CN117316831B - Pressure controller, semiconductor processing apparatus, and air pressure control method - Google Patents

Pressure controller, semiconductor processing apparatus, and air pressure control method Download PDF

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Publication number
CN117316831B
CN117316831B CN202311598542.9A CN202311598542A CN117316831B CN 117316831 B CN117316831 B CN 117316831B CN 202311598542 A CN202311598542 A CN 202311598542A CN 117316831 B CN117316831 B CN 117316831B
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pressure
temperature
pressure gauge
value
temperature sensor
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CN117316831A (en
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徐志鹏
连增迪
倪图强
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Nanchang Medium And Micro Semiconductor Equipment Co ltd
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Nanchang Medium And Micro Semiconductor Equipment Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67098—Apparatus for thermal treatment
    • H01L21/67109—Apparatus for thermal treatment mainly by convection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67248—Temperature monitoring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67253—Process monitoring, e.g. flow or thickness monitoring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6831—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using electrostatic chucks
    • H01L21/6833—Details of electrostatic chucks

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

The invention provides a pressure controller, a semiconductor processing apparatus and a pressure control method. The pressure controller of the present invention comprises: the shell is covered on the fluid pipeline to form an installation space, the branch pipeline of the fluid pipeline extends towards the shell, and the maximum conveying pressure in the fluid pipeline is the first pressure; the pressure gauge is arranged in the shell and arranged at the tail end of the branch pipeline through the mounting seat, and at least part of the branch pipeline is positioned in the first area of the mounting seat; the maximum range pressure of the pressure gauge is a second pressure which is at least 5 times the first pressure; a temperature sensor at least partially disposed in the first region, the end of the temperature sensor being opposite to the side wall of the branch pipe, and the side surface of the temperature sensor being opposite to the bottom surface of the pressure gauge; the calculating unit compensates the measurement result of the pressure gauge based on the measurement result of the temperature sensor to obtain a calibrated pressure value; and a control valve that adjusts the calibration pressure value based on the calibration pressure value so that the calibration pressure value remains constant for a certain period of time.

Description

Pressure controller, semiconductor processing apparatus, and air pressure control method
Technical Field
The present invention relates to the field of semiconductor technologies, and in particular, to a pressure controller, a semiconductor processing apparatus, and a pneumatic control method.
Background
In the field of semiconductor manufacturing technology, it is often desirable to perform plasma processing on wafers to be processed within a semiconductor processing apparatus. The semiconductor processing apparatus has a vacuum chamber that includes an electrostatic chuck (Electrostatic chuck, ESC) for providing electrostatic clamping to a wafer during processing.
In semiconductor processing, in order to ensure the process effect of wafer processing, it is important to control the temperature of the wafer surface, and the temperature of the wafer surface can be ensured to meet the process requirement by improving the heat dissipation of the back surface of the wafer.
One approach relies on the electrostatic chuck to conduct heat to the wafer. The metal base of the electrostatic chuck is internally provided with a cooling fluid channel communicated with an external refrigerator, and the heat conducted to the base by the wafer is conducted away by cooling liquid flowing in the cooling fluid channel so as to control the temperature of the base and control the temperature of the wafer. In another method, a plurality of cooling gas channels are arranged in the electrostatic chuck, and cooling gas is introduced into the back surface of the wafer through the plurality of cooling gas channels to control the temperature of the wafer. The two methods may also be used in combination.
When cooling gas is introduced into the back surface of the wafer, the gas pressure value of the cooling gas channel needs to be monitored, and the measurement of the gas pressure has the requirements of low pressure and high response to precision. However, the existing high-precision pressure gauge generally adopts a capacitance pressure gauge, has the characteristics of small measuring range and high precision, but has higher cost, larger size and larger installation space, so that the whole pressure controller occupies larger space, and is not beneficial to modularized miniaturized design.
And compared with the prior art, the wide-range pressure gauge has the characteristics of low cost and small size, can enable the whole pressure controller to be miniaturized and intensified, and is beneficial to the miniaturized modular design of the pressure controller, such as a silicon resistance pressure gauge and the like. However, such a pressure gauge has a larger measuring range than a capacitance pressure gauge, and the cost and accuracy of the pressure gauge product are inversely proportional to the measuring range thereof, and proportional to the volume thereof, and the measuring accuracy in the low pressure measuring range (less than 1/3 of the measuring range) is low.
On the other hand, the measurement results of the pressure gauge in its small measuring range are more susceptible to the ambient temperature. When a large temperature gradient exists in a temperature field where the pressure gauge is located, temperature compensation is also complicated on a measurement result of the pressure gauge, and required measurement accuracy is difficult to achieve.
How to provide a pressure gauge with low cost and miniaturization, accurately control the air pressure in a cooling fluid channel, ensure the safety of wafer processing, and solve the problem in the prior art.
