Polishing performance evaluation method, device and polishing system for improving polishing performance

Abstract

The present application relates to a polishing performance evaluation method, device and a polishing system for improving polishing performance, the polishing performance evaluation method comprising obtaining the track length of all abrasive grains of a polishing disc; based on the track length of all abrasive grains, calculating the track average and variance; based on the track average and variance, calculating the track distribution uniformity. The advantages are that the combination of the rotational motion of the polishing disc unit and the linear motion of the polishing pad unit can improve the uniformity of wafer polishing, shorten the polishing time and improve the polishing efficiency; the combination of the rotational motion of the polishing disc unit and the linear motion of the polishing pad unit can avoid uneven wear of the polishing pad unit, improve the service life of the polishing pad unit and reduce the cost.

Description

Technical Field

[0001] This invention relates to the field of wafer fabrication technology, and to a polishing performance evaluation method, a polishing performance evaluation device, a polishing system for improving polishing performance, a computer device, and a computer-readable storage medium. Background Technology

[0002] In the semiconductor manufacturing field, wafer polishing (CMP) is one of the core processes that determines chip performance and yield. As chip manufacturing processes evolve towards advanced nodes below 7nm, the requirements for wafer surface quality have reached "sub-nanometer" precision. For example, the surface roughness of critical layers in logic chips needs to be controlled within Ra ≤ 0.1nm, and the flatness error needs to be ≤ 0.5μm / 200mm. Any surface defects (such as scratches, localized over-polishing / under-polishing, and residual impurities) will directly lead to subsequent photolithography alignment deviations, circuit short circuits, or leakage, ultimately causing chip failure. The core influencing factor on wafer polishing quality lies in the uniformity of the abrasive grain movement trajectory on the wafer surface. Only when the abrasive grains cover the entire wafer surface with a consistent frequency and pressure can uniform material removal be achieved, ensuring surface precision. Currently, over 90% of semiconductor wafer polishing in the industry still relies on "traditional rotary polishing equipment," whose core working principle is based on "planetary motion": the polishing pad at the bottom of the equipment rotates at a constant speed around its own axis, while the "pressure head" carrying the wafer drives the wafer to simultaneously complete two movements: rotation around its own axis and revolution around the center of the polishing pad. The abrasive grains (usually suspended in the polishing slurry) combine with the rotation of the polishing pad and the movement of the wafer to form a continuous motion trajectory on the wafer surface, achieving material removal through the synergistic effect of mechanical grinding and chemical etching. This structure has long dominated the market due to its mature principle and ease of operation. However, under the high-precision polishing requirements of advanced process wafers, its inherent defects have gradually become apparent, becoming a key bottleneck restricting surface quality and production efficiency. Specifically, this manifests in the following aspects: First, the core defect of traditional rotary polishing equipment is poor trajectory uniformity, leading to an imbalance in the precision of the wafer surface. The planetary motion mode of traditional equipment determines that the abrasive grain trajectory is mainly in the form of "concentric circles" or "spirals". This trajectory shape has the natural characteristic of "dense in the center and sparse at the edges", which directly causes uneven material removal on the wafer surface. Specifically, it manifests as: (i) "overpolishing" in the central area of ​​the wafer, resulting in excessive material removal and surface damage. In the central region corresponding to the center of the polishing pad on the wafer surface, the rotational linear velocity of the polishing pad, the wafer's rotational linear velocity, and its revolution linear velocity are all superimposed, resulting in a "high-frequency overlap" characteristic in the movement trajectory of the abrasive particles. This high overlap means that the number of polishing passes and the pressure per unit area in this region are significantly higher, leading to "over-polishing." The amount of silicon material removed in the central region is 10%-20% higher than the design value, causing local thickness deviations in the wafer, damaging flatness, and affecting the focal plane consistency of the lithography machine in subsequent photolithography processes. High-frequency polishing exacerbates lattice distortion on the wafer surface, generating subsurface defects. Although these defects are invisible to the naked eye, they reduce the chip's electrical performance (such as increasing leakage current and reducing carrier mobility). The abrasive particles in the central region fail rapidly due to high-frequency friction, requiring continuous replenishment of fresh polishing slurry to maintain the polishing effect, resulting in a slurry consumption that is 15%-25% higher than the theoretical value. (ii) Under-polishing of the wafer edge area leaves residual defects that affect chip yield. In contrast to the central region, the wafer edge (typically a ring-shaped area 10-20mm from the edge) is located outside the orbital trajectory, resulting in limited coverage of the abrasive particles. Furthermore, the linear velocity at the edge of the polishing pad exhibits a "boundary attenuation effect" (the edge of the polishing pad is prone to slight deformation due to centrifugal force, leading to a decrease in contact pressure with the wafer), significantly reducing the trajectory density in this area. Insufficient abrasive polishing cycles at the edge fail to completely remove micron-level scratches left by previous processes (such as cutting and grinding), resulting in a surface roughness Ra value of 0.3-0.5nm, far exceeding the 0.1nm upper limit. This makes it prone to becoming an "anchor point" for impurity adhesion, causing circuit contamination. Wafer edges are typically designed with chamfers at specific angles. Underpolishing leads to excess material remaining in the chamfered areas, forming "burrs" or "steps." These can cause particle shedding during subsequent wafer handling and packaging, contaminating other wafers. To compensate for underpolishing at the edges, some companies extend the polishing time, but this further exacerbates overpolishing in the central region, creating a dilemma: either accept edge defects or tolerate central damage, making it impossible to achieve overall surface accuracy. Secondly, the trajectory pattern is too simple to adapt to diverse polishing needs. The abrasive trajectory of traditional rotary polishing equipment is determined solely by three parameters: polishing pad speed, wafer rotation speed, and revolution radius. Regardless of changes in wafer material properties (such as hardness and brittleness) or polishing precision requirements, the trajectory remains confined to concentric circles or spirals, lacking flexibility. Specific drawbacks are as follows: (a) Incompatible with wafer materials of different hardness Semiconductor wafer materials have expanded from traditional single-crystal silicon to wide-bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN). Single-crystal silicon has relatively low hardness (Mohs hardness 7), requiring avoidance of surface damage caused by high-frequency grinding; while silicon carbide has extremely high hardness (Mohs hardness 9.5, second only to diamond), requiring higher density tracks and greater grinding pressure for effective removal. However, the single track of traditional equipment cannot meet both requirements. If the track is set according to the needs of single-crystal silicon (low density), the silicon carbide wafer will be under-polished due to insufficient grinding, requiring multiple reworks and extending polishing time by more than 50%. If the track is set according to the needs of silicon carbide (high density), the single-crystal silicon wafer will develop surface microcracks due to over-grinding, reducing yield by 15%-20%. (ii) Unable to meet differentiated accuracy requirements Different types of chips have significantly different requirements for wafer surface precision. For example, memory chips require strict control over flatness (to avoid alignment deviations during multi-layer stacking), while logic chips require strict control over surface roughness (to ensure circuit linewidth accuracy). The fixed trajectories of traditional equipment cannot be optimized for these specific needs. For flatness requirements, the trajectory needs to uniformly cover the entire surface to achieve "equal thickness removal," but the center-edge differences of traditional trajectories cannot meet this requirement. For roughness requirements, the trajectory needs to be "intersecting" to eliminate unidirectional scratches, but traditional concentric circle / spiral trajectories easily form directional scratches, requiring an additional "fine polishing" process, which increases polishing time by 30% and significantly reduces efficiency. Third, derivative defects: long polishing time, low efficiency, and short polishing material lifespan. Trajectory defects in traditional equipment can also trigger a series of derivative problems, further increasing production costs and reducing production efficiency: (i) Long polishing time and limited production capacity To compensate for the contradiction between "over-polishing" and "under-polishing", companies need to adopt a "multi-stage polishing" strategy (such as first rough polishing to remove most of the material, then fine polishing to adjust the precision, and finally trimming the edges). This increases the total polishing time of a single wafer, reduces the number of wafers that a single machine can process per day, and the production capacity can only meet 50%-60% of the design value, which cannot meet the "mass production" requirements of the semiconductor industry. (ii) Polishing materials have short lifespans and high consumable costs. The lifespan of polishing pads (usually made of polyurethane) depends on "uniform wear." However, traditional trajectories cause the central area of ​​the polishing pad to wear out rapidly due to high-frequency grinding, while the edge areas wear out slowly due to insufficient grinding. When the wear in the central area exceeds the limit, even if the edges are still usable, the entire polishing pad needs to be replaced, resulting in a significant reduction in the lifespan of the polishing pad and an increase in consumable costs by 40%-50%. At the same time, due to the excessive consumption in the central area, the amount of polishing slurry used per wafer is 20%-30% higher than the theoretical value, further increasing costs. Fourth, industry demand and technological bottlenecks As semiconductor manufacturing processes advance towards 3nm and 2nm nodes, the requirements for wafer surface precision will further increase. The defects of traditional rotary polishing equipment, namely "poor trajectory uniformity and monotonous shape," have become insurmountable technical bottlenecks. Currently, although the industry has attempted to improve these issues by optimizing rotation speed parameters and adjusting polishing slurry formulations, none of these methods have addressed the core problem of "trajectory shape optimization," and thus cannot fundamentally solve problems such as over-polishing, under-polishing, and low efficiency.

