Ultrathin substrate polishing head and ultrathin substrate polishing device

Abstract

The invention provides an ultrathin substrate polishing head and an ultrathin substrate polishing device.The ultrathin substrate polishing head comprises a polishing head body, a substrate holding part and a substrate holding ring, the substrate holding part and the substrate holding ring are both connected to the bottom of the polishing head body, the substrate holding ring is arranged on the periphery of the substrate holding part in a sleeving mode, an elastic film is arranged on the bottom face of the substrate holding part, and the elastic film is arranged on the bottom face of the substrate holding part. An adsorption hole is formed in the substrate holder in a penetrating manner, a through hole is formed in the elastic film, and the substrate holder is used for adsorbing the substrate to the bottom wall of the elastic film. According to the ultrathin substrate polishing device provided by the invention, the elastic film is arranged below the substrate holder, so that the adsorption force of the air bag on the substrate can be effectively buffered, the problems of non-uniform stress and overlarge local deformation of the substrate are avoided, the deformation quantity of the substrate in the grinding process is effectively controlled, the probability of occurrence of fragments is reduced, and the polishing quality of the ultrathin substrate is improved. The high flatness, uniformity and consistency of the surface of the substrate are improved, and meanwhile the polishing rate of the edge position of the substrate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of substrate polishing, and more specifically, relates to an ultra-thin substrate polishing head and an ultra-thin substrate polishing device. Background Art

[0002] The integrated circuit manufacturing process usually refers to the deposition of conductors, semiconductors, and insulating layers on a specific substrate (such as a silicon-based substrate) in a certain process sequence. In the manufacturing process, CMP (chemical mechanical polishing) equipment is mainly used to perform global flattening on the microscopic rough surface of the substrate after the film deposition process. This flattening method usually requires the substrate to be mounted on the polishing head of the equipment, and the surface of the substrate to be polished is placed against the rotating polishing pad for grinding. First, the grinding head adsorbs the substrate and places it on the grinding pad. The grinding head applies downward pressure to the substrate. At the same time, the grinding liquid is supplied to the grinding pad through the delivery system. The grinding process of the substrate is realized by the same-direction rotation of the grinding head and the grinding pad.

[0003] However, as the diameter of the substrate increases, the processing difficulty of uniformity and consistency of the substrate surface becomes increasingly greater. Ultra-thin substrates refer to substrates smaller than silicon substrates (0.75mm). The deformation of such substrates is too large during the transmission and process polishing, and they are prone to fragmentation. At the same time, the polishing rate of the edge area of ​​the substrate is poor, and the uniformity and consistency are also poor.

[0004] In the prior art, the substrate holder forms a secondary vacuum effect through the hole structure to adsorb the substrate. During the film transfer process, it is very easy for the substrate to be unevenly stressed due to excessive adsorption force, causing excessive local deformation of the substrate and resulting in substrate fragmentation. During the grinding process, the uneven force on the substrate can easily cause a large deformation of the substrate and cause fragmentation. In addition, the edge area of ​​the substrate is subjected to abnormal force during grinding, which can also lead to an uncontrolled edge grinding rate, and even worse, fragmentation. It can also cause damage to the holder and polishing pad on the equipment, increasing the cost of consumables. Summary of the invention

[0005] The object of the present invention is to provide an ultra-thin substrate polishing head and an ultra-thin substrate polishing device, which can effectively control the deformation of the ultra-thin substrate during the polishing process, ensure the stability of the substrate edge grinding speed, and improve the processing quality of the substrate.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide an ultra-thin substrate polishing device, including a polishing head body, a substrate holding member and a substrate holding ring, the substrate holding member and the substrate holding ring are both connected to the bottom of the polishing head body, and the substrate holding ring is sleeved on the outer periphery of the substrate holding member, an elastic membrane is provided on the bottom surface of the substrate holding member, adsorption holes are penetrated through the substrate holding member, the elastic membrane is provided with through holes corresponding to the adsorption holes above and below, and an air bag is provided on the outer lower cover of the substrate holding member and the elastic membrane.

[0007] In a possible implementation, the adsorption holes are arranged in a plurality of circles at intervals along the radial direction of the substrate holder, and each circle of adsorption holes includes a plurality of adsorption holes arranged in a plurality of circles at intervals along the circumferential direction of the substrate holder.

