Lifting pin and lifting pin device with same

Abstract

The utility model relates to a lifting pin and a lifting pin device with the same, and aims to solve the problem that a lifting pin bracket in the prior art is easy to lose efficacy in a high-temperature and high-fluorine-ion environment. The lifting pin body and the support are combined into a whole and are made of sapphire materials, so that the lifting pin has the advantages of being resistant to high temperature and corrosion, the service life can be remarkably prolonged, and the downtime and the maintenance cost of equipment are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of semiconductor manufacturing, especially a novel lift pin structure for semiconductor manufacturing process. BACKGROUND

[0002] Semiconductor manufacturing is the foundation of modern electronics industry. In the manufacturing process, wafer processing equipment plays a crucial role. Among these devices, the lift pin is a seemingly simple but actually very critical component that directly affects the stability of the entire manufacturing process and product quality.

[0003] The main function of the lift pin is to support and move the wafer during different stages of wafer processing. In a typical semiconductor manufacturing process, the wafer needs to go through multiple processing steps such as thin film deposition, photolithography, etching, ion implantation, etc. Between these steps, the wafer needs to be accurately moved and positioned. The lift pin is a key component in this process.

[0004] Traditional lift pin systems are usually composed of three main parts: lift pins, holders, and caps. The lift pins are usually made of high-temperature and corrosion-resistant materials such as sapphire, while the holders are usually made of metal materials such as aluminum alloy. The original intention of this design is to use the elasticity of the metal holder to fix the lift pin, so that it can remain stable during the lifting and lowering process.

[0005] However, this traditional design has exposed some serious problems in practical application. The first is the problem of material degradation. In the process of semiconductor manufacturing, there are often harsh special environments. For example, in the 3D-NAND manufacturing process, there is usually a high-temperature and high-concentration fluoride ion environment in the chamber. Such harsh conditions can cause the metal holder to quickly degrade. According to industry data, most holders lose most of their elasticity within 1 to 1.5 years, making it impossible to effectively fix the lift pin. This is far below the original design life of the equipment supplier.

[0006] When the holder loses its elasticity, it will not be able to effectively fix the lift pin. This will cause the lift pin to fail to return to its original position during the lowering process, triggering an equipment alarm and causing downtime. This failure usually requires preventive maintenance (PM) to replace the holder, which requires the work of two engineers for about 96 hours each time.

[0007] According to estimates, the cost of restoring the chamber to normal operation after each holder failure is about $10,000. Considering that a typical semiconductor manufacturing plant may have dozens or even hundreds of such chambers, the annual maintenance cost can be millions of dollars.

[0008] Moreover, each equipment downtime not only means direct maintenance cost, but also causes significant loss of production capacity. In the competitive semiconductor industry, such loss of production capacity can lead to loss of market share. According to industry estimates, each downtime can cause about 1.09% of machine availability (MA) loss.

[0009] More seriously, failure of the support can lead to product quality issues. When the lift pins are not properly positioned, it can cause one side of the wafer to be thicker while the other side is thinner. This non-uniformity can affect subsequent processing steps, and can cause serious problems when forming electrode contacts (such as word line contacts). In the worst case, this can lead to the entire batch of products being scrapped.

[0010] To address these issues, the industry has generally adopted a preventive maintenance strategy. For example, the replacement cycle of the support is set to one year, or a tension gauge is used to test the state of the support at each PM, and the support is replaced when it cannot withstand a force of 14N. However, this method also has obvious defects. First, too frequent replacement can significantly increase maintenance costs. Second, even with this strategy, some supports will fail before the expected lifetime (such as 0.7 years of use), and the potential impact on product quality and production capacity cannot be completely eliminated.

[0011] In addition, some chemicals used in semiconductor manufacturing are corrosive and toxic. Frequent maintenance of the lift pin system not only increases the opportunity for workers to come into contact with these dangerous substances, but also increases the risk of environmental pollution.

[0012] Modern semiconductor manufacturing is moving towards a more highly automated and precisely controlled direction. Any instability of the lift pin system can affect the reliability of the entire automated system, and can even cause expensive wafer damage.

[0013] For example, in the field of 3D-NAND, as technology continues to evolve, the number of layers is increasing (from the early 32 layers to the current more than 100 layers, and in the future even more than 300 layers), which means that the processing time of a single wafer is getting longer and longer, and the requirement for equipment stability is getting higher and higher. Under this trend, the reliability of the lift pin system becomes more and more critical.

