TW517325B - Device and method for polishing outer peripheral chamfered part of wafer - Google Patents

Abstract

A wafer outer peripheral chamfered part polishing device is provided, capable of polishing the outer peripheral chamfered part of a wafer by allowing a rotatably held wafer outer peripheral chamfered part to abut on a rotating cylindrical polishing drum having an adhesive cloth stuck thereon and sliding the outer peripheral chamfered part relative to the polishing drum to uniform a polishing speed varying depending on polished portions so as to uniform a polishing amount, characterized in that an angle formed by the principal plane of the wafer and the rotating axis of the rotating cylindrical polishing drum is differentiated continuously or intermittently, and the wafer and cylindrical polishing drum are moved relatively to each other in such directions as to move toward and away from each other, following up to or in synchronous with a variation of the angle.

Description

517325 Domain V. Description of the invention (1) The technical concept of the invention is relevant. The previous technique is briefly described as a crystal layer and a mechanical layer. Through such processes, steps. Patterns, etc. Combined steps from the viewing part for even during processing. Make. Therefore, there is a lack of manufacturing of 4 shell crystals, or a method of grinding a tapered portion of a wafer's periphery and a grinding device thereof. A semiconductor wafer or a semiconductor compound semiconductor is firstly produced by drawing a circular prototype such as a crystal. The wafer is then cut to produce a wafer with surface flatness and processing, and the surface is removed by chemical etching. However, the mirror crystals such as semiconductors produced by this method, but the device manufacturing process still includes the wiring steps related to the formation of the basic device structure based on the substrate step. Observe the steps from single crystal ingot to semi-wafer processing, mirror device manufacturing steps, and substrate steps. Frequently repeated use of automatic disc-shaped wafers that are still tangent as a result of rounding results in particles attached to the yield. Therefore, it is necessary to perform taper processing on the wafer. The manufacturing steps of the mirror wafers such as the outer surface body are cut into a disc-shaped premature crystal bond. The surface has a relatively large unevenness, and the parallel surface is ground. After this, if there is a damaged layer, it will be processed and deteriorated. Finally, the surface will be mirror-polished, and it will enter the next device manufacturing board step, wiring step, and test substrate structure. Then, after wiring, it will be cut to each device wafer and passed to the conductor device. It can be seen that it is needless to say that when the large-face wafer manufacturing step is performed in the wafer state and the wiring step are carried in a wafer state, such as when the wafer outer peripheral portion is in a right-angled state, the main surface is likely to be generated, and the outer peripheral portion of the subsequent steps is formed to have a certain angle of the inclined surface. When rough, it cannot be completely

Page 5 517325 V. Description of the invention (2) ---- Washed neodymium and carved # ^^ effect. In addition, the chemical substances and residues are not suitable for the following steps: ^ High wafer system Q ': far: epitaxial growth is performed on the main surface of the t wafer, etc., when the workability is in the form of crystals. The surface of the part is irregular and lacks pi, or it is related to the occurrence of the so-called knot (n〇duie) plural i, and 'Q length) and other unfavorable Sundays. 0 processing is not only the main surface processing, but also the peripheral processing. F + # ^: In addition to the taper processing and grinding into a mirror-like surface in the outer peripheral portion, the weight is equal to the state, and the surface state is highly prepared. 状 ， 以 伤 # Θ = Twenty-two weeks are processed through the taper section 'step, and then handed over to the taper section of the outer section of the π π ::::. The step of processing in the taper section is for finishing. At this step, because of the worn stone section: face contour 'First perform grinding and addition, etc., and produce deep streaks (loss /) of abrasive grains or the effect of the change in the shape of the grindstone to remove the streak .... So at least the taper part also needs to be engraved or mirror-polished. Wafer outer periphery $ 4, to perform the reduction of polishing cloth :: processing of the surface with abrasive particles on the surface, there is Compared with grinding Jf: cone, work load, but using this tape to completely remove the deformation, the result needs to be carefully used: f raw processing deformation 'for the completion of this mirror polishing research = polishing tape mirror taper processing. Cylinder Shaped grinding drum 21, such as / exposed, has the following equipment: Grinding drum peripheral surface; wafer holding ^ = do not stick the polishing cloth 21a to the cylindrical grinding edge, and press the outer tapered part of the edge Rotating wafer W shows nozzles at a certain angle ..., grinding agent: grinding drum wheel 21;