[0008] In some embodiments, the diameter of the adsorption holes is 1-20 mm, and the distance between adjacent edges of two adjacent adsorption holes is 1-20 mm.

[0009] In a possible implementation manner, an adhesive layer is provided on the top surface of the elastic film, and the adhesive layer is used to bond the elastic film and the substrate holder.

[0010] In some embodiments, the thickness of the elastic film gradually increases from the center to the peripheral edge.

[0011] In a possible implementation, in the up-down direction, the substrate retaining ring protrudes downward from the substrate by 1-2 mm.

[0012] In a possible implementation, a lower annular groove is provided on the bottom wall of the substrate holder, and the lower annular groove is provided close to the outer peripheral edge of the substrate holder. The elastic membrane is connected to the inner bottom wall of the lower annular groove and the bottom wall of the substrate holder.

[0013] In a possible implementation, a lower convex ring is provided on the bottom wall of the substrate holder, the lower convex ring is arranged close to the outer peripheral edge of the substrate holder, and the elastic membrane is connected to the lower convex ring and the bottom wall of the substrate holder.

[0014] In a possible implementation, the elastic membrane is a flexible material component, the compressibility of the elastic membrane is 8%-9%, and the density of the elastic membrane is 0.6g / cm³-0.7g / cm³.

[0015] The invention also provides an ultra-thin substrate polishing device, which comprises an ultra-thin substrate polishing head. Compared with the prior art, the solution shown in the embodiment of the present application can effectively buffer the adsorption force of the airbag on the substrate by arranging an elastic film under the substrate holder, thereby avoiding the problems of uneven force on the substrate and excessive local deformation, so that the deformation of the substrate during the grinding process is effectively controlled, the probability of fragmentation is reduced, the flatness, uniformity and consistency of the substrate surface are improved, the polishing rate of the edge of the substrate is improved, the use cost of consumables such as substrate holding rings and polishing pads is reduced, the equipment downtime is reduced, and the processing efficiency of the substrate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 A schematic diagram of a front cross-sectional structure of a first embodiment of an ultra-thin substrate polishing device provided by an embodiment of the present invention; Figure 2 For the embodiment of the present invention Figure 1 The partially enlarged structural diagram of middle Ⅰ; Figure 3 A schematic diagram of a front cross-sectional structure of a second embodiment of an ultra-thin substrate polishing device provided by an embodiment of the present invention; Figure 4 A schematic diagram of a front cross-sectional structure of a third embodiment of an ultra-thin substrate polishing device provided by an embodiment of the present invention; Figure 5 A schematic diagram of a front cross-sectional structure of a fourth embodiment of an ultra-thin substrate polishing device provided by an embodiment of the present invention; Figure 6 For the embodiment of the present invention Figure 5 The schematic diagram of the structure viewed from above with the middle base plate remaining visible.

[0018] Among them, the reference numerals in the figure are: 1. Polishing head body; 2. Substrate holder; 21. Adsorption hole; 22. Lower ring groove; 23. Lower convex ring; 3. Substrate holding ring; 4. Elastic membrane; 41. Through hole; 5. Air bag; 6. Substrate. DETAILED DESCRIPTION In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on another element or indirectly on another element. It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0020] Please also read Figures 1 to 6 The ultra-thin substrate polishing head and the ultra-thin substrate polishing device provided by the present invention are now described. The ultra-thin substrate polishing device comprises a polishing head body 1, a substrate holder 2 and a substrate holder ring 3. The substrate holder 2 and the substrate holder ring 3 are both connected to the bottom of the polishing head body 1, and the substrate holder ring 3 is sleeved on the outer periphery of the substrate holder 2. An elastic film 4 is provided on the bottom surface of the substrate holder 2. Adsorption holes 21 are penetrated on the substrate holder 2. Through holes 41 corresponding to the upper and lower adsorption holes 21 are provided on the elastic film 4. An air bag 5 is provided on the outer lower cover of the substrate holder 2 and the elastic film 4.

