Gas path control system, gas path control method and semiconductor processing equipment

Abstract

This invention discloses a gas path control system, a gas path control method, and a semiconductor processing device. The gas path control system includes a vacuum gas path, a vacuum adsorption device, a vacuum proportional valve, and a control terminal. The vacuum gas path is connected to a vacuum source. The vacuum adsorption device has at least one adsorption surface, and airflow holes on the adsorption surface are connected to the vacuum gas path. The vacuum proportional valve is disposed in the vacuum gas path and is used to adjust the vacuum adsorption force supplied to the vacuum adsorption device. The control terminal is signal-connected to the vacuum proportional valve. The control terminal is used to output a continuously varying analog control signal to the vacuum proportional valve to drive the vacuum adsorption force of the vacuum adsorption device to linearly increase from a basic set value to a formal set value. Therefore, this invention can solve the technical problem that during wafer adsorption, a single set adsorption value causes a significant change in stress distribution or local deformation when the wafer contacts the chuck, resulting in poor measurement accuracy near the wafer edge.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and specifically to a pneumatic control system, a pneumatic control method, and a semiconductor processing equipment. Background Technology

[0002] In semiconductor thin-film metrology equipment, a wafer carrier is essential for stable wafer support and fixation, ensuring accurate measurement by the optical system. The current mainstream wafer carrier is the vacuum chuck, which works by using the negative pressure created by a vacuum to adhere the wafer to its surface. In existing designs, the vacuum system typically only has a manual pressure regulating valve. After adjusting the vacuum pressure to a suitable value for wafer adhesion during the commissioning phase, no further adjustments are usually made during subsequent processes.

[0003] With the continuous advancement of semiconductor manufacturing processes, thin-film metrology equipment needs to process increasingly thinner wafers. These wafers are more sensitive to the stress distribution on the adsorption surface and the geometry of the chuck, especially at the edges, where measurement results are more easily affected by the adsorption method. Currently, the method of using a single vacuum pressure to adsorb the entire wafer causes a drastic change in stress state at the moment of contact between the wafer and the chuck, even leading to localized deformation, particularly noticeable at the wafer edges. This problem ultimately causes deviations in the optical system's measurement of the thin film thickness at the wafer edges, affecting measurement accuracy. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a gas path control system, a gas path control method, and a semiconductor processing device to avoid drastic changes in stress state or even local deformation caused by the instant the wafer contacts the chuck.

[0005] To achieve the above and other related objectives, the present invention provides a gas path control system, which includes:

[0006] The vacuum circuit is connected to the vacuum source;

[0007] A vacuum adsorption device has at least one adsorption surface, and the airflow holes on the adsorption surface are connected to the vacuum path, for performing wafer adsorption operation under vacuum pressure.

[0008] A vacuum proportional valve, located in the vacuum circuit, is used to adjust the vacuum adsorption force supplied to the vacuum adsorption device.

[0009] The control terminal is connected to the vacuum proportional valve signal; the control terminal is used to output a continuously changing analog control signal to the vacuum proportional valve to drive the opening of the vacuum proportional valve to increase linearly, thereby controlling the vacuum adsorption force of the vacuum adsorption device to increase linearly from the basic set value to the formal set value.

[0010] Optionally, the control terminal is also used to output a control signal to the vacuum proportional valve to control the vacuum pressure of the vacuum adsorption device to reach the basic set value.

[0011] Optionally, the calculation formulas for the basic setting value and the formal setting value are: P0 + kt = P1, where: P0 is the basic setting value; P1 is the formal setting value; k is the negative pressure change value per unit time; and t is the linearly increasing time.

[0012] Optionally, the ratio of the basic setting value to the formal setting value is between 0.5 and 0.8.

[0013] Optionally, the gas path control system also includes:

[0014] The first on / off valve is located upstream of the vacuum proportional valve and is used to control the opening and closing of the vacuum circuit.

[0015] Optionally, the gas path control system also includes:

[0016] A pressure sensor is installed between the vacuum proportional valve and the vacuum adsorption device to detect the actual vacuum pressure supplied to the vacuum adsorption device in real time and feed it back to the control terminal.

[0017] Optionally, the gas path control system also includes:

[0018] The second on / off valve is located between the vacuum proportional valve and the vacuum adsorption device, and is used to control the on / off state of the vacuum proportional valve and the vacuum adsorption device.