[0003] Therefore, developing a wafer polishing technology that can achieve "uniform trajectory coverage across the entire surface" and "adapt to diverse process requirements" has become a key area that urgently needs to be addressed in the semiconductor manufacturing field. It is of great significance for improving chip yield, reducing production costs, and promoting the implementation of advanced processes.

[0004] In summary, no effective solutions have yet been proposed to address the existing problems of poor polishing uniformity, long polishing time, low polishing efficiency, and short polishing material life. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a polishing performance evaluation method, evaluation device, polishing system for improving polishing trajectory uniformity, computer equipment, and computer-readable storage medium, in order to solve problems such as poor polishing uniformity, long polishing time, low polishing efficiency, and short polishing material life in related technologies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, a method for evaluating polishing performance is provided, including: Obtain the trajectory length of all abrasive grains on the polishing pad; Based on the trajectory lengths of all abrasive grains, the average trajectory value and variance are calculated. The uniformity of trajectory distribution is calculated based on the trajectory mean and variance. The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. For variance; The formula for calculating the average trajectory value is as follows: The formula for calculating variance is as follows: .

[0007] In some embodiments, the trajectory length of the abrasive grains is calculated as follows: Obtain the rotational speed and relative movement speed of the polishing pad, as well as the distance and initial angle of the abrasive grains relative to the center of the polishing pad; Based on the rotational speed and relative movement speed of the polishing pad, the distance and initial angle of the abrasive grain relative to the center of the polishing pad, the first motion trajectory equation of the abrasive grain is constructed. The length of the first trajectory of the abrasive grain is calculated based on the first motion trajectory equation. The formula for calculating the first motion trajectory equation of the abrasive grains is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. denoted as the relative moving speed of the polishing pad, 'a' as the maximum single moving distance of the polishing pad, and 'p' as the initial phase. The formula for calculating the length of the first trajectory of the abrasive grain is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0008] In some embodiments, the method for calculating the trajectory length of the abrasive grains further includes: Based on the coordinate system of the polishing pad and the coordinate system of the wafer, the second motion trajectory equation of the abrasive grains is constructed. The length of the second trajectory of the abrasive grain is calculated based on the second motion trajectory equation. The formula for calculating the second motion trajectory equation of the abrasive particles is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. The rotational speed of the wafer. denoted as , where is the relative moving speed of the polishing pad, e is the X-axis distance between the center point of the wafer and the center point of the polishing pad, a is the maximum single moving distance of the polishing pad, and p is the initial phase. The formula for calculating the second trajectory length of the abrasive grains is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0009] In some embodiments, the relative moving speed of the polishing pads is calculated as follows: Obtain the first length, second length, and rotation angle of the reciprocating motion mechanism; Based on the first length, the second length, and the rotation angle, the displacement equation of the polishing pad is constructed; The relative moving speed of the polishing disk is calculated based on the displacement equation. The formula for calculating the displacement equation is as follows: Where s is the displacement of the polishing pad, r is the first length, l is the second length, and θ is the rotation angle; The formula for calculating relative speed is as follows: Where t is time.

[0010] In some of these embodiments, it also includes: The polishing disc is divided into multiple concentric rings; Obtain the trajectory density of all concentric rings; Based on the trajectory density of all concentric rings, the mean and standard deviation of the trajectory density are calculated, where the standard deviation is the sample standard deviation; The wear uniformity coefficient of the polishing pad is calculated based on the average value and standard deviation of the trajectory density. The formula for calculating the wear uniformity coefficient of the polishing pad is as follows: Among them, VCSD W The wear uniformity coefficient of the polishing pad. The average trajectory density. Standard deviation; The formula for calculating the average trajectory density is as follows: The formula for calculating the standard deviation is as follows: .

[0011] In some of these embodiments, the trajectory density is calculated using the following formula: in, The length of the trajectory within the concentric circular rings. Let be the area of ​​the concentric rings.

[0012] In a second aspect, a polishing performance evaluation apparatus is provided for performing the polishing performance evaluation method of the first aspect, including: The first acquisition module is used to acquire the trajectory lengths of all abrasive grains on the polishing disc; The first calculation module is used to calculate the average value and variance of the trajectory based on the trajectory length of all abrasive grains; The second calculation module is used to calculate the uniformity of trajectory distribution based on the trajectory mean and variance. The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. For variance; The formula for calculating the average trajectory value is as follows: The formula for calculating variance is as follows: .

[0013] Thirdly, a polishing system for improving polishing performance is provided, applicable to the polishing performance evaluation method of the first aspect, including: Vertical motion unit; A polishing disc unit, connected to the vertical motion unit, is used to reciprocate in the vertical direction under the action of the vertical motion unit, carry at least one wafer, and drive the wafer to rotate in the horizontal direction; A crank-connecting rod motion unit, wherein the crank-connecting rod motion unit is disposed on one side of the vertical motion unit; A polishing pad unit is connected to the crank-connecting rod motion unit and located below the polishing disk unit. It is used to reciprocate in the horizontal direction under the action of the crank-connecting rod motion unit to polish the wafer located on the polishing disk unit. The control unit is communicatively connected to the vertical motion unit, the polishing disc unit, and the crank-connecting rod motion unit.

