TW201440954A - Double-sided lapping and polishing process - Google Patents

Abstract

The present invention discloses an double-sided lapping and polishing process. The major differences between the present invention and the prior art is, the rotation direction of the inner ring module and the outer ring module are adjusted to be opposite mutually so as to randomize the orbit of the template carrier and improve the flatness thereof.

Description

Double-side grinding and polishing method and system thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a double side abrasive polishing method and system thereof, and more particularly to a double side abrasive polishing method and system thereof having the effect of optimizing the total thickness variation of the wafer surface.

Chemical-Mechanical Polishing is widely used in the manufacturing process of semiconductor devices. It uses chemical etching and mechanical force to planarize germanium wafers or other substrate materials during processing. Among them, one grinding method is a double-sided Lapping and Polishing process. A planetary double-sided lapping and polishing system is applied to double-sidedly polish the wafer. Briefly, the apparatus consists of an upper disc, a lower disc, and a planetary gear set disposed therebetween. The aforementioned planetary gear set is roughly divided into an outer ring module, an inner ring module and a workpiece carrier. The outer ring module, the inner ring module and the workpiece carrier are all measured to have a plurality of corresponding teeth. The workpiece carrier is disposed between and interlocked with the outer ring module and the inner ring module. In application, the upper grinding disc is held against the upper side surface of the workpiece in the workpiece carrier and is ground down There is a downward pressure on the direction. At the same time, the outer ring module and the inner ring module will rotate in the same direction, such as clockwise, rotating to drive the workpiece carrier to perform a concentric rotation in a corresponding direction, so as to achieve uniform grinding effect. It should be noted that the purpose of rotating the outer ring module and the inner ring module in the same direction is to reduce the rotation speed of the workpiece carrier, thereby avoiding the occurrence of workpiece fragmentation. The design of the aforementioned double-side lapping and polishing system will be described below.

When the user applied the aforementioned device, the inventors unexpectedly discovered a simple, reliable method with extremely low peripheral cost and improved accuracy of the current double-side lapping and polishing process. Briefly, the inventors have found that when the process is in progress, if the direction of rotation of the outer ring module and the inner ring module is adjusted so that the directions of rotation of the outer ring module are opposite, the appropriate rotational speed parameters and pressure are It is extremely obvious to improve the effect of the conventional process and to control the fragmentation rate to a certain extent. In some cases, after applying the method of the present invention, the distribution of the total thickness variation (TTV) value (um) of the surface of the target wafer can be reduced to one-half or better of the original process.

In addition, in the prior art, the user sets the rotation direction of the outer ring module and the inner ring module to be the same direction to control the rotation speed of the workpiece carrier, thereby preventing the workpiece from increasing due to the excessive rotation speed. The situation. Rather, the present invention overcomes the stereotypes of the prior art and assumes the grinding of the wafer in a manner contrary to conventional recognition.

In the following, the specific design of the present invention will be further advanced. Detailed description.

1‧‧‧Double-side grinding and polishing system

10‧‧‧Upper plate

11‧‧‧Upper surface

20‧‧‧ Lower grinding disc

21‧‧‧ under the grinding surface

30‧‧‧ planetary gear set

31‧‧‧Outer ring module

311‧‧‧ A screw

32‧‧‧ Inner Ring Module

321‧‧‧E.

33‧‧‧Workpiece carrier

331‧‧ ‧ screw teeth

332‧‧‧Perforation

40‧‧‧Workpiece

41‧‧‧Working face

42‧‧‧Under work

X‧‧‧ common axis

1A and 1B are schematic views showing the use of the planetary double-side lapping and polishing system of the present invention during use.

Figure 1C depicts a top view of a planetary gear set in a planetary double side grinding and polishing system of the present invention.

Figure 2 is a graph comparing the effects of the present invention and prior art.

As described above, the present invention proposes a planetary double-side lapping polishing process. First of all, it should be noted that the planetary double-side lapping and polishing system to which the process and method of the present invention are applied has been widely used and well-known in the field of wafer grinding, and the invention of the present invention focuses on the operation of the process. The manner in which the present invention is applied to an existing device without requiring a change or simply updating its software is applied. More specifically, the planetary double-sided grinding and polishing system (device) in which the outer ring module and the inner ring module are reversely rotated can be used in the application environment of the present invention.

More specifically, please refer to FIG. 1A to FIG. 1C. FIG. 1A and FIG. 1B respectively illustrate schematic diagrams of the planetary double-side lapping and polishing system of the present invention during use. 1 and C are plan views of the planetary gear set in the planetary double-side lapping and polishing system of the present invention.