[0019] Optionally, the vacuum adsorption device is a wafer vacuum chuck.

[0020] Optionally, the wafer adsorption device includes:

[0021] Supporting protrusions are spaced apart on the adsorption surface and are higher than the adsorption surface;

[0022] A sealed structure is located at the edge of the adsorption surface;

[0023] During vacuum adsorption, the wafer, adsorption surface, sealing structure, and support bumps form a vacuum cavity.

[0024] Optionally, the wafer adsorption device further includes:

[0025] The robotic arm receiving groove is recessed from the edge of the adsorption surface towards the center of the adsorption surface, and is used to accommodate the robotic arm that transports wafers.

[0026] Optionally, the adsorption surface of the wafer adsorption device is provided with a central partition and at least one edge partition surrounding the central partition. Each partition is individually connected to a vacuum circuit, and the control terminal is used to control the vacuum adsorption value of the central partition to increase linearly from a basic set value to a formal set value.

[0027] Optionally, a second on / off valve is provided on each branch connecting the partition to the vacuum circuit, and the control terminal is used to control each partition from the center to the edge to open sequentially within a preset time interval.

[0028] Optionally, the vacuum chuck includes a first edge partition and a second edge partition, the first edge partition being arranged around the center partition, and the second edge partition being arranged around the first edge partition.

[0029] The present invention provides a semiconductor processing apparatus, which includes a gas path control system for a vacuum adsorption device, wherein the gas path control system is the aforementioned gas path control system.

[0030] According to one aspect of the present invention, a gas path control method is also provided, which is executed by the aforementioned gas path control system. The gas path control method includes:

[0031] Control the valve opening of the vacuum proportional valve connected to the vacuum circuit to keep the vacuum pressure of the vacuum adsorption device at the basic set value.

[0032] The gas path is opened, and the vacuum adsorption device initially adsorbs the wafer at the basic set vacuum pressure.

[0033] By controlling the opening of the vacuum proportional valve, the vacuum pressure of the vacuum adsorption device is linearly increased from the basic set value to the official set value, and the wafer gradually comes into contact with the adsorption surface of the vacuum adsorption device.

[0034] According to one aspect of the present invention, a gas path control method is also provided, which is executed by the aforementioned gas path control system. The gas path control method includes: controlling the valve opening of a vacuum proportional valve connected to a vacuum gas path to control the vacuum pressure of the central section of the vacuum adsorption device at a basic set value.

[0035] The gas path is opened, and the vacuum adsorption device initially adsorbs the wafer at the basic set vacuum pressure.

[0036] By controlling the opening of the vacuum proportional valve, the vacuum pressure in the central section of the vacuum adsorption device increases linearly from the basic set value to the official set value, and the wafer or the part of the wafer corresponding to the central section gradually comes into contact with the adsorption surface of the vacuum adsorption device.

[0037] Optionally, the adsorption surface of the vacuum adsorption device includes a first edge zone and a second edge zone, the first edge zone surrounding the central zone, and the second edge zone surrounding the first edge zone; the gas path control method includes:

[0038] Control the opening of the vacuum proportional valve to keep the vacuum pressure in the first edge zone of the vacuum adsorption device at the set value.

[0039] The gas path is opened, and the vacuum adsorption device adsorbs the wafer and the area corresponding to the first edge partition at the officially set vacuum pressure.

[0040] Control the opening of the vacuum proportional valve to keep the vacuum pressure in the second edge zone of the vacuum adsorption device at the set value.

[0041] The gas path is opened, and the vacuum adsorption device adsorbs the wafer and the area corresponding to the second edge partition at the officially set vacuum pressure.

[0042] Compared with the prior art, the gas path control system, gas path control method, and semiconductor processing equipment of the vacuum adsorption device of the present invention have at least the following beneficial effects:

[0043] The gas path control system of the vacuum adsorption device of the present invention includes a vacuum gas path, a vacuum adsorption device, a vacuum proportional valve, and a control terminal. The vacuum gas path is connected to a vacuum source. The vacuum adsorption device has at least one adsorption surface, and airflow holes on the adsorption surface are connected to the vacuum gas path for performing wafer adsorption under vacuum pressure. The vacuum proportional valve is disposed in the vacuum gas path and is used to adjust the vacuum adsorption force supplied to the vacuum adsorption device. The control terminal is signal-connected to the vacuum proportional valve and is used to output a continuously varying analog control signal to the vacuum proportional valve to drive the opening of the vacuum proportional valve to increase linearly, thereby controlling the vacuum adsorption force of the vacuum adsorption device to increase linearly from a basic set value to a formal set value. Therefore, the present invention can solve the technical problem that during wafer adsorption, a single set adsorption value causes a significant change in stress distribution or local deformation when the wafer contacts the chuck, resulting in poor measurement accuracy near the wafer edge.