[0014] Fourthly, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the polishing performance evaluation method as described in the first aspect.

[0015] Fifthly, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the polishing performance evaluation method as described in the first aspect.

[0016] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: 1) By combining the rotational motion of the polishing disc unit with the linear motion of the polishing pad unit, the uniformity of wafer polishing can be improved, the polishing time can be shortened, and the polishing efficiency can be increased. 2) By combining the rotational motion of the polishing disc unit with the linear motion of the polishing pad unit, uneven wear of the polishing pad unit can be avoided, the service life of the polishing pad unit can be improved, and costs can be reduced. Attached Figure Description

[0017] Figure 1A This is a schematic diagram of a polishing system according to an embodiment of the present invention; Figure 1B This is a cross-sectional view of a polishing system according to an embodiment of the present invention; Figure 2 This is a flowchart (I) of a polishing performance evaluation method according to an embodiment of the present invention. Figure 3 This is a schematic diagram of a coordinate system according to a specific embodiment of the present invention; Figure 4 This is a schematic diagram of mesh division and trajectory length calculation on a wafer according to a specific embodiment of the present invention; Figure 5 This is a schematic diagram of a wear trajectory according to a specific embodiment of the present invention; Figure 6 , Figure 7 These are, respectively, a 2D distribution map of trajectory length and a 3D distribution map of trajectory length in existing technologies; Figure 8 , Figure 9 These are, respectively, a 2D distribution map of trajectory length and a 3D distribution map of trajectory length according to embodiments of the present invention; Figure 10 This is a normalized trajectory density radial distribution diagram comparing the present invention with existing technologies; Figure 11The trajectory length 2D distribution map of this invention is unoptimized. Figure 12 The trajectory length 2D distribution map (optimized) of this invention is used. Figure 13 This is a normalized trajectory density radial distribution map comparing the present invention before and after optimization with existing technologies.

[0018] The reference numerals in the attached figures are as follows: 100. Polishing system; 110. Vertical motion unit; 111. First drive element; 112. First base element; 120. Polishing disc unit; 121. Second drive element; 122. Clamping element; 130. Crank-connecting rod motion unit; 31. Third drive element; 132. Rotating disc element; 133. Connecting rod element; 134. Second base element; 140. Polishing pad unit; 141. Polishing pad element; 142. First sliding element; 150. Frame unit; 151. Frame element; 152. Second sliding element. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0022] Example 1 This embodiment relates to a polishing system for improving polishing performance according to the present invention.

[0023] An illustrative embodiment of the present invention, such as Figures 1A-1BAs shown, a polishing system 100 for improving polishing performance includes a vertical motion unit 110, a polishing disc unit 120, a crank-connecting rod motion unit 130, a polishing pad unit 140, and a control unit. The polishing disc unit 120 is connected to the vertical motion unit 110 and is used to reciprocate vertically under the action of the vertical motion unit 110, carry at least one wafer, and drive the wafer to rotate horizontally. The crank-connecting rod motion unit 130 is disposed on one side of the vertical motion unit 110. The polishing pad unit 140 is connected to the crank-connecting rod motion unit 130 and is located below the polishing disc unit 120, used to reciprocate horizontally under the action of the crank-connecting rod motion unit 130 to polish the wafer located on the polishing disc unit 120. The control unit is communicatively connected to the vertical motion unit 110, the polishing disc unit 120, and the crank-connecting rod motion unit 130.

[0024] It should be noted that the control unit includes, but is not limited to, microcontrollers, PLCs, and other mechanisms, which are common technical means in this field and will not be elaborated upon here.

[0025] It should be noted that the term "connection" as used in this invention includes mechanical connections, communication connections, etc. Mechanical connections include, but are not limited to, fixed connections (such as welding, integral molding), detachable connections (such as bolted connections, plug-in connections), etc., while communication connections include, but are not limited to, wired connections, wireless connections, etc. The above-mentioned connections are all conventional technical means in this field and will not be elaborated further here.

[0026] The working principle of this invention is as follows: Place the wafer in polishing disk unit 120; The vertical motion unit 110 operates, driving the polishing disk unit 120 to move from the initial position to the polishing position, so that the wafer contacts the polishing pad unit 140. The polishing disc unit 120 and the crank-connecting rod motion unit 130 work simultaneously, and the polishing pad unit 140 performs the polishing process on the wafer. After the polishing process is completed, the polishing disc unit 120 and the crank connecting rod motion unit 130 stop simultaneously, and the vertical motion unit 110 works to move the polishing disc unit 120 from the polishing position to the initial position. Then the wafer is separated from the polishing disc unit 120.

[0027] In this invention, the polishing trajectory of the wafer is a combination of the rotational motion of the polishing disk unit 120 and the linear motion of the polishing pad unit 140. This can be equivalent to the polishing disk unit 120 simultaneously performing rotational motion (with the Z-axis as its axis of rotation) and linear motion (reciprocating motion along the X-axis) if the polishing pad unit 140 is relatively stationary; or equivalently, the polishing pad unit 140 simultaneously performing rotational motion (with the Z-axis as its axis of rotation) and linear motion (reciprocating motion along the X-axis) if the polishing disk unit 120 is relatively stationary. Compared with existing methods that only perform rotational polishing, this polishing method results in more uniform polishing, a longer polishing pad life, significantly improved polishing efficiency, and reduced polishing costs.

[0028] Furthermore, there are multiple vertical motion units 110 and polishing pad units 120, meaning there is a one-to-one correspondence between the polishing pad units 120 and the vertical motion units 110. These multiple vertical motion units 110 are spaced apart along the extending direction of the polishing pad unit 140. Using this design, the same polishing pad unit 140 can be used to polish wafers from multiple polishing pad units 120 simultaneously.

[0029] Furthermore, the polishing disk unit 120 simultaneously carries multiple smaller wafers. The multiple wafers are arranged around the polishing disk unit 120. Using this design, multiple wafers can be polished simultaneously using the same polishing disk unit 120.

[0030] In this invention, the vertical motion unit 110 is a module capable of linear motion, including but not limited to electric modules and pneumatic modules. In this invention, an electric module is used as an example for illustration.

[0031] In this invention, the vertical motion unit 110 includes a first driving element 111, a first transmission element, a second transmission element, and a first mounting element. The first driving element 111 is disposed on the side of the polishing disc unit 120 and is communicatively connected to the control unit; the first transmission element is connected to the first driving element and is used to rotate under the action of the first driving element 111; the second transmission element is movably connected to the first transmission element and is used to reciprocate vertically under the action of the first transmission element; the first mounting element is disposed on the side of the second transmission element and is connected to the polishing disc unit 120, and is used to drive the polishing disc unit 120 to reciprocate vertically under the action of the second transmission element.

[0032] It should be noted that the first driving element 111 includes, but is not limited to, a servo motor, a geared motor, etc.

[0033] It should be noted that the first transmission element is a lead screw, and the second transmission element is a slider. The second transmission element is threadedly connected to the first transmission element.

