Annular air supply chamber for particle control in wafer conveying process and design method

Abstract

The invention provides an annular air supply chamber for particle control in the wafer conveying process, and the chamber comprises an annular air supply cavity, and the inner ring region of the annular air supply cavity is used for placing a wafer; an air inlet; the fan is arranged on the surface of the annular air supply cavity; the first-stage pressure stabilizing cavity is formed in the annular air supply cavity and communicates with the air inlet hole; the second-stage pressure stabilizing cavity is formed in the annular air supply cavity, and interstage gas transmission of the first-stage pressure stabilizing cavity and interstage gas transmission of the second-stage pressure stabilizing cavity are communicated through a micro gap; the air outlet hole is formed in the annular air supply cavity, located on the outer side of the wafer and communicated with the second-stage pressure stabilizing cavity; wherein the first-stage pressure stabilizing cavity is used for carrying out primary speed reduction and primary pressure homogenization on clean gas introduced from the gas inlet hole under the action of high flow resistance of the micro gap, the second-stage pressure stabilizing cavity is used for carrying out secondary speed reduction and secondary pressure homogenization on the clean gas subjected to primary pressure homogenization, and the gas outlet hole is used for spraying out the clean gas subjected to secondary pressure homogenization; and a uniform and stable closed annular air curtain is formed around the wafer.

Description

Technical Field

[0001] This disclosure relates to the field of microelectronic integrated circuit technology, specifically to an annular air supply chamber and its design method for particulate matter control in the wafer transport process. Background Technology

[0002] The development of microelectronic integrated circuit technology depends to a certain extent on the surface quality of silicon wafer semiconductor materials. High-performance silicon wafers not only need to have high surface flatness, but also need to ensure surface cleanliness. Particulate contamination on the surface of silicon wafers will greatly affect the process and product yield.

[0003] As the size of photolithographic patterns continues to shrink, the impact of defects on device yield becomes increasingly significant. Wafers are at the greatest risk of environmental contamination during wafer transport. Particulate matter falling onto or adhering to the wafer surface can severely affect subsequent processing steps, making surface particle control crucial. Furthermore, the wafer transport process also involves surface inspection, making physical sealing of the wafer impossible. Moreover, due to advancements in integrated circuit technology, process flows have increasingly stringent requirements for environmental conditions and wafer surface conditions, rendering existing environmental control methods inadequate for providing higher levels of protection during wafer transport. Summary of the Invention

[0004] In view of the above problems, this disclosure provides an annular air supply chamber and its design method for particulate matter control in the wafer transport process, which at least partially solves the above technical problems.

[0005] One aspect of this disclosure provides an annular air supply chamber for particulate matter control during wafer transport, comprising: an annular air supply chamber body, the inner ring region of which is used to place the wafer; an air inlet; disposed on the surface of the annular air supply chamber body; a primary pressure regulating chamber disposed in the annular air supply chamber body and communicating with the air inlet; a secondary pressure regulating chamber disposed in the annular air supply chamber body, the interstage gas transmission between the primary and secondary pressure regulating chambers being connected through a micro-gap; and an air outlet disposed on the annular air supply chamber body body and located outside the wafer, communicating with the secondary pressure regulating chamber body; wherein, the primary pressure regulating chamber body is used to initially decelerate and initially homogenize the clean gas introduced through the air inlet under the high flow resistance of the micro-gap; the secondary pressure regulating chamber body is used to further decelerate and further homogenize the pressure of the initially pressure homogenized clean gas transported through the micro-gap; and the air outlet is used to eject the further pressure homogenized clean gas, forming a stable annular air curtain around the wafer.

[0006] According to an embodiment of this disclosure, the primary pressure stabilizing chamber includes: a gas expansion section connected to an air inlet for initially reducing the velocity of the clean gas introduced through the air inlet; the width of the gas expansion section is greater than the width of the air inlet along the flow direction perpendicular to the clean gas; the primary pressure stabilizing chamber is connected to the gas expansion section for initially equalizing the pressure of the clean gas after the initial velocity reduction under the action of high flow resistance in the micro-gap.

