ri 13 ° When grinding, the work piece must be fixed first! Fix it on the lower surface of the upper washer 13

5. Description of the invention (2), and then the work piece 丨 is pushed down by an upright movable cylinder to the abrasive cloth u provided on the upper surface of the turntable 12. At the same time, a polishing liquid (poshing soliit 10n) Q is supplied from the supply nozzle 14 between the lower surface of the work piece i and the polishing surface of the polishing cloth 11. The year 12 and the upper washer 13 are rotated at different speeds. As shown in FIG. 5, the position of the upper washer 13 is located so that the edge of the work piece i is separated from the center and edge of the turntable 12 by a distance of “a” and “b”, so that the work piece 1 The entire surface can be uniformly ground during high-speed rotation. As shown in the figure, the diameter D of the turntable 12 is selected according to the following relationship, so that D is greater than twice the diameter d of the work piece 1: D = 2 ( d + a + b) The ground work piece 1 is then placed in the washing machines 23a, 23b, and after several washing and drying steps, it is' transported to the loading / unloading unit 21 and stored in the portable work piece card Box 24. This includes a step of brushing 'which can use, for example, a cleaning brush made of nylon (nylon) or wool (mohair)' or a polyvinyl alcohol (poloining 1 alc0h01, pVA In this conventional polishing device, the advantage is that, because the polishing cloth 11 is elastic, it can adjust the undulations and twists of the wafer itself, so that the surface of the wafer can be polished fairly uniformly. However, its disadvantage is that it is prone to edge wear. Grinding the periphery of the wafer. And 'when grinding a wafer with a printed circuit pattern, it is necessary to remove any tiny dogs and objects' to achieve a flatness of less than 1000 $ (angstroke), but the grinding Emery cloth 11 cannot meet this requirement because the elastic nature of abrasive cloth makes it

Page 5 V. Description of the invention (3) Easy to deform 'At the same time, the material of the workpiece is removed from the recessed area and the protruding area at the same time. Sincerity of the invention The object of the present invention is to provide a polishing device with a compact structure, which can achieve a high degree of flatness of the polishing object. The grinding device of this month includes: a grinding table provided with an abrasive plate (abradjng Plate); and a pressing device (pressing dev ice) for pressing a work piece so that its work surface (work SUrfaCe) is pressed against the grinding surface of the grinding plate ), And a driving device (driving center (⑶)) for driving the abrasive surface and the machining surface to perform a relative cyclic movement (reUtive circulative translation motioon) with a specific trajectory pattern. The above-mentioned relative cyclic movement refers to The two surfaces do not change their relative orientation during planar motion, in other words, their moving trajectories follow a set pattern without relative rotational motion, or refer to relative motions that perform such cyclic movement. 1¾ trajectory can be-a straight line Reciprocating graphics, polygonal graphics, etc. 'However, from the practical point of view of the efficiency and quality of grinding and the simplicity of mechanical settings, the graphics are preferably circular, that is, circular motion is better. In cyclic motion, All contact areas of the abrasive are performed with the same trajectory pattern. Since the device uses a polishing plate as a grinding tool, this set Suitable for a wide range of grinding needs, from coarse grinding to fine grinding, as long as the size of the abrasive grains suitable for each work piece, the method of supplying polishing solution and the transfer can be completed. Various operations, that is, when rough grinding, the grinding surface must be rough,

The same rotation speed and larger pressure; while fine grinding, the grinding surface must be made finer. 'Use a lower rotation speed and lower pressure. When fine grinding is performed, a suitable solution can be used to hob to remove particles attached to the surface of the work piece. Details. Abrasive grains are used for rough grinding, and deionized water and solution can be used for fine grinding. Abrasive particles are not usually used for fine grinding, but when used, a small amount of ultrafine particles is used. The surface of the part is equipped with crystal tools that can be used for mounting and wafer grinding. Due to the size of the device, the smaller size of the same height is smaller than the size of the flipped loading ruler, so that even in the grinding structure, this is smaller than the conventional flatness research drive element. When the whole research system is increased in size, the whole wafer is a large-scale grinding tool for a hard grinding board at a low-speed grinding board. It only needs the simplification of the grinding equipment and the advantages of the surface material grinding. Therefore, the size of the device is easier to design. The device is smaller and can be adjusted at any time. The structural power, including cleaning and replacement, is important. The speed of removal is not greater than the quality of the entire watch. It requires a washing device at the same time. When it needs to be studied, the flat surface with uniform polishing rate is easily deformed, so that the wafer provided with the circuit pattern can selectively remove protruding parts' to produce a wafer with a uniform and flat surface. The rotation period of at least one of the work piece and the grinding tool may be significantly longer than the rotation period of the cyclic movement. Therefore, the contact surface between the processing surface and the polishing surface will gradually shift its position, thereby achieving the function of uniformly polishing the entire wafer surface. The grinding surface can be provided with a plurality of channels ′ 俾 for supplying the grinding solution to the contact surface between the grinding surface and the processing surface. So the chip