[0044] The semiconductor processing apparatus of the present invention includes the above-mentioned gas path control system, and the gas path control method is executed by the gas path control system, thus possessing the above-mentioned technical effects. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the gas path control system in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the gas path control process in an embodiment of the present invention;

[0047] Figure 3This is a schematic diagram of the vacuum chuck in an embodiment of the present invention;

[0048] Figure 4 for Figure 3 A magnified view of a medium vacuum chuck;

[0049] Figure 5 This is a schematic diagram of the structure of a vacuum chuck in another embodiment of the present invention;

[0050] Figure 6 for Figure 5 A schematic diagram of the gas path control system of a medium vacuum chuck.

[0051] Illustration of reference numerals in the attached diagram:

[0052] 10. Vacuum circuit; 11. First on / off valve; 12. Check valve; 13. Vacuum proportional valve; 14. Second on / off valve; 15. Pressure sensor; 16. Vacuum adsorption device.

[0053] 161. Adsorption surface; 162. Airflow hole; 163. Support protrusion; 164. Sealing structure; 165. Fixing hole; 166. Robot arm receiving groove; 167. Central partition; 168. First edge partition; 169. Second edge partition. Detailed Implementation

[0054] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0055] It should be understood that the illustrations provided in the embodiments of this invention are merely schematic representations of the basic concept of the invention. Although the illustrations only show components relevant to the invention and are not drawn according to the actual number, shape, and size of components in implementation, the shape, quantity, and proportion of each component can be arbitrarily changed in actual implementation, and the component layout may also be more complex. The structures, proportions, sizes, etc., shown in the accompanying drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the invention can produce, should still fall within the scope of the technical content disclosed in this application.

[0056] In existing technologies, vacuum pressure control of vacuum chucks often uses only a single set value. When the vacuum chuck simultaneously adsorbs various parts of the wafer, it can cause a significant change in stress distribution or localized deformation at the moment of contact between the wafer and the chuck, resulting in poor measurement accuracy near the wafer edge. To address the background technology and the aforementioned technical problems, this embodiment provides a gas path control system for a vacuum adsorption device and a semiconductor processing apparatus to solve the technical problem of poor measurement accuracy near the wafer edge caused by a single set adsorption value leading to a significant change in stress distribution or localized deformation at the moment of contact between the wafer and the chuck.

[0057] The present invention will now be described in detail with reference to specific embodiments.

[0058] Example 1

[0059] This embodiment provides a gas path control system for a vacuum adsorption device, referring to... Figure 1 The gas path control system includes a vacuum air path 10, a vacuum adsorption device 16, a vacuum proportional valve 13, and a control terminal (not shown in the figure).

[0060] The vacuum path 10 is connected to a vacuum source. Optionally, the vacuum source is a plant vacuum source, typically provided by a vacuum generator at the plant level or within the equipment. The vacuum adsorption device 16 is used to adsorb wafers under vacuum pressure. Optionally, the vacuum adsorption device 16 is one of a vacuum chuck, a robotic arm, or a pre-alignment unit. In this embodiment, the vacuum adsorption device 16 is a vacuum chuck, which has at least one adsorption surface 161. Airflow holes 162 on the adsorption surface 161 are connected to the vacuum path 10, and are used to perform wafer adsorption operations under vacuum pressure.