[0021] Compared with the prior art, the ultra-thin substrate polishing device provided in the present embodiment can effectively buffer the adsorption force of the airbag 5 on the substrate 6 by arranging an elastic membrane 4 under the substrate retaining member 2, thereby avoiding the problem of uneven force on the substrate 6 and excessive local deformation, so that the deformation amount of the substrate 6 during the grinding process is effectively controlled, the probability of fragmentation is reduced, the flatness, uniformity and consistency of the surface of the substrate 6 are improved, the polishing rate of the edge position of the substrate 6 is improved, the use cost of consumables such as the substrate retaining ring 3 and the polishing pad is reduced, the equipment downtime is reduced, and the processing efficiency of the substrate 6 is improved.

[0022] In this embodiment, an elastic membrane 4 is provided at the bottom of the substrate holder 2 to form a downward elastic force on the substrate 6 during the polishing process of the substrate 6, thereby reducing deformation of the substrate 6 caused by excessive local force and helping to improve the polishing efficiency of the substrate 6.

[0023] The adsorption holes 21 provided on the substrate holder 2 and the through holes 41 on the elastic membrane 4 are arranged one by one, so that the adsorption force can be evenly dispersed, forming an effect of uniform adsorption on the top surface of the substrate 6, avoiding deformation and fragmentation caused by excessive force on the local part of the substrate 6, and helping to improve the processing quality of the substrate 6. Specifically, the aperture of the through hole 41 is slightly smaller than the aperture of the adsorption hole 21, and the difference between the two is between 0.1mm and 1mm.

[0024] There are multiple adsorption holes 21 distributed on the substrate holder 2, which can be distributed in a matrix or in multiple circles, to ensure that the spacing between adjacent adsorption holes 21 is as close as possible, so as to improve the uniformity of the distribution of the adsorption holes 21, and thus achieve uniform distribution of the adsorption force on the substrate 6. The above design optimizes the layout position of the adsorption holes 21 and sets the adsorption holes 21 in multiple circles, so as to reduce the deformation of the substrate 6 and reduce the probability of fragmentation.

[0025] In one possible implementation, see Figure 6 The adsorption holes 21 are arranged in a plurality of circles at intervals along the radial direction of the substrate holder 2 , and each circle of adsorption holes 21 includes a plurality of adsorption holes 21 arranged at intervals along the circumferential direction of the substrate holder 2 .

[0026] In this embodiment, the adsorption holes 21 are arranged in a plurality of circles, and each circle of adsorption holes 21 includes a plurality of adsorption holes 21 evenly distributed in the circumferential direction. The spacing between adjacent inner and outer circles is kept basically the same, so that the arrangement of the adsorption holes 21 has good uniformity and a certain arrangement density is maintained, so that the negative pressure adsorption force on the substrate 6 is relatively uniform.

[0027] The smaller the adsorption torque on the substrate 6 is, the smaller the deformation of the substrate 6 is. In order to reduce the adsorption torque, the aperture size and the specific value of the spacing of the adsorption holes 21 should be controlled. The spacing between the adsorption holes 21 is equal or approximately equal to ensure that the magnitude of the adsorption force at different positions of the substrate 6 is consistent. In addition, the apertures of the multiple adsorption holes 21 are set to be equal, so that the force arm of the above-mentioned adsorption force (corresponding to the radius value of the adsorption hole 21) is kept consistent. When the adsorption force and the adsorption force arm are equal, the adsorption torque is kept equal, which helps to reduce the deformation of the substrate 6.

[0028] In some embodiments, the aperture of the adsorption hole 21 is 1-20 mm, and the spacing between adjacent edges of two adjacent adsorption holes 21 is 1-20 mm. In actual design, the aperture size of the adsorption hole 21 and the size of the hole spacing are designed according to the size of the wafer. The aperture size of the adsorption hole 21 can be in the range of 1 mm-20 mm. For substrates 6 with smaller areas, smaller adsorption holes 21, such as an aperture of 1 mm-5 mm, can be used. For substrates 6 with larger areas, larger adsorption holes 21, such as an aperture of 10 mm-20 mm, can be set. Compared with the prior art, the above design can reduce the adsorption force and the adsorption force arm by reducing the diameter of the adsorption hole 21, thereby significantly reducing the deformation of the substrate 6 and reducing the probability of fragmentation.

[0029] During design, the distance between the closest edge positions of two adjacent adsorption holes 21 can be selected to be close to the aperture of the adsorption holes 21, so as to achieve effective dispersion of the force on the surface of the substrate 6 and reduce deformation and damage of the substrate 6.