[0014] In the increasingly competitive semiconductor industry, production efficiency and cost control are crucial. The unreliability of the lift pin system has become a factor affecting overall competitiveness.

[0015] In view of the above challenges, the industry is in urgent need of a new lift pin design to solve many problems in the prior art. The ideal solution should be able to significantly extend the service life, reduce maintenance requirements, improve equipment reliability, and ultimately improve product quality and production efficiency. This will not only directly reduce manufacturing costs, but also bring significant competitive advantage to semiconductor companies.

[0016] In this context, the utility model provides an innovative lift pin structure design, aiming to fundamentally solve the problems in the prior art, and provide a more reliable and efficient solution for wafer processing in the semiconductor manufacturing process. Utility model content

[0017] The utility model provides a lift pin, it includes: at the upper end, support the wafer's support part, set up in support part below, for providing counterweight's counterweight part, and set up in counterweight part below, for with fixed lid cooperation, to fix lift pin on the base part of workbench, lift pin is integral structure, support part, counterweight part and base part all are composed of same kind of material.

[0018] The lift pin as described above, wherein the support part, the counterweight part and the base are all composed of sapphire.

[0019] The lift pin as described above, wherein the support part is in the shape of an elongated cylinder, the counterweight part is in the shape of a cylinder with a larger diameter than the support part, and the base part is in the shape of a cylinder with a diameter much larger than the counterweight part.

[0020] The lift pin as described above, wherein the top end of the support part is in the shape of a spherical surface.

[0021] The utility model provides a lift pin device, it includes: the workbench for bearing the piece to be handled, a plurality of lift pins for supporting the piece to be handled when being elevated to the designated height are arranged on the workbench in a liftable manner, and a fixed lid for fixing the lift pins on the workbench, the lift pin is the lift pin as described above.

[0022] The lift pin device as described above, wherein the fixed lid is in the shape of a ring structure with a hole in the center allowing the lift pins to pass through.

[0023] The lift pin device as described above, wherein the workbench has a plurality of lift pin holes arranged symmetrically for the lift pins to pass through.

[0024] Effect of the utility model

[0025] The lift pin structure of the utility model integrates the lift pin and the bracket, and is made of sapphire, which has the following advantages:

[0026] 1. High temperature resistant, corrosion resistant, greatly extend the service life;

[0027] 2. No need to replace the support, reduce maintenance costs;

[0028] 3. Reduce the risk of equipment downtime, improve productivity;

[0029] 4. Protect product quality, reduce scrap. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structure diagram of the lifting pin of the present application.

[0031] Figure 2 is a structure diagram of the lifting pin and the fixed cover of the present application installed together.

[0032] Figure 3 is a structure diagram of the lifting pin of the present application installed on the workbench through the fixed cover.

[0033] Figure 4 is a diagram of the lifting pin body of the prior art.

[0034] Figure 5 is a diagram of the support of the prior art.

[0035] Figure 6 is a diagram of the fixed cover of the prior art and the present application.

[0036] Figure 7 is a structure diagram of the lifting pin body and the support of the prior art installed together.

[0037] Figure 8 is a structure diagram of the lifting pin body and the support of the prior art installed on the workbench through the fixed cover.

[0038] Figure 9 is a structure diagram of the lifting pin of the prior art installed on the workbench through the fixed cover.

[0039] Figure 10 is a diagram of the lifting pin of the prior art when a problem occurs. DETAILED DESCRIPTION

[0040] The lifting pin of the embodiment and example of the present application will be described below. In order to explain the structure of the lifting pin of the present application, the structure of the prior art needs to be described in detail first. First, according to the structure of the prior art, Figures 4-10 The structure of the lifting pin of the prior art and its defects will be described.

[0041] Figure 4 is a diagram of the lifting pin body of the prior art. Figure 5is a diagram showing a support of the prior art. Figure 6 is a diagram showing a fixed cover of the prior art and the present application. Figure 7 is a diagram showing the structure of the prior art in which the lift pin body and the support are installed together. Figure 8 is a diagram showing the structure of the prior art in which the lift pin body and the support are installed on the workbench through the fixed cover.

[0042] The lift pin structure of the prior art mainly includes a lift pin body 2, a support 3 and a fixed cover 4. As shown in Figure 4 , the lift pin body 2 is in the shape of an elongated cylinder and is made of a material resistant to high temperature and corrosion, such as sapphire. Its length may vary depending on the specific application, but is generally sufficient to pass through the thickness of the base and support the wafer. The lift pin body 2 includes a support portion 21 for supporting the wafer as the upper part and an insertion portion 22 as the lower part, the diameter of the insertion portion 22 being able to match the support 3 described later. The top end of the support portion 21 of the lift pin body 2 is slightly rounded to directly contact and support the wafer, avoiding scratching the wafer.

