TW440500B - A planarization method and device for compensation CMP machine - Google Patents

Abstract

This invention provides a planarization method and device for a compensation CMP machine. The invention utilizes one or more polishing pad carriers to apply a pressure to the wafer for compensation polishing so as to eliminate the dishing or erosion occurred in the polishing process while such a compensation device and the primary polishing device can be operated simultaneously, so as to reduce the non-uniformity of the polished wafer and to achieve the object of planarization. Further, the multiple polishing carriers as disclosed in this invention further reduce the overall area of the machine bed and operation cost.

Description

440500 V. Description of the invention (1) Field of the invention The present invention relates to a method and device for flattening a compensating chemical mechanical polishing machine. Generally speaking, there are two characteristics that semiconductor polishing machines are most required to achieve, one is Grinding accuracy; the other is productivity efficiency, that is: (1) a semiconductor polishing machine that can simultaneously achieve planarization and uniformity on the wafer surface. (2) From the viewpoint of semiconductor manufacturing, what is needed is a polishing machine that has a fast wafer processing speed, high efficiency, and is lightweight and miniaturized. The present invention provides a method and device capable of compensating during the polishing process, which can reduce the non-uniformity of the wafer being polished and achieve the purpose of the planarization process; further, the present invention provides The device of one or more polishing pad carriers can further reduce the machine area and the operating cost. Creative background When the size of semiconductor wafers is getting larger, the following problems in semiconductor wafer grinding will become more and more troublesome and serious:

4405 〇〇

V. Description of the invention ¢ 2) (1) About the non-uniformity (N ο η-U nif 0 rmity), because the wafer size is too large, so when the wafer is all pressed on the polishing pad for polishing, no matter what None of these methods can prevent the occurrence of non-uniformity during wafer polishing. However, the generation of these non-uniformities causes the metal grinding in the copper process, and the shallow trench isolation STI (Shallow Trench Iso 丨 ation) oxide layer grinding. Over-Polishing method is used to remove the 'residual copper metal' or shallow trench isolation STi (Shal 1〇w Trench Isolation) oxide in the steel process, but this will cause over-polished areas The state of Dishing or Erosion is shown in Figure _. At the same time, when the wafer size becomes 300nm, this kind of Dishing or Erosion will be more serious. This is a problem that cannot be solved by the traditional rotary grinding machine, as shown in Figure 2. Each (2 ^ from the stomach in the conventional technology, the wafer is covered by a polishing pad and a polishing head, which makes it very inconvenient to measure changes in wafer thickness or material during polishing; in addition, because the wafer is masked, it is also difficult to polish. It is easy to cause uneven temperature and uniformity. A Eight (3) traditional rotary (planetary, planetary motion) bite linear (Llnear) grinding machine, when changing wafers (such as by diameter 3 0 0iiim wafers are increased to a diameter of 40 0 with wafers) The machine may all need to be updated, as shown in Figure 2, and the ground area of the machine after the update will also increase significantly, making it impossible to use the existing plant.

Page 6 44 05 0 0 V. Description of the invention (3) Purpose of creation The present invention aims to solve the above problems on the wafer polishing machine and effectively solve them. The present invention first discloses a method and a flattening method for compensating chemical mechanical polishing machines. As shown in FIG. 3, 'at least includes a polishing table, which is used to set a wafer; one or more polishing pad carriers'. The surface of each polishing pad carrier facing the polishing table is connected to a polishing pad. When the polishing pad carrier presses the polishing table to make the polishing surface of the polishing pad polish the aa circle and a measuring device is located on the wafer polishing Surface to measure wafer thickness or material changes during polishing. In this solution, the measured thickness Point is also lightly configured because of the nature. This size reduction is due to the device that applies pressure, and the situation; and because the hair directly detects the EPD (End connection) on the wafer surface. And real-time measurement; the uneven temperature generated by the chemical mechanical polishing unit reduces the grounding surface of the machine, and at the same time it is relatively reduced; the more special wafer size is larger, the use of the polishing pad carrier as compensation = (Dishing ) Or grinding drill (ErSiOn) wafer is not covered by other devices, so the change in material grinding can be straightened to the surface of the wafer with the end point ^ tect 10n) method. Therefore, the conventional grinding method is used to solve the problem. In addition, as shown in Figure 4: Figure, the grinding device of the present invention can greatly As far as the design of the machine is concerned, when

440500 V. Description of the invention ¢ 4) (for example, when 30 Omm is converted to 450 mm), it can be easily converted and can save a lot of development costs. Brief description of the drawings. Figure 1 is a schematic diagram of the state of causing depression or abrasion in an excessively abrasive region. Figure 2 is a conventional rotary grinder. Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 is a schematic diagram of the configuration of a chemical mechanical polishing unit. The schematic diagram of the unit configuration when the wafer is converted according to the present invention is a flowchart of the planarization process of the present invention. The figure of the integrated flattening process flow chart is illustrated as Erosion 11 Dishing 12 Grinding table 21 Grinding head 22 Grinding table 31