[0034] It should be noted that the first mounting element includes, but is not limited to, mounting base, mounting plate, fixing plate, etc.

[0035] Furthermore, the vertical motion unit 110 also includes at least one first auxiliary motion element and at least one second auxiliary motion element. The first auxiliary motion element is disposed on the side of the first transmission element; the second auxiliary motion element is disposed on the side of the second transmission element and is slidably connected to the first auxiliary motion element, for preventing the second transmission element from rotating and assisting the second transmission element in moving along the first transmission element.

[0036] It should be noted that there can be several first auxiliary motion elements. Several first auxiliary motion elements are symmetrically arranged on both sides of the first transmission element.

[0037] It should be noted that there can be several second auxiliary motion elements. Several second auxiliary motion elements are symmetrically arranged on both sides of the second transmission element, and correspond one-to-one with several first auxiliary motion elements.

[0038] It should be noted that the first auxiliary motion element includes, but is not limited to, guide rods, sliding rods, etc., and the second auxiliary motion element includes, but is not limited to, guide grooves, guide holes, sliding grooves, sliding holes, etc.

[0039] Furthermore, the vertical motion unit 110 also includes a first base element 112. The first base element 112 is connected to the first drive element 111 and is used to support the first drive element 111.

[0040] It should be noted that the first base element 112 includes, but is not limited to, support frame, mounting frame, etc.

[0041] In this invention, the polishing disc unit 120 includes a second driving element 121 and a clamping element 122. The second driving element 121 is mounted on the vertical motion unit 110 and communicatively connected to the control unit, and is used for reciprocating motion in the vertical direction under the action of the vertical motion unit 110. The clamping element 122 is disposed at the bottom end of the second driving element 121 and is used to support at least one wafer and to drive the wafer to rotate in the horizontal direction under the action of the second driving element 121.

[0042] Specifically, the second drive element 121 is mounted on the first mounting element.

[0043] It should be noted that the second drive element 121 includes, but is not limited to, a geared motor.

[0044] It should be noted that the clamping element 122 includes, but is not limited to, a clamp with an open bottom structure. It can directly clamp wafers or clamp ceramic disks on which multiple wafers are mounted.

[0045] Furthermore, the polishing disc unit 120 also includes a spindle element. The spindle element is located inside the clamping element 122, the top end of the spindle element is connected to the second drive element 121, and the bottom end of the spindle element abuts against the wafer or ceramic disc.

[0046] In this invention, the crank-connecting rod motion unit 130 includes a third drive element 131, a rotating disk element 132, and a connecting rod element 133. The third drive element 131 is disposed on the side of the vertical motion unit 110 and is communicatively connected to the control unit; the rotating disk element 132 is connected to the third drive element 131 and is used to rotate under the action of the third drive element 131; the first end of the connecting rod element 133 is connected to the rotating disk element 132, and the second end of the connecting rod element 133 is connected to the polishing pad unit 140, used to drive the polishing pad unit 140 to reciprocate horizontally under the action of the rotating disk element 132.

[0047] It should be noted that the third drive element 131 includes, but is not limited to, a geared motor.

[0048] It should be noted that the rotating disk element 132 is horizontally positioned, and its rotation direction is around its center axis, that is, the rotation direction is the same as the rotation direction of the polishing disk unit 120.

[0049] It should be noted that the rotating disk element 132 includes, but is not limited to, a disk.

[0050] It should be noted that the connection position between the first end of the connecting rod element 133 and the rotating disk element 132 is approximately close to the edge of the rotating disk element 132.

[0051] It should be noted that the connecting rod element 133 has a first limit position and a second limit position. When the connecting rod element 133 is in the first limit position, it is basically parallel to the X-axis, and the distance between the polishing pad unit 140 and the rotating disk element 132 is at its maximum. When the connecting rod element 133 is in the second limit position, it is basically parallel to the X-axis, and the distance between the polishing pad unit 140 and the rotating disk element 132 is at its minimum.

[0052] It should be noted that even when the distance between the polishing pad unit 140 and the rotating disk element 132 is at its minimum, there is still a certain gap between the polishing pad unit 140 and the rotating disk element 132, meaning that the two do not contact each other.

[0053] Furthermore, the crank-connecting rod motion unit 130 also includes a second base element 134. The second base element 134 is connected to the third drive element 131 and is used to support the third drive element 131.

[0054] Specifically, the second base element 134 is disposed on the side of the first base element 112.

[0055] It should be noted that the second base element 134 includes, but is not limited to, support frames, mounting frames, etc.

[0056] In this invention, the polishing pad unit 140 includes a polishing pad element 141. The polishing pad element 141 is located below the polishing disk unit 120 and is connected to the crank-connecting rod motion unit 130. It is used to reciprocate in the horizontal direction under the action of the crank-connecting rod motion unit 130 to polish the wafer located in the polishing disk unit 120.

[0057] Specifically, the polishing pad element 141 is located below the clamping element 122 and connected to the second end of the connecting rod element 133, and is used to reciprocate in the horizontal direction under the action of the connecting rod element 133 to polish the wafer located on the clamping element 122.

[0058] It should be noted that the polishing pad element 141 has a rectangular structure.

[0059] Furthermore, the polishing system 100 also includes a frame unit 150. The upper part of the frame unit 150 is provided with a vertical motion unit 110 and a polishing disc unit 120, and the side of the frame unit 150 is provided with a crank connecting rod unit 130, which is slidably connected to the polishing pad unit 140.

[0060] Furthermore, the polishing unit 140 also includes at least one first sliding element 142. The first sliding element 142 is disposed at the lower part of the polishing pad element 141 and is slidably connected to the frame unit 150 to define the movement direction of the polishing pad element 141.

[0061] It should be noted that there can be multiple first sliding elements 142. Multiple first sliding elements 142 are arranged at intervals along the width direction of the polishing pad element 141.

[0062] It should be noted that the length of the first sliding element 142 is approximately the same as the length of the polishing pad element 141.

[0063] It should be noted that the first sliding element 142 includes, but is not limited to, a sliding block.

[0064] In this invention, the frame unit 150 includes a frame element 151 and at least one second sliding element 152. The upper part of the frame element 151 is provided with a vertical motion unit 110 and a polishing disc unit 120, and the side part of the frame element 151 is provided with a crank-connecting rod unit 130. The second sliding element 152 is disposed on the upper part of the frame element 151 and is slidably connected to the polishing pad unit 140.

[0065] Specifically, the upper part of the frame element 151 is provided with a first base element 151 and a clamping element 122, and the side of the frame element 151 is provided with a second base element 134; the second sliding element 152 is slidably engaged with the first sliding element 142.

[0066] It should be noted that rack component 151 includes, but is not limited to, racks.

[0067] It should be noted that there can be multiple second sliding elements 152. Multiple second sliding elements 152 are spaced apart along the width direction of the frame element 151.

[0068] Generally, a number of second sliding elements 152 correspond one-to-one with a number of first sliding elements 151.

[0069] It should be noted that the length of the second sliding element 152 is approximately the same as the length of the frame element 151. The length of the second sliding element 152 is greater than the length of the first sliding element 142.