517325 V. Description of the invention (3) Zhou Cong in the peripheral part of this mirror-polished wafer ^ _ Ding & Shi Lingsheng 丨 fuye # 1 step, when quantitative control is needed _ > : Grinding 2. To be specific, t, it is necessary to grasp the unevenness of wafer roughness and the grinding time I of the mother's early position, the amount of grinding. Decide on the appropriate processing time and such a previous device, that is, the method of often maintaining fixed mirror polishing After detailed observation of the outer periphery of the wafer, it is found that the polishing amount is different, and the most appropriate polishing cannot be performed. For example, as shown in the figure, the wafer holding device 2 () is fixed so that the crystal 2U is usually at an angle of 45 degrees. The wafer holding device 20 is fixed so that the wafer disc polishing cloth 21a is in contact, but it is confirmed that the polishing amount (polishing speed) of the wafer outer peripheral portion such as the enlarged view ①, ②, and ③ is different. ^ Grinding first 1 Based on the weight change before and after processing, only the overall average can be rounded, and there is no mechanism for measuring the thickness of each part. The Japanese inventor first invented the Japanese special wish 丨 丨 37 1 6 5 5 No. "Method for Evaluating Processing Capability of Wafer Section" The surface of the wafer covers the processing speed of the workpiece processed at the outer periphery of the processing wafer. The material with a clear ratio, such as a polycrystalline silicon layer, is set as a reference position in the processing direction, and the evaluation of the invention with the processing speed of the covering material is used. The wafer processing speed is used to convert the processing speed of the actual product processing from this relative ratio, and the thickness of each part of the wafer outer periphery can be measured. 2. According to the present invention, when the processed product wafer is a single crystal silicon wafer, if a polycrystalline silicon layer is formed on the surface of the single crystal silicon wafer that becomes the substrate, a clear boundary between single crystal silicon and polycrystalline silicon is formed in the processing direction. Based on this position, the machining amount is correctly evaluated.

517325 V. Description of the invention (4) Relying on technology '~ If the surface of the above monocrystalline silicon wafer is covered with a polycrystalline silicon bank on the surface of the wafer with a tapered mirror, the surface of the crystal is particularly mirrored, so the correct value can be obtained. . The reason is clearer because of the boundary part. However, the above-mentioned technology only evaluates the polishing ability. The percentage of the outer peripheral cone of the wafer that cannot be suppressed and is evaluated according to the above invention is shown in the enlarged view of FIG. 1. Peripheral cone: Workplaces ①, ② and the occurrence of grinding residues (the grinding amount is less than the roughness of the surface residues, which is the second degree of the surface. Conversely, in order to suppress the occurrence of grinding residues, it is necessary to lengthen the shape, or the phase productivity is the highest. ^ 4 control, affecting the disclosure of the invention: In view of the above problems, the present invention, 苴 its device, when grinding the tapered part of the outer periphery of the wafer; :: heavy :: method and = degree to achieve uniformity of polishing amount, that is to change = ;; = Uneven distribution and grinding amount. To solve this problem within the plane of the surface, the present invention proposes a crystal [Fangbian which is a cylindrical shape where a polishing cloth is attached to the peripheral surface of a cylinder; -Press the outer peripheral part of the wafer with the same rotation side on the upper wheel: the cloth rubs the tapered part of the outer periphery of the wafer to grind the outer taper of the wafer: top: continuously or segmentally changes the wafer contact with the abrasive cloth 2: Step: Change in Angle of Commentary 'Taper the wafer periphery Two tracks on the polishing cloth 'back and forth relative to the engagement direction from the cylindrical wafer