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2: In the material, that is, it is difficult to apply the polishing solution from the outside of the wafer. The driving device for fully obtaining the grinding solution at the internal position of the grinding tool may include: a base part; a surface plate (surface 7: part: = for receiving the grinding lift; a support provided on the base for supporting the panel to cause cyclic movement It is used to drive the panel to perform cyclic movement. The ###### of the supporting branch part needs to receive at least three or more of the top positions of the panel. Even under the local high pressure, the panel can also be stably supported: The accurate flatness of the polished wafer is maintained, thereby improving the quality of the polished wafer. The supporting structure may include a connecting member, which has a pair of shaft members aligned with the eccentric shaft and extending in opposite directions, etc. The shaft is rotatably embedded in the grooves provided on the panel and the base part, respectively, to provide a simple and tight connection function. The driving part may include: a rotation shaft, which is eccentrically set on the rotation The drive end on the shaft and the recessed portion provided on the panel to receive the drive end effectively transmit torque. The grinding device may include A piece clamping portion is provided with a flexible sheet member 'between the work piece and the clamping surface of the work piece fixing portion, so that the surface condition of the wafer clamping surface does not affect the polished wafer Conditions to ensure the precise flatness of the polished wafer. The polishing equipment used to achieve the purpose of the present invention includes at least one main polishing unit and at least one fine polishing unit. Among them, the main polishing unit includes five. Description of the invention (6) Including: a grinding table with a grinding plate; a pressing device for pressing the processing surface of the work piece to the grinding surface of the grinding plate; and a driving device for driving the grinding surface to be opposed to the processing surface with a specific trajectory pattern The driving device for the cyclic movement of the 'and the fine grinding unit includes: a grinding lift with a grinding cloth; a pressing device for pressing the processing surface of the work piece to the grinding surface of the grinding cloth; and a driving device for driving the grinding The driving device for the relative circular movement of the abrasive cloth and the machined surface with a specific trajectory pattern. Therefore, the greatest advantage of the present invention lies in the full use of hard abrasive plates and softness. The characteristics of the abrasive cloth are used to achieve various grinding requirements. Explanation of the drawings FIG. 1 is a plan view of the structure of the grinding equipment of the present invention; FIG. 2 is a wearing view of the grinding device of the present invention; Figure 3A of the device is a front view showing the driving motor of the grinding dress shown in Figure 2; Figure 3B is a wearing view of the panel shown in Figure 2; Figure 4 is a conventional grinding The perspective view of the equipment; Figure 5 is a cross-sectional view of a conventional grinding device. The detailed description of the preferred embodiment is shown in Figure 1. Figure 1 is a diagram of the grinding equipment configuration of the embodiment of the present invention. There are I // load the work pieces to be ground into the grinding device and carry out 6 疋 21 俾 俾 There are two main grinding units $ grinding work pieces on the other end of the rectangular platform. units) 30a, 30b. In the present embodiment, a white-off / unloading unit 21 and an automatic mechanical transport device are provided between the main grinding units 30a and 30b.