Disclosure of Invention
The invention aims to provide a pressure controller, semiconductor processing equipment and an air pressure control method, which can overcome the influence of a surrounding environment temperature field (with larger temperature gradient) on the measurement result of a wide-range pressure gauge, improve the measurement precision of the wide-range pressure gauge in a low-pressure measurement section of the wide-range pressure gauge, and improve the accuracy of air pressure in a control fluid pipeline (used for providing cooling air for a gas channel in an electrostatic chuck).
In order to achieve the above object, the present invention provides a pressure controller provided on a fluid line for delivering a process fluid, a maximum delivery pressure of the process fluid being a first pressure, the pressure controller comprising:
a housing that is provided to cover the fluid line, and that forms an installation space for the pressure controller, the fluid line having a branch line that extends toward the housing;
the pressure gauge is arranged in the shell and arranged at the tail end of the branch pipeline through a mounting seat, the mounting seat is provided with a first area, the first area is a projection area of the pressure gauge on the mounting seat, and the branch pipeline is at least partially positioned in the first area; the maximum range pressure of the pressure gauge is a second pressure which is at least 5 times the first pressure;
the temperature sensor is positioned in the temperature measuring hole and at least partially arranged in the first area, and the tail end of the temperature sensor is opposite to the branch pipeline; the side surface of the temperature sensor is opposite to the bottom surface of the pressure gauge;
The calculating unit is electrically connected with the pressure gauge and the temperature sensor, and compensates the measurement result of the pressure gauge based on the measurement result of the temperature sensor to obtain a calibrated pressure value;
a control valve disposed on the fluid line and upstream of the branch line;
and a control unit that adjusts the opening degree of the control valve based on the calibration pressure value so that the calibration pressure value is maintained constant for a certain time.
Optionally, the end of the temperature sensor has a first distance from the side wall of the branch pipe, the side surface of the temperature sensor has a second distance from the bottom surface of the pressure gauge, and the first distance is greater than the second distance.
Optionally, an installation groove is formed in the pipe wall of the fluid pipeline, the installation seat is installed in the installation groove, and the installation seat is arranged in a manner of sinking into the pipe wall of the fluid pipeline.
Optionally, a space cavity is formed between the mounting seat and the mounting groove.
Optionally, the upper end face of the interval cavity is sealed and plugged, and a vacuumizing environment is arranged in the interval cavity.
Optionally, a heating unit is further included, the heating unit being at least partially located within the spacer cavity.
Optionally, the heating unit is not in contact with the mounting groove.
Optionally, the heating unit is wrapped with a heat insulation layer.
Optionally, the thermal insulation layer is not in contact with the mounting groove.
Optionally, the pressure controller further comprises a driving device, wherein the driving device is arranged in the mounting seat, and the driving device drives the temperature sensor to move towards a direction approaching to or away from the branch pipeline based on a command signal of the control unit.
Optionally, the pressure gauge includes: a pressure sensing film layer and four piezoresistors; the pressure sensing film layer generates corresponding deformation based on the air pressure of the branch pipeline; the four piezoresistors are arranged on the pressure sensing film layer and form a Wheatstone bridge, and the Wheatstone bridge outputs voltage signals corresponding to the deformation.
Optionally, two piezoresistors of the four piezoresistors are arranged in a positive strain area of the pressure sensing film layer, and the other two piezoresistors are arranged in a negative strain area of the pressure sensing film layer.
Optionally, a conformal insulating layer is further arranged on the pressure sensing film layer; the four piezoresistors are arranged on the insulating layer.
Optionally, the pressure gauge further comprises a rigid base; the pressure sensing film layer is arranged on the substrate in an arch shape.
Optionally, a vacuum arch cavity is formed between the pressure sensing film layer and the substrate.
Optionally, the distance between any two points on the pressure sensing film layer is not more than 2cm.
Optionally, the outer surface of the shell is coated with a thermal insulation material.
Optionally, the pressure controller further comprises a heating unit, and the heating unit is arranged around the pressure gauge.
Optionally, a heat insulation layer is arranged outside the heating unit.
Optionally, a portion of the thermal insulation layer near the fluid pipeline has a first thickness, and a portion of the thermal insulation layer far from the fluid pipeline has a second thickness, and the first thickness is greater than the second thickness.
Optionally, the temperature sensor includes a first temperature probe and a second temperature probe; the first temperature probe is opposite to the branch pipeline, and the second temperature probe is opposite to the pressure gauge; the calculating unit calculates a calibration temperature value based on the temperature value measured by the first temperature probe and the temperature value measured by the second temperature probe; the calculation unit calculates the calibration pressure value based on the calibration temperature value.
Optionally, the control unit controls the heating power of the heating unit based on the temperature value measured by the temperature sensor, so that the absolute value of the difference between the measured temperature value and a preset temperature value is smaller than a set temperature difference threshold.