44 05 ο Ο 5. Description of the invention (5) Wafer 3 2 Polishing pad carrier 33 Polishing carrier (Carrier-1) 331 Polishing pad carrier (Carr ier-2) 332 Polishing pad carrier (Carrier-3) 333 Measuring device 34 polishing pad 35 soft pad ~ 36 polishing pad carrier speed Wp polishing table rotation speed Ww 3 0 Omm wafer polishing table 51 4 50 mm wafer polishing table 52 polishing carrier (Carrier-1) 531 polishing pad carrier (Carrier-2) 532 polishing pad carrier (Carrier-3) 533 Detailed description of the embodiment of the present invention The embodiment of the present invention is shown in FIG. 3 (A), which includes: a polishing table 31, which is located below a wafer 32 to fix the wafer 3 2; one or more polishing pad carriers 3 3; and a measuring device 34. Each of the polishing pad carriers 3 3 is connected to a polishing pad 3 3 1 on the surface facing the polishing table 31 as shown in FIG. 3 (B). When the polishing pad carrier 3 3 presses the polishing table 31, the Grind

Page 9 4 4 05 Ο Ο 5. Description of the invention (6) The polishing surface of 研磨 331 grinds the wafer 32; wherein the polishing table 31 is as shown in FIG. 3 (B), the polishing table 3 1 and wafer 3 2 A soft pad 3 1 1 'is set in between. The soft pad 3 1 1 is used to carry the wafer 3 2 and evenly distribute the pressure on the wafer surface; the measuring device 34 is located on the polishing table. 3 1's wafer polishing surface 'to measure wafer 3 2 thickness or material changes during polishing. The flattening method of the compensating chemical mechanical polishing machine disclosed in the embodiment of the present invention and the method of polishing the polishing pad 331 on the polishing pad carrier 33 can use the same or different polishing pads at the same time, as shown in the embodiment. It is shown that the plurality of polishing pad carriers 33 are Carrier-1, Carrier-2 and

Carrier-3 'Among them Carrier-1 and Carrier-2's polishing pad carriers 3 3 are connected to the main polishing pad 1 and the main polishing pad 2 respectively, and (: 31_1 ^ 61__3 can be connected to a polishing pad with a compensation effect. When the polishing table 3 1 When rotating, the polishing pad carrier 3 3 cooperates with the polishing table 3 1 Rotate the polishing pad carrier 3 3 and the polishing table 3 1 at an appropriate rotation speed ratio. According to the present invention, it is found through inspection that when the wafer radius is about 1 At 50 mm, the rotation speed ratio (wp / Ww) of the polishing pad carrier 33 to the polishing table 31 is in the range of i / 4 to 3/8 (0.25 to 0.37 5). It can have the best effect. Θ From this, it can be found that when the wafer size is getting larger and larger (from 300 mm diameter wafers to 2.5 mm wafers), the planarization process and The device 'provides a solution to the problems that cannot be solved by the traditional rotary grinding machine, such as Dishing or Errosion as shown in Figure 2.

Page 10 4 4 Ο 5 q q V. Description of the invention (7) ~~ '~ " The best way out. FIG. 6 is a compensation chemical mechanical polishing machine planarization method provided by the present invention: Step 6: 1: Before planarizing a wafer, it is necessary to determine a suitable process, such as metal CMP or oxide film CMP in a copper process, Even the process of planarizing the organic insulating layer. Step 6-2: After judging the suitable process, install the appropriate polishing pad and soft pad on the polishing pad carrier according to the requirements of the suitable process. The multiple polishing pad carriers are Carrier-1, Carrier-2, and Carrier-3. Among them, Carrier-1 and Carrier-2's polishing pad carriers are connected to the main polishing pad 1 and the main polishing pad 2, respectively, and Carrier-3 can be connected to a polishing pad with a compensation effect. Step 6-3: Start the compensating chemical mechanical grinder. Step 6-4: It is a flexible process pass, and it enters the selected process pass according to the process determined by step 6-1. Step 6-5: Grinding starts. Steps 6-6: During the grinding process, a measurement device is used for real-time monitoring and measurement. The measurement device compares the end point of the polishing time with the EPD measurement database. If it ends, go to step 6-7, otherwise go back Go to steps 6-6. Step 6-7: Carrier-1 and Carrier-2 stop grinding, and C a r r e e r-3 performs compensating grinding. Step 6-8: In the compensating polishing process of Carrier-3, use E P D to sense the position of the residual material for database comparison, and set the compensation level