[0070] It should be noted that the second sliding element 152 includes, but is not limited to, the guide rail.

[0071] The method of using this invention is as follows: Place the wafer in the clamping element 122; The first driving element 111 operates, driving the second driving element 121 to move from the initial position to the polishing position, so that the wafer contacts the polishing pad element 141; The second driving element 121 and the third driving element 131 work simultaneously, and the polishing pad element 141 performs a polishing process on the wafer. After the polishing process is completed, the second driving element 121 and the third driving element 131 stop simultaneously, the first driving element 111 starts working, driving the second driving element 121 to move from the polishing position to the initial position, and then the wafer is separated from the clamping element 122.

[0072] It should be noted that, in this invention, the rotation speed of the second driving element 121, the rotation speed of the third driving element 131, the specifications (radius) of the rotating disk element 132, the distance between the first end of the connecting rod element 133 and the center of the rotating disk element 132, and the specifications (length) of the connecting rod element 133 can be adjusted to meet different polishing requirements and improve polishing uniformity.

[0073] The technical effects of this invention are as follows: 1) By combining the rotational motion of the polishing disc unit with the linear motion of the polishing pad unit, the uniformity of wafer polishing can be improved, the polishing time can be shortened, and the polishing efficiency can be increased. 2) By combining the rotational motion of the polishing disc unit with the linear motion of the polishing pad unit, uneven wear of the polishing pad unit can be avoided, the service life of the polishing pad unit can be improved, and costs can be reduced.

[0074] Example 2 This embodiment relates to the polishing performance evaluation method, computer equipment, and computer-readable storage medium of the present invention.

[0075] An illustrative embodiment of the present invention, such as Figure 2 As shown, a polishing performance evaluation method includes: Step S202: Obtain the trajectory length of all abrasive grains on the polishing pad; Step S204: Based on the trajectory length of all abrasive grains, calculate the average trajectory value and variance; Step S206: Calculate the uniformity of trajectory distribution based on the trajectory mean and variance.

[0076] The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. Let Variance be the variance.

[0077] The formula for calculating the average trajectory value is as follows: .

[0078] The formula for calculating variance is as follows: .

[0079] In step S202, the polishing disk is a general concept, which can be a polishing disk that carries multiple wafers or a single wafer.

[0080] In step S202, the abrasive grain is a virtual concept, and its size is much smaller than that of the polishing disc. If the diameter of the polishing disc is 'a', then the diameter of the abrasive grain is much smaller than 'a', generally less than 1 mm. If the polishing disc is divided into a grid (the grid size is 1 mm * 1 mm), then each grid contains multiple abrasive grains.

[0081] In step S202, the trajectory length of the abrasive grains is the product of the combination of the rotational motion of the polishing disc unit 120 and the linear motion of the polishing pad unit 140. Specifically: Set up two virtual circles of the same size, corresponding vertically, as the first circle and the second circle respectively; Divide the first circle into a grid; The first circle remains stationary, while the second circle rotates and moves in a straight line. After the second circle stops moving for a certain period of time, the trajectory of a single abrasive grain (random position) in the second circle can be mapped onto the first circle. At this time, the first circle presents the trajectory of the abrasive grain. The trajectory is equivalent to a straight line, which is the trajectory length of the abrasive grain.

[0082] Therefore, the trajectory length of all abrasive grains is the same as the trajectory length of all abrasive grains in the second circle in the first circle.

[0083] The trajectory of the abrasive particles is related to the rotation speed of the polishing disc unit and the movement speed of the polishing pad.

[0084] Furthermore, step S202 can also be understood as obtaining the trajectory length of all abrasive grains on the polishing pad. That is, the trajectory length of the abrasive grains of the polishing pad unit 140 on the polishing disk unit 120 during the combined motion of the linear motion of the polishing pad unit 140 and the rotational motion of the polishing disk unit 120.

[0085] In step S204, i refers to the serial number of the abrasive grains, and n refers to the quantity of the abrasive grains.

[0086] Through steps S202 to S206, the uniformity of the polishing of the polishing disk unit can be determined by the uniformity of the trajectory distribution, avoiding local over-polishing or under-polishing, improving wafer polishing efficiency, and increasing yield.

[0087] For the first method of calculating the trajectory length of abrasive grains, the calculation method is as follows: Step S302: Obtain the rotational speed and relative movement speed of the polishing disc, as well as the distance and initial angle of the abrasive grains relative to the center of the polishing disc; Step S304: Based on the rotational speed and relative movement speed of the polishing pad, the distance and initial angle of the abrasive grains relative to the center of the polishing pad, construct the first motion trajectory equation of the abrasive grains; Step S306: Calculate the first trajectory length of the abrasive grains based on the first motion trajectory equation.

[0088] The formula for calculating the first motion trajectory equation of the abrasive grains is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. denoted as , where is the relative moving speed of the polishing pad, 'a' is the maximum single moving distance of the polishing pad, and 'p' is the initial phase.

[0089] The formula for calculating the length of the first trajectory of the abrasive grain is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0090] In step S302, the relative moving speed of the polishing disk is the moving speed of the polishing pad unit 140.

[0091] In step S302, the polishing disk can be a polishing disk that carries multiple wafers or a single wafer.

[0092] In step S304, the first motion trajectory equation is constructed based on the coordinate system of the polishing disk. The coordinate system of the polishing disk is X1O1Y1, with point O1 being the center point of the polishing disk, and its coordinates being (0, 0).

[0093] In step S304, the first motion trajectory equation is an equation constructed based on the first circle.

[0094] In step S306, j is the trajectory number. Generally, a trajectory within one grid of the first circle is calculated as one trajectory. Typically, there is only one trajectory within one grid, meaning there are no two non-touching trajectories.

[0095] By constructing the trajectory equation of the abrasive particles through steps S302 to S306, the trajectory length of the abrasive particles can be obtained, which facilitates the subsequent calculation of the trajectory average value and variance.

[0096] The second method for calculating the trajectory length of abrasive grains is as follows: Step S402: Based on the coordinate system of the polishing pad and the coordinate system of the wafer, construct the second motion trajectory equation of the abrasive particles; Step S404: Calculate the second trajectory length of the abrasive grains based on the second motion trajectory equation.

[0097] The formula for calculating the second motion trajectory equation of the abrasive particles is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. The rotational speed of the wafer. denoted as , where is the relative moving speed of the polishing pad, e is the X-axis distance between the center point of the wafer and the center point of the polishing pad, a is the maximum single movement distance of the polishing pad, and p is the initial phase.

[0098] The formula for calculating the second trajectory length of the abrasive grains is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0099] In step S402, the polishing disk is a polishing disk that carries multiple wafers, and the wafers are arranged around the polishing disk.

[0100] In step S402, the second motion trajectory equation is constructed based on the wafer coordinate system. The wafer coordinate system is X2O2Y2, with point O2 being the center point of the wafer, and its coordinates in X1O1Y1 being (e, 0).

[0101] In step S402, the second motion trajectory equation is an equation constructed based on the first circle.