Optionally, the control unit includes:
the signal processing module amplifies and filters the voltage signal;
the A/D conversion module is used for converting the amplified and filtered voltage signals into corresponding digital signals; the calculation unit calculates and generates an air pressure value corresponding to the digital signal, and compensates the air pressure value based on the temperature value measured by the temperature sensor to obtain the calibration pressure value.
Optionally, the pressure controller further comprises a flow sensor for measuring the flow of air in the fluid line and providing the measurement to the control unit.
Optionally, the pressure controller further comprises a communication module, and the signal connection of the communication module is arranged between the control unit and the upper computer and is used for realizing data transmission between the control unit and the upper computer.
The present invention also provides a semiconductor processing apparatus comprising:
the reaction chamber is internally provided with an electrostatic chuck, and a wafer to be processed is supported and fixed through the electrostatic chuck; a plurality of gas channels are arranged in the electrostatic chuck, and cooling gas is supplied to the plurality of gas channels through a fluid pipeline communicated with an external cooling gas source; the plurality of gas channels are connected in parallel with the branch pipe;
A pressure controller according to the present invention; the pressure controller is used for controlling the air pressure value of the air channel.
Optionally, the pressure controller controls the gas pressure in the gas channel to be constant when the wafer is fixed on the electrostatic chuck.
Optionally, when the wafer is fixed on the electrostatic chuck, a flow sensor is used to detect a fixed mass of the electrostatic chuck to the wafer.
The invention also provides a pneumatic control method for the semiconductor processing equipment, which comprises the following steps:
based on the process in the reaction cavity, driving the temperature sensor to reach a designated position in the temperature measuring hole;
the calculation unit generates a corresponding air pressure value based on the measurement result of the pressure gauge, compensates the air pressure value based on the measurement result of the temperature sensor, and obtains a calibration pressure value;
the controller adjusts the opening degree of the control valve based on the calibrated pressure value.
Optionally, before generating the air pressure value, the method further includes:
the controller controls the heating power of the heating unit based on the measurement result of the temperature sensor, so that the absolute value of the difference value between the temperature value measured by the temperature sensor and the preset temperature value is smaller than the set temperature difference threshold value.
Compared with the prior art, the invention has the following beneficial effects:
1) The pressure controller, the semiconductor processing equipment and the air pressure control method can overcome the influence of complex environment temperature on the measurement result of the wide-range pressure gauge, compensate the measurement result of the pressure gauge through the measurement result of the temperature sensor, and obviously improve the measurement range of the wide-range pressure gauge in the low-pressure measurement range (smaller than that of the wide-range pressure gaugeMaximum range of (a) of the measurement accuracy. The actual requirement of air pressure control on the fluid pipeline in the wafer processing process is met, and the stability and consistency of wafer processing are effectively ensured. The invention can also keep the wafer at the set temperature in the process, thereby improving the yield of wafer processing.
2) The pressure gauge provided by the invention has the advantages that the area of the pressure sensing film is small, the volume of the pressure gauge is greatly reduced on the premise of ensuring the measurement accuracy, and the miniaturized design of the pressure gauge is realized.
3) If the pressure gauge is in a temperature field with a larger temperature gradient and the voltage value output by the pressure gauge is compensated based on a single temperature value measured at a single position of the pressure gauge, the calculated pressure value of the fluid pipeline still has larger deviation from the actual pressure value of the fluid pipeline, and the functional relationship between the single temperature value and the actual pressure value of the fluid pipeline is difficult to be fitted. The temperature sensor of the invention simultaneously collects the temperature measuring outer surface of the pressure gauge (one outer surface of the pressure gauge closest to the Wheatstone bridge) and the temperature of the contact area of the mounting seat and the pressure gauge, and forms a comprehensive temperature measuring result to compensate the measuring result of the pressure gauge, thereby greatly improving the air pressure measuring precision of the fluid pipeline.
4) According to the invention, the temperature of the contact area of the mounting seat and the pressure gauge is obtained by collecting the temperature of the first temperature measuring area (which is positioned on the same temperature contour line as the contact area) of the branch pipeline, so that the problem that the temperature of the contact area is inconvenient to collect is solved. Through the overall arrangement of temperature sensor, manometer, branch pipeline for mount pad internal structure is compact, has reduced the volume of mount pad greatly, and then has realized the miniaturized design of mount pad.
5) According to the invention, based on the intensity of correlation among the temperature of the outer surface of the temperature measurement of the pressure gauge, the temperature of the first temperature measurement area and the output voltage of the pressure gauge, the distance between the tail end of the temperature sensor and the first temperature measurement area (namely, the first distance) and the distance between the side surface of the temperature sensor and the outer surface of the temperature measurement of the pressure gauge (namely, the second distance) are controlled, so that a more accurate comprehensive temperature measurement result is obtained. The invention can dynamically regulate the first distance through the driving device, and further improves the air pressure measurement precision of the fluid pipeline.
