A polishing head and a polishing apparatus

Abstract

The utility model provides a kind of grinding head and grinding device, including head main body, backing piece and retaining ring, the bottom of the head main body is equipped with the backing piece, the retaining ring is around and is set to the circumferential outside of the backing piece, and with the head main body forms detachable connection;The head main body, the backing piece and the retaining ring three coaxial arrangements of axis, and jointly enclose and form wafer adsorption space for adsorbing and fixed wafer;The retaining ring is ringed with sealing structure at the outside joint seam of the head main body.The utility model is ringed with sealing structure at the outside joint seam of retaining ring and head main body, effectively prevents grinding fluid from penetrating into the interior of grinding head, avoids the failure of grinding head caused by water entering central passage, improves grinding stability and guarantees the effect of wafer processing quality.

Description

Technical Field

[0001] This utility model relates to the field of chemical mechanical grinding technology, and in particular to a grinding head and grinding device. Background Technology

[0002] Chemical mechanical polishing (CMP) technology achieves global surface planarization and ultra-precision machining of workpieces through the synergistic effect of chemical action and mechanical grinding, and is a key technology in high-precision fields such as semiconductor manufacturing.

[0003] A typical CMP system comprises four core components: a polishing head that clamps and presses the workpiece, a polishing disk that carries and rotates the polishing pad, a dresser that dresses the surface of the polishing pad to maintain grinding performance, and a polishing slurry supply system that delivers abrasive particles and chemical reagents. During polishing, the wafer is held in place by the polishing head and fixed by adsorption. The polishing head applies preset pressure through internal pressure channels, pressing the wafer against the polishing pad on the surface of the polishing disk. Simultaneously, the polishing head rotates around its own axis and oscillates back and forth relative to the polishing disk, forming a combined motion. The polishing slurry is continuously delivered to the contact interface, where the chemical reagents react with the wafer surface to form an easily removable layer. The abrasive particles remove this layer through mechanical grinding, achieving uniform material removal.

[0004] As a core component of a CMP system, the polishing head's structural stability and reliability directly affect polishing accuracy, wafer quality, and production yield. However, in practical applications, some polishing heads experience functional failure after prolonged use, and disassembly reveals water ingress into their central channels. This issue significantly increases the risk of failure, leading to abnormal polishing pressure distribution, causing defects such as wafer surface scratches and out-of-tolerance flatness, and in severe cases, directly resulting in wafer scrapping, significantly increasing production costs and reducing production efficiency. Utility Model Content

[0005] To address all or part of the problems in the prior art, this utility model provides a grinding head and grinding device. By providing a sealing structure at the joint between the retaining ring and the outer side of the head body, it effectively prevents the grinding fluid from seeping into the interior of the grinding head, avoids grinding head failure caused by water entering the central channel, improves grinding stability, and ensures wafer processing quality.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A grinding head includes a head body, a backing member, and a retaining ring. The backing member is mounted on the bottom of the head body. The retaining ring is arranged around the circumferential outer side of the backing member and is detachably connected to the head body. The head body, the backing member, and the retaining ring are coaxially arranged and together enclose a wafer adsorption space for adsorbing and fixing a wafer. A sealing structure is provided at the outer joint between the retaining ring and the head body.

[0007] The sealing structure is an elastic waterproof strip with a width of 10mm to 30mm; the sealing structure fits onto the outside of the joint between the head body and the retaining ring, and completely covers the seam between the two.

[0008] The sealing structure is made of one of the following materials: fluororubber, silicone rubber, nitrile rubber, EPDM rubber, and polyurethane.

[0009] The bottom outer edge of the retaining ring is provided with a slope that slopes downwards and outwards. The bottom of the retaining ring is also provided with a number of guide grooves. The guide grooves are straight, and one end of each guide groove is connected to the inner space of the retaining ring, while the other end extends to the surface of the slope.

[0010] Several of the guide grooves are evenly distributed at the bottom of the retaining ring with the axis of the retaining ring as the center, and the included angle between two adjacent guide grooves is equal.

[0011] The guide groove forms a fixed angle with the radial direction of the retaining ring, and the angle ranges from 45 degrees to 65 degrees.

[0012] The number of the flow guide grooves is 8 to 12; the width of the flow guide grooves is 3 mm to 5 mm, and the depth of the grooves is 3 mm to 5 mm.

[0013] The outer edge corners of the retaining ring are rounded, with a radius of 2mm to 4mm.

[0014] The bottom of the head body is provided with at least two mounting holes evenly distributed along the circumference, and the top of the retaining ring is provided with a threaded hole corresponding to each mounting hole. The head body and the retaining ring are detachably connected by a fastener.

