TW202224850A - Polishing device - Google Patents

Abstract

A polishing device, comprising a base, the base being provided with polishing head seats; the polishing head seats are provided with two polishing heads for fixing wafers and a linear driving mechanism which is located between the two polishing heads and which is used for driving the two polishing heads to move. During a polishing process, the base is located above a polishing platform, the polishing heads drive wafers to rotate, and the polished wafers are taken away along a curved slide rail.

Description

polishing device

The present invention relates to the technical field of semiconductor processing equipment, in particular to a polishing device.

During the wafer production process, chemical planarization and polishing are required to make the wafer surface reach qualified flatness and smoothness. During the chemical planarization polishing process, the polishing pad, polishing head, polishing liquid, polishing pad conditioner, motion trajectory, and force all affect the final flatness and smoothness of the wafer. How to ensure the quality and yield of polished wafers at the same time is one of the main research directions in the field of wafer processing.

The existing mainstream wafer polishing devices include a polishing table and a corresponding polishing head. The polishing table has one degree of freedom for rotation, the polishing head has two degrees of freedom (rotation and sweeping and swinging on the polishing head table), and three degrees of freedom. At the same time, it can realize polishing operation. The sweeping and swinging action of the polishing head on the polishing head can fully and uniformly consume the polishing pad on the surface of the polishing head; at the same time, the sweeping and swinging action of the polishing head can transfer the wafer from the polishing head to other transfer platforms such as the wafer stage.

However, in the existing wafer polishing device, although one polishing head corresponds to two polishing heads can improve the polishing efficiency, it is difficult to ensure the consistency of the polishing process of two or more wafers, and generally it can only be used for low polishing accuracy requirements. industry.

Therefore, how to improve polishing consistency while ensuring polishing efficiency is a technical problem that those skilled in the art need to solve urgently.

The purpose of the present invention is to provide a polishing device, which drives two polishing heads to move symmetrically through a linear drive assembly, so that the consistency of the wafers on the two polishing heads is significantly improved.

In order to achieve the above object, the present invention provides a polishing device, including a base, the base is provided with two polishing head seats, the polishing head seats are provided with a polishing head for fixing a wafer and a polishing head for driving the polishing head Linear drive mechanism for linear movement. The polishing device further includes a bottom plate, the bottom plate is provided with a curved slide rail, and the base is provided with a slider connected with the curved slide rail.

Preferably, the base is provided with a linear slide rail for restricting the moving path of the polishing head base, the linear drive mechanism drives the polishing head base to move linearly along the linear slide rail, and each polishing head base moves linearly along the linear slide rail. Each of the polishing heads is provided with one of the polishing heads, the moving trajectories of the two polishing head seats are symmetrically distributed, and the axis of symmetry is the mid-perpendicular line of the line segment formed by the midpoints of the two polishing heads.

Preferably, the linear drive mechanism includes a lead screw connected to the polishing head and a driving part for driving the lead screw to rotate.

Preferably, there are two linear slide rails corresponding to the single polishing head base, and the two linear guide rails corresponding to the same polishing head base are arranged in parallel.

Preferably, a curved drive mechanism for driving the base to move on the curved slide rail is further provided between the base and the bottom plate.

Preferably, the polishing device further includes a polishing table located under the base, the polishing table is provided with a liquid supply arm for outputting polishing liquid between the polishing head and the polishing table, and the polishing table is provided with a liquid supply arm for outputting polishing liquid between the polishing head and the polishing table. The arrangement position of the liquid arm is symmetrical about the center of the polishing table midpoint.

Preferably, the curved drive mechanism comprises a curved magnetic rail arranged on the base plate and concentric with the curved sliding rail, and a curved direct drive motor arranged in the base and matched with the curved magnetic rail .

Preferably, the curved slide rail is in a circular arc or ring shape, and at least one of the polishing table and the wafer carrier for carrying the finished wafer is arranged below the curved slide rail. The polishing table and the The slide tables are all located within the range covered by the projection of the curved slide rail on the horizontal plane.

Preferably, the curved slide rail is in the shape of a circular arc or a ring shape, and only at least two polishing tables are arranged below the curved slide rail, and all the polishing tables are located under the projection of the curved slide rail on the horizontal plane. The slide table is located outside the range covered by the projection of the curved slide rail on the horizontal plane.