22a, 2 2b for transporting work pieces_ There is a reversing setting for turning the work pieces. A fine grinding unit (finish p〇1l set 25 on the side of the conveying path), a washing machine on the other side of the conveying path 233, 235, and 23 ... As shown in Fig. 2 ^ Poison 1030, and three grinding units 30a, dove and fine grinding Fig. 2 = = 3, basically the main .. ^ t The structure of the milled single 疋 30c is the same as that of the ancient mobile station (translation taM J 得 也 邗 ", Bai Yan also has a grinding tool to push the ground * be Sectlon) 31 俾 to make the research XU cyclically move , As well as used to fix the work piece 1 taxi board hemp and so on its surface to be ground down and push the work piece to the surface of the grinding tool with a set pressure. The history of X 疋 = 台: 份 3i The structure includes: Cylindrical shell 34, which is internally set up to 33, protrudes inwardly from the ring on the upper part of the cylindrical shell: the board exit injury (base part) 35, and three are arranged on the protruding plate part π == the supporting part 36 on the side; α and the surface supported by the side of the support are sighed with a grinding plate 59 or a polishing cloth 59a. Panel 37 Together with the polishing plate = or polishing cloth 59a, a polishing table is formed. As shown in FIG. 3B, the upper surface of the protruding plate portion 35 and the bottom surface of the panel 37 are provided with a plurality of groove portions 3 8, 39, respectively. The grooves are arranged at equal intervals along the peripheral direction, and the sockets 40 and 4i are respectively provided in the grooves. The sockets 40 and 4 are used to receive the upper and lower shafts of the three coupling elements 44 respectively. Each terminal part of the members 42 and 43. As shown in FIG. 3, the axis of the upper shaft member 42 of each coupling element 44 is set at an eccentric distance from the center of the lower shaft member 43 so that the panel 37 can perform circular movement with a radius of "e". The bottom portion of the panel 3 7 is provided with a groove portion 48 at the center of the bottom surface, which is used to install the drive bearing 4 7 '俾 to receive the main shaft 45 provided on the drive motor 33 Above table

Page 10 V. Description of the invention (8) The driving end 46 on the surface, the axis Z2 of the groove structure 48 is located at the position "e " offset from the axis Z1 of the main axis 45. The driving motor 33 is installed The main shaft 45 of the motor chamber 49 provided in the casing 34 is received by the upper and lower bearings 50 and 51. In addition, the device is provided with a pair of balancers 5 2a and 5 2b, which are used to achieve an eccentric load state. The dynamic balance of the panel 37 must be greater than the radius of the offset distance "quote" plus the radius of the work piece to be ground. The structure is composed of two circular disc members 5 3 and 54 stacked. Used for transportation The fluid channel 55 of the grinding solution is provided between the two stacked disc plates 53 and 54. The channel 55 communicates with the grinding solution input port 56 provided on the outer side of the panel 37 and a plurality of upper surfaces of the disc plate 53. Polishing solution output port 57. The polishing plate 59 is attached to the upper surface of the face plate 37 of the main grinding members 30a, 30b, and the 'abrasive cloth 59a is attached to the face plate 37 of the fine grinding unit 30c. The polishing plate 59 and the polishing cloth 59a are provided with a plurality of Opening (solution output port) 58). The solution output ports 57 and 58 are usually uniformly distributed on the entire surface of the panel 37 'grinding plate 59 and the abrasive cloth 59a. The grinding plates 5 and 9 are bonded to the main grinding unit 3. a, 30b on the upper surface of the panel 37, and the abrasive cloth 59 巳 is adhered to the surface of the panel 37 of the fine grinding unit 30c. The abrasive plate 59 is a disc made of resin, which can be used to adhere Abrasive particles (for example, CeO2). In order to ensure the flatness of the grinding surface, appropriate materials and manufacturing methods must be selected so that the grinding plate does not twist and deform during manufacturing and inventory. The surface of the grinding plate 5 9 can be provided with a plurality of Have some types of sermon structure, such as grid, thread or radial, etc. (来 '显 ·

5. Description of the invention (9) ^), the openings for distributing the grinding solution and excluding the grinding are aligned with the grooves. The size of each particle included in the grinding solution is selected according to different needs. The size of the abrasive particles used in the coarse grinding unit a, 〇: is larger, and the size of the fine grinding unit 30c is smaller or No abrasive grains are used. = The ring 32 is used to press the work piece u moving table 31. The pad can be moved to the bottom of the shaft piece 60 by a joint for a certain period of time *, and kee tllting. The rotational force applied by the air cylinder (not shown) and the motor is transmitted to the top via the shaft 60 = 2 = 2 The top ring 32 is provided with a flexible volt on the clamping part 61 of the work piece ^ 俾Prevent the surface of the work piece clamping portion 61 from being wavy and printed on the processing surface of the wafer 1. The structure of the top washer 32 is the same as that of the third outer ring 3 'except that the washer is rotated at a relatively low speed. On the upper and outer side is provided a solution collecting fine, #for collecting and grinding: The operation of the above-mentioned grinding device will be described in detail below. tThe wafer with E24 (refer to Fig. 4) * is placed (the work piece is automatically loaded by +, 22, and 22b, and if necessary, it is loaded by the wafer turning device 25 = then the wafer is loaded) It is set to the main grinding unit 3Qa or on the ground, and the s: ί: 32 is bonded for rough grinding. The rough ground wafer is then transported to the cleaning section 23a by the 5 feeding machine 22a, 22b for cleaning, and then Fine grinding is performed by the fine grinding device 30c. The details of the grinding operation will be described below. The panel 37 is cyclically moved by the drive of the drive motor 33, and is joined to the top washer 32.