苐 Page 8 5 Π325 V. Description of the invention (5) Wheel = grinding wafer outer peripheral cone To effectively implement this process 4. -Set, it is a mechanism that has the research and development of Ma Ma ^ out-a kind of wafer outer taper part of the wafer > the cylindrical outer surface of the round outer taper part of the mechanism, will: = Perimeter factory firm in the above grinding: Wheel: = The same crystal part of the rotating side is characterized by having the following mechanism: the above-mentioned abrasive cloth rubs the wafer outer cone forward and retreat mechanism, and is connected to the ancient cylindrical grinding drum; With the angle changing mechanism, when the grinding section changes the upper part of the Japanese yen and the outer tapered part, the patient can control the angle of the abrasive cloth, and then force ^ or synchronize with the above-mentioned angle change and accept her ^, The angle of the tapered portion of the wafer outer periphery is pressed and abutted, and the angle is changed to a forward and backward mechanism. ^ To control the above 4 polishing cloths, in the present invention, the angle changing mechanism may not be a mechanism capable of changing the angle while grinding. That is, " Bu Wei, as long as the circular holding device is used for the cylindrical grinding drum, the angle can be centered on the drawing line parallel to the main surface of the wafer; the axis is straight. Quantitative reciprocating L :: " Again: the angular velocity at this time does not need to be fixed during grinding. Can be continuous or segmented. The so-called continuity refers to the range of the change, such as 、, 欠, and ^ (for example, 0 degrees to 55 degrees), and a certain or different = will change the angle of thinking, and the segmentation will stop the plural angles intermittently ( Change 55 degrees) Change the angle and polish. τ stop (e.g. 45 degrees, 50 degrees, why not explain the effect of the invention.

Page 9 517325 V. Description of the invention (6) The unevenness of the grinding part of the grinding device with a certain angle of mm ^ ^ is not uniform. The reason is that w is due to different pressures on various parts-its car: ¾ when changing the crystal The angle of contact between the circle and the abrasive cloth,. It is invented that the grinding force is uniform to reduce the unevenness of the grinding amount. ; At this time, the pressure of the outer periphery of the circle is caused by the wafer angle change at this time:: f J ^ Second, the tapered portion of the wafer periphery is pressurized to meet the research progress: Up and down the advance and retreat mechanism can be set Jing Yan advances and retreats. Drum wheel stand-square or both, ',, clothing /, cylindrical grinding force application mechanism, air cylinder, pressure cylinder and other spring force or mass stepping motor drive with ball screw: 2 The body pressure mechanism is achieved by controlling the trip π 丄 μs dry mechanical movement mechanism. & The mechanism can change the detection signal obtained from the encoder and pressure gauge driving source of the angle changing mechanism (for example, stepping out the order of the circular angle change), according to its detection, fluid and horse mechanism. , Ηδ, change the position, control the advance and retreat. Previously, the wafer was pressed against the circle of the polishing cloth using the grinding drum method. The wafer outer cone production and research = grinding drum-shaped cylinder. Adjust and change the angle during grinding. Contact angle, but there is no mechanism to control the relative position of the angle grinding drum. 3 3 Holder and cylindrical grinding circle angle ’Change the wafer / crystal held on the wafer holding device by changing the angle.

Page 10 The structure of this Ming can be in love during grinding 517325 V. Description of the invention (7) Grinding and grinding of the previous crystal taper part 'There is a belt with fixed abrasive particles on the surface:

~ Similar mechanism taper grinding method. These tapes are used; since the taper processing by L _ ^ ▼ ^ ^ taper processing can continue to supply the tape, there is no problem of the grinding ability due to the deterioration of the polishing surface. However, when the cylindrical grinding drum of the grinding cloth is used, if the continuous grinding j is set, the deterioration of the grinding ability will be accelerated and the life of the grinding cloth will be the same :: Although the lifting and lowering of the cylindrical grinding drum can also correspond, the present invention Because the edge change = B plus: grinding at the angle, the life of the abrasive cloth is higher at the position where it contacts the abrasive cloth. Owe k Μ: to improve the life of the polishing cloth, there is also a technology of pressing the peripheral part of the wafer: J cloth ’to polish with a wide range of polishing cloth areas: gj. ^ 4 ask. In this regard, the ability to attach the abrasive cloth to a cylindrical abrasive cloth that can be rotated at high speed is preferred. The method of π Η 豉 wheel can better improve the grinding room, ie ϊ i ϊ: When the cylindrical grinding drum is polished, the relative length of the cloth during processing can be shortened, and the crystal on the wafer holding device can be shortened. It can change the contact position on the side of the polishing cloth continuously or eight times in a wide range, and improve productivity. Moreover, because the edge is being polished, the knife ’has been changed by the wafer, and it is too scratchy to control the contact angle of the polishing cloth and the polishing cloth, and the grinding drum can be processed. That is, using the grinding device for attaching the polishing cloth to the cylinder to change the shape and shape, the technology of changing the angle (changing the π) as in the present invention is particularly effective. m The present invention can be seen in ★ style rod 钍, etc., ordering in s bin A ... according to the shape of the taper or the effect of the previous step-to change the angular velocity of the angle change, or once it is stopped