[0007] According to embodiments of this disclosure, the volume of the secondary voltage regulator chamber is greater than the volume of the primary voltage regulator chamber.

[0008] According to an embodiment of this disclosure, the secondary pressure stabilizing chamber further includes: a terminal air supply chamber, which is connected between the secondary pressure stabilizing chamber and the air outlet, for making the clean gas output from the secondary pressure stabilizing chamber form a low-speed and pressure-uniform fluid state in the terminal air supply chamber, and for stably and uniformly delivering the clean gas to the air outlet.

[0009] According to an embodiment of this disclosure, the air outlet is an expansion hole, which is used to expand the ejected clean gas to ensure the airtightness of the annular air curtain.

[0010] According to embodiments of this disclosure, the porosity of the air outlet is related to the height of the annular air curtain and the diameter of the air outlet.

[0011] According to embodiments of this disclosure, the porosity of the vent is in the range of 0.3 to 0.8.

[0012] According to embodiments of this disclosure, the size of the inlet is related to the size of the wafer and the gas flow rate of the outlet.

[0013] According to embodiments of this disclosure, the number of air inlets is one or more.

[0014] Another aspect of this disclosure provides a design method for an annular air supply chamber, used to design an annular air supply chamber for particulate matter control in the wafer transport process according to this disclosure, comprising: selecting the flow rate of the gas ejected from the outlet; determining the circumference of the stable annular air curtain to be formed around the wafer based on the wafer size; obtaining the air supply flow rate based on the flow rate of the gas ejected from the outlet, the circumference of the annular air curtain, and the effective thickness of the annular air curtain; determining the intake flow rate based on the design air velocity of the inlet and the selected size of the inlet, and determining the size of the outlet and the size of the micro-gap between the primary and secondary pressure regulating chambers based on the size of the inlet; performing a preliminary design of the primary and secondary pressure regulating chambers based on the air supply flow rate, intake flow rate, inlet size, outlet size, height of the annular air curtain, and size of the micro-gap to obtain an initial annular air supply chamber; performing fluid simulation on the initial annular air supply chamber, and iteratively optimizing the size of the primary and secondary pressure regulating chambers based on the fluid simulation results to obtain the final annular air supply chamber.

[0015] The annular air supply chamber and its design method for particulate matter control in the wafer transport process disclosed herein have at least the following technical advantages:

[0016] When ultra-clean gas enters the primary pressure-stabilizing chamber through the inlet, the interstage gas transport between the primary and secondary pressure-stabilizing chambers is connected by a micro-gap. This narrow gap creates significant flow resistance, causing the gas to flow from the primary chamber into the secondary pressure-stabilizing chamber at a relatively uniform and stable velocity. The gas then fills the entire primary pressure-stabilizing chamber, undergoing a process of fluid deceleration and pressure homogenization. After flowing into the secondary pressure-stabilizing chamber at a lower velocity through the micro-gap, the gas undergoes secondary pressure homogenization and is discharged through the outlet connected to the end air supply chamber. This creates a sealed annular air curtain around the wafer, forming a high-cleanliness, flexible protective layer that safeguards the wafer surface from becoming too clean.

[0017] By rationally designing the porosity of the air vents, the uniformity of the gas flow rate at the outlet and the airtightness of the annular air curtain are ensured. Attached Figure Description

[0018] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0019] Figure 1 The diagram schematically illustrates the overall structure of an annular air supply chamber for particulate matter control in a wafer transport process according to an embodiment of the present disclosure.

[0020] Figure 2 A schematic cross-sectional view of an annular air supply chamber for particulate matter control in a wafer transport process according to an embodiment of the present disclosure is shown.

[0021] Figure 3 The diagram schematically illustrates the structure of a primary voltage regulator chamber and a secondary voltage regulator chamber according to embodiments of the present disclosure.

[0022] Figure 4 A schematic diagram illustrating the dimensions of an annular air supply chamber for a 4-inch wafer according to an embodiment of the present disclosure is shown.