V. Description of the invention (10) ------- The wafer 1 is pressed against the polishing plate 59 of the panel 37. The grinding solution is output from the solution input port 56, the fluid channel 55, and the solution output port 5? To the processing surface of the work piece, and is finally supplied to the interface between the crystal and the polishing plate 59 through the grooves of the polishing plate 59. An instantaneous cycle (moving radius e) between the wafer 1 and the polishing surface of the polishing plate 59 enables uniform polishing of the entire processed surface of the wafer 1. When the wafer 1 is displaced in a fixed relative relationship corresponding to the polishing plate 59, problems are caused due to the different surface conditions of the various parts of the polishing plate 59. To avoid these problems, the top washer 32 can be rotated slowly , ^ Changes the relative position of the wafer 1 with respect to the polishing plate 59. The fine grinding operation is basically the same as the rough grinding operation. In the main polishing operation, the polishing conditions are that the wafer 1 and the polishing tool (polishing plate) 59 are running at a higher speed, the pushing force used is larger, and the grinding included in the grinding solution is rougher and honing Material. On the other hand, the purpose of the fine grinding operation is to further flatten and smooth the processing surface of the work piece, and to remove any particles attached to the wafer surface. Therefore, the roughness of the grinding surface of the grinding tool (abrasive cloth) 59a is relatively fine, and the relative movement rate between the grinding tool and the wafer and the pressing force used are smaller than those of the main grinding process. The grinding solution used is usually deionized water, but occasionally a solution or slurry can be used. When using a slurry, in some cases, the abrasive particles of the slurry can use the same material as the abrasive plate to produce good results. After the wafer 1 is finely ground, it is transported to the cleaning devices 23a to 23c for several cleaning and drying steps, and then stored in the wafer cassette 24. In the grinding device of the embodiment, two main grinding units 30a and 3 "are provided.

The main grinding step and a fine grinding unit 30c to perform the fine grinding step 2 are so arranged because the time of the main grinding operation is longer than that of the fine grinding industry. Therefore, during the main grinding process, the two units Among them: one unit can be operated, and the other unit can be stopped, and the efficiency of the operation is improved in the grinding device of this embodiment. Because the two steps of the grinding operation are performed in parallel, the size of the abrasive particles and the solution outlet can be selected. 57 and 58 俾 are suitable for the conditions of each grinding operation, and shorten the time required for each grinding operation. Therefore, compared with the conventional grinding apparatus shown in Figs. 4 and 5, the rate of the entire grinding operation can be significantly increased. At the same time, since the grinding units 30a to 30c are moved in a cyclic movement mode, the size of the panel 37 only needs to be larger than the wafer 1 by an offset " e ". Therefore, compared with the conventional grinding unit 10, the required installation space can be significantly reduced. In addition, "the device of the present invention is easy to redesign a combined unit layout" such as a cleaning machine and a wafer turning device, etc., and the original layout is improved. Furthermore, 'the panel 37 in the grinding units 30a to 30c is cyclically moved', as shown in FIG. 2, the surface plate 37 is supported at a number of specific positions along its periphery. This structure and knowledge Compared with the high-speed rotary table, the polishing device can improve the flatness of the polished wafer. Below are some comparisons of the operating parameters of the typical 槊 in the first and second grinding steps. Grinding n solution Depends on the material to be ground.