Page 11 44 05 ο ο 5. Description of the invention (8), determine whether the compensation is completed, if it is completed, go to step 6-9, otherwise go back to step 6-7. Steps 6-9: End the periodic grinding. Because Carrier-1, Carrier-2, or Carrier-3 can use different material polishing pads, the polishing process can obtain the maximum flexibility. For example, in the copper process, as shown in Figure 7, different polishing pads can be used to attach On different polishing pad carriers, different elastic pressure methods can be used to polish different metal materials on the same wafer surface. With the EDP function of the measuring device, the Cu and Ta / TaN layers can be completed in one step. Of grinding. FIG. 8 is an integrated planarization method in the planarization process of the compensated chemical mechanical polishing machine provided by the present invention, which includes the following steps: Step 7-1: Wafer loading step 7-2: Wafer alignment step 7-3: Enter the polishing process Step 7-4: Light buffing Step 7-5: Wafer cleaning Step 7-6: Wafer loading During the polishing process, compensatory polishing may also cause partial flatness The problem is that a grinding table with a light buffing function is necessary. Therefore, the entire chemical mechanical grinding unit can be simplified, as shown in Figure 4.

Page 12 44 05 Ο Ο 5. Description of the invention (9)-A schematic diagram of the chemical mechanical polishing unit configuration, which includes two polishing processes, Polisher 1 and Pohnsher 2 ', and at least one light polishing process Buffing and A wafer cleaning process CUaner. The wafers are loaded and unloaded by automatic operation between the processes. The wafers are loaded by F0Up Loading into Polisher 1 and publisher 2, and the polishing device provided by the present invention performs a single step. Grinding and polishing, then enter the light polishing table for light polishing, and finally send it in for cleaning and cleaning. Therefore, the grinding device provided by the present invention can greatly reduce the grounding area of the machine, which is a very important cost influencing factor for the clean room. At the same time, due to the reduction in size, the required motors, pneumatic cylinders and other components are also relatively reduced; more particularly, For the machine design of the present invention, unlike traditional rotary, planetary (Orbital) or linear near grinding machines, when changing wafers (from 300 mm diameter wafers) Raise to 45mm diameter wafer) The machine must be completely updated, but when changing the wafer, the present invention only needs to add a set of 4 50mm wafer polishing table 52 compared to the old 300_ wafer polishing table 51 It is ready for production, as shown in Figure 5. In addition, during polishing, the pressure on the polishing pad is not uniform. After the test, another ring-shaped polishing pad is proposed to reduce = contact area with the wafer, which can solve the deformation and deformation of the polishing pad under pressure: A good pressure distribution is obtained, so that the polishing pad can have a contact area with the wafer of about 22, which is about half of the contact area. Collision area

440500 V. Description of the invention (10) The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of implementation of the present invention; that is, all equal changes and modifications made in accordance with the scope of the patent application for the present invention are Covered by the patent scope of the present invention.

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Claims (1)