Preferably, at least two of the bases are connected to the curved slide rail.

Wafer polishing requires extremely high precision, and factors such as the movement trajectory of the polishing process and the flow direction of the polishing liquid will affect the polishing results.

The polishing device provided by the present invention includes a base, the base is provided with a polishing head seat, and the polishing head seat is provided with two polishing heads for fixing the wafer and a polishing head located between the two polishing heads for driving the two polishing heads to move. A linear drive mechanism, the polishing device further comprises a bottom plate, the bottom plate is provided with a curved slide rail, and the base is provided with a slider connected with the curved slide rail.

During the polishing process, the base is located above the polishing table, the polishing head drives the wafer to rotate, and the linear drive mechanism simultaneously drives the two wafers to linearly translate and scan, and the polished wafer is moved along the curved slide rail. Sweeping in a straight line results in a more uniform slurry distribution and more uniform pad wear, resulting in significantly improved polishing consistency between the two wafers. Wafers in the same batch are polished the same, which ensures stable product quality and simplifies the steps to check product quality in subsequent processing.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to make those skilled in the art better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Please refer to FIGS. 1 to 6. FIG. 1 is a schematic structural diagram of the polishing device provided by the present invention; FIG. 2 is a side view of the polishing device in FIG. 1; Fig. 4 is a schematic structural diagram of a polishing device in a specific embodiment at a first station; Fig. 5 is a schematic structural diagram of a polishing device in a specific embodiment in a second station; Fig. 6 is a schematic structural diagram of a polishing device in another specific embodiment .

The polishing apparatus provided by the present invention has a structure as shown in FIG. 1 , including a base 101 and a polishing assembly 100 . The base 101 is located above the polishing table 201, the polishing pad is provided on the upper end surface of the polishing table 201, the lower end surface of the base 101 faces the polishing table 201, and the polishing assembly 100 is provided on the lower end surface of the base 101. The polishing assembly 100 includes The two polishing head seats 104 , the linear driving mechanism and the two polishing heads 200 are arranged on the lower end surface of the base 101 . The two polishing head bases 104 are movably connected to the base 101 , and the linear driving mechanism is connected to the two polishing head bases 104 , and the polishing head base 104 is driven by the linear driving mechanism to move in a straight line. Each of the two polishing heads 200 fixes a wafer, and the two polishing head bases 104 are connected to the two polishing heads 200 respectively. The polishing head base 104 drives the polishing heads 200 to move synchronously during the linear movement.

During the polishing process, the polishing head seat 104 is located above the polishing table 201 . The polishing head 200 can rotate and drive the wafer to rotate. The wafer fixed by the polishing head 200 is attached to the polishing pad, and is rotated under the driving of the polishing head 200, and at the same time rubs against the polishing pad to realize wafer polishing. The linear drive mechanism drives the two polishing heads 200 to move linearly through the polishing head seat 104 .

Optionally, the moving trajectories of the two polishing heads 200 are symmetrically distributed, and the axis of symmetry is the mid-perpendicular line of the line segment formed by connecting the midpoints of the two polishing heads 200 in the same polishing assembly 100 . Driven by the polishing head 200, the wafer rotates relative to the polishing pad and simultaneously translates, thereby improving the polishing effect. In addition, the polishing head 200 and the linear driving mechanism are both connected with a control device mechanism, and the control mechanism can control the wafers fixed by the two polishing heads 200 to be polished along a symmetrical trajectory, so that the two wafers have higher consistency. The specific structure of the polishing head 200 may refer to the prior art, and one or more bases 101 may be provided in the polishing apparatus. One or two sets of polishing assemblies 100 may be provided on the lower end surface of each base 101 . The linear drive mechanism may specifically be an air cylinder, an oil cylinder, a connecting rod slider or a lead screw, etc., which is not limited herein. For the control mechanism, reference may be made to the controller of the polishing equipment in the prior art, which will not be repeated here.

In this embodiment, the polishing device drives the two polishing heads 200 to translate along a straight line through a linear drive mechanism, and at the same time, the two polishing heads 200 respectively drive a wafer to rotate. The wafer polishing tracks in the two polishing heads 200 are symmetrical, so that the polishing effects of the two wafers are almost the same, thereby improving the consistency of the wafers.