6) The temperature sensor can also be provided with the first temperature probe and the second temperature probe, the temperature of the first temperature measuring area is measured through the first temperature probe, the temperature of the outer surface of the temperature measurement of the pressure meter is measured through the second temperature probe, a more accurate calibration temperature value is obtained through weighting calculation on temperature values acquired by the first temperature probe and the second temperature probe, the voltage value output by the pressure meter is compensated based on the calibration temperature value, and the air pressure measurement precision of the fluid pipeline is further improved.
7) According to the invention, the heating unit surrounds the pressure gauge, so that the temperature value measured by the temperature sensor is maintained at a constant preset temperature value, and the temperature compensation calculation of the measurement result of the pressure gauge can be simplified.
8) According to the invention, the heat insulation layer outside the heating unit has a variable thickness, so that the temperature gradient of the pressure gauge can be reduced, and the accuracy of temperature compensation of the measurement result of the pressure gauge can be improved.
Drawings
For a clearer description of the technical solutions of the present invention, the drawings that are needed in the description will be briefly introduced below, it being obvious that the drawings in the following description are one embodiment of the present invention, and that, without inventive effort, other drawings can be obtained by those skilled in the art from these drawings:
FIG. 1 is a schematic view of a semiconductor processing apparatus;
FIG. 2 is a schematic diagram of a pressure controller according to an embodiment of the present invention;
FIG. 3 is a schematic illustration of a pressure gauge and a temperature sensor of a pressure controller disposed in a fluid line in accordance with an embodiment of the present invention;
FIG. 4 is a schematic diagram showing the connection of the components of the pressure controller according to one embodiment of the present invention;
FIG. 5 shows a state of the pressure sensitive membrane layer and the pressure sensitive resistor without external force in an embodiment of the present invention;
FIG. 6 shows the state of the pressure sensitive film and the pressure sensitive resistor when an external force is applied in an embodiment of the present invention;
FIG. 7 is a top view of a varistor according to one embodiment of the present invention;
FIG. 8 is a schematic diagram of a Wheatstone bridge in accordance with an embodiment of the invention;
FIG. 9 is a schematic diagram of a temperature sensor with two temperature probes in another embodiment of the invention;
FIG. 10 is a schematic view of a pressure gauge wrapped by a heating unit according to another embodiment of the present invention;
FIG. 11 is a schematic diagram showing a connection relationship between a driving device and a temperature sensor according to another embodiment of the present invention;
FIG. 12 is a schematic view of a mounting block having a spacer cavity between the mounting block and a mounting groove of a fluid line according to another embodiment of the present invention;
FIG. 13 is a flow chart of a pneumatic control method of the present invention;
FIG. 14 is a flow chart of a method for controlling air pressure in an embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
In addition, in the description of the present application, the terms "first," "second," "third," etc. are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.
In fig. 1, a semiconductor processing apparatus 1 is shown, which comprises a vacuum reaction chamber 10, the reaction chamber 10 comprising a substantially cylindrical reaction chamber sidewall 101 made of a metallic material, and an opening 102 provided in the reaction chamber sidewall 101 for receiving a wafer W therein and therein.
The gas shower head 110 and the electrostatic chuck 120 are disposed opposite to each other in the reaction chamber 10. The gas shower head 110 is connected to a gas supply 111 for supplying a process gas into the reaction chamber 10 while acting as an upper electrode of the reaction chamber 10. The electrostatic chuck 120 comprises a base 121 and a dielectric layer 122. After applying a dc voltage to the electrode 123 inside the dielectric layer 122 (connected to an external dc power source 126), the dielectric layer 122 generates an electrostatic attraction to fix the wafer W placed thereon. The susceptor 121 simultaneously serves as a lower electrode of the reaction chamber 10, forming a reaction region between the upper electrode and the lower electrode. At least one rf power source 140 is applied to one of the upper electrode or the lower electrode to generate an rf electric field between the upper electrode and the lower electrode for dissociating the process gas into plasma. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, free radicals and the like, and the active particles can react with the surface of the wafer W to be processed in various physical and chemical ways, so that the appearance of the surface of the wafer is changed, and the etching process is completed. An exhaust pump 150 is further disposed below the reaction chamber 10 for exhausting the reaction byproducts out of the reaction chamber 10, and maintaining the vacuum environment of the reaction chamber 10.
The etching and deposition rates of different material layers have different sensitivity to temperature. Different process steps often require different wafer temperatures, and therefore wafer temperature is one of the key parameters affecting process performance. Taking an etching process as an example, the wafer W is usually kept at a set temperature during the process, the sensitivity of the material layer to the temperature is utilized to adjust the etching selection ratio of the current material layer to the next material layer, so as to increase the process window for interface etching, and control the process index (such as critical dimension Critical Dimension, CD). For some wafers W of complex structure, different interfaces will occur, as will the temperature requirements for each stage of processing. For example, in the photoresist mask etching (mask open) stage, a relatively low temperature is needed to prevent the opening from being oversized; in the over etch (over etch) stage, it is necessary to increase the selectivity to the stop layer (landing layer) with high temperature while controlling the bottom critical dimension.