[0102] In step S404, j is the trajectory number. Generally, a trajectory within one grid of the first circle is calculated as one trajectory. Typically, there is only one trajectory within one grid, meaning there are no two non-touching trajectories.

[0103] By constructing the trajectory equation of the abrasive particles through steps S402 to S404, the trajectory length of the abrasive particles can be obtained, which facilitates the calculation of the mean and variance of the trajectory.

[0104] The method for calculating the relative moving speed of the polishing disc is as follows: Step S502: Obtain the first length, second length, and rotation angle of the reciprocating motion mechanism; Step S504: Based on the first length, the second length, and the rotation angle, construct the displacement equation of the polishing pad; Step S506: Calculate the relative moving speed of the polishing disk based on the displacement equation.

[0105] The formula for calculating the displacement equation is as follows: Where s is the displacement of the polishing pad, r is the first length, l is the second length, and θ is the rotation angle.

[0106] The formula for calculating relative speed is as follows: Where t is time.

[0107] In step S502, the reciprocating motion mechanism is the crank-connecting rod motion unit 130.

[0108] In step S502, the first length is the distance between the first end of the connecting rod element 133 and the center of the rotating disk element 132, and the second length is the length of the connecting rod element 133.

[0109] In step S504, the rotation angle is the rotation angle of the rotating disk element 132.

[0110] In step S506, the relative moving speed of the polishing disk is the moving speed of the polishing pad.

[0111] Through steps S502 to S506, the relative moving speed of the polishing disc can be limited using the relevant parameters of the reciprocating motion mechanism, which facilitates the subsequent calculation of the trajectory length.

[0112] Furthermore, polishing performance evaluation methods also include: Step S602: Divide the polishing pad into multiple concentric rings; Step S604: Obtain the trajectory density of all concentric rings; Step S606: Based on the trajectory density of all concentric rings, calculate the average and standard deviation of the trajectory density, where the standard deviation is the sample standard deviation; Step S608: Calculate the wear uniformity coefficient of the polishing disc based on the average value and standard deviation of the trajectory density.

[0113] The formula for calculating the wear uniformity coefficient of the polishing pad is as follows: Among them, VCSD W The wear uniformity coefficient of the polishing pad. The average trajectory density. The standard deviation is denoted as .

[0114] The formula for calculating the average trajectory density is as follows: .

[0115] The formula for calculating the standard deviation is as follows: .

[0116] In step S602, the spacing between each concentric ring is the same, that is, for each concentric ring, the difference between its outer diameter and inner diameter is a fixed value.

[0117] In step S604, the calculation of the trajectory density of the concentric rings needs to be combined with the trajectory length. Specifically, each concentric ring has multiple grids of the same size. By calculating the trajectory length of each grid and then summing them up, the trajectory length of the entire concentric ring can be obtained.

[0118] In some of these embodiments, the trajectory density is calculated using the following formula: in, The length of the trajectory within the concentric circular rings. Let be the area of ​​the concentric rings.

[0119] Through steps S606 to S608, the wear condition of the polishing pad unit / polishing pad unit can be determined by the wear uniformity coefficient of the polishing pad, thereby improving the service life of the polishing pad unit.

[0120] Furthermore, the polishing performance evaluation method of this application embodiment can be implemented by a computer device. Components of the computer device may include, but are not limited to, a processor and a memory storing computer program instructions.

[0121] In some embodiments, the processor may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0122] In some embodiments, the memory may include a mass storage device for data or instructions. For example, and not limitingly, the memory may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory may include removable or non-removable (or fixed) media. Where appropriate, the memory may be internal or external to a data processing device. In a particular embodiment, the memory is non-volatile memory. In a particular embodiment, the memory includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random-Access Memory (FPMDRAM), Extended Data Out Dynamic Random-Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0123] Memory can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor.

[0124] The processor reads and executes computer program instructions stored in memory to implement any of the polishing performance evaluation methods in the above embodiments.

[0125] In some embodiments, the computer device may further include a communication interface and a bus. The processor, memory, and communication interface are connected via the bus and communicate with each other.

[0126] The communication interface is used to enable communication between the various units, devices, and / or equipment in the embodiments of this application. The communication interface can also enable data communication with other components such as external devices, image / data acquisition devices, databases, external storage, and image / data processing workstations.

[0127] A bus, including hardware, software, or both, couples components of a computer device together. Buses include, but are not limited to, at least one of the following: data bus, address bus, control bus, expansion bus, and local bus. For example, and not as a limitation, a bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, a bus may include one or more buses. Although specific buses are described and illustrated in the embodiments of this application, this application considers any suitable bus or interconnection.

[0128] The computer device can execute the polishing performance evaluation method in the embodiments of this application.

[0129] Furthermore, in conjunction with the polishing performance evaluation methods in the above embodiments, this application embodiment can provide a computer-readable storage medium for implementation. This computer-readable storage medium stores computer program instructions; when executed by a processor, these computer program instructions implement any of the polishing performance evaluation methods in the above embodiments.

[0130] The technical effects of this invention are as follows: Example 3 This embodiment relates to the polishing performance evaluation device of the present invention.

[0131] An illustrative embodiment of the present invention provides a polishing performance evaluation device for performing the polishing performance evaluation method as described in Embodiment 2, comprising a first acquisition module, a first calculation module, and a second calculation module. The first acquisition module acquires the trajectory lengths of all abrasive grains on the polishing pad; the first calculation module calculates the average trajectory length and variance based on the trajectory lengths of all abrasive grains; and the second calculation module calculates the trajectory distribution uniformity based on the average trajectory length and variance.

[0132] The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. Let Variance be the variance.

[0133] The formula for calculating the average trajectory value is as follows: .

[0134] The formula for calculating variance is as follows: .

[0135] Furthermore, the polishing performance evaluation device also includes a second acquisition module, a first construction module, and a third calculation module. The second acquisition module acquires the rotational speed and relative movement speed of the polishing disc, as well as the distance and initial angle of the abrasive grains relative to the center of the polishing disc. The first construction module constructs a first motion trajectory equation for the abrasive grains based on the rotational speed and relative movement speed of the polishing disc, the distance and initial angle of the abrasive grains relative to the center of the polishing disc, and the first motion trajectory equation. The third calculation module calculates the first trajectory length of the abrasive grains based on the first motion trajectory equation.

[0136] The formula for calculating the first motion trajectory equation of the abrasive grains is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. denoted as , where is the relative moving speed of the polishing pad, 'a' is the maximum single moving distance of the polishing pad, and 'p' is the initial phase.

[0137] The formula for calculating the length of the first trajectory of the abrasive grain is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0138] Furthermore, the polishing performance evaluation device also includes a second construction module and a fourth calculation module. The second construction module is used to construct the second motion trajectory equation of the abrasive grains based on the coordinate system of the polishing disk and the coordinate system of the wafer; the fourth calculation module is used to calculate the second trajectory length of the abrasive grains based on the second motion trajectory equation.

[0139] The formula for calculating the second motion trajectory equation of the abrasive particles is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. The rotational speed of the wafer. denoted as , where is the relative moving speed of the polishing pad, e is the X-axis distance between the center point of the wafer and the center point of the polishing pad, a is the maximum single movement distance of the polishing pad, and p is the initial phase.