As can be seen from the figure, the planetary double-sided grinding and polishing system 1 of the present invention The system is generally identical to the prior art system, as well as including a top disc 10, a lower disc 20, and a planetary gear set 30 disposed therebetween. The aforementioned planetary gear set 30 is roughly divided into an outer ring module 31, an inner ring module 32, and a workpiece carrier 33. The inner or outer sides of the outer ring module 31, the inner ring module 32, and the workpiece carrier 33 respectively have a plurality of corresponding teeth. The workpiece carrier 33 is disposed between and interlocked with the outer ring module 31 and the inner ring module 32. In application, the upper grinding disc 10 is abutted against the upper side surface of the workpiece in the workpiece carrier 33 and applies a working pressure to the downward grinding disc 20 to hold the workpiece between the upper grinding disc 10 and the lower grinding disc 20, while The upper grinding disc 10 and the lower grinding disc 20 are respectively axially rotated to grind the upper and lower side surfaces of the workpiece in contact therewith. At the same time, the outer ring module 31 and the inner ring module 32 are rotated to drive the workpiece carrier 33 to rotate in a corresponding direction to drive the workpiece carrier 33 to revolve along an axis to make the surface of the workpiece uniform. Grinding.

What is different from the prior art is that when the planetary double-sided lapping and polishing system 1 of the present invention is actuated, the outer ring module 31 and the inner ring module 32 rotate in opposite directions, and cooperate with the upper disc 10 and the lower In the opposite direction of rotation of the grinding disc 20, the grinding path of the workpiece carrier 33 will be more random than the conventional one, and the rotation speed of the workpiece carrier 33 will also be higher, thereby improving the processing quality of the surface of the workpiece.

In order to explain the present invention more clearly, the detailed design of each element will be described below by way of an embodiment. First, in this example, the procedure of the present invention requires the use of a double-sided lapping and polishing system (machine) 1. The polishing system (device) 1 includes an upper grinding disc 10, a lower grinding disc 20, and an outer ring module 31 (also called a ring gear). Group) and an inner ring module 32 (also known as a central gear set). The upper grinding disc 10 has an upper grinding surface 11. The lower grinding disc 20 has a lower grinding surface 21, and the upper grinding disc 10 and the lower grinding disc 20 have a grinding surface 11 and a lower grinding surface 21 which face each other and are horizontally disposed. The inner side of the outer ring module 31 has a plurality of nail teeth 311, and is also connected to a power source (not shown) for horizontal rotation. The outer ring module 32 has a plurality of teeth 321 on the outer side. Further, the inner ring module 32 is also connected to another power source. In this example, the power source is a motor.

Next, a workpiece carrier 33 is prepared. In this example, the workpiece carrier 33 is a template carrier, and the outer side of the star wheel has a plurality of perforations 332 and a plurality of screw teeth 331. The through holes 332 are used for the workpiece 40, and the screw teeth 331 are used for meshing and interlocking with the nail teeth 311 and the teeth. In this example, the star wheel has a diameter of 516 mm and has 170 screw teeth, and the perforation of the star wheel is a circular perforation of a size of four inches.

Subsequently, a plurality of workpieces 40 are prepared, the thickness of the plurality of workpieces 40 being slightly larger than the thickness of the workpiece carrier 33 to expose portions of the workpiece 40 to be in contact with the upper grinding disc 10 and being ground. In this example, the shape of the workpiece is corresponding to the shape of the through hole 332 and is a disk shape, and the plurality of workpieces 40 respectively have an upper working surface 41 and a lower working surface 42. In this example, the perforation of the star wheel is a circular perforation having a diameter of four turns.

Then, the workpiece carrier 33 is disposed on the surface of the B surface of the lower grinding disc 20 at a gap between the outer ring module 31 and the inner ring module 32 and the workpiece The screw teeth 331 of the carrier 33 simultaneously mesh with and interlock with the respective helical teeth 311 and the female teeth 321 of the outer ring module 31 and the inner ring module 32. A plurality of workpieces 40 are embedded in the plurality of perforations 332 of the workpiece carrier 33 such that the lower working surface 42 of the workpiece 40 contacts the lower abrasive surface 21 of the lower grinding disc 20. Next, the upper grinding table 10 is moved to the lower grinding table 20, or the lower grinding table 20 is moved to the upper grinding table 10, so that the upper grinding surface 11 is in contact with the upper working surface 41 of the plurality of workpieces 40, so that the workpiece 40 is It is clamped between the upper grinding table 10 and the lower grinding table 20 so that the respective workpieces 40 are respectively applied with a working pressure.