Optionally, the polishing head seat 104 is provided with a linear slide rail 105 , the upper end surface of the polishing head 200 is provided with a chute matching the linear slide rail 105 , and the chute slides along the linear slide rail 105 to realize the connection between the polishing head 200 and the base. 101's removable connection. The two bases 101 move along the linear slide rails 105 driven by the linear drive mechanism, and the movement trajectories of the two bases 101 are symmetrical with respect to the preset vertical line of the linear slide rails 105 . The preset vertical line is usually the center vertical line of the linear slide rail 105 , of course, the user can also select other vertical lines other than the center vertical line as required, which is not limited herein.

Optionally, the driving mechanism includes a lead screw 204 and a driving part. Wherein, both ends of the lead screw 204 are respectively connected with the two polishing head bases 104 , and both ends of the lead screw 204 are provided with spirals, and the spiral directions of the two ends are opposite. The driving part is connected to the middle of the lead screw 204 in a driving manner, and drives the lead screw 204 to rotate. Specifically, the drive part selects a drive motor, and the drive motor and the lead screw 204 are driven by gears or timing belts. When the lead screw 204 rotates, an axial force is applied to the two polishing heads 200 to drive the two polishing heads 200 to move symmetrically. When the polishing head seat 104 is located above the polishing table 201 , the midpoint of the lead screw 204 coincides with the projection of the midpoint of the polishing table 201 in the horizontal direction.

In addition, the lead screw 204 is parallel to the linear slide rail 105 , and the polishing head 200 is driven by the lead screw 204 to move along the linear slide rail 105 . There are two linear slide rails 105 on the polishing head base 104 . The ends of the two linear slide rails 105 are flush and parallel to each other. In a specific embodiment of the present application, the driving part is arranged between the two polishing head bases 104. To facilitate the installation of the driving part, the middle of the two linear guide rails 105 is provided with a vacant gap, and the two polishing head seats 104 are set in the vacated gap. on both sides. Of course, the user can also set one linear slide rail 105 on the base 101 as required, or set two linear guide rails 105 on the lower end surface of the base 101 for each polishing head base 104 , which is not limited here.

Optionally, the polishing table 201 is provided with a liquid supply arm 303, and the liquid supply arm 303 is used for outputting the polishing liquid between the wafer and the polishing pad. As shown in FIG. 4 , there are two liquid supply arms 303 , which are symmetrical with respect to the midpoint of the polishing table 201 . That is to say, during polishing, the two liquid supply arms 303 are symmetrical about the center of the midpoint of the lead screw 204, and the outlets of the two liquid supply arms 303 are respectively directed toward one polishing head 200, and the polishing liquid is directly sprayed between the wafer and the polishing pad. The role of heat dissipation and flushing. In addition, the outlets of the two liquid supply arms 303 may be located on a normal line passing through the midpoint of the lead screw 204 .

Optionally, the polishing table 201 is further provided with two groups of polishing conditioners 301 , and the two groups of polishing conditioners 301 are also symmetrical about the center of the midpoint of the polishing table 201 . The polishing dresser 301 is in the shape of a rod, one end of which is fixedly arranged, and the other end is rotatably connected to the dressing disc 302 through a main shaft, so as to dress the polishing layer on the upper surface of the polishing head 200 along an arc track.

Optionally, the bottom plate 300 is provided with a curved slide rail 102, the base 101 is provided with a slider 103 connected with the curved slide rail 102, and a curved drive mechanism is further provided between the base 101 and the bottom plate 300, and the base 101 is in the curved drive mechanism. It moves along the curved slide rail 102 under the driving force. The curved slide rail 102 is located above the polishing table 201 , the base 101 moves the polishing head 200 above the polishing table 201 , and the polishing head 200 cooperates with the polishing table 201 to perform polishing operations. The quantity of the base 101 and the polishing table 201 can be set according to the needs of the user. For example, the polishing apparatus can be provided with one base 101, which cooperates with one or more polishing tables 201 to perform the polishing operation. The polishing device can also be provided with more than two bases 101 , each base 101 corresponds to one polishing table 201 , and the wafers fixed on the base 101 are polished on the corresponding polishing table 201 . The polishing device can also be provided with more than two bases 101, and the polishing table 201 can be divided into multiple groups according to different polishing precisions. All polishing tables 201 required to complete the polishing of a wafer are one group, and the polishing device can be provided with one or more groups. For the polishing table 201 , the number of groups of the polishing table 201 is usually not more than the number of the bases 101 .