[0030] In a possible implementation, an adhesive layer is provided on the top surface of the elastic film 4, and the adhesive layer is used to bond the elastic film 4 to the substrate holder 2. The elastic film 4 is adhered to the bottom of the substrate holder 2 by the adhesive layer, which is convenient for installing the elastic film 4, ensuring the reliability of the connection between the elastic film 4 and the substrate holder 2, and having good assembly convenience, facilitating the inspection and maintenance of the results, improving the operating efficiency, and shortening the downtime of the equipment.

[0031] For some examples, see Figure 3 , the thickness of the elastic film 4 gradually increases from the center to the peripheral edge. The thickness of the elastic film 4 near the peripheral edge is greater than the thickness of the middle position, and the position near the edge of the periphery of the top surface of the substrate 6 can be elastically pressed downward to avoid the situation where the edge of the substrate 6 is not polished properly due to the concentrated force on the middle of the substrate 6, thereby improving the polishing efficiency of the edge of the substrate 6 and ensuring the consistency of the polishing rate.

[0032] In a possible implementation, in the vertical direction, the substrate holding ring 3 protrudes downward from the substrate 6 by 1-2 mm. The thickness difference between the substrate holding ring 3 and the substrate 6 is 1 mm -2 mm. By reducing the height of the basic holding ring, the spatial height inside the substrate holding ring 3 is effectively reduced, which is convenient for reducing the vertical position movement of the substrate 6 during the polishing process, further avoiding the deformation degree of the substrate 6 during the polishing process, improving the consistency of the polishing rate of the edge area, and ensuring the polishing quality of the edge position of the substrate 6.

[0033] In one possible implementation, see Figure 5A lower annular groove 22 is provided on the bottom wall of the substrate holder 2 . The lower annular groove 22 is provided close to the outer peripheral edge of the substrate holder 2 . The elastic membrane 4 is connected to the inner bottom wall of the lower annular groove 22 and the bottom wall of the substrate holder 2 .

[0034] In this embodiment, for a specific type of substrate 6, such as a substrate 6 with a downward bulge in the middle, in order to meet the polishing quality requirements, a lower annular groove 22 close to the outer peripheral edge can be provided on the bottom wall of the substrate holder 2. The concave structure of the lower annular groove 22 is used to match the upward extension trend of the outer peripheral edge of the substrate 6. An elastic membrane 4 is provided at the bottom of the substrate holder 2. When the substrate 6 is pressed down, the elastic membrane 4 matches the structure of the outer peripheral edge of the substrate 6 extending upward, so that the middle and outer peripheral edge positions of the substrate 6 can obtain uniform pressure, which is convenient for improving the overall polishing rate of the edge of the substrate 6.

[0035] As a parallel example, see Figure 4 A lower convex ring 23 is provided on the bottom wall of the substrate holder 2 . The lower convex ring 23 is arranged close to the outer peripheral edge of the substrate holder 2 . The elastic membrane 4 is connected to the lower convex ring 23 and the bottom wall of the substrate holder 2 .

[0036] In this embodiment, for a specific type of substrate 6, such as a substrate 6 with a bulge in the middle, in order to meet the polishing quality requirements, a lower convex ring 23 close to the outer peripheral edge can be provided on the bottom wall of the substrate holder 2. The outer convex structure of the lower convex ring 23 is used to match the downward extension trend of the outer peripheral edge of the substrate 6. An elastic membrane 4 is provided at the bottom of the substrate holder 2. When the substrate 6 is pressed down, the elastic membrane 4 matches the upward convex structure of the middle part of the substrate 6, so that the middle part and the outer peripheral edge of the substrate 6 can obtain uniform pressure, which is convenient for improving the overall polishing rate of the edge of the substrate 6.

[0037] In a possible implementation, the elastic membrane 4 is a flexible material component, the compressibility of the elastic membrane 4 is 8%-9%, and the density of the elastic membrane 4 is 0.6g / cm³-0.7g / cm³. The thickness of the elastic membrane 4 can be selected as needed, including but not limited to 0.6mm-1mm.