Therefore, to ensure the process effect of wafer processing, it is important to control the wafer surface temperature. The heat dissipation performance of the back surface of the wafer can be improved to ensure that the temperature of the surface of the wafer meets the process requirement. One method is to provide a cooling fluid channel 124 inside the susceptor 121, and to control the temperature of the susceptor 121 by guiding the heat transferred from the wafer W to the susceptor 121 through the cooling fluid flowing in the cooling fluid channel 124. Another method is to convey a cooling gas (such as helium) between the upper surface of the dielectric layer 122 and the bottom surface of the wafer W through the gas channels 125 penetrating the base 121 and the dielectric layer 122, and adjust the temperature of the wafer surface by using a method of convective heat exchange of the cooling gas, so that the cooling gas in the gas channels 125 can be used as a heat exchange medium, and the plurality of gas channels 125 are equivalent to a heat pipe structure for exchanging heat with the outside.
Liquid helium is stored in a high pressure tank 160, vaporized by a vaporizer 170 (as a cooling gas source), sent to a fluid line 180, and delivered to a gas channel 125 inside the electrostatic chuck 120 through the fluid line 180. When helium gas is introduced into the back of the wafer, the pressure value in the fluid pipeline 180 needs to be monitored by the first pressure gauge 190, so that the damage to the wafer W caused by excessive helium gas pressure flowing out of the gas channel 125 is prevented. In addition, at this time, since the heat exchange rate of the equivalent heat pipe is directly related to the air pressure in the air channel, in order to precisely control the temperature, a high requirement is put on the accuracy of the air pressure in the air channel 125.
The first pressure gauge 190 generally includes a capacitance gauge and a strain gauge. The capacitance manometer is expensive, although the measurement accuracy is high. On the other hand, in order to ensure sufficient measurement accuracy and sensitivity, it is also necessary to provide a capacitance manometer with a small measuring range with a large pressure-sensitive film (area is usually more than 100cm 2 ) Resulting in a small scale capacitance manometer volume increase that affects the layout of other components in the semiconductor processing equipment. The strain gauge is generally larger in measuring range than the capacitance gauge, smaller in size and lower in cost, and the cost and accuracy of the strain gauge are inversely proportional to the measuring range and proportional to the volume of the strain gauge. Has certain advantages for the low-cost miniaturized pressure control unit, but the strain-type pressure gauge with wide range can measure the low pressure The measurement accuracy of the measurement range is low.
The strain gauge comprises a measuring circuit formed by a plurality of piezoresistors, and a corresponding air pressure value is obtained based on the output voltage of the measuring circuit. The change of the ambient temperature can cause the fluctuation of the resistance value of the piezoresistor, thereby affecting the accuracy of the measurement result of the pressure gauge, and the measurement result needs to be subjected to temperature compensation.
However, when the strain gauge is in a temperature field with a larger temperature gradient, it is difficult to accurately compensate the temperature of the measurement result, especially when one end of the gauge is close to the cryogenically cooled pipeline and the other end is heated by the circuit device, how to use the simplest measurement means, reduce the cost, avoid the stability and consistency of the gauge from being reduced without disassembling and modifying the gauge itself, and obtain the accurate temperature to be compensated is a problem to be solved urgently.
The pressure controller of the invention adopts a strain type pressure gauge with a large measuring range, in particular a silicon resistance pressure gauge, and can obviously reduce the size and cost of the pressure gauge, and meanwhile, the temperature sensor 293 is arranged at a specific position, so that the temperature sensor 293 can obtain the temperature measurement results of different temperature contour lines of a temperature field (with larger temperature gradient) where the pressure gauge is positioned, thereby obviously improving the temperature compensation precision and the measurement precision of the strain type pressure gauge with a large measuring range in a low pressure measurement region and with larger temperature gradient.
The pressure controller can adjust the valve opening of the control valve at the upstream of the fluid pipeline 180 based on the calibration pressure value output by the calculation unit and the pressure value of the fluid pipeline required by the process, so as to adjust the pressure of the fluid pipeline 180, provide safety guarantee for wafer processing, realize that the wafer W is kept at a set temperature in the process, and improve the yield of wafer processing.
According to one aspect of the present invention, a pressure controller is provided on a fluid line 280, the fluid line 280 being configured to deliver a process fluid having a maximum delivery pressure of a first pressure. The pressure controller includes: a housing 291, a pressure gauge 290, a temperature sensor 293, a computing unit 294, a control valve 298, a control unit 295.