[0023] Figure 5 The illustration shows a schematic diagram of the fluid domain modeling of the functional areas of each level of the pressure stabilizing chamber and the air outlet during fluid simulation analysis of an annular air supply chamber for a 4-inch wafer according to an embodiment of the present disclosure.

[0024] Figure 6A The diagram schematically illustrates the gas velocity distribution within the chamber near the air inlet and near the air outlet according to an embodiment of the present disclosure.

[0025] Figure 6BThe diagram schematically illustrates the gas velocity distribution away from and near the vent according to an embodiment of the present disclosure.

[0026] Figures 7A-7D The diagram schematically illustrates the outlet velocity distribution (XZ plane) at different locations corresponding to the annular air supply chamber with 60 air outlets according to an embodiment of the present disclosure.

[0027] Figure 8A The diagram schematically illustrates the outlet velocity distribution (XZ plane) at 1 mm corresponding to the annular air supply chamber with 120 air outlets according to an embodiment of the present disclosure.

[0028] Figure 8B The diagram schematically illustrates the outlet velocity distribution (XZ plane) at 5 mm corresponding to the annular air supply chamber with 120 air outlets according to an embodiment of the present disclosure. Detailed Implementation

[0029] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0030] Figure 1 The diagram schematically illustrates the overall structure of an annular air supply chamber for particulate matter control in a wafer transport process according to an embodiment of the present disclosure. Figure 2 A schematic cross-sectional view of an annular air supply chamber for particulate matter control in a wafer transport process according to an embodiment of the present disclosure is shown.

[0031] like Figure 1 and Figure 2 As shown, the annular air supply chamber for particulate matter control in the wafer transport process of this embodiment may include an annular air supply chamber, an air inlet, a primary voltage stabilizing chamber, a secondary voltage stabilizing chamber, and an air outlet.

[0032] The inner ring area of ​​the annular air supply cavity is used to place the wafer. The inner ring area can be understood as the inner circular area of ​​the annular air supply cavity.

[0033] The air inlet is located on the surface of the annular air supply cavity.

[0034] The primary pressure stabilizing chamber is located in the annular air supply chamber and is connected to the air inlet.

[0035] The secondary pressure stabilizing chamber is located in the annular air supply chamber, and the interstage gas transmission between the primary and secondary pressure stabilizing chambers is connected through a micro gap.

[0036] The vent is located on the annular air supply cavity and on the outer side of the wafer, and the vent is connected to the secondary voltage stabilizing cavity.

[0037] The primary pressure regulating chamber is used to initially reduce the speed and equalize the pressure of the clean gas introduced through the inlet under the high flow resistance of the micro gap. The secondary pressure regulating chamber is used to further reduce the speed and equalize the pressure of the clean gas after the initial pressure equalization through the micro gap. The outlet is used to spray out the clean gas after the pressure equalization, forming a stable annular air curtain around the wafer.

[0038] According to embodiments of this disclosure, ultra-high cleanliness gas is first introduced into the primary pressure-stabilizing chamber of the annular air supply chamber through an air inlet. The gas undergoes homogenization and pressure stabilization within the primary pressure-stabilizing chamber. The gas then flows through a micro-gap between the primary and secondary pressure-stabilizing chambers to the secondary pressure-stabilizing chamber, where it undergoes pressure homogenization again before being ejected through the air outlet of the annular air supply chamber. The airflow forms a stable, sealed annular air curtain around the wafer, preventing external contaminants such as particles from entering the wafer surface area.

[0039] Figure 3 The diagram schematically illustrates the structure of a primary voltage regulator chamber and a secondary voltage regulator chamber according to embodiments of the present disclosure.

[0040] like Figure 3 As shown, the primary pressure regulating chamber may include a gas expansion section and a primary pressure regulating chamber.

[0041] The gas expansion section is connected to the air inlet and is used to initially reduce the speed of the clean gas introduced through the air inlet.

[0042] Along the direction perpendicular to the flow of clean gas, the width of the gas expansion section is greater than the width of the inlet. After passing through the inlet, the gas enters the expansion section at the front end, where the space suddenly expands, the gas velocity decreases, and initial flow stabilization is achieved.