Subsequently, the inner ring module 32 and the outer ring module 31 are driven to The two are axially rotated along a common axis X to define the grinding path of the workpiece. It should be noted that in order to achieve a more random path, the rotation directions of the inner ring module 32 and the outer ring module 31 are opposite, and the rotation speed can be freely adjusted according to the needs of the user. For better results, it is recommended that the axial rotation speeds of the outer ring module 31 and the inner ring module 32 should be set to 4 to 26 revolutions per minute counterclockwise and 10 to 60 revolutions per minute clockwise. good. Incidentally, the axial rotation speeds of the outer ring module 31 and the inner ring module 32 are respectively 8 to 13 revolutions per minute counterclockwise and 20 to 30 revolutions clockwise, respectively, and the effect is optimal and can be taken into consideration. Its benefits. In terms of efficiency, it is more clear that the fragmentation rate will be positively correlated with the rotational speed of each component, and the work efficiency is negatively correlated with the rotational speed of each component. Accordingly, the aforementioned suggested value is not meaningless. The recommended values obtained through a large number of experiments.

In addition to the inner ring module 32 and the outer ring module 31, the upper grinding wheel 10 And the lower grinding disc 20 will also be driven together to axially rotate the upper grinding disc 10 along the common axis to press and grind the workpiece. Similarly, the rotational speeds of the upper grinding disc 10 and the lower grinding disc 20 are not rigidly defined. However, if a better grinding effect is to be obtained, the rotational speeds of the upper grinding disc 10 and the lower grinding disc 20 are preferably set to be clockwise 5 to 40 revolutions per minute, respectively. Counterclockwise between 10 and 60 revolutions per minute. Incidentally, when the rotational speeds of the upper grinding disc 10 and the lower grinding disc 20 are respectively 10 to 20 revolutions per minute clockwise and 20 to 30 revolutions per minute counterclockwise, the effect is optimal and can be taken into consideration. benefit.

And the above-mentioned work applied from the upper grinding table to the lower grinding table The pressure is preferably 0.01 to 0.12 Kg/cm2. When the pressure is between 0.02~0.06 Kg/cm2, the effect is best.

In order to illustrate the effects of the present invention, please refer to FIG. 2 and FIG. A comparison chart of the effects of the present invention and the prior art. More specifically, Figure 2 is a box of whiskers whose Y-axis is a total thickness variation (TTV) value. The values at the top and bottom of the gray block in the figure represent the quartile and the lower quartile above the surface to be tested, that is, the distribution range of seventy-five percent and twenty-five percent. The lower thin line represents the distribution interval of less than twenty-five percent, while the bottom end is the minimum. The upper thin line represents a distribution interval greater than seventy-five percent, and its top is its maximum. It should be noted that these data exclude the data of the inferior product that is too curved to be used (Warp NG lot). As can be seen from the figure, the maximum thickness variation, the fourth lower quantile, the fourth upper quantile, and the minimum value of the prior art on the right side are about 0.9 um, 2.6 um, respectively. 5.6 um and 10um. In contrast to the present invention, the maximum thickness variation, the fourth lower quantile, the fourth upper quantile, and the minimum value of the prior art on the right side are about 1 um, 2.3 um, 4 um, and 5.6 um, respectively.

In simple terms, in the field of surface grinding, the total surface of the workpiece

The thickness variation is regarded as the processing quality of the surface of the workpiece. The smaller the interval of the total thickness variation, the flatter and uniform the surface of the workpiece, and vice versa. The difference between the maximum and minimum values of the total thickness variation of the prior art workpiece is about 9.1 um, while the difference of the present invention is only 4.6 um, which is about twice as flat as the prior art. More specifically, there has not been any prior art that utilizes a planetary double-sided lapping and polishing apparatus/system to derive a process in which the difference between the maximum and minimum values of the total thickness variation (TTV) is less than 6 um. The technical contribution of the present invention should be demonstrated by this and is not obvious.

In summary, the main difference between the present invention and the prior art is In the planetary double-side polishing method of the present invention, the traveling trajectory of the workpiece carrier disposed therebetween is relatively random and the surface of the workpiece is made by adjusting the rotation directions of the inner ring module and the outer ring module to be opposite. More even.

It should be understood that the presently described in this specification is only numerous of the present invention. Any of the example methods, in the actual use of the present invention, may be any method or means similar or equivalent to those described in the specification. Furthermore, one or more of the numbers mentioned in the specification include the number itself.

It should be understood that the present disclosure discloses performing the disclosed functions. Some methods and procedures are not limited to the order described in the specification. Except that the specification is clearly excluded or the procedures and steps are necessarily causally related, otherwise the execution time is free from the requirements of the user. Adjustment. Further, since the properties of the respective elements of the present invention are considered to be similar to each other, the descriptions and reference numerals between the respective elements apply to each other. It should be noted that the components, modules, devices, components and other components mentioned in this specification are not limited to hardware that is actually independent of each other. It can also be individually or integrated with software, firmware or The hardware is presented in a way that is stated first.