Page 14 V. Description of the invention (12) Abrasive particle size, relative pressure, grinding rate, grinding time, second grinding step (fine ^, grinding solution, abrasive cloth, pressing force, relative rate, grinding time, the above can also make the work design by Ma Cheng However, other X and Y directions move. And, however, it is also possible to use a seat (dry beari to limit its rotation range. To sum up, this position needs only to be slightly larger than the comparison, this device is frank. This device is set, and only needs to be implemented. In the example, the design of the drive shaft is the same, and the component of the sample is also connected with other types of ngs) of the panel, as long as the purpose of the surrounding. Ming Zhi's ruler for grinding the work piece is easier to make the structure of the research less power.

15th stomach 0 '1 to 1 0 # m 200 to 500g / cm2 0.07 to 0.6m / sec. Depending on the removal rate Water, chemicals, mortar soft abrasive cloth (non-woven, flannel, etc.) 0 to 200g / cm2 0.07 to 0.6 m / sec. 10 to 12 sec. The movement of the grinding tool is cyclically moved. In addition, the eccentric movement generated by the end of the cyclic movement ^ is achieved by using an XY step method. The production of supporting structures that enable the surface and square plates to follow the same trajectory is to use a crank-type structure, such as a magnetic bearing or a dry bearing, to provide a panel to move at the same time. The entire large surface of the known large-scale grinding table achieves an accurate flat surface, and the installation space required is smaller when a smaller driving device can be used. The entire 5. Description of the invention (13) The design of the grinding equipment, including the cleaning device and the wafer turning device, is simplified and can be adjusted and replaced at any time. These advantages become even more important as the size of the wafer to be polished increases. Because the grinding tool does not rotate, the relative speed between the wafer and the polishing plate is the same across the wafer surface, so even at low speeds, high-quality flat surfaces can be produced. Although the invention has been described in detail above, it should be understood that appropriate modifications and changes can be made without departing from the spirit and scope of the invention.

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Claims (1)

六 2 3. 4. 7. Scope of patent application ---: ------ A grinding device includes: a grinding table provided with a grinding plate; used to push the work piece so that the processing surface of the work piece is crimped to The pressing device of the grinding surface of the grinding plate; and ... the driving device for moving the grinding surface and the machining surface in a relative hapi cycle with a specific trajectory pattern, according to the scope of patent application! The grinding device of item: wherein the relative cyclic movement is orbital motion. According to the grinding device according to item i of the scope of the patent application, the work piece and the grinding tool are among the ——, the movement cycle of the ring movement ^ ^ The rotation period is significantly larger. Wherein the grinding surface has a plurality of grooves, the grinding solution is supplied to the interface between the grinding surface and the processing surface. 2A patent application for a grinding device of item η, in which the driving device. The base portion has an upper surface, the surface receiving the grinding table, a support portion provided on the base portion, and supporting the panel if board. Cyclic movement; and a driving part for driving the panel for cyclic movement. = Grinding device for item 5 of the patent application, "In the part of the branch, there are two support structures for supporting the panel, which are set on the periphery of the panel. The grinding device of Π Shen Wai Item 6, wherein the branch part contains a link member, and the link structure has a pair of opposite eccentric shaft edges. Page 17 VI. The shafts extending in the opposite direction of the patent application are embedded in the panel 8. According to the scope of the patent application, the shaft includes an eccentric shaft that is eccentrically set on the panel for bearing 9. According to the patent application scope, the work piece Clamping part, 10. Grinding device of the clamping part of the work piece, including a fine grinding unit, in which a grinding device is provided for pushing the work piece surface; and, such The shaft is rotatably distributed in the recess of the base portion. 71. The grinding device according to item 5, wherein the driving portion is disposed on the driving end of the rotating shaft, and a recessed portion is connected to the driving end. The "grinding device of 1 item" wherein the device includes: a work piece clamping portion provided with a flexible sheet member between the work piece and the clamping surface. At least one main grinding unit and at least one of the main grinding units include: a grinding table; a grinding surface of the processing surface crimped to the grinding plate for driving the grinding surface and the processing surface to perform a relative cyclic movement with a specific trajectory pattern The device; wherein the fine grinding unit comprises: a grinding table provided with a grinding abrasive cloth; a pressing device for pressing a processing surface of the work piece to be pressed against the surface of the grinding abrasive cloth; and a driving device for driving the grinding abrasive cloth and the processing surface Driving device for relative cyclic movement with a specific trajectory map 0 Page 18