[0043] The primary pressure regulating chamber is connected to the gas expansion section and is used to perform initial pressure homogenization of the clean gas after the initial deceleration under the action of high flow resistance in the micro-gap.

[0044] Because the gas transmission gaps between stages are small, the gas encounters significant pipe resistance as it passes through. As the flow rate increases, the resistance increases dramatically, forcing the gas to fill the entire first-stage pressure-stabilizing chamber, thus achieving a preliminary pressure-stabilizing effect.

[0045] In some embodiments, an interstage gas transfer gap connects the primary and secondary pressure-stabilizing chambers via a micro-gap. Because the narrow gap creates significant flow resistance to the passing airflow, the airflow flows from the primary pressure-stabilizing chamber into the secondary pressure-stabilizing chamber at a relatively uniform and stable velocity. The secondary pressure-stabilizing chamber further decelerates and homogenizes the initially pressure-homogenized clean gas delivered through the micro-gap. Through these two deceleration and homogenization processes, a uniformly pressurized airflow is obtained.

[0046] The volume of the secondary pressure-regulating chamber can be larger than that of the primary pressure-regulating chamber. Since both the primary and secondary pressure-regulating chambers primarily function to homogenize pressure, their cross-sectional dimensions are much larger than those of the inlet, and the gas velocity is lower than that of the inlet and outlet. However, the airflow within the primary pressure-regulating chamber is unstable; high-speed airflow can create eddies. The secondary pressure-regulating chamber primarily serves to eliminate these eddies and homogenize the airflow. By designing the secondary pressure-regulating chamber to have a slightly larger volume than the primary chamber, the gas entering through the micro-gap further reduces its velocity due to the larger space, resulting in more uniform pressure and a more stable airflow.

[0047] In some embodiments, the secondary pressure stabilizing chamber may further include: an end air supply chamber, connected between the side wall of the secondary pressure stabilizing chamber and the air outlet, for making the clean gas output from the secondary pressure stabilizing chamber form a low-speed and pressure-uniform fluid state in the end air supply chamber, and for stably and uniformly delivering the clean gas to the air outlet.

[0048] After the gas is stabilized in the secondary pressure stabilizing chamber, it enters the terminal air supply chamber. The design of this area makes the gas flow rate lower and the pressure more uniform, providing a stable airflow to the air outlet.

[0049] In some embodiments, due to the presence of porosity, the air outlet is designed as an expansion hole, which is used to expand the ejected clean gas to ensure the airtightness of the annular air curtain.

[0050] In some embodiments, the porosity of the air outlet is related to the height of the annular air curtain and the diameter of the air outlet.

[0051] For example, the empirical formula for the porosity of the air outlet can be k>1.5 / (1+0.36h / d), where: k is the porosity; h is the height of the annular air curtain; and d is the diameter of the air outlet.

[0052] Furthermore, the porosity of the vent is in the range of 0.3 to 0.8.

[0053] In some embodiments, the vent diameter is related to the wafer size. For example, based on experimental experience, the vent diameter φ for a 4-inch wafer is 2mm, for an 8-inch wafer it is 4mm, for a 12-inch wafer it is 6mm, and so on.

[0054] In some embodiments, the number of air inlets is one or more. When the number of air inlets is multiple, the multiple air inlets are evenly distributed.

[0055] Embodiments of this disclosure also provide a design method for an annular air supply chamber. The method includes: selecting the flow velocity of the gas ejected from the outlet; determining the circumference of the stable annular air curtain to be formed around the wafer based on the wafer's dimensions; obtaining the air supply flow rate based on the gas flow velocity from the outlet, the circumference of the annular air curtain, and the effective thickness of the annular air curtain; determining the intake flow rate based on the design air velocity of the inlet and the selected inlet size; determining the outlet size and the size of the micro-gap between the primary and secondary pressure-stabilizing chambers based on the inlet size; performing a preliminary design of the primary and secondary pressure-stabilizing chambers based on the air supply flow rate, intake flow rate, inlet size, outlet size, height of the annular air curtain, and the size of the micro-gap to obtain an initial annular air supply chamber; performing fluid simulation on the initial annular air supply chamber; and iteratively optimizing the dimensions of the primary and secondary pressure-stabilizing chambers based on the fluid simulation structure to obtain the final annular air supply chamber.