With the details of the above preferred embodiments, it is hoped that The features and spirit of the invention are clearly described, and the scope of the invention is not limited by the preferred embodiments disclosed herein. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed in the broadest

30‧‧‧ planetary gear set

31‧‧‧Outer ring module

311‧‧‧ A screw

32‧‧‧ Inner Ring Module

321‧‧‧E.

33‧‧‧Workpiece carrier

331‧‧ ‧ screw teeth

332‧‧‧Perforation

40‧‧‧Workpiece

Claims (9)

A double-side lapping and polishing method comprising the steps of: preparing a double-side lapping and polishing system, the double-side lapping and polishing system comprising: an upper grinding disc having an upper grinding surface; and a lower grinding disc having a lower grinding surface, The inner surface of the outer ring module has a plurality of nail teeth; and an inner ring module, the inner ring module The outer side has a plurality of teeth; a workpiece carrier is prepared, the workpiece carrier has a plurality of perforations and a plurality of screw teeth, the plurality of C-spirals are disposed around the workpiece carrier; preparing a plurality of workpieces, the plurality The thickness of the workpiece is larger than the thickness of the workpiece carrier, and the shape of the workpiece corresponds to the perforation respectively. The plurality of workpieces respectively have an upper working surface and a lower working surface; the workpiece carrier is disposed on the lower grinding disc The surface of the B is caused to engage the plurality of helical teeth and the plurality of helical teeth simultaneously; the plurality of workpieces are embedded in the plurality of perforations of the workpiece carrier to make the workpiece The lower working surface is in contact with the lower grinding surface of the lower grinding disc; the inner ring module is driven to rotate along a common axis; and the outer ring module is driven to rotate along the common axis, the inner ring mold The rotation direction of the set is opposite to the outer ring module; the upper grinding disk is driven to axially rotate the upper grinding disk along the common axis; the lower grinding disk is driven to axially rotate the lower grinding disk along the common axis; The distance between the upper grinding table and the lower grinding table is such that the upper grinding surface and the lower grinding surface are respectively in contact with the upper working surface and the lower working surface of the plurality of workpieces, thereby applying a work to the plurality of workpieces Pressure and grinding the plurality of workpieces. The method of claim 1, wherein the direction of axial rotation of the lower grinding disc is opposite to the direction of the upper grinding disc. The method of claim 2, wherein the workpiece carrier comprises a template carrier, and the plurality of workpieces are each a wafer wafer. The method of claim 3, wherein the workpiece is a wafer wafer having a diameter of 4 。. The method of claim 4, wherein the axial rotation speed of the upper grinding disc is 5 to 40 revolutions per minute clockwise, and the axial rotation speed of the lower grinding disc is 10 to 60 revolutions per minute counterclockwise. The axial rotation speed of the outer ring module is 4 to 26 revolutions per minute counterclockwise, the axial rotation speed of the inner ring module is 10 to 60 revolutions per minute clockwise; and the working pressure is 0.01 to 0.06 Kg/cm. ² . The method of claim 4, wherein the difference between the maximum value and the minimum value of the total thickness variation (TTV) of the workpiece is less than 6 um. A double-side grinding and polishing system for simultaneously performing double-side grinding on a plurality of workpieces, comprising: an upper grinding disc having an upper grinding surface; and a lower grinding disc having a lower grinding surface, the lower grinding surface and the upper surface The outer surface of the outer ring module has a plurality of nail teeth; and an inner ring module, the inner ring module has a plurality of snails on the outer side of the outer ring module a workpiece carrier having a plurality of perforations and a plurality of C-threads disposed on a periphery of the workpiece carrier; wherein, in application, the workpiece carrier is disposed on the lower disc The surface of the B is such that the screw teeth are simultaneously meshed with the plurality of nail teeth and the plurality of teeth. The plurality of workpieces are embedded in the plurality of perforations of the workpiece carrier such that the lower working surface of the workpiece is in contact with the lower grinding surface of the lower grinding disc, and the inner ring module is rotated along a common axis The outer ring module rotates along the common axis, and the inner ring module rotates in a direction opposite to the outer ring module, and the upper grinding disc rotates axially along the common axis, and the lower grinding disc is along the common The axis is axially rotated, and the upper grinding surface and the lower grinding surface are respectively in contact with the upper working surface of the plurality of workpieces and the lower working surface, thereby applying a working pressure to the plurality of workpieces and the plurality of workpieces The workpiece is ground. The system of claim 7, wherein the direction of axial rotation of the lower grinding disc is opposite to the upper grinding disc. The system of claim 7, wherein the workpiece carrier comprises a Template Carrier.