Page 11 517325 V. Description of the invention (10) The grinding drum (rotating drum) 1 is rotated at a high speed by a non-random motor built in or installed in the stand 7. These are mounted on the stand 17 and form an advancing and retracting mechanism 45 on the stand 17. The air cylinder 13 is connected to a drive source including a compressed air supply mechanism (not shown); the wheels 8 are transmitted by the air cylinder. The driving force rotates and moves horizontally on the platform 40 and in the direction indicated by the arrow away from the processing position of the crystal cone, and the stage 17 moves left and right in the figure, that is, away from the polishing drum to the polishing drum. Go forward in the direction of the wheel 丨 quot; ^ Retreat freely. The wafer W to be polished is fixed by a wafer holding member 2 such as a vacuum holder that can be rotated in the wafer holding device 25, and is rotated by a stepping motor (not shown) provided in the intermediate stage 4. The rotation amount is detected by the unillustrated transcoding code set in the middle stage 4 and the detection signal is sent to the unillustrated uncontrolled circuit set in the middle stage 4 as a control signal feedback to the stepper motor to control the rotation . Since this structure is publicly known, detailed descriptions are omitted in the text. = Wafer holding device 25 has an angle changing mechanism Η, which holds the wafer during polishing, that is, the taper processing position angle of the outer periphery of the wafer. The wafer companion data of the Japanese yen holding device 25 / "The holding member can be re-installed on the intermediate stage 4, but the intermediate stage 4 is centered on the support shaft j mouth ...? At the center of Han 5 On the main upper stage 1 6 a, shake the angle-shaped saddle support by T. The circle of the heart of the heart is attached to the house t, and the body θ is held in the same shape as the wafer. The position of the opposite side of the grinding drum, that is, the contact surface of wheel 1, increases the rotation angle. In other words, the position of the grinding wheel is changed by a small angle change to change the processing position. l6a. Therefore, the wafer holding member 2 ′ 〇 can be rotated around the support shaft 5 as the axis center, and the degree of the main surface of the circular grinding drum W can be changed. Horn of horse against spinning car

Page 14 517325, Description of the invention (π) The description of the angle and degree changing mechanism 11. One is driven by an intermediate stage with a wafer holding member 2 > rotation (angle change), # historian ★, support for pumping 5 as the axis, thereby forming Α, check connection ", ν feed motor 9 rotating ball The screw rod 6 and the dagger become the connecting locks fitted to the Qing J Yan Zhuan} 曰 ρ ρ 侉 ❿ ❿ ❿ = 、, 糸, 糸 Capability 6 of the male bolt 7 and the intermediate platform 4 HI 7 away from the fixed axis The linear movement of the connecting rod 8 is performed by the rotating force distance of the male screw-song% piano stem in the y wire to the intermediate platform 4. 10 series rotation, angle change) speed and direction.