The housing 291 is provided to cover the fluid line 280 to form an installation space for the pressure controller, and the fluid line 280 has a branch line 281 extending toward the housing 291. The housing 291 is used for modularly packaging the pressure controller, and thus, the internal electric device is heated and then heat-sealed in the housing 291, and heat cannot be directly transferred to the outside of the housing 291.
The pressure gauge 290 is disposed within the housing 291 and at the end of the lateral conduit 281 via a mount 296, the mount 296 having a first region 2961, the first region 2961 being a projected region of the pressure gauge 290 within the mount 296, the lateral conduit 281 being at least partially within the first region 2961; the maximum range pressure of pressure gauge 290 is a second pressure that is at least 5 times the first pressure.
The side wall of the mounting seat 296 is provided with a temperature measuring hole, and the temperature sensor 293 is located in the temperature measuring space and at least partially disposed in the first region 2961. The end of the temperature sensor 293 is opposite the branch line 281, and the side wall of the temperature sensor 293 is opposite the bottom surface of the pressure gauge 290.
The calculation unit 294 is electrically connected to the pressure gauge 290 and the temperature sensor 293, and the calculation unit 294 compensates the measurement result of the pressure gauge 290 based on the measurement result of the temperature sensor 293 and outputs a calibration pressure value.
The control valve 298 is disposed on the fluid line 280 upstream of the branch line 281.
And a control unit that adjusts the opening degree of the control valve 298 based on the calibration pressure value so that the calibration pressure value is maintained constant for a certain period of time.
When considering that the fluid in the fluid line 280 is in a low temperature state, the branch line 281 is in contact with the lower end of the pressure gauge 290, and the pressure gauge 290 is mounted on the mounting seat 296, the mounting seat 296 is often made of metal material so as to have better heat conductivity, and the branch line 281 penetrates through the mounting seat 296, so that the low temperature fluid in the branch line 281 cools the mounting seat 296 and is outwardly diffused by the branch line 281 in the mounting seat 296 to form a temperature gradient. While the upper end of the pressure gauge 290 is in an electric-appliance dense area, and when the pressure gauge 290 is affected by heating, the pressure gauge 290 is in a high-temperature gradient environment with upper heat and lower cold. Thus, a problem arises in temperature compensation, namely how to accurately feed back the true temperature that the manometer 290 should compensate.
On the one hand, the contact area a of the mounting 296 with the pressure gauge 290 has a greater influence on the temperature of the pressure gauge 290 and thus on the temperature of the environment surrounding the piezoresistor within the pressure gauge 290. On the other hand, the piezo-resistor is disposed on the side of the pressure gauge 290 proximate the fluid line 280, and we will note that the outer surface of the pressure gauge 290 closest to the piezo-resistor as the outer pressure gauge surface 2901, the temperature of the outer pressure gauge surface 2901 also has a greater effect on the temperature of the environment surrounding the piezo-resistor. Therefore, we compensate the barometric pressure value measured by pressure gauge 290 (based on the output voltage U of the Wheatstone bridge) based on the temperature measurement result of the contact area A and the pressure gauge exterior surface 2901 0 Calculated, this is the prior art and will not be described in detail here).
However, it is inconvenient to arrange a temperature measuring element between the mounting seat 296 and the pressure gauge 290, and the temperature of the contact area a cannot be directly measured. We have found a first temperature measurement region B (opposite to the end of the temperature sensor 293) on the branch line 281 in the first region 2961 at the same temperature contour as the above-mentioned contact region a, and then the temperature of the contact region a can be obtained by measuring the temperature of the first temperature measurement region B.
It was found that the temperature change of the first temperature measuring region B resulted in an output voltage U 0 Produces less float and causes an output voltage U due to temperature changes in the manometer thermometric outer surface 2901 0 To increase the measurement accuracy, the temperature sensor 293 is at least partially disposed in the first region 2961, the end of the temperature sensor 293 is opposite to the branch pipe 281, and the side wall of the temperature sensor 293 is opposite to the bottom surface of the pressure gauge 290, so that the temperature of the outer surface 2901 of the pressure gauge can be acquired, and the temperature of the first temperature measuring region B can be acquired to form a comprehensive temperature measurement result Tc.
In one embodiment, the temperature of the manometer thermometric outer surface 2901 is found with the output voltage U 0 Is related to (a)The sex is stronger. Therefore, the end of the temperature sensor 293 has a first distance from the branch pipe 281, and the temperature sensor 293 has a second distance from the pressure gauge 290, so that the first distance is greater than the second distance, thereby obtaining a more accurate comprehensive temperature measurement result Tc, further improving the measurement accuracy of the air pressure in the fluid pipe 280, and guaranteeing the safety of wafer processing.