[0140] The formula for calculating the second trajectory length of the abrasive grains is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

[0141] Furthermore, the polishing performance evaluation device also includes a second acquisition module, a third construction module, and a fifth calculation module. The second acquisition module acquires the first length, second length, and rotation angle of the reciprocating motion mechanism; the third construction module constructs the displacement equation of the polishing pad based on the first length, second length, and rotation angle; and the fifth calculation module calculates the relative moving speed of the polishing disc based on the displacement equation.

[0142] The formula for calculating the displacement equation is as follows: Where s is the displacement of the polishing pad, r is the first length, l is the second length, and θ is the rotation angle.

[0143] The formula for calculating relative speed is as follows: Where t is time.

[0144] Furthermore, the polishing performance evaluation device also includes a division module, a third acquisition module, a sixth calculation module, and a seventh calculation module. The division module divides the polishing disk into multiple concentric rings; the third acquisition module acquires the trajectory density of all concentric rings; the sixth calculation module calculates the average and standard deviation of the trajectory density based on the trajectory density of all concentric rings; and the seventh calculation module calculates the wear uniformity coefficient of the polishing disk based on the average and standard deviation of the trajectory density.

[0145] The formula for calculating the wear uniformity coefficient of the polishing pad is as follows: Among them, VCSD W The wear uniformity coefficient of the polishing pad. The average trajectory density. Let be the standard deviation. Where the standard deviation is the sample standard deviation. The formula for calculating the average trajectory density is as follows: .

[0146] The formula for calculating the standard deviation is as follows: .

[0147] In some of these embodiments, the trajectory density is calculated using the following formula: in, The length of the trajectory within the concentric circular rings. Let be the area of ​​the concentric rings.

[0148] The technical effects of this embodiment are basically the same as those of Embodiment 2, and will not be repeated here.

[0149] Example 4 This embodiment relates to a specific implementation of the present invention.

[0150] A device for improving polishing uniformity includes a module, a first geared motor, a support frame, a polishing pad, a motor mounting plate, a spindle, a workpiece wafer, a fixture, a mounting plate, a second geared motor, a disc, a bracket, a connecting rod, and a slide rail. The second geared motor, the disc, the bracket, and the connecting rod constitute a crank-slider actuation structure.

[0151] The basic process of the device of the present invention is as follows: First, a fixed plate is built, then the module and geared motor one are supported by a support frame, and geared motor two is fixed by a bracket.

[0152] The disc and connecting rod are driven by the second geared motor, and the connecting rod then drives the polishing pad to move in a reciprocating parallel motion.

[0153] Vertically above the crank-slider push structure, the module drives the geared motor to move downwards, and after pressing the workpiece wafer through the main shaft, the horizontal polishing and grinding of the workpiece wafer is completed.

[0154] Then, when the geared motor drives the fixture to rotate the workpiece wafer, the polishing and grinding of the workpiece wafer in the direction of rotation is completed, so that the polishing of the workpiece wafer is more uniform and complete.

[0155] Furthermore, to improve the grinding efficiency of the polishing pad, its length can be increased, and multiple polishing modules can be added in the middle. Each module includes a support frame, a module assembly, a geared motor, a motor mounting plate, a clamp, and a spindle. This increases the grinding capacity and improves the efficiency of the polishing process.

[0156] Regarding the grinding trajectory of the present invention, it is as follows: Figure 3 As shown, coordinate systems X1O1Y1 for the polishing pad and X2O2Y2 for the wafer are constructed respectively. The coordinates of the wafer's center point in X1O1Y1 are as follows: .

[0157] In addition, Figure 3 In this context, R is the radius of the polishing pad, and r is the radius of the wafer. The rotational speed of the polishing disc. The rotational speed of the wafer. The speed at which the crank-slider pusher structure moves.

[0158] Because the polishing disc not only has rotational motion, but also reciprocating translational motion at a constant speed (relative motion). Its reciprocating motion can be regarded as a linear triangular wave oscillation along the X1 axis.

[0159] Let R be the distance from any point P on the polishing disk to point O1. p The initial angle is Then the abrasive point P(R) p , The equation of the trajectory of motion in the X1O1Y1 coordinate system is: .

[0160] Based on the conversion relationship between X1O1Y1 and X2O2Y2, the abrasive particle point P(R) p , The equation of the trajectory of the motion in the X2O2Y2 coordinate system is: .

[0161] The conversion relationship between X1O1Y1 and X2O2Y2 is as follows: (1) (2) (3).

[0162] As can be seen from the above, there are two trajectory equations for abrasive particles: one based on the X1O1Y1 coordinate system and the other based on the X2O2Y2 coordinate system.

[0163] The displacement of the polishing pad is calculated as follows: .

[0164] Where r is the length of the crank (i.e., the distance from the center of the disk to the connection point between the connecting rod and the disk), and l is the length of the connecting rod (i.e., the distance from the connection point between the connecting rod and the disk to the connection point between the connecting rod and the polishing pad). is the crank angle (zero degrees from the initial horizontal position, positive for counterclockwise rotation, which varies with time), and s is the translational displacement of the polishing pad (originating from the slider position at the initial crank position).

[0165] Furthermore, regarding the moving speed of the crank-slider driven structure... The calculation method is as follows: .

[0166] Where t is time.

[0167] The trajectory length of the abrasive grains can be calculated using the above equations, as follows: Sampling is performed at time intervals Δt = 0.001s, let t i The coordinates of the abrasive grains in the workpiece mesh region are ( , After Δt = 0.001s, the coordinates of the abrasive grain in the workpiece mesh region are ( , Then, the approximate length of the abrasive particle's trajectory at this point is: .

[0168] Based on the above formula, the trajectory length within each grid can be represented by L. i If we represent it this way, then the lengths of all trajectories can be expressed as: .

[0169] Therefore, based on the above formula, the average value of all trajectories can be calculated. and variance ,as follows: .

[0170] .

[0171] Therefore, based on the above formula, the uniformity of the trajectory distribution can be calculated as follows: .

[0172] In addition to the uniformity of the trajectory distribution, the wear uniformity coefficient of the polishing disc (grinding disc / polishing pad) can also be calculated using the above formula. Specifically: First, the polishing pad is divided into a grid, consisting of concentric rings of different sizes, such as... Figure 5 As shown.

[0173] Second, construct the surface trajectory equation of the polishing pad (grinding disc / polishing mat) as follows: .

[0174] Third, calculate the trajectory density of each concentric ring. ,as follows: .

[0175] Where n = 1, 2, ..., M. A n Let S be the area of ​​the region of concentric rings. n Let be the length of the trajectory of the concentric circular rings.

[0176] Fourth, calculate the standard deviation of the trajectory density. ,as follows: .

[0177] Fifth, calculate the wear uniformity coefficient of the polishing disc (grinding disc / polishing pad), as follows: Among them, VCSD W The wear uniformity coefficient of the polishing pad. This represents the average trajectory density.

[0178] Example 4 This embodiment involves a comparative verification experiment of the present invention, mainly comparing the trajectory uniformity coefficient.