[0056] Effective thickness refers to the thickness of the airflow at a certain wind speed on the cross-section of the target height of the annular air curtain. The greater the thickness, the better the protection effect. For example, airflow with a wind speed greater than 0.03 m / s has an air curtain effect.

[0057] It should be noted that the height of the annular air curtain varies in different wafer transport processes. A higher annular air curtain provides better particle protection, but also has a greater impact on the wafer's microenvironment temperature and micro-vibration. Therefore, the appropriate annular air curtain height should be determined based on the application scenario. The air curtain height, wafer circumference, and annular air curtain velocity (to ensure laminar flow, the velocity at the outlet is generally 0.3-0.5 m / s) are three parameters that determine the airflow rate of the annular air curtain. The inlet velocity should generally not exceed 10 m / s; excessively high velocities can easily generate whistling and flow-induced vibrations, disrupting the wafer's microenvironment. The size and number of inlets can be determined by combining the airflow rate.

[0058] To more clearly illustrate the dimensional design process of the annular air supply chamber provided in the embodiments of this disclosure, a specific example is given below.

[0059] Application Case: For a 4-inch wafer (approximately 10cm in diameter), a closed annular air curtain is required to be formed within 5mm above the wafer. To achieve good particle control, the effective thickness of the annular air curtain is set to 3mm based on experience, with an air velocity of 0.03m / s.

[0060] Design process: Air supply flow rate Q = 2πrtv = 2 × 3.14 × 0.05 × 0.003 × 0.03 = 0.101736 m³ 3 / h.

[0061] If the selected inlet diameter D1 is φ2mm and the inlet flow velocity is 6m / s, the single-hole inlet flow rate is q=vπr. 2 =6×3.14×0.001 2 =0.067824m 3 / h; Since Q>q, the number of air inlets is Q / q≈2.

[0062] The diameter of the vent is D2 = 0.6D1 = 1.2 mm;

[0063] Porosity k > 1.5 / (1+0.36h / D2) = 1.5 / (1+0.36×5 / 1.2) = 0.6; In this example, the height h of the annular air curtain is 5mm, and the diameter D2 of the air outlet is 1.2mm. In this example, 120 air outlets correspond to k = 0.708 (to compare the effect of air curtains with low porosity, a simulation example of an annular air curtain with 60 air outlets was added for comparison).

[0064] The micro-gap d1 = 0.3D1 = 0.6 mm;

[0065] For the first-stage voltage stabilizing chamber, h1 ≥ 6D1 = 12 mm, and in this example, h1 = 15 mm; W1 ≥ 2D1 = 4 mm, and in this example, W1 = 4 mm; W2 ≥ 3D1 = 6 mm, and in this example, W2 = 7 mm.

[0066] Secondary voltage regulator chamber h2=15mm; W3≥3D1=6mm, in this example W3=6mm;

[0067] For the terminal air supply cavity, h3 ≥ 1 / 2h1 = 7.5 mm, and in this example, h3 = 8 mm; W4 ≥ 2D1 = 4 mm, and in this example, W4 = 6 mm; d2 ≥ D1 = 2 mm, and in this example, d2 = 3 mm.

[0068] Figure 4 A schematic diagram illustrating the dimensions of an annular air supply chamber for a 4-inch wafer according to an embodiment of the present disclosure is shown.

[0069] like Figure 4 As shown, the diameter of the air inlet of the annular air supply chamber facing the 4-inch wafer is 2mm, the width of the micro gap is 0.6mm, the height of the first-stage voltage regulator chamber is 15mm, the width of the first-stage voltage regulator chamber is 7mm, the width of the second-stage voltage regulator chamber is 6mm, the width of the end air supply chamber is 6mm, the diameter of the air outlet is 1.2mm, the total height of the annular air supply chamber is 20mm, and the total width is 19mm.