[0015] This utility model also provides a polishing device, including a polishing pad and a polishing head, wherein the polishing head is placed on the polishing pad to support the wafer and bring it into contact with the polishing pad, and the polishing head is the polishing head described above. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a partial side sectional view of a grinding head in an uninstalled state according to Embodiment 1 of this utility model.

[0018] Figure 2This is a partial side sectional view of a grinding head in the installed state according to Embodiment 1 of this utility model.

[0019] Figure 3 This is a top view of the bottom surface of a retaining ring in a grinding head according to Embodiment 1 of this utility model.

[0020] Figure 4 This is a top view of a grinding device according to Embodiment 2 of this utility model.

[0021] Figure 5 This is a side view of the grinding head and grinding pad in a grinding device according to Embodiment 2 of this utility model.

[0022] Reference numerals: 1. Grinding head; 2. Head body; 3. Backing; 4. Retaining ring; 401. Slope; 402. Guide groove; 5. Wafer adsorption space; 6. Sealing structure; 7. Fixing component; 8. Grinding pad. Detailed Implementation

[0023] The technical solutions in specific embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] The implementation of this utility model will be described in detail below with reference to specific embodiments.

[0025] Example 1 In this embodiment of the utility model, in conjunction with reference to the reference Figures 1 to 3 As shown, a grinding head is provided to solve the problem of water ingress into the central channel of existing grinding heads, which leads to failure. It is especially suitable for the grinding process of 200mm wafers.

[0026] The grinding head 1 includes a head body 2, a backing 3, and a retaining ring 4. The backing 3 is bolted to the bottom of the head body 2 and is used to directly contact and buffer the pressure on the wafer. The retaining ring 4 is arranged around the outer circumference of the backing 3 and is detachably connected to the head body 2 for easy maintenance and replacement. The head body 2, the backing 3, and the retaining ring 4 are coaxially arranged to ensure uniform force during grinding. Together, they form a wafer adsorption space 5 for adsorbing and fixing the wafer. This space is connected to an external negative pressure device through an air channel inside the backing 3 to achieve stable adsorption of the wafer.

[0027] To prevent the polishing slurry from seeping into the interior through the gap between the retaining ring 4 and the head body 2, a sealing structure 6 is provided at the outer joint of the retaining ring 4 and the head body 2. Specifically, the sealing structure 6 is an elastic waterproof strip with a width of 10mm to 30mm. This width ensures a sufficient sealing area for reliable waterproofing without excessively increasing the assembly volume. The elastic waterproof strip can be directly adhered or applied to the outer side of the joint between the head body 2 and the retaining ring 4 using high-temperature resistant adhesive, completely covering the joint to form a continuous sealing barrier. The elastic waterproof strip is made of one of the following materials: fluororubber, silicone rubber, nitrile rubber, EPDM rubber, or polyurethane, with fluororubber being preferred due to its excellent chemical corrosion resistance and high-temperature resistance, allowing it to withstand the erosion of the polishing slurry and temperature changes during the polishing process.

[0028] Combined with the bottom top view of retaining ring 4 (e.g.) Figure 3 As shown, the outer edge of the retaining ring 4 has a downward-sloping ramp 401. The angle of the ramp 401 allows excess polishing fluid to flow naturally outward during the polishing process, reducing fluid accumulation at the bottom of the retaining ring 4. The bottom of the retaining ring 4 also has several guide grooves 402. These guide grooves 402 are straight, with one end connected to the inner space of the retaining ring 4 and the other end extending to the surface of the ramp 401. These guide grooves are used to quickly drain the polishing fluid from the wafer edge, preventing it from accumulating near the wafer adsorption space 5. Furthermore, the guide grooves 402 are evenly distributed at the bottom of the retaining ring, centered on the axis of the retaining ring 4, with equal angles between adjacent guide grooves 402 to ensure uniform flow. The guide grooves 402 form a fixed angle with the radial direction of the retaining ring 4, ranging from 45 degrees to 65 degrees. This angle setting maximizes flow efficiency without affecting the structural strength of the retaining ring 4. The width of the flow channel 402 is 3mm to 5mm and the depth is 3mm to 5mm. This size range can ensure sufficient flow rate and avoid the bottom of the retaining ring 4 from being unstable in contact with the wafer due to excessive depth of the channel.

[0029] To prevent the retaining ring 4 from scratching the wafer edge during the grinding process, the corner of the retaining ring 4 facing the wafer can be rounded. The rounded corner transition can effectively reduce stress concentration with the wafer edge and protect the wafer edge. The outer corner of the retaining ring 4 facing away from the wafer, which contacts the grinding pad 8, is designed with a rounded corner with a radius of 2mm to 4mm. This rounded corner design can reduce the frictional resistance between the grinding head 1 and the grinding pad 8 when rotating and oscillating, reduce grinding noise, reduce energy loss and reduce component wear.

