Protective check ring for welding and bonding position of electrostatic chuck

Abstract

The utility model discloses a protective retainer ring for a welding and bonding position of an electrostatic chuck, and relates to the technical field of protective retainer rings, the protective retainer ring comprises a retainer ring main body, the retainer ring main body is of a circular structure, the whole retainer ring main body is made of ultra-pure Teflon materials, and the inner side and the outer side of the retainer ring main body are of plane structures. The check ring is more easily attached to a protection position and is easy to install, the machining result is not affected, the particle state of a cavity is improved, the service life is greatly prolonged by more than three times, the inner and outer double-plane structures of the check ring body are not distinguished from the front face and the back face, the direction does not need to be adjusted during installation, the operation time is shortened, and sealing failure caused by direction errors is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of protection baffle, especially to a protection baffle for the welding and bonding of electrostatic chuck. BACKGROUND

[0002] In the semiconductor wafer manufacturing process, high corrosive gas containing fluorine group (such as CF4, SF6) needs to be introduced into the cavity of the plasma etching equipment (such as American Panlin 300mm etching machine), and high-frequency electric field is used to excite plasma for etching. As the core component of wafer bearing and temperature control, the structure of electrostatic chuck (ESC) is usually connected by welding or bonding between the ceramic disc on the surface and the aluminum disc base at the bottom. Since the welding / bonding interface is exposed to the cavity environment, the area needs to be sealed and protected by a protection baffle to prevent corrosive gas, plasma and by-products from eroding the interface, causing ESC failure or particle contamination.

[0003] The prior art has the following defects:

[0004] 1. Insufficient material performance:

[0005] The traditional protection baffle is made of perfluorinated rubber (such as FFKM), which has a high temperature limit of about 300°C. However, the local temperature in the etching cavity during the process may exceed this threshold, causing the rubber to age, harden, and even crack. To improve the high-temperature resistance and plasma resistance of perfluorinated rubber, a large amount of filler (such as carbon fiber, metal oxide) needs to be added, which reduces the purity of the material and makes it prone to release volatile organic compounds (VOC) or particles under plasma bombardment, polluting the cavity environment. The rubber material will swell or chemically degrade when exposed to fluorine-containing corrosive gas for a long time, causing the sealing surface of the baffle to gradually fail, leading to gas leakage or interface corrosion. The average service life is only 3-6 months, and frequent downtime is required for replacement.

[0006] 2. Design defects:

[0007] As shown in Figure 3 , Figure 4 , the traditional baffle is a circular cross-section ring structure with a concave surface on one side and a flat surface on the other side. Due to the thinness of the baffle and the small radius of the concave surface, it is difficult to distinguish the front and back surfaces, and the front and back surfaces need to be strictly distinguished during installation, making the operation cumbersome and prone to misalignment, resulting in gaps and accelerated corrosion. The contact area of the circular baffle with the ESC groove is limited, and due to the difference in thermal expansion coefficient, local stress concentration is easily generated at high temperatures, causing the baffle to deform or fall off, and metal / ceramic particles contaminate the wafer.

[0008] 3. Process reliability issues:

[0009] After the deterioration of the check ring, the falling particles will be deposited on the cavity wall or wafer surface, causing etching uniformity to decrease or device short circuit and other defects, which needs to be cleaned and maintained to interrupt the production, reducing the utilization rate of the equipment.

[0010] The protection range of the existing check ring to the ESC welding / bonding interface is uneven, and the edge area is easy to be etched by plasma due to insufficient protection, resulting in the decrease of the structural strength of the ESC and the shortening of the overall service life.

[0011] Therefore, in order to solve the foregoing problems, we propose a protection check ring for the welding and bonding place of an electrostatic chuck. Content of the utility model

[0012] The utility model aims at solving the defects in the prior art and proposes a protection check ring for the welding and bonding place of an electrostatic chuck.

[0013] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0014] A protection check ring for the welding and bonding place of an electrostatic chuck, comprising a check ring main body, the check ring main body is a circular structure, the check ring main body is integrally made of ultra-pure Teflon material, and the inner and outer sides of the check ring main body are plane structures.

[0015] Further, the height of the check ring main body is between 2.77mm-3.07mm.

[0016] Further, the length and width of the outer diameter of the check ring main body are between 293.8mm-295.4mm.

[0017] Further, the length and width of the inner diameter of the check ring main body are between 292.2mm-293.8mm.

[0018] Further, the thickness of the check ring main body is between 0.88mm-0.72mm.

[0019] Compared with the prior art, the utility model has the beneficial effects that:

[0020] 1. The extreme environment tolerance is improved

[0021] High temperature resistance and corrosion resistance: the ultra-pure Teflon (PFA) material can resist temperature above 260 DEG C (short-term resistance to 300 DEG C), and does not need to add any filler, and its intrinsic chemical inertness can resist the long-term erosion of fluorine-containing gas (such as CF4, SF6) and plasma, avoiding swelling, carbonization or chemical degradation problem, and the service life is improved to more than 3 times of the traditional rubber check ring.

[0022] 2. Anti-plasma performance: Teflon material has smooth surface and low dielectric constant, which can reduce etching damage caused by plasma bombardment and avoid particle pollution caused by material decomposition.