[0061] A vacuum proportional valve 13 is installed in the vacuum circuit 10 to adjust the vacuum adsorption force supplied to the vacuum adsorption device 16. A control terminal is signal-connected to the vacuum proportional valve 13 and outputs a continuously varying analog signal to control the opening of the valve, linearly increasing the vacuum adsorption force of the vacuum adsorption device 16 from a basic set value to a final set value. Thus, when the vacuum chuck adsorbs a wafer, it first initially adsorbs and fixes the wafer at the basic set value, and then gradually increases the vacuum pressure linearly, allowing the wafer adsorption to proceed gradually until it fully adheres to the adsorption surface 161 of the wafer adsorption device. This two-stage wafer adsorption ensures safety while preventing significant changes in stress distribution or localized deformation, especially at the wafer edges, during the moment of contact with the chuck under high adsorption force. Optionally, before controlling the linear increase, the control terminal first outputs a control signal to the vacuum proportional valve to control the vacuum pressure of the vacuum adsorption device to reach the basic set value. Optionally, the formula for calculating the basic setting value and the formal setting value is: P0 + kt = P1, where: P0 is the basic setting value; P1 is the formal setting value; k is the negative pressure change value per unit time; and t is the linear increase time. The value of t, the linear increase time, is obtained based on tests of the warp state of different wafers, and can be, for example, 1 to 3 seconds. It should be noted that the vacuum pressure is actually negative pressure, and the linear increase in this invention refers to the increase in the absolute value of the negative pressure or the increase in pressure. Optionally, the ratio of the basic setting value to the formal setting value ranges from 0.5 to 0.8; for example, the basic setting value P0 is -40 kPa, and P1 is -70 kPa.

[0062] In this embodiment, the vacuum proportional valve 13 is an electronic vacuum proportional pressure regulating valve. The control terminal is a host computer. The vacuum proportional pressure regulating valve communicates with the host computer and adjusts the vacuum pressure through electrical proportional signals. Specifically, after receiving the pressure setpoint from the host computer, the vacuum proportional pressure regulating valve controls the on / off state of the internal vacuum solenoid valve and atmospheric solenoid valve, as well as the vacuum pressure valve core state, through its internal control loop. It then forms a closed-loop control system based on feedback from the pressure sensor 15, ultimately outputting the set vacuum pressure. The pressure sensor 15 monitors the vacuum pressure that finally reaches the vacuum chuck and uploads the signal to the host computer.

[0063] The gas path control method of the above-mentioned gas path control system includes: controlling the valve opening of the vacuum proportional valve 13 connected to the vacuum air path 10 to control the vacuum pressure of the vacuum adsorption device 16 at a basic set value. The gas path is opened, and the vacuum adsorption device 16 initially adsorbs the wafer at the basic set vacuum pressure. The valve opening of the vacuum proportional valve 13 is controlled so that the vacuum pressure of the vacuum adsorption device 16 increases linearly from the basic set value to the formal set value, and the wafer gradually adheres to the adsorption surface of the vacuum adsorption device 16.

[0064] Specifically, after the adsorption process begins, refer to Figure 1 and Figure 2 The host computer controls the vacuum proportional valve 13 to bring the vacuum pressure to the basic set value. Then, it opens the two-position three-way valve, generating negative pressure on the vacuum chuck. The robotic arm places the wafer onto the vacuum chuck, where it is initially adsorbed and fixed. After the robotic arm completes its operation, the host computer controls the vacuum proportional valve 13 to gradually and linearly increase the pressure to the formal set value. The host computer then checks whether the pressure value measured by the pressure sensor 15 has reached or is close to the formal pressure value. If so, the adsorption is successful; otherwise, the adsorption has failed. The basic set value here is lower than the formal set value, primarily serving as an initial adsorption and fixation for the wafer. During the measurement process of the thin-film metrology equipment, the vacuum chuck carries the wafer to different positions for measurement. The small adsorption force at the basic set value may cause the wafer to slip or even fall off under high acceleration. Therefore, it is necessary to further increase the pressure to the formal set value. In this process, the vacuum pressure is controlled to increase gradually and linearly, allowing the wafer adsorption to be a gradual process until it gradually and completely adheres to the adsorption surface 161 of the wafer adsorption device. This two-stage approach ensures safety while also preventing significant changes in stress distribution or localized deformation of the wafer at the moment of contact with the chuck under high suction force, especially at the wafer edge.

[0065] Optionally, the gas path control system further includes a first on / off valve 11, which is located upstream of the vacuum proportional valve 13 and is used to control the on / off of the gas path within the vacuum gas path 10. This first on / off valve 11 is a manual shut-off valve, which can be used to cut off the vacuum source during maintenance or repair. Optionally, a one-way valve 12 is also provided between the first on / off valve 11 and the vacuum proportional valve 13, which can prevent backflow of gas. Optionally, the gas path control system further includes a second on / off valve 14, located between the vacuum proportional valve 13 and the vacuum adsorption device 16, and is used to control the on / off of the connection between the vacuum proportional valve 13 and the vacuum adsorption device 16. In this embodiment, the second on / off valve 14 is a two-position three-way valve, and these two three-way valves can be used to connect other gas paths.