[0038] Specifically, the hardness of the elastic membrane 4 is Shore A. Shore A hardness refers to the hardness value measured using a Shore durometer. The Shore durometer presses a blunt needle onto the surface of the elastic membrane 4 through an external force, and indicates the hardness of the rubber according to the depth of the blunt needle's penetration, and is used to measure the hardness of soft rubber. The principle of the Shore hardness test is to drop a specified diamond punch from a fixed height onto the surface of the elastic membrane 4, and the punch bounces up to a certain height. The ratio of the bounce height to the drop height is used to calculate the Shore hardness. In this embodiment, the Shore hardness value of the elastic membrane 4 used is 85-95. The elastic membrane 4 adopts this hardness value, which not only meets its elastic buffering performance, but also ensures the uniformity of the force on the substrate 6, thereby reducing the deformation of the substrate 6 and reducing the probability of fragmentation.

[0039] Based on the same inventive concept, the embodiment of the present application also provides an ultra-thin substrate polishing device, which includes an ultra-thin substrate polishing head. The ultra-thin substrate polishing device can effectively buffer the adsorption force of the airbag 5 on the substrate 6 by arranging an elastic membrane 4 under the substrate holder 2, thereby avoiding the problem of uneven force on the substrate 6 and excessive local deformation, so that the deformation amount of the substrate 6 during the grinding process is effectively controlled, the probability of fragmentation is reduced, the high flatness, uniformity and consistency of the surface of the substrate 6 are improved, the polishing rate of the edge position of the substrate 6 is improved, the use cost of consumables such as the substrate holding ring 3 and the polishing pad is reduced, the equipment downtime is reduced, and the processing efficiency of the substrate 6 is improved.

[0040] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Ultra-thin substrate polishing head, characterized in that: The invention comprises a polishing head body (1), a substrate holder (2) and a substrate holder ring (3), wherein the substrate holder (2) and the substrate holder ring (3) are both connected to the bottom of the polishing head body (1), and the substrate holder ring (3) is sleeved on the outer periphery of the substrate holder (2), an elastic film (4) is provided on the bottom surface of the substrate holder (2), adsorption holes (21) are penetrated through the substrate holder (2), and through holes (41) corresponding to the adsorption holes (21) above and below are provided on the elastic film (4), and an air bag (5) is provided on the outer lower cover of the substrate holder (2) and the elastic film (4).

2. The ultra-thin substrate polishing head according to claim 1, characterized in that: The adsorption holes (21) are arranged in a plurality of circles at intervals along the radial direction of the substrate holder (2), and each circle of the adsorption holes (21) includes a plurality of adsorption holes (21) arranged at intervals along the circumferential direction of the substrate holder (2).

3. The ultra-thin substrate polishing head according to claim 2, characterized in that: The diameter of the adsorption holes (21) is 1-20 mm, and the distance between adjacent edges of two adjacent adsorption holes (21) is 1-20 mm.

4. The ultra-thin substrate polishing head according to claim 1, characterized in that: An adhesive layer is provided on the top surface of the elastic film (4), and the adhesive layer is used to bond the elastic film (4) and the substrate holder (2).

5. The ultra-thin substrate polishing head according to claim 1, characterized in that: The thickness of the elastic membrane (4) gradually increases from the center to the peripheral edge.

6. The ultra-thin substrate polishing head according to any one of claims 1 to 5, characterized in that: In the up and down direction, the substrate retaining ring (3) is arranged to protrude downward from the substrate (6) by 1-2 mm.

7. The ultra-thin substrate polishing head according to any one of claims 1 to 5, characterized in that: A lower annular groove (22) is provided on the bottom wall of the substrate holder (2), and the lower annular groove (22) is arranged close to the outer peripheral edge of the substrate holder (2). The elastic membrane (4) is connected to the inner bottom wall of the lower annular groove (22) and the bottom wall of the substrate holder (2).

8. The ultra-thin substrate polishing head according to any one of claims 1 to 5, characterized in that: A lower convex ring (23) is provided on the bottom wall of the substrate holder (2), and the lower convex ring (23) is arranged close to the outer peripheral edge of the substrate holder (2). The elastic membrane (4) is connected to the lower convex ring (23) and the bottom wall of the substrate holder (2).

9. The ultra-thin substrate polishing head according to any one of claims 1 to 5, characterized in that: The elastic membrane (4) is a flexible material component, the compressibility of the elastic membrane (4) is 8%-9%, and the density of the elastic membrane (4) is 0.6 g / cm³.

10. Ultra-thin substrate polishing device, characterized in that: The invention comprises the ultra-thin substrate polishing head according to any one of claims 1 to 9.

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