Optionally, a wafer stage 304 can be further arranged under the curved slide rail 102. When the wafer is polished, the curved drive mechanism drives the base 101 to move above the wafer stage 304, and the polishing head 200 places the wafer on the wafer stage. 304 on. There are usually two slide tables 304, and the distribution method is the same as that of the polishing heads 200. When the susceptor 101 moves above the slide table 304, the two polishing heads 200 are just aligned with the two slide tables 304, so the slide table 304 should be Located in the projection of the curved rail 102 . Of course, the wafer carrier 304 may not be provided under the user's curved slide rail 102 , and the wafer may be moved onto the carrier table 304 by a mechanism such as a robot arm.

Optionally, the number of curved slide rails 102 may be two, the two curved slide rails 102 are two concentric arcs or two concentric circles, and two sliders 103 are respectively provided on the inside and outside of the base 101 for They are matched with the two curved slide rails 102 respectively. The two curved sliding rails 102 can make the force on the inner and outer sides of the base 101 more uniform, and the user can also use one curved sliding rail 102 as required, which is not limited herein.

Optionally, the curved drive mechanism includes a curved magnetic track 202 and a curved direct drive motor 203 . The curved magnetic rail 202 is arranged on the base plate 300 and is concentric with the curved sliding rail 102 , and the curved direct drive motor 203 is arranged in the base 101 . The curved direct drive motor 203 cooperates with the curved magnetic rail 202 to generate power, so that the base 101 can move along the curved sliding rail 102 .

In a specific embodiment of the present application, as shown in FIG. 4 , the curved slide rail 102 is semicircular, a base 101 is provided in the curved slide rail 102 , and one end of the curved slide rail 102 is located above the slide stage 304 , The other end is above the polishing table 201 . During the polishing process, the susceptor 101 first moves to the top of the polishing table 201 to polish the wafer. As shown in FIG. 4 , the position of the susceptor 101 above the polishing table 201 is the first station. After polishing, the susceptor 101 is moved to the top of the stage 304, the wafer is placed on the stage 304 and a new wafer is taken. As shown in FIG. 5, the position of the susceptor 101 above the stage 304 is the first Second station. During the movement of the base 101 from the first station to the second station, the liquid supply arm 303 and the dresser 301 are rotated and moved out of the top of the polishing table 201 to avoid the curved movement of the polishing device. Of course, the user can also adopt other distribution methods of the base 101 and the polishing table 201 , for example, two polishing tables 201 can be arranged under the curved slide rail 102 , and the polishing precision of the two is different. The susceptor 101 moves between the two polishing tables 201 , and the polished wafer is moved to the wafer stage 304 by the robot arm.

In another specific embodiment of the present application, the curved slide rail 102 is annular, and at least two bases 101 are provided in the curved slide rail 102 . In the specific embodiment shown in FIG. 6 , three polishing tables 201A, 201B, 201C and two wafer stages 304 are provided below the curved slide rail 102 , and the two wafer stages 304 are used as a group with the three polishing stages 201A, 201B, 201C Evenly distributed along the circumferential direction, the distribution position is roughly square. Correspondingly, each of the three polishing tables 201A, 201B, and 201C is provided with one set of dressers 301A, 301B, and 301C and one liquid supply arm 303A, 303B, and 303C. The curved slide rail 102 is provided with four bases 101 , and the four bases 101 correspond to the three polishing tables 201A, 201B, 201C and a set of slide tables 304 respectively. Each base 101 is provided with a set of polishing assemblies 100A, 100B, 100C, 100D, all bases 101 rotate clockwise or counterclockwise along the curved slide rail 102, and the polishing pads on the three polishing tables 201A, 201B, 201C rotate along the base The accuracy of the rotation direction of the seat 101 is gradually improved. Therefore, finer grinding is performed after the susceptor 101 is transferred to the polishing station, and finally the polished wafer is moved to the two wafer stages 304 . During the polishing process, the three susceptors 101 perform wafer polishing on the three polishing tables 201A, 201B, and 201C respectively, and the other susceptor 101 moves the polished wafer to the wafer stage 304 and acquires a new wafer. round. Of course, the user can also set the number of polishing tables 201 , slide tables 304 and susceptors 101 as required, for example, a combination of multiple polishing tables 201 such as 2, 4, 6, etc., 2, 4, 6, etc. Various combinations of wafer stages 304 can meet the requirements of different yields and process flows, which are not limited herein.