[0070] Figure 5The illustration shows a schematic diagram of the fluid domain modeling of the functional areas of each level of the pressure stabilizing chamber and the air outlet during fluid simulation analysis of an annular air supply chamber for a 4-inch wafer according to an embodiment of the present disclosure.

[0071] like Figure 5 As shown, clean gas enters the primary and secondary pressure regulating chambers sequentially through the inlet for deceleration and pressure homogenization, and is ejected through the circumferentially distributed outlet structure, forming a gas-sealed and stable flow field in the bottom cylindrical fluid domain.

[0072] Figure 6A The diagram schematically illustrates the gas velocity distribution within the chamber near the air inlet and near the air outlet according to an embodiment of the present disclosure. Figure 6B The diagram schematically illustrates the gas velocity distribution away from and near the air outlet according to an embodiment of the present disclosure. Simulation results show that the gas velocity in the primary pressure-stabilizing chamber on the inlet side is high, and unstable turbulence exists. However, in the primary pressure-stabilizing chamber away from the inlet side, the gas velocity decreases, and initial homogenization is achieved. Comparing the simulation results at the two locations, the airflow is stable in the secondary pressure-stabilizing chamber, thus ensuring a uniform and stable outlet velocity at the air outlets at different locations. In this example, the velocity at each air outlet is close to 0.4 m / s, which is close to the design expectation.

[0073] Figures 7A-7D The diagram schematically illustrates the outlet velocity distribution (XZ plane) at different locations corresponding to the annular air supply chamber with 60 air outlets according to an embodiment of the present disclosure.

[0074] like Figures 7A-7D As shown, the velocity distributions correspond to the air outlet, 1 mm from the air outlet, 5 mm from the air outlet, and 8 mm from the air outlet, respectively. From Figures 7A-7D It can be seen that due to the unreasonable setting of porosity, there are gaps in the annular air curtain formed at the outlet.

[0075] Cross-sections of the flow field at different distances from the outlet reveal that the outlet velocity decreases rapidly with increasing gas ejection distance, while the diffused gas gradually forms a closed annulus. The porosity of the outlet affects the continuity of the flow field at the outlet, and a lower outlet velocity also leads to a lower velocity in the annular air curtain, resulting in decreased airtightness. Fluid parameters and the design of the outlet structure have a significant impact on the effectiveness of the annular air curtain.

[0076] Figure 8A The diagram schematically illustrates the outlet velocity distribution (XZ plane) at 1 mm corresponding to an annular air supply chamber with 120 air outlets according to an embodiment of the present disclosure. The left figure shows the simulation results of a structure with 60 air outlets, the upper right figure shows the simulation results of a structure with a single air inlet and 120 air outlets, and the lower right figure shows the simulation results of a structure with two air inlets and 120 air outlets.

[0077] Figure 8B The diagram schematically illustrates the outlet velocity distribution (XZ plane) at 5 mm corresponding to the annular air supply chamber with 120 air outlets according to an embodiment of the present disclosure. The left figure shows the simulation results of a 60-air-outlet structure, the upper right figure shows the simulation results of a 120-air-outlet structure with a single air inlet, and the lower right figure shows the simulation results of a 120-air-outlet structure with two air inlets.

[0078] The comparison revealed that increasing the number of air outlets and the porosity resulted in a faster formation of a sealed annular air curtain at the air outlets (a relatively uniform annular air curtain had already formed 5mm from the air outlet). Simultaneously, increasing the number of air inlets facilitated gas homogenization; the sealed annular air curtain formed by 120 air outlets from two air inlets exhibited even higher uniformity.

[0079] Based on the simulation results above, it can be seen that to achieve homogenization and static pressure of the high-speed gas source, the gas velocity inside the pipe reaches 6 m / s before the clean gas reaches the annular air supply chamber. The annular air supply chamber needs to reduce the gas velocity and stabilize the pressure. By rationally designing the secondary pressure stabilizing chamber and the porosity of the air outlet, the air velocity at the air outlet is stabilized at 0.4 m / s, achieving the stability and sealing of the annular air curtain. This also proves that the annular air supply chamber used for wafer particle control can form a uniform and stable sealed annular air curtain around the wafer, preventing particulate matter in the environment from intruding into the space above the wafer, thereby protecting the cleanliness of the wafer surface.