[0043] The lower part of the lift pin body 2 is the insertion portion 22, which is used to insert the lift pin body 2 into the support 3 described later. A clamping groove 23 is provided on the insertion portion 22. The clamping groove 23 is an annular groove with a diameter smaller than that of the insertion portion 22. The position of the clamping groove 23 is carefully designed to ensure that when the insertion portion 22 is fully inserted into the support 3, the clamping groove 23 is aligned with the neck portion 33 of the support 3.

[0044] The support 3 is a metal component, usually made of aluminum alloy or other materials, which takes advantage of its good elastic deformation capability. As shown in Figure 5 , the support 3 is overall in an axisymmetric structure, from top to bottom in turn is the bell mouth 34, the abdomen 31 and the base 32. Between the bell mouth 34 and the abdomen 31 is the neck portion 33. The inner diameter of the opening of the neck portion 33 is slightly smaller than the outer diameter of the lift pin, but since the aluminum alloy material has a certain elasticity, it can slightly expand when the insertion portion 22 of the lift pin body 2 is inserted, so that the insertion portion 22 can enter the abdomen 31. When the insertion portion 22 of the lift pin body 2 is inserted into the abdomen 31 at the appropriate position, the neck portion 33 just clamps the clamping groove 23 on the insertion portion 22, thus completing the fixation.

[0045] The base 32 is in the shape of a cylinder with a diameter much larger than that of the abdomen 31, which is used to stabilize the support 3 and the lift pin body 2 cooperating with it, and cooperates with the fixed cover 4 described later, so as to be fixed on the workbench 5 described later. The surface of the support 3 can be specially treated, such as anodizing, to enhance its corrosion resistance.

[0046] The fixed cover 4 is used to fix the support 3 on the workbench 5. As shown in Figure 6As shown, the fixing cover 4 is in a ring structure with a hole in the center. The inner diameter of the hole is slightly larger than the outer diameter of the belly 31 of the bracket 3, allowing the bracket 3 and the fixed lift pin body 2 to pass through. The fixing cover 4 can be made of the same aluminum alloy as the bracket 3, or other corrosion-resistant metal materials. The fixing cover 4 can be connected to the workbench 5 by threads, buckles or other mechanisms. This mechanism needs to be designed to be both firm and easy to disassemble.

[0047] Figure 7 The prior art lift pin body 2 and bracket 3 are shown fixed together. As can be seen, the lift pin body 2 passes through the center of the bracket 3, and its clamping groove 23 is aligned with the neck 33 of the bracket and clamped together. Figure 8 The prior art lift pin body 2, bracket 3 and fixing cover 4 are shown fixed together. As can be seen, the bracket 3 is pressed from above by the fixing cover 4, ensuring that it is fixed to the workbench 5 described below.

[0048] The workbench 5 is a large disc-shaped structure, which is a platform in semiconductor manufacturing equipment for placing wafers for processing. The workbench 5 is provided with a plurality of lift pin holes 51, which can be inserted into the support portion 21 of the lift pin body 2. The number of lift pin holes 51 is usually more than three, symmetrically distributed to ensure stable support of the wafer.

[0049] The working mode of the prior art lift pin structure and its problems will be introduced below Figure 9 and Figure 10 The working mode of the prior art lift pin structure and its problems will be introduced below Figure 9 is a diagram showing the structure of the prior art lift pin mounted on the workbench by the fixing cover. Figure 10 is a diagram showing the prior art lift pin when it has a problem.

[0050] In the normal working state, as shown in Figure 9 , the lift pin body 2 is tightly fixed in place by its clamping groove 23 and the neck 33 of the bracket 3; the bracket 3 is pressed by the fixing cover 4 into the lift pin hole 51 of the workbench 5. When the lift pin is in the lowered position, its top end is flush with or slightly below the surface of the workbench 5.

[0051] When the wafer needs to be lifted, the mechanism (not shown) below the workbench 5 will push the lift pin body 2 upwards. The lift pin body 2 passes through the lift pin hole 51 of the workbench 5, and its top end protrudes above the surface of the base. Multiple lift pins (usually 3) are lifted simultaneously to support the wafer together.