[0023] 3. Optimization of chamber cleanliness and wafer yield

[0024] Ultra-pure material characteristics: Teflon purity is as high as 99.99% or more, without the risk of additive volatilization, reducing the release of metal ions and organic particles in the chamber from the source, reducing particle contamination and significantly improving wafer yield.

[0025] 4. Enhanced structural sealing: The fitting area of the rectangular retaining ring and the groove at the welding / bonding place of the ESC is increased by more than 30%, combined with the inner and outer side plane design, realizing uniform and gapless sealing, preventing corrosive gas penetration or byproduct accumulation, and further inhibiting particle generation.

[0026] 5. Improved installation convenience and stability

[0027] Error-proof design: The inner and outer double-plane structure has no front and back side distinction, so there is no need to adjust the direction during installation, the operation time is shortened, and the sealing failure caused by incorrect direction is avoided.

[0028] Size adaptability: The thickness of the retaining ring body is controlled at 0.72-0.88mm, and the inner and outer diameter tolerances are strictly matched with the ESC groove (outer diameter 293.8-295.4mm, inner diameter 292.2-293.8mm), the difference in thermal expansion coefficient between the metal / ceramic base at high temperature is smaller, avoiding stress cracking or deformation and falling off.

[0029] The inner and outer diameters of the retaining ring body have multiple specifications, and in the case of thickness inconvenience, the inner and outer diameter sizes can vary between 300mm-200mm, which can adapt to electrostatic chucks of different diameters.

[0030] 6. Economic benefits and equipment efficiency improvement

[0031] Reduced maintenance cost: The service life of the retaining ring is extended to 3 times of the original, reducing the replacement frequency, shortening the equipment downtime, and effectively improving the production capacity.

[0032] Optimized comprehensive cost: Reduce maintenance frequency and wafer rework loss, significantly reduce annual operating cost of a single device. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application.

[0034] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0035] Figure 2 is a partial sectional view of the utility model;

[0036] Figure 3 is a perspective view of a traditional protective baffle ring;

[0037] Figure 4 is a partial sectional view of the traditional protective baffle ring.

[0038] In the drawing: 1, baffle ring main body. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model;

[0040] With reference to Figures 1-2 A protective baffle ring for the welding and bonding part of an electrostatic chuck, comprising a baffle ring main body 1, the height of the baffle ring main body 1 is between 2.77mm-3.07mm, the outer diameter of the baffle ring main body 1 is between 293.8mm-295.4mm in length and width, the inner diameter of the baffle ring main body 1 is between 292.2mm-293.8mm in length and width, the thickness of the baffle ring main body 1 is between 0.88mm-0.72mm, and the baffle ring main body 1 is made of ultra-pure Teflon material as a whole.

[0041] The inner and outer diameters of the above-mentioned baffle ring main body 1 have multiple specifications, and in the case that the thickness is inconvenient, the inner and outer diameters can be changed between 300mm-200mm, which can be adapted to electrostatic chucks of different diameters.

[0042] The carbon-fluorine bond energy of ultra-pure Teflon is high (about 485kJ / mol), and almost no chemical reaction occurs in the fluorine-containing plasma environment, a stable physical barrier can be formed, and the corrosion of corrosive gas to the ESC aluminum-ceramic welding / bonding surface is blocked. The Teflon material still maintains flexibility when used for a long time below 260℃, a dense oxide layer is formed on the surface at high temperature, further thermal aging is slowed down; at the same time, its low thermal conductivity coefficient (0.25W / m·K) can reduce the heat transfer to the welding interface, and reduce the risk of thermal stress damage.

[0043] The surface roughness (Ra) of the Teflon material is less than 0.2μm, the etching surface area when bombarded by plasma is reduced, and the generation of particles is inhibited; at the same time, the smooth surface is not easy to adsorb reaction by-products (such as polymer residues), and the risk of particle falling is reduced. Teflon has moderate electrical conductivity, which can avoid the problem of particle adsorption caused by the accumulation of static electricity, and further ensure the cleanliness of the cavity.

[0044] The inner and outer sides of the retainer ring body 1 are both flat structures, the inner and outer flat structures make the force of the retainer ring be evenly distributed, when the temperature of the cavity fluctuates or mechanical vibration occurs, the micro cracks or deformation caused by local stress concentration are avoided, the sealing integrity is maintained for a long time, and the inner and outer double flat structures are not distinguished by front and back, so that the direction does not need to be adjusted during installation, the operation time is shortened, and the sealing failure caused by the wrong direction is avoided.

Claims

1. A protective retaining ring for a soldered joint of an electrostatic chuck, comprising a retaining ring body (1), characterized in that The stop ring body (1) is circular structure, the whole stop ring body (1) is made of ultra-pure Teflon material, the inside and outside of the stop ring body (1) are plane structure.

2. A protective retaining ring for a soldered bond of an electrostatic chuck as defined in claim 1, wherein The height of the stop ring body (1) is between 2.77mm-3.07mm.

3. A protective retaining ring for a soldered bond of an electrostatic chuck as defined in claim 1, wherein The length and width of the outer diameter of the stop ring body (1) are between 293.8mm-295.4mm.

4. A protective retaining ring for a soldered bond of an electrostatic chuck as defined in claim 1, wherein The length and width of the inner diameter of the stop ring body (1) are between 292.2mm-293.8mm.

5. A protective retaining ring for a soldered bond of an electrostatic chuck as defined in claim 1, wherein The thickness of the stop ring body (1) is between 0.88mm-0.72mm.

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