[0080] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An annular air supply chamber for particulate matter control in wafer transport processes, characterized in that, include: An annular air supply cavity, wherein the inner annular region of the annular air supply cavity is used to place wafers; An air inlet is provided on the surface of the annular air supply cavity; A primary pressure-stabilizing chamber is disposed in the annular air supply chamber and communicates with the air inlet. A secondary pressure-stabilizing chamber is disposed in the annular air supply chamber, and the interstage gas transmission between the primary pressure-stabilizing chamber and the secondary pressure-stabilizing chamber is connected through a micro gap; An air outlet is provided on the annular air supply cavity and located on the outside of the wafer, and is connected to the secondary voltage stabilizing cavity; The primary pressure regulating chamber is used to initially reduce the speed and equalize the pressure of the clean gas introduced through the inlet under the high flow resistance of the micro gap. The secondary pressure regulating chamber is used to further reduce the speed and equalize the pressure of the clean gas after the initial pressure equalization through the micro gap. The outlet is used to spray out the clean gas after the pressure equalization, forming a stable annular air curtain around the wafer.

2. The annular air supply chamber according to claim 1, characterized in that, The primary voltage stabilizing chamber includes: A gas expansion section, connected to the air inlet, is used to initially reduce the velocity of the clean gas introduced through the air inlet; the width of the gas expansion section is greater than the width of the air inlet along the flow direction perpendicular to the clean gas. The primary pressure regulating chamber, connected to the gas expansion section, is used to perform initial pressure homogenization of the clean gas after initial deceleration under the action of high flow resistance in the micro-gap.

3. The annular air supply chamber according to claim 1 or 2, characterized in that, The volume of the secondary voltage regulator chamber is greater than the volume of the primary voltage regulator chamber.

4. The annular air supply chamber according to claim 3, characterized in that, The secondary voltage stabilizing chamber also includes: The terminal air supply chamber is connected between the secondary pressure stabilizing chamber and the air outlet. It is used to make the clean gas output from the secondary pressure stabilizing chamber form a low-speed and pressure-uniform fluid state in the terminal air supply chamber, and to stably and uniformly deliver the clean gas to the air outlet.

5. The annular air supply chamber according to claim 1, characterized in that, The air outlet is an expansion hole, which is used to expand the ejected clean gas to ensure the airtightness of the annular air curtain.

6. The annular air supply chamber according to claim 1 or 5, characterized in that, The porosity of the air outlet is related to the height of the annular air curtain and the diameter of the air outlet.

7. The annular air supply chamber according to claim 6, characterized in that, The porosity of the air outlet is in the range of 0.3 to 0.

8.

8. The annular air supply chamber according to claim 2, characterized in that, The size of the air inlet is related to the size of the wafer.

9. The annular air supply chamber according to claim 1, characterized in that, The number of air inlets is one or more.

10. A design method for an annular air supply chamber, used to design the annular air supply chamber for particulate matter control in the wafer transport process as described in any one of claims 1 to 8, characterized in that, include: Select the flow rate of the gas ejected from the vent, and determine the circumference of the stable annular air curtain that needs to be formed around the wafer based on the wafer size; The airflow rate is obtained based on the flow rate of the gas ejected from the air outlet, the circumference of the annular air curtain, and the effective thickness of the annular air curtain. The intake flow rate is determined based on the design wind speed of the intake port and the selected size of the intake port. The size of the exhaust port and the size of the micro gap between the primary and secondary pressure regulating chambers are also determined based on the size of the intake port. Based on the air supply flow rate, air intake flow rate, air intake hole size, air outlet hole size, height of the annular air curtain, and the size of the micro gap, the initial design of the primary and secondary pressure stabilizing chambers is carried out to obtain the initial annular air supply chamber. Fluid simulation was performed on the initial annular air supply chamber. Based on the fluid simulation results, the dimensions of the primary and secondary pressure stabilizing chambers were iteratively optimized to obtain the final annular air supply chamber.

Images