[0052] When the wafer processing is complete and the lift pins need to be lowered, the mechanism under the worktable 5 releases the pressure, allowing the lift pin body 2 to drop. Ideally, the lift pin body 2 should return to its original position under its own gravity and the elasticity of the support 3. The top end of the lift pin body 2 should be flush or slightly below the surface of the worktable 5.

[0053] However, as mentioned above, the material of the support 3 will degrade. In the harsh environment of semiconductor manufacturing, especially in the presence of high temperature and high concentration of fluoride ions, aluminum alloy supports will accelerate oxidation and corrosion. The mechanical properties of the support material, especially the elasticity, will quickly decrease. According to industry data, most supports will lose most of their elasticity within 1 to 1.5 years, and will not be able to effectively secure the lift pin body.

[0054] As shown in Figure 10 When the support 3 loses its elasticity, the neck 33 of the support 3 cannot tightly hold the clamping groove 23 of the lift pin body 2. During the descent of the lift pin body 2, due to the lack of sufficient elastic force, the lift pin body 2 may not return to its original position completely. This will cause the top end of the lift pin body 2 to protrude above the surface of the worktable 5, for example Figure 10 the support portion 21 of the lift pin body 2 on the left side of the figure protrudes.

[0055] When the top end of the lift pin protrudes above the surface of the base, it will cause the wafer to be placed unevenly. This unevenness can cause deviations in subsequent process steps, such as uneven film deposition, misalignment of photolithography, etc. In the worst case, it can cause wafer damage or entire batch of product to be scrapped.

[0056] Lift pin system failure usually triggers an equipment alarm, causing the production line to shut down. Each shutdown requires preventive maintenance (PM), which usually requires replacement of the support. The maintenance process is complex and usually requires the involvement of two engineers for about 96 hours of work time each time. This not only increases the direct maintenance cost, but also causes considerable loss of production capacity.

[0057] Frequent maintenance and replacement bring huge economic burden, with a cost of about $10,000 for each replacement of the support. Considering that a typical semiconductor manufacturing plant may have dozens or even hundreds of such chambers, the annual maintenance cost can be in the millions of dollars, not including the loss of production capacity and possible product quality problems caused by shutdown.

[0058] To cope with these problems, the industry generally adopted preventive maintenance strategy. For example, the replacement cycle of the support is set to one year, or use the tension meter test support state when the support can not withstand 14N force, then replace. But this method also has obvious defects: too frequent replacement will significantly increase maintenance costs. Even with this strategy, there are still some support will fail before the expected life (such as only 0.7 years of failure), can not completely eliminate the potential impact on product quality and capacity.

[0059] It is to solve the above-mentioned defects and problems of the prior art, the inventor designed the lifting pin structure of the utility model, the following according to Figures 1-3 Detailed description.

[0060] The biggest feature of the utility model is that the lifting pin body 2 and the support 3 in the prior art are combined into one whole, which is made of corrosion-resistant material (such as sapphire) to maximize the durability.

[0061] As Figure 1 The lifting pin 1 of the utility model includes a support part 11, a counterweight part 12 and a base 13 from top to bottom. The support part 11 is equivalent to the support part 21 of the prior art, which is in the shape of an elongated cylinder, and its length may vary depending on the specific application, usually enough to pass through the thickness of the base and support the wafer. The top end of the support part 11 is slightly rounded, in the shape of a general sphere, for direct contact and support of the wafer, to avoid scratching the wafer.

[0062] The counterweight part 12 is thicker in diameter than the support part 11, and serves as a counterweight. This part corresponds to the insertion part 22 of the lifting pin body 2 and the abdomen 31 of the support 3 of the prior art. Considering that the weight of this part of the prior art is greater than that of the support part 11, this part of the utility model is also thickened, which helps to stabilize and balance the lifting pin during movement.

[0063] The base 13 is equivalent to the base 32 of the support 3 of the prior art, which is in the shape of a cylinder with a diameter much larger than that of the counterweight part 12, and is used to stabilize the entire lifting pin 1, and cooperates with the fixed cover 4 described later, so as to be fixed on the workbench 5 described later.

[0064] In the utility model, the support part 11, the counterweight part 12 and the base 13 are made of sapphire as a whole. This material has excellent high temperature resistance and corrosion resistance, and is very suitable for semiconductor manufacturing environment.