Enter the main lower side gantry under the main upper side gantry 163, and install the two withdrawal mechanism 46, 1 wafer w processing position away from the direction to make the main stage advance =% 1 卩 2: Air Knowledge 11 3, not The picture shows the drive of the compressed air supply mechanism: the driver, t, and the wheel 18 are rotated by the driving force transmitted by the air cylinder 13; = if back mechanism 46, the crystal is moved from the direction of the arrow shown by the grinding drum 1 Yuan Zuo " σ and σ frame 16 is forward and backward freely in the direction of the figure, that is, away from the grinding drum 1. The 44 series fluid pressure control circuit follows or synchronizes with the angle changing mechanism 11 to press the tapered part of the outer periphery of the wafer against the polishing cloth to control the advancement and retreat mechanisms 45 and 46. The control circuit 44 detects and follows the execution crystal

Round W corner. Angle change mechanism of degree change 丨 The driving source of stepping motor 9 rotates the encoder to detect the signal change amount to control the fluid pressure of air cylinders 3 and 4 While supplying the nozzle, the alkaline solution abrasive containing colloidal silicon monoxide is supplied to the wafer and the cylindrical cylindrical grinding drum contacts, and the outer periphery of the wafer W is polished for a certain period of time.

Page 15 517325 V. Description of the invention (12) The pressure of pressing the wafer W and the polishing cloth 1 a is attached to the wafer holding member 2 A (not shown) and the weight of the cylinder 1 3 and the control of the cylinder 1 4 are 2 kg. Load execution. The cylindrical grinding drum performs grinding at 800 r p m and the wafer W is rotated at 30 seconds. During the processing, the stepping motor 9 of the angle changing mechanism 11 is controlled, and the angle 0 (refer to FIG. 2) is changed in stages to 45 degrees, 50 degrees, and 55 degrees, and the wafer W is rotated at each angle 0 (the total polishing time is 9 as in the comparative example). 0 second), the same area as the comparative example. At this time, when the angle θ at which the wafer W contacts the polishing cloth 1 a changes, the wafer w does not contact the cylindrical polishing drum, or vice versa. The possibility of pressure. Therefore, the air cylinder 13 is controlled according to the control circuit 44, and the PM is synchronized with the angle change of the angle changing mechanism 11 to change the relative position of the wafer holding mechanism 25 and the cylindrical grinding drum 1. The relative change between the wafer holding device 25 and the cylindrical polishing drum 1 is provided by advance and retreat mechanisms 46 and 45 which are mounted on the gantry 6 and gantry 7 and cylinders 13 and 14 and wheels 18 and 19. Adjust the whole hole. Regarding Comparative Example 1, Comparative Example 2, and Example 1, the polishing ability, that is, the i-milling speed and unevenness of each part were confirmed. The results are shown in FIG. 6. P research The measurement of the polishing part and polishing speed of each part of the peripheral part of the wafer is performed according to the method described in Hei 1 1 -37 1 6 55. That is, as shown in FIG. 5, the surface of the wafer w is mirror-polished, and the polycrystalline silicon film is measured with a scanning electron microscope before and after the polycrystalline silicon is coated. Polycrystalline stone film after grinding = ^ ^ ° flat. The grinding speed is determined by the grinding part / grinding door VII, & taper. Due to various shapes, this embodiment is shown in Fig. 5; J ^ 乂 ^ ^ 用 用 is evaluated using Japanese Yen W, wafer w which does not have a certain angle inclined shape. Test a

5. Description of the invention (13) Measurement of 卩 (part ③ in Fig. 5 (a)). The second part of the wafer is taken as the second part, and the part is rotated 90 degrees to calculate the price. To the flat part Example 2 This is a long time to conclude / we know that the comparative example implemented by the previous fixed method! In comparison, the grinding capacity of each part is quite different and compared. The unevenness of each part in Example 1 has been improved. In aspect 2 of the practical embodiment of the present invention, FIG. 7 is another energy source of the angle changing mechanism 11; holding the device vertically (holding the wafer horizontally) //, ° ~ FIG. 7 (3) is maintaining the wafer state, Figure 7 shows the state of changing the angle: State: "This is the wafer holding device 32; A is the axis in more detail, and the piston 2 is supported by the air cylinder 39" supporting the shaft 35 structure. This mechanism can also be implemented The implementation of the ship is the same: the machine that rotates the torque is changed in the advancing and retreating angle during machining, and it can be ground at the same time. That is, it can be continuously rotated at any angle by ⑼. The period is changed in stages to be changed and polished. The flower knife is changed and the same mirror study is performed. The present invention is not limited to the above-mentioned cautious power w, σ m & Β Β Β centric. Technical considerations described in the beneficial scope ... Anyone who has an effect in this scope is included in, for example, the comparative examples and embodiments of the present invention with respect to the wafer ... the main surface side cone 517325