[0066] Optionally, the gas path control system also includes a pressure sensor 15, which is disposed between the vacuum proportional valve 13 and the vacuum adsorption device 16. This pressure sensor 15 monitors the actual vacuum pressure supplied to the vacuum adsorption device 16 in real time and feeds it back to the control terminal. The control terminal, in conjunction with the pressure sensor 16, performs closed-loop calibration to ensure that the actual adsorption value increases at a preset slope. In this embodiment, refer to... Figure 3 and Figure 4The vacuum chuck has support protrusions 163 and a sealing structure 164 on its adsorption surface 161. The support protrusions 163 are spaced apart on the adsorption surface 161 and are higher than the plane on which the adsorption surface 161 is located. The sealing structure 164 is located at the edge of the adsorption surface 161 and is at the same height as the support protrusions 163. During vacuum adsorption, the wafer placed on the support protrusions 163, the adsorption surface 161, and the sealing structure 164 form a vacuum cavity. Negative pressure is introduced through the airflow holes 162 on the adsorption surface 161. The negative pressure is drawn away by the air in the sealing cavity to form a vacuum cavity, thereby achieving the purpose of adsorbing the wafer. Optionally, the wafer adsorption device is also provided with a robotic arm receiving groove 166. The robotic arm receiving groove 166 is recessed from the edge of the adsorption surface 161 towards the center of the adsorption surface 161 to accommodate the robotic arm that transports the wafer, ensuring that the robotic arm does not interfere with the body of the vacuum adsorption device 16 when placing the wafer. Optionally, the wafer adsorption device includes a fixing hole 165 for fixing the wafer chuck, and a sealing structure is also provided around the fixing hole 165.

[0067] However, in the above scheme, only one vacuum cavity can be formed between the wafer and the vacuum chuck during wafer adsorption. This embodiment forms multiple vacuum cavity structures by changing the distribution of the sealing structure 164 and the supporting bumps 163 of the vacuum chuck. Specifically, refer to... Figure 5 The wafer adsorption device has an adsorption surface 161 with a central partition 167 and at least one edge partition surrounding the central partition 167. Each partition has a sealing structure 164 at its edge, and each partition contains airflow holes 162 and support protrusions 163. The adsorption gas path for each partition is independently configured, and each region has a certain number of airflow holes 162 to accommodate wafers of different sizes. When adsorbing large wafers, the adsorption process can be initiated sequentially from the center to the edge. This allows for a gradual adsorption process from the center to the edge and avoids large-scale high-side stress distribution or localized deformation at the moment the wafer edge contacts the vacuum chuck under high adsorption force.

[0068] Optionally, refer to Figure 6Each partition is individually connected to vacuum path 10. The control terminal is used to control the vacuum adsorption value of the central partition 167 to increase linearly from a basic set value to a formal set value. A second on / off valve is installed on each partition's connection branch to the vacuum path. The control terminal is used to control the sequential opening of each partition from the center to the edge within a preset time interval. In this embodiment, the second on / off valve is a two-position three-way valve 14. Optionally, a pressure sensor 15 is also installed on each partition's connection branch to monitor and provide real-time feedback of the branch pressure. During gas path control, the opening degree of the vacuum proportional valve 13 connected to vacuum path 10 is first controlled to maintain the vacuum pressure of the central partition 167 of the vacuum adsorption device 16 at the basic set value. The gas path is then opened, and the vacuum adsorption device 16 initially adsorbs the wafer at the basic set vacuum pressure. The opening degree of the vacuum proportional valve 13 is controlled to linearly increase the vacuum pressure of the central partition 167 of the vacuum adsorption device 16 from the basic set value to the formal set value, so that the wafer or the part of the wafer corresponding to the central partition 167 gradually comes into contact with the adsorption surface of the vacuum adsorption device 16. When the wafer size is small and only matches the size of the central partition 167, vacuum adsorption can be activated only in the central partition 167. For large wafers, the vacuum of the corresponding partitions can be activated sequentially from the central partition 167 to the edge partitions. In this case, only the vacuum adsorption value of the central partition 167 can be set to increase linearly, while the other edge partitions can be set to fixed formal set values. Specifically, when performing gas path control, after the wafer adsorption in the central partition 167, the following steps are also included: controlling the opening degree of the vacuum proportional valve 13 to control the vacuum pressure of the first edge partition 168 of the vacuum adsorption device 16 at the formal set value. The gas path is opened, and the vacuum adsorption device 16 adsorbs the area of ​​the wafer corresponding to the first edge partition 168 at the formal set vacuum pressure. The opening degree of the vacuum proportional valve 13 is controlled to maintain the vacuum pressure of the second edge zone 169 of the vacuum adsorption device 16 at the officially set value. The gas path is opened, and the vacuum adsorption device 16 adsorbs the wafer into the area corresponding to the second edge zone 169 at the officially set vacuum pressure.