[0179] The existing technology only uses rotational motion, and the relevant parameters are as follows: Substituting the above parameters into the formula, the trajectory uniformity coefficient is calculated to be 0.378.

[0180] This invention combines rotational and linear motion, and the relevant parameters are as follows: Substituting the above parameters into the formula, the trajectory uniformity coefficient is calculated to be 0.088.

[0181] Reference Figures 6-9 As can be seen from the above parameters, after adopting the present invention, the surface quality of the workpiece is better and the trajectory distribution uniformity coefficient is smaller.

[0182] Example 5 This embodiment involves a comparative verification test of the present invention, mainly comparing the wear uniformity coefficient of the grinding disc.

[0183] The existing technology only uses rotational motion, and the relevant parameters are as follows: Substituting the above parameters into the formula, the wear uniformity coefficient of the grinding disc is calculated to be 0.7293, and the average trajectory density is 109.1 mm / mm. 2 .

[0184] This invention combines rotational and linear motion, and the relevant parameters are as follows: Substituting the above parameters into the formula, the wear uniformity coefficient of the grinding disc is calculated to be 0.6586, and the average trajectory density is 124.1 mm / mm. 2 .

[0185] Reference Figure 10 As can be seen from the above parameters, after adopting the present invention, there is less wear during polishing pad processing, which reduces processing costs, reduces downtime for pad repair, and improves equipment utilization.

[0186] Example 6 This embodiment involves comparative verification experiments of the present invention, mainly comparing parameter optimization.

[0187] The processing parameters for the equipment using the present invention are as follows: The relevant parameters for using this invention without parameter optimization and for using this invention with parameter optimization are as follows: Reference Figures 11-13 As can be seen from the above parameters, after adopting the present invention and optimizing the parameters, the workpiece surface quality is better, the trajectory distribution uniformity coefficient is smaller, the wear of the polishing pad is less during processing, the processing cost is reduced, the number of downtime for maintenance is reduced, and the equipment utilization rate is improved.

[0188] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating polishing performance, characterized in that, include: Obtain the trajectory length of all abrasive grains on the polishing pad; Based on the trajectory lengths of all abrasive grains, the average trajectory value and variance are calculated. The uniformity of trajectory distribution is calculated based on the trajectory mean and variance. The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. For variance; The formula for calculating the average trajectory value is as follows: The formula for calculating variance is as follows: The method for calculating the trajectory length of abrasive particles is as follows: Obtain the rotational speed and relative movement speed of the polishing pad, as well as the distance and initial angle of the abrasive grains relative to the center of the polishing pad; Based on the rotational speed and relative movement speed of the polishing pad, the distance and initial angle of the abrasive grain relative to the center of the polishing pad, the first motion trajectory equation of the abrasive grain is constructed. The length of the first trajectory of the abrasive grain is calculated based on the first motion trajectory equation. The formula for calculating the first motion trajectory equation of the abrasive grains is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. denoted as the relative moving speed of the polishing pad, 'a' as the maximum single moving distance of the polishing pad, and 'p' as the initial phase. The formula for calculating the length of the first trajectory of the abrasive grain is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

2. The polishing performance evaluation method according to claim 1, characterized in that, Methods for calculating the trajectory length of abrasive particles also include: Based on the coordinate system of the polishing pad and the coordinate system of the wafer, the second motion trajectory equation of the abrasive grains is constructed. The length of the second trajectory of the abrasive grain is calculated based on the second motion trajectory equation. The formula for calculating the second motion trajectory equation of the abrasive particles is as follows: in, , These are the x and y coordinates of the abrasive grain, respectively. The distance between the abrasive grains and the center of the polishing pad. The initial angle of the abrasive grains relative to the center of the polishing disk. The rotational speed of the polishing disc. The rotational speed of the wafer. denoted as , where is the relative moving speed of the polishing pad, e is the X-axis distance between the center point of the wafer and the center point of the polishing pad, a is the maximum single moving distance of the polishing pad, and p is the initial phase. The formula for calculating the second trajectory length of the abrasive grains is as follows: in, , Let x and y be the coordinates of the abrasive grain at time t, respectively. , The abrasive grains are respectively in The x and y coordinates at time, and n is the number of individual trajectories of the abrasive grains.

3. The polishing performance evaluation method according to claim 1 or 2, characterized in that, The method for calculating the relative moving speed of the polishing disc is as follows: Obtain the first length, second length, and rotation angle of the reciprocating motion mechanism; Based on the first length, the second length, and the rotation angle, the displacement equation of the polishing pad is constructed; The relative moving speed of the polishing disk is calculated based on the displacement equation. The formula for calculating the displacement equation is as follows: Where s is the displacement of the polishing pad, r is the first length, l is the second length, and θ is the rotation angle.

4. The polishing performance evaluation method according to claim 1, characterized in that, Also includes: The polishing disc is divided into multiple concentric rings; Obtain the trajectory density of all concentric rings; Based on the trajectory density of all concentric rings, the mean and standard deviation of the trajectory density are calculated, where the standard deviation is the sample standard deviation; The wear uniformity coefficient of the polishing pad is calculated based on the average value and standard deviation of the trajectory density. The formula for calculating the wear uniformity coefficient of the polishing pad is as follows: Among them, VCSD W The wear uniformity coefficient of the polishing pad. The average trajectory density. Standard deviation; The formula for calculating the average trajectory density is as follows: The formula for calculating the standard deviation is as follows: 。 5. The polishing performance evaluation method according to claim 4, characterized in that, The formula for calculating trajectory density is as follows: in, The length of the trajectory within the concentric circular rings. Let be the area of ​​the concentric rings.

6. A polishing performance evaluation apparatus, used to perform the polishing performance evaluation method as described in any one of claims 1 to 5, characterized in that, include: The first acquisition module is used to acquire the trajectory lengths of all abrasive grains on the polishing disc; The first calculation module is used to calculate the average value and variance of the trajectory based on the trajectory length of all abrasive grains; The second calculation module is used to calculate the uniformity of trajectory distribution based on the trajectory mean and variance. The formula for calculating the uniformity of trajectory distribution is as follows: Wherein, VCSD represents the uniformity of trajectory distribution. The average value of the trajectory. For variance; The formula for calculating the average trajectory value is as follows: The formula for calculating variance is as follows: 。 7. A polishing system for improving polishing performance, applicable to any polishing performance evaluation method as described in claims 1 to 5, characterized in that, include: Vertical motion unit; A polishing disc unit, connected to the vertical motion unit, is used to reciprocate in the vertical direction under the action of the vertical motion unit, carry at least one wafer, and drive the wafer to rotate in the horizontal direction; A crank-connecting rod motion unit, wherein the crank-connecting rod motion unit is disposed on one side of the vertical motion unit; A polishing pad unit is connected to the crank-connecting rod motion unit and located below the polishing disk unit. It is used to reciprocate in the horizontal direction under the action of the crank-connecting rod motion unit to polish the wafer located on the polishing disk unit. The control unit is communicatively connected to the vertical motion unit, the polishing disc unit, and the crank-connecting rod motion unit.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the polishing performance evaluation method as described in any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the polishing performance evaluation method as described in any one of claims 1 to 5.

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