V. Description of the invention (14) Example of polishing the degree portion (parts ①②③) ', except that the wafer outer peripheral portion is polished not only on the front side but also on the back side. That is, it is possible to grind the workman's side first, and then remove the wafer from the holding device to turn it over and hold it at the holding position. Set = 5 the front side and then grind the back side side, as shown in Figure 4. The cylindrical polishing drums 5 1 and 5 1 of 5 cloth sandwich the wafer holding device 2 5 and are arranged at 8o. The symmetrical position 'abuts the front peripheral portion and the back peripheral portion of the wafer W at the same time, and the angle is changed by the angle changing mechanism. ° σ 'The angle changing mechanism may also include a stepping motor and a rack and pinion. This embodiment is composed of a fine-toothed gear (angle changing mechanism 41) driven by a stepper motor or the like between the fixed main stage 16 and the intermediate stage 42. The rotation angle of the stepped motor is used to detect the rotation angle of the fine-toothed gear 41 using an encoder (not shown), and the detection signal is transmitted to the control circuit 44 to control the fluid of the cylindrical grinding drums 51 and 51. Press, follow or synchronize with the above-mentioned angle change mechanism

The wafer's peripheral taper is pressed against the polishing cloth, and the advancing and retracting mechanisms 45 and 46 are used. ^^ I

This two-side arrangement method can be processed by only one side of suction (holding), so there is no harm to the surface of the device and the benefit of processing. Others can also change the angle changing mechanism in a range that can process the entire periphery of the wafer. However, the device shown in FIG. 4 or a device capable of adjusting the angle in a comprehensive range of the front and back of the peripheral portion of the wafer w, the relationship between the wafer holding device and the cylindrical grinding drum is complicated, and the size and configuration of each part need to be considered. Because the contact angle of the outer periphery of the wafer and the polishing cloth is easily changed during the polishing process, it can be processed according to the tapered shape, for example, it can be processed according to a round shape or a certain angle, and other shapes. No taper shape

517325 V. Description of invention (15) Special restrictions. ：: Industrial applicability: According to the present invention, when polishing the outer periphery of the wafer, the polishing speed of each part is uniform, and the uniformity of the polishing amount can be achieved, and the in-plane distribution of the polishing speed can be improved, in other words, the surface in a certain time The internal grinding amount is uneven. By changing the angle β of the contact portion of the polishing cloth by changing the angle, the life of the polishing cloth can be extended.

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Claims (1)

517325 6. Scope of patent application Grinding method with tapered part of the outer periphery of the L wafer. The cylindrical peripheral surface is adhered to the outer periphery Λ, and the cylindrical grinding drum and wafer are rotated together to crystallize them. Press on the abrasive cloth, rub the wafer with the abrasive cloth, and polish the tapered part of the outer periphery of the wafer, which is characterized by the degree, il = f. The angle of the wafer contacting the abrasive cloth is changed continuously or in sections. The polishing degree changes, adding a grinding drum to the outer tapered portion of the wafer, and advancing and retreating the wafer and the cylindrical 2.-kind of tapered portion in the direction of separation from the wafer. ^ The mechanism of the taper part of the outer periphery; = grinding device 'It has a grinding wafer drum and a wafer, edge-same as two = cylindrical grinding cloth with a grinding cloth affixed on the peripheral surface' to grind the above grinding cloth ^: The outer peripheral portion of the wafer is pressed against the above-mentioned polishing advance and retreat mechanism, and is characterized in that: the peripheral taper portion is provided with: and a cylindrical grinding drum; " the angle changing mechanism for advancing and retreating the above-mentioned outer peripheral taper portion of the wafer, or changes in sections Said on the above-mentioned, the wafer peripheral taper control is based on the angle of the polishing cloth, which changes the angle of the tapered part of the wafer peripheral taper to the advance and retreat mechanism. Abut on the abrasive cloth and control the above page 21