[0069] Optionally, all zones can be configured for gradual vacuum adsorption. In this case, a vacuum proportional valve 13 needs to be installed on the vacuum branch of each zone to regulate the vacuum pressure. Of course, it is also possible to set a fixed vacuum pressure adsorption value for all zones.

[0070] In this embodiment, refer to Figure 5The vacuum disk features a central partition 167 surrounded by two edge partitions: a first edge partition 168 and a second edge partition 169. The first edge partition 168 surrounds the central partition 167, and the second edge partition 169 surrounds the first edge partition 168. The vacuum paths 10 of each edge partition are independent, and each region contains a certain number of airflow holes 162. This design can adsorb wafers of different sizes. For example, small wafers can be adsorbed using only the vacuum cavity created by the central partition 167, while large wafers can be adsorbed using two or three vacuum cavities created by the central partition 167, the first edge partition 168, or the second edge partition 169.

[0071] When adsorbing large-sized wafers, the vacuum passages 10 of the center partition 167, the first edge partition 168, and the second edge partition 169 can be opened sequentially at time intervals. When adsorbing the wafer, the two-position three-way valve of the gas passage in the center partition 167 can be opened first to adsorb the small inner diameter area of ​​the wafer. Then, the two-position three-way valves of the gas passages in the first edge partition 168 and the second edge partition 169 can be opened sequentially. This allows for a gradual adsorption process of the wafer from the center to the edge, avoiding a significant change in stress distribution or local deformation at the moment of contact between the wafer edge and the chuck under high adsorption force.

[0072] Example 2

[0073] This embodiment provides a semiconductor processing apparatus, which includes a gas path control system for a vacuum adsorption device. The gas path control system is the same as that in Embodiment 1. Optionally, the semiconductor processing apparatus is a thin film measurement device.

[0074] Existing thin film measurement equipment often uses a vacuum chuck to adsorb wafers, employing a single set vacuum pressure for instantaneous adsorption. This can cause significant changes in stress distribution or localized deformation at the wafer edge, leading to inaccurate film thickness measurements at the wafer edge by the optical system. This embodiment uses a vacuum proportional valve to control the gradual pressure or divides the vacuum chuck into sections, allowing for gradual adsorption of the wafer over time. This reduces changes in stress distribution or localized deformation at the wafer edge, resulting in more accurate film thickness measurements.

[0075] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A pneumatic control system, characterized in that, The gas path control system includes: The vacuum circuit is connected to the vacuum source; A vacuum adsorption device has at least one adsorption surface, wherein airflow holes on the adsorption surface are connected to the vacuum air path, and is used to perform wafer adsorption operation under vacuum pressure. A vacuum proportional valve is installed in the vacuum circuit to adjust the vacuum adsorption force supplied to the vacuum adsorption device. A control terminal is connected to the vacuum proportional valve via a signal connection. The control terminal is used to output a continuously varying analog control signal to the vacuum proportional valve to drive the opening of the vacuum proportional valve to increase linearly, thereby controlling the vacuum adsorption force of the vacuum adsorption device to increase linearly from the basic set value to the formal set value.

2. The gas path control system according to claim 1, characterized in that, The control terminal is also used to output a control signal to the vacuum proportional valve to control the vacuum pressure of the vacuum adsorption device to reach the basic set value.

3. The gas path control system according to claim 1, characterized in that, The calculation formulas for the basic setting value and the formal setting value are: P0 + kt = P1, where: P0 is the basic setting value; P1 is the formal setting value; k is the negative pressure change value per unit time; and t is the linearly increasing time.