44 05 0 0 6. Scope of patent application 1. A compensating chemical mechanical polishing device, comprising: a polishing table with a support ring on its surface to fix a wafer on the surface of the polishing table, and the polishing table and the crystal A soft pad is arranged between the circles; one or more polishing pad carriers, wherein each polishing pad carrier is connected to a polishing pad on a surface thereof facing the polishing table, and the polishing pad carrier can press the polishing table to make the grinding pad grinding The wafer is surface-polished. 2. The polishing device according to item 1 of the scope of the patent application, wherein the polishing table fixes the wafer by vacuum suction. 3. The grinding device according to item 1 of the scope of patent application, wherein the grinding table is a spin-table platform. 4. The polishing device according to item 1 of the scope of patent application, wherein the soft pad is used to carry the wafer and evenly distribute the pressure on the wafer surface. 5. The polishing device described in item 1 of the scope of the patent application, wherein the one or more polishing pad carriers are spin-on carriers and can be independently moved horizontally or vertically with respect to the plane of the polishing table. 6. The polishing device according to item 1 of the scope of the patent application, wherein the polishing pad can use one or more polishing pad materials, and the material of the polishing pad depends on the surface of the wafer to be polished or the effect to be achieved. Page 17 44 05 〇 6. Patent application scope 7. The polishing device described in item 1 of the patent application scope, wherein the grinding 塾 carrier applies pressure to the polished wafer by air pressure or net weight. 8. According to the polishing device described in item 1 of the scope of patent application, when using more than one polishing pad carrier, one or more of the polishing pad carriers can be used alone as a compensating pressure tool, and selected Suitable polishing pads to increase wafer polishing flatness. 9. The polishing device described in item 1 of the scope of the patent application, which further includes a measuring device located on the wafer polishing surface. The measuring device can be used as an endpoint debt measurement EPD (End P oint Detec ΐ i ο η) method, and directly and instantly measure the wafer surface. 10. The polishing device according to any one of item 1 or item 6 of the patent application scope, wherein the shape of the polishing pad has a disc-shaped structure. 11. The polishing device according to any one of the items 1 or 6 of the scope of patent application, wherein the shape of the polishing pad has a hollow disc structure. 1 2. The polishing device according to any one of the items 1 or 2 or 3 in the scope of patent application, wherein the diameter of the polishing table can be changed according to the diameter of the polishing wafer. 1 3. If the scope of patent application is 4 or 5 or 6 or 6 or 7 or 8 Page 18 4 4 05 oq 6. The polishing device according to any one of the scope of patent application, wherein the diameter of the polishing pad carrier or polishing pad can be changed according to the diameter of the polishing wafer, and the diameter of the polishing pad carrier or polishing pad Is smaller than the diameter of the wafer. 1 4. A chemical mechanical polishing device capable of compensating and reducing the area of a machine, including: a grinding table, a surface of which is provided with a support ring to fix a wafer on the surface of the grinding table, and the grinding table and the crystal A soft pad is arranged between the circles, the polishing table can rotate in the first direction; one or more polishing pad carriers, wherein each polishing pad carrier is connected to a polishing pad on the surface facing the polishing table, and when the polishing pad carrier The pressure is applied to the polishing surface of the polishing pad to grind the wafer, and each polishing pad carrier can rotate in the second direction; and a measuring device is located on the polishing surface of the wafer to measure the thickness or material of the wafer. Changes during grinding. 15. The polishing apparatus according to item 14 of the scope of patent application, wherein the polishing table is used to fix the wafer by vacuum adsorption. 16. The grinding device according to item 14 of the scope of patent application, wherein the first direction of rotation of the grinding table can be clockwise or counterclockwise. 17. The polishing device according to item 14 of the scope of patent application, wherein the first direction in which the polishing table rotates is the same as the second direction in which the polishing pad carrier rotates. P.19.440500 6. Application scope of patent 18. The grinding device described in item 14 of the scope of application for patent, wherein the one or more polishing pad carriers can be individually made horizontally or vertically with respect to the plane of the polishing table. Mobile. 19. The polishing device according to item 14 of the scope of patent application, wherein the polishing pad can use one or more polishing pad materials, and the polishing pad material is based on the surface of the wafer to be polished or the effect to be achieved. It depends. 20. The polishing device according to item 14 of the scope of the patent application, wherein the one or more polishing pad carriers apply pressure to the polished wafer by a pneumatic or net weight method. 2 1. According to the polishing device described in item 14 of the scope of patent application, when more than one polishing pad carrier is used, one or more of the polishing pad carriers can be used alone as a compensating pressure tool, and Select a suitable polishing pad to increase wafer polishing flatness. 2 2. The polishing device as described in item 14 of the scope of the patent application, wherein the measuring device is an EPD (End Point Detecti ο) method using an end point debt measurement to directly and directly Instant measurement. 2 3. The grinding device according to any one of item 14 or item 18 in the scope of patent application, wherein the shape of the polishing pad has a hollow disc-shaped structure. Page 20 44 05 06. Application for patent scope 24. For the grinding device described in any one of the fourteenth or fifteenth or fifteenth or sixteenth or seventeenth of the scope of patent application, wherein the The diameter of the polishing table can be changed according to the diameter of the polishing wafer. 25. The polishing device according to any one of the 18th or 19th or 20th or 21st scope of the patent application scope, wherein the diameter of the polishing pad carrier or the polishing pad can be 1 according to the polishing crystal. The diameter of the circle varies, and the diameter of the polishing pad carrier or polishing pad is smaller than the diameter of the wafer. 2 6. — A compensating chemical mechanical polishing machine planarization method, which uses the polishing device described in item 14 of the scope of patent application, which method includes the following steps: a. Before planarizing the wafer, first determine the appropriate planarity B_ Install appropriate polishing pads and soft pads on the polishing pad carrier according to its suitable process requirements. The multiple polishing pad carriers are Carrier-1, Carrier-2, and Carrier-3, of which Carrier-1 Carrier-2's polishing pad carrier is connected to the main polishing pad 1 and the main polishing pad 2 respectively, and Carrier-3 can be connected to a polishing pad with compensation function; c. Start the compensation type chemical mechanical polishing machine; d. The production process passes according to the process determined by step a, and enters the selected production process; e. Grinding starts; f. During the grinding process, a measuring device is used for real-time monitoring and measurement Page 21 44 05 〇g 6. Apply for patent range measurement. The measuring device compares the polishing time end point with the EPD measurement database. If it ends, go to step g, otherwise go back to step e; g · Carrier-1 and Carrier-2 stops grinding and uses Carrier-3 for compensating grinding. H · During Carrier-3's compensating polishing process, EPD senses the residual material position for database comparison, and sets the compensation position to determine whether the compensation is correct. Complete, if completed, go to step i, otherwise go back to step g; Γ · End the stage grinding. Page 22