[0030] The detachable connection between the head body 2 and the retaining ring 4 is achieved through the following structure: at least two mounting holes are evenly provided on the bottom of the head body 2 along the circumference, and the top of the retaining ring 4 is provided with a threaded hole corresponding to each mounting hole. The head body 2 and the retaining ring 4 are fixedly connected by fasteners such as bolts or screws passing through the mounting holes and screwed into the threaded holes. This connection method is not only convenient to assemble and disassemble, but also ensures the coaxiality of the connection between the two.

[0031] Example 2 This utility model also provides a grinding device, in conjunction with the reference. Figures 4 to 5 As shown, the device includes a polishing pad 8 and a polishing head 1. The polishing head 1 is placed on the polishing pad 8 to support the wafer and bring it into contact with the polishing pad 8. The polishing head 1 is the polishing head described in Example 1. By using a polishing head 1 with a sealing structure 6 and a flow channel 402, the device can effectively reduce the risk of polishing fluid seeping into the interior of the polishing head 1 and improve polishing stability.

[0032] Specifically, the polishing apparatus includes a worktable, a polishing pad 8, a polishing head 1, a drive mechanism, and a polishing slurry supply mechanism. The polishing pad 8 is laid on top of the worktable, and the polishing head 1 is placed above the polishing pad 8 to support the wafer and ensure that the bottom surface of the wafer contacts the top surface of the polishing pad 8. The drive mechanism is connected to both the polishing head 1 and the worktable, driving the polishing head 1 to rotate around its own axis and the worktable to rotate around its own axis. Simultaneously, it can drive the polishing head 1 to reciprocate relative to the worktable, forming a composite polishing motion. The output end of the polishing slurry supply mechanism faces the contact area between the polishing pad 8 and the wafer, continuously supplying polishing slurry containing abrasive particles and chemical reagents to this contact area. Because the polishing head 1 of Example 1 is used, the apparatus can significantly reduce the probability of failure of the polishing head 1 due to water ingress during long-term use, reducing the risk of wafer scrap and improving production yield.

[0033] It should be noted that, for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A grinding head, characterized in that, The device includes a head body, a backing, and a retaining ring. The backing is mounted on the bottom of the head body, and the retaining ring is arranged around the outer circumference of the backing and is detachably connected to the head body. The head body, the backing, and the retaining ring are coaxially arranged and together form a wafer adsorption space for adsorbing and fixing the wafer. A sealing structure is provided at the outer joint between the retaining ring and the head body.

2. The grinding head according to claim 1, characterized in that, The sealing structure is an elastic waterproof strip with a width of 10mm to 30mm; the sealing structure fits onto the outside of the joint between the head body and the retaining ring, and completely covers the seam between the two.

3. The grinding head according to claim 2, characterized in that, The sealing structure is made of one of the following materials: fluororubber, silicone rubber, nitrile rubber, EPDM rubber, and polyurethane.

4. The grinding head according to claim 1, characterized in that, The bottom outer edge of the retaining ring is provided with a slope that slopes downwards and outwards. The bottom of the retaining ring is also provided with a number of guide grooves. The guide grooves are straight, and one end of each guide groove is connected to the inner space of the retaining ring, while the other end extends to the surface of the slope.

5. The grinding head according to claim 4, characterized in that, Several of the guide grooves are evenly distributed at the bottom of the retaining ring with the axis of the retaining ring as the center, and the included angle between two adjacent guide grooves is equal.

6. The grinding head according to claim 5, characterized in that, The guide groove forms a fixed angle with the radial direction of the retaining ring, and the angle ranges from 45 degrees to 65 degrees.

7. The grinding head according to claim 4, characterized in that, The number of the flow guide grooves is 8 to 12; the width of the flow guide grooves is 3 mm to 5 mm, and the depth of the grooves is 3 mm to 5 mm.

8. The grinding head according to claim 1, characterized in that, The outer edge corners of the retaining ring are rounded, with a radius of 2mm to 4mm.

9. The grinding head according to claim 1, characterized in that, The bottom of the head body is provided with at least two mounting holes evenly distributed along the circumference, and the top of the retaining ring is provided with a threaded hole corresponding to each mounting hole. The head body and the retaining ring are detachably connected by a fastener.

10. A grinding apparatus, characterized in that, The device includes a polishing pad and a polishing head, wherein the polishing head is placed on the polishing pad to carry a wafer and bring it into contact with the polishing pad, and the polishing head is a polishing head as described in any one of claims 1-9.

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