The polishing apparatus of this specific embodiment is provided with a plurality of polishing tables 201 and a base 101, and the polishing process is divided into a plurality of steps. Several polishing steps are performed at the same time, which improves polishing efficiency, thereby increasing wafer yield.

It should be noted that, in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such existence between these entities. The actual relationship or sequence.

The polishing device provided by the present invention has been described in detail above. The principles and implementations of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the scope of the patent application of the present invention.

100, 100A, 100B, 100C, 100D: Polished Components 101: Pedestal 102: Curved rails 103: Slider 104: Polished head seat 105: Linear slide 200: Polishing head 201, 201A, 201B, 201C: Polishing table 202: Curved Magnetic Track 203: Curved direct drive motor 204: Screw 300: Bottom plate 301, 301A, 301B, 301C: Dresser 302: Dressing Disc 303, 303A, 303B, 303C: Liquid supply arm 304: slide table

FIG. 1 is a schematic structural diagram of the polishing apparatus provided by the present invention. FIG. 2 is a side view of the polishing apparatus of FIG. 1 . FIG. 3 is a schematic structural diagram of the cooperation between the curved slide rail and the curved driving mechanism. FIG. 4 is a schematic structural diagram of a polishing apparatus in a first station according to a specific embodiment. FIG. 5 is a schematic structural diagram of a polishing apparatus in a second station according to a specific embodiment. FIG. 6 is a schematic structural diagram of a polishing apparatus according to another specific embodiment.

100: Polished Components

101: Pedestal

102: Curved rails

103: Slider

104: Polished head seat

105: Linear slide

200: Polishing head

Claims (10)

A polishing device includes a base, the base is provided with two polishing head seats, the polishing head seats are provided with a polishing head for fixing a wafer and a linear drive mechanism for driving the polishing head to move linearly, so The polishing device further includes a bottom plate, the bottom plate is provided with a curved slide rail, and the base is provided with a slider connected with the curved slide rail. The polishing device according to claim 1, wherein the base is provided with a linear slide rail for restricting the moving path of the polishing head base, and the linear drive mechanism drives the polishing head base to move linearly along the linear slide rail , each of the polishing head seats is provided with one polishing head, the movement trajectories of the two polishing head seats are symmetrically distributed, and the axis of symmetry is the mid-perpendicular line of the line segment formed by the midpoints of the two polishing heads. The polishing device according to any one of claims 1 or 2, wherein the linear drive mechanism comprises a lead screw connected to the polishing head and a driving part for driving the lead screw to rotate. The polishing device according to claim 2, wherein the number of the linear slide rails corresponding to the single polishing head seat is two, and the two linear guide rails corresponding to the same polishing head seat are arranged in parallel. The polishing device according to claim 3, wherein a curved drive mechanism for driving the base to move on the curved slide rail is further provided between the base and the bottom plate. The polishing apparatus according to claim 5, further comprising a polishing table under the base, the polishing table is provided with a liquid supply arm for outputting polishing liquid between the polishing head and the polishing table, The arrangement position of the liquid supply arm is center-symmetrical about the center point of the polishing table. The polishing apparatus of claim 5, wherein the curved drive mechanism comprises a curved magnetic rail disposed on the base plate and concentric with the curved sliding rail, and a curved magnetic rail disposed in the base and concentric with the curved magnetic rail Rail-matched curve direct drive motor. The polishing device according to claim 4, wherein the curved slide rail is in the shape of a circular arc or a ring shape, and at least one polishing table and a wafer stage for carrying the finished wafer are arranged below the curved slide rail, so Both the polishing table and the slide table are located within the range covered by the projection of the curved slide rail on the horizontal plane. The polishing device according to claim 4, wherein the curved sliding rail is in the shape of a circular arc or a ring shape, only at least two polishing tables are arranged below the curved sliding rail, and all the polishing tables are located on the curved sliding rail Within the range covered by the projection of the horizontal plane, the slide table is located outside the range covered by the projection of the curved slide rail on the horizontal plane. The polishing apparatus of claim 4, wherein the curved slide rail is connected with at least two of the bases.

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