4. The gas path control system according to claim 3, characterized in that, The ratio of the base setting value to the official setting value ranges from 0.5 to 0.

8.

5. The gas path control system according to claim 1, characterized in that, The gas circuit control system also includes: The first on / off valve is located upstream of the vacuum proportional valve and is used to control the on / off state of the vacuum circuit.

6. The gas path control system according to claim 1, characterized in that, The gas circuit control system also includes: A pressure sensor is installed between the vacuum proportional valve and the vacuum adsorption device to detect the actual vacuum pressure supplied to the vacuum adsorption device in real time and to feed it back to the control terminal.

7. The gas path control system according to claim 1, characterized in that, The gas circuit control system also includes: The second on / off valve is located between the vacuum proportional valve and the vacuum adsorption device, and is used to control the on / off connection between the vacuum proportional valve and the vacuum adsorption device.

8. The gas path control system according to claim 1, characterized in that, The vacuum adsorption device is a wafer vacuum chuck.

9. The gas path control system according to claim 1, characterized in that, The wafer adsorption device includes: Supporting protrusions are spaced apart on the adsorption surface and are higher than the adsorption surface; A sealing structure is provided at the edge of the adsorption surface; During vacuum adsorption, the wafer, the adsorption surface, the sealing structure, and the support bumps form a vacuum cavity.

10. The gas path control system according to claim 1, characterized in that, The wafer adsorption device has a central partition and at least one edge partition surrounding the central partition. Each partition is individually connected to the vacuum air path. The control terminal is used to control the vacuum adsorption value of the central partition to increase linearly from a basic set value to a formal set value.

11. The gas path control system according to claim 10, characterized in that, Each of the partitions is equipped with a second on / off valve on the connection branch between the partition and the vacuum circuit. The control terminal is used to control each partition from the center to the edge to open sequentially within a preset time interval.

12. The gas path control system according to claim 10, characterized in that, The adsorption surface of the wafer adsorption device includes a first edge partition and a second edge partition, wherein the first edge partition is arranged around the central partition and the second edge partition is arranged around the first edge partition.

13. A semiconductor processing apparatus, characterized in that, The semiconductor processing device includes a gas path control system, which is the gas path control system according to any one of claims 1 to 12.

14. A gas path control method, characterized in that, The gas path control method is executed using the gas path control system described in claims 1-12, and the gas path control method includes: Control the valve opening of the vacuum proportional valve connected to the vacuum circuit to keep the vacuum pressure of the vacuum adsorption device at the basic set value. With the gas passage opened, the vacuum adsorption device initially adsorbs the wafer at a vacuum pressure set at a basic value. By controlling the opening degree of the vacuum proportional valve, the vacuum pressure of the vacuum adsorption device is linearly increased from the basic set value to the formal set value, and the wafer gradually comes into contact with the adsorption surface of the vacuum adsorption device.

15. A gas path control method, characterized in that, The gas path control method is executed using the gas path control system as described in claim 10, and the gas path control method includes: Control the valve opening of the vacuum proportional valve connected to the vacuum circuit to keep the vacuum pressure in the central section of the vacuum adsorption device at the basic set value. With the gas passage opened, the vacuum adsorption device initially adsorbs the wafer at a vacuum pressure set at a basic value. By controlling the opening degree of the vacuum proportional valve, the vacuum pressure in the central section of the vacuum adsorption device is linearly increased from the basic set value to the formal set value, and the wafer or the part of the wafer corresponding to the central section gradually comes into contact with the adsorption surface of the vacuum adsorption device.

16. The gas path control method according to claim 15, characterized in that, The adsorption surface of the vacuum adsorption device includes a first edge partition and a second edge partition, the first edge partition surrounding the central partition, and the second edge partition surrounding the first edge partition; the gas path control method includes: Control the valve opening of the vacuum proportional valve to control the vacuum pressure of the first edge zone of the vacuum adsorption device at the officially set value. The gas path is opened, and the vacuum adsorption device adsorbs the wafer and the area corresponding to the first edge partition at a vacuum pressure of a formally set value. Control the valve opening of the vacuum proportional valve to control the vacuum pressure of the second edge zone of the vacuum adsorption device at the set value. With the gas path opened, the vacuum adsorption device adsorbs the wafer and the area corresponding to the second edge partition at a vacuum pressure set to a specific value.

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