Specifically, in one embodiment, as shown in FIGS. 2 and 3, the pressure controller of the present invention is disposed on a fluid line 280 (having a thicker tube wall). The fluid line 280 in this embodiment is used to deliver a process fluid (e.g., helium gas having a lower temperature) to a gas channel within the electrostatic chuck, the process fluid having a maximum delivery pressure of a first pressure. As shown in fig. 2, 3 and 4, the pressure controller of the present invention includes: housing 291, pressure gauge 290, temperature sensor 293, computing unit 294, control valve 298, control unit 295, flow sensor 299, communication module 220.
As shown in fig. 2 and 3, the housing 291 is provided to cover the fluid line 280, and the fluid line 280 has a branch line 281 extending toward the housing 291. In the present invention, the housing 291, the fluid pipe 280 and the branch pipe 281 are all made of metal, and have good thermal conductivity. In a preferred embodiment, the outer surface of housing 291 is also coated with a thermal insulating material.
As shown in fig. 2 and 3, the surface of the fluid pipe 280 is provided with a mounting groove, and a mounting seat 296 is fixedly arranged in the mounting groove. Pressure gauge 290 is disposed within housing 291 and is disposed at the end of branch conduit 281 by mount 296. The provision of the mounting seat 296 submerged in the wall of the fluid line 280 helps reduce the temperature gradient of the mounting seat 296 since the mounting seat 296 is less exposed to the environment above the fluid line 280. Meanwhile, the mounting seat 296 is sunk into the wall of the fluid pipeline 280, so that the pressure gauge 290 is closer to the fluid pipeline 280, the branch pipeline 281 is shorter, the pressure loss of the branch pipeline 281 is reduced, and the measured value of the pressure gauge is closer to the actual pressure value of the parallel part of the fluid pipeline 280 and the branch pipeline 281.
The maximum range pressure of pressure gauge 290 is a second pressure that is at least 5 times the first pressure. If the first pressure is less than 50torr and the second pressure is greater than 250torr; or the first pressure is less than 30torr and the second pressure is greater than 150torr, etc. It is apparent that the first pressure falls within the low pressure measurement region of pressure gauge 290, thereby allowing for a smaller volume, less costly pressure gauge and presenting a measurement accuracy challenge.
Because the fluid pipe 280, the mounting base 296 and the housing 291 are all made of metal with good thermal conductivity, heat transfer exists between the fluid pipe 280 and the mounting base 296 and between the fluid pipe 280 and the housing 291. Let T1, T2, T3 denote the temperatures of fluid line 280, mount 296, and housing 291, respectively, and T1< T2< T3. It is readily understood that pressure gauge 290 is in a temperature field with a large temperature gradient.
As shown in fig. 3, in this embodiment, a stepped hole is formed in a side of the mounting seat 296 facing the housing 291, an outwardly protruding flange 2902 is provided on an outer surface of the pressure gauge 290, and the pressure gauge 290 is partially inserted into the stepped hole and supported by the stepped hole for the flange 2902. To further secure the pressure gauge 290, the wall of the stepped bore is secured against loosening by the pressure gauge 290 (also understood as the mounting 296 surrounding the portion of the pressure gauge 290 within the stepped bore). Heat transfer occurs between pressure gauge 290 and mount 296, causing heat loss from pressure gauge 290, further causing non-uniformity in the temperature of pressure gauge 290.
As shown in fig. 3, the side wall of the mounting base 296 is provided with a temperature measuring hole, and the temperature sensor 293 is located in the temperature measuring hole. The temperature sensor 293 is at least partially disposed in the first area 2961, the end of the temperature sensor 293 has a first distance from the branch pipe 281, the temperature sensor 293 has a second distance from the pressure gauge 290, and the first distance is greater than the second distance, so that the temperature of the end of the branch pipe 281 can be obtained relatively while the temperature is measured at the bottom of the pressure gauge 290. I.e. the measured value of the temperature sensor 293 is obtained by the combined action of the bottom of the pressure gauge 290 and the end of the branch pipe 281, so that the temperature compensation of the cold end, i.e. the end of the branch pipe 281, is increased compared with the temperature of the pressure gauge 290 measured alone, and the obtained temperature is more fit to the corresponding compensation temperature of the pressure gauge 290. The accuracy of the compensated pressure value of pressure gauge 290 is improved. Therefore, the problem of serious temperature drift in a low-range area, which is caused by the fact that the pressure gauge 290 selects a large-range pressure gauge with the working pressure being more than 5 times, can be solved to a certain extent, and the compensated pressure gauge 290 can be suitable for accurate measurement and control of the fluid pressure with small working pressure.
In one embodiment, as shown in fig. 5, 6 and 7, the pressure gauge 290 is internally provided with: four varistors (R1, R2, R3, R4, only varistors R2 and R4 are shown in FIGS. 4 and 5, respectively), an insulating layer 2903, a pressure sensitive film 2904, and a rigid substrate 2905.