[0065] The fixed cover 4 is the same as the fixed cover of the prior art, and the fixed cover of the prior art can be used. The fixed cover 4 is used to fix the lifting pin 1 on the workbench 5. As Figure 6As shown, the fixed cover 4 is in a ring structure with a through hole in the center. The inner diameter of the hole is slightly larger than the outer diameter of the weight part 12, allowing the lifting pin 1 to pass through. The fixed cover 4 can be made of aluminum alloy, or other corrosion-resistant metal materials. The fixed cover 4 can be connected with the workbench 5 by threads, buckles or other mechanisms. This mechanism needs to be designed to be firm and easy to disassemble.

[0066] The working mode of the utility model is the same as that of the prior art in normal state. When the lifting pin 1 is in the lowered position, the top end is flush with or slightly lower than the surface of the workbench 5.

[0067] When the wafer needs to be lifted, the mechanism (not shown) below the workbench 5 pushes the lifting pin body 2 to move upward. The lifting pin body 2 passes through the lifting pin hole 51 of the workbench 5, and the top end protrudes from the surface of the base. Multiple lifting pins (usually 3) are lifted at the same time to support the wafer together. When the wafer is processed and needs to be lowered, the mechanism below the workbench 5 releases the pressure to allow the lifting pin body 2 to descend.

[0068] Compared with the prior art, the utility model is integrated, and the whole is made of sapphire, avoiding the use of easily corroded metal materials, with excellent chemical stability, capable of resisting various corrosive gases and chemicals. Moreover, it has excellent thermal stability and stable performance in high temperature environment. Therefore, it has excellent stability even in harsh environments such as high temperature and high fluorine.

[0069] Moreover, the utility model adopts integrated design, without the need for separate supports, simplifying the structure. And it can avoid the generation of particles in the joints and gaps between different components, causing pollution. And it avoids the complexity and cost brought by the assembly of multiple components. It can also avoid the wear and tear and shortening of life caused by the relative movement between multiple components.

[0070] Due to the high durability of sapphire, the utility model greatly reduces the replacement frequency of the lifting pin support, reducing the maintenance cost of each support failure from 10,000 US dollars to almost zero. This not only reduces the direct financial expenditure, but also reduces the production interruption and related losses caused by maintenance.

[0071] The utility model adopts innovative integrated lifting pin structure design, uses sapphire material, maintains stability in high temperature and high fluoride ion environment. Adopting integrated design, without the need for separate supports, it can simplify the structure. Prolong the service life of the lifting pin, reduce the replacement frequency. Reduce the risk of equipment downtime, improve production efficiency. Thus protect the product quality, reduce the product defects caused by the failure of the lifting pin.

[0072] Industrial availability

[0073] The lifting pin of the utility model is superior to the prior art in structure design, material selection, performance and economic benefits. It not only solves a plurality of key problems in the current semiconductor manufacturing process, but also provides new possibilities for the further development of the industry. This innovation is expected to promote the development of semiconductor manufacturing technology to higher precision, higher cleanliness and higher efficiency, and bring revolutionary progress to the entire industry.

Claims

1. A lift pin, characterized in that, Comprising: a support portion at the upper end for supporting a wafer; a counterweight portion disposed below the support portion for providing a counterweight; and a base portion disposed below the counterweight portion for cooperating with a fixing cover to fix the lift pin on the worktable, the lift pin is of an integrated structure, the support portion, the counterweight portion and the base portion are all made of the same material.

2. The lift pin according to claim 1, wherein: the support portion, the counterweight portion and the base portion are all made of sapphire.

3. The lift pin according to claim 1 or 2, wherein: the support portion is in the shape of an elongated cylinder, the counterweight portion is in the shape of a cylinder with a larger diameter than the support portion, the base portion is in the shape of a cylinder with a diameter much larger than the counterweight portion.

4. The lift pin according to claim 1 or 2, wherein: the top end of the support portion is in the shape of a spherical surface.

5. A lift pin apparatus, characterized by, Comprising: a worktable for carrying a piece to be processed; a plurality of lift pins disposed on the worktable in a liftable manner for supporting the piece to be processed when lifted to a specified height; and a fixing cover for fixing the lift pins on the worktable, the lift pins are the lift pins according to any one of claims 1-4.

6. The lift pin apparatus of claim 5, wherein, Comprising: the fixing cover is in the shape of a ring structure with a hole in the center allowing the lift pins to pass through.

7. A lift pin apparatus as claimed in claim 5 or 6, wherein, Comprising: the worktable has a plurality of lift pin holes symmetrically disposed thereon for the lift pins to pass through.

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