The pressure-sensitive film 2904 is provided on the substrate 2905 in an arch shape, and fig. 5 shows a state of the pressure-sensitive film 2904 when no external force acts. Helium gas flowing out of the branch pipe 281 has a certain pressure, and the pressure sensitive film 2904 deforms correspondingly under the pressure as shown in fig. 6. In this embodiment, in order to increase the sensitivity of deformation of the pressure sensitive film 2904, a vacuum dome 2906 is formed between the pressure sensitive film 2904 and the substrate 2905.
In the invention, the distance between any two points on the pressure sensing film layer 2904 is not more than 2cm, so that the pressure sensing film layer 2904 used by the pressure gauge 290 is small in area, the volume of the pressure gauge 290 is greatly reduced, and the miniaturized design of the pressure gauge 290 is realized.
As shown in fig. 5 and 6, an insulating layer 2903 is provided on the pressure sensitive film layer 2904 and follows the pressure sensitive film layer 2904. As shown in fig. 7 and 8, four piezoresistors are disposed on the insulating layer 2903 and form a wheatstone bridge, which is supplied with power by a constant current power supply Ia, and has an output voltage U 0 。
As shown in fig. 7, the piezoresistors R2, R4 are disposed in the positive strain area of the pressure sensitive film layer 2904, and the piezoresistors R1, R3 are disposed in the negative strain area of the pressure sensitive film layer 2904. When the pressure sensing film 2904 is stressed to deform, the piezoresistors R2 and R4 are stressed by outward tension to generate positive strain, and the resistance is increased; the piezoresistors R1, R3 are subjected to an inward pressing force to generate a negative strain, and the resistance is reduced. Therefore, the greater the pressure applied to the pressure-sensitive membrane layer 2904, the greater the deformation thereof, and the output voltage U of the Wheatstone bridge 0 The larger. Can be theoretically based on the output voltageU 0 The air pressure in the fluid line 280 is calculated (this is a prior art and will not be described in detail herein).
However, the resistance of the varistor varies with ambient temperature, resulting in an output voltage U of the Wheatstone bridge 0 Is not matched to the pressure experienced by the pressure sensitive membrane layer 2904. The piezoresistor is sealed and packaged in the pressure gauge 290, so that the temperature sensor 293 is not convenient to be arranged in the pressure gauge 290 to directly measure the temperature of the piezoresistor, otherwise, once the temperature sensor 293 needs to be replaced, the whole pressure gauge 290 needs to be replaced, and the economic cost is too high. It is desirable to obtain the temperature of the environment surrounding the piezo-resistor (located within the pressure gauge 290) by measuring the temperature of the pressure gauge surface or the environment external to the pressure gauge, and to compensate the temperature of the output of the pressure gauge 290.
Because of the heat transfer between pressure gauge 290 and mounting bracket 296, contact area a of mounting bracket 296 and pressure gauge 290 has a greater effect on the temperature of pressure gauge 290 and thus the temperature of the environment surrounding the piezoresistor within pressure gauge 290. On the other hand, the piezo-resistor is disposed on the side of the pressure gauge 290 proximate the fluid line 280, and we will note that the outer surface of the pressure gauge 290 closest to the piezo-resistor as the outer pressure gauge surface 2901, the temperature of the outer pressure gauge surface 2901 also has a greater effect on the temperature of the environment surrounding the piezo-resistor. Therefore, it is desirable to obtain the integrated temperature measurement result Tc by simultaneously measuring the temperature of the contact area a and the temperature of the manometer-measured outer surface 2901, and compensate the output result of the manometer 290 by Tc.
Because the first temperature measuring area B on the branch pipe 281 and the contact area a are located at the same temperature contour line (as shown by the dotted arc line in fig. 3), the invention obtains the temperature of the contact area a by measuring the temperature of the first temperature measuring area B by the end of the temperature sensor 293, thereby solving the problem that the temperature of the contact area a is inconvenient to collect. Meanwhile, the layout of the temperature sensor 293, the pressure gauge 290 and the branch pipe 281 is facilitated, so that the internal structure of the mounting seat 296 is compact, the volume of the mounting seat 296 is greatly reduced, and further the miniaturized design of the mounting seat 296 is realized.
As shown in fig. 3, the end of the temperature sensor 293 is connected toThe first temperature measurement region B has a first distance (in the X-axis direction in fig. 3), and the side surface of the temperature sensor 293 has a second distance (in the Y-axis direction in fig. 3) from the pressure gauge temperature measurement outer surface 2901. It has been found by research that the temperature change of the first temperature measuring region B results in an output voltage U 0 Produces less float and causes an output voltage U due to temperature changes in the manometer thermometric outer surface 2901 0 And larger floating is generated, so that the first distance is larger than the second distance, a more accurate comprehensive temperature measurement result Tc is obtained, the measurement accuracy of the air pressure in the fluid pipeline 280 is further improved, and the safety of wafer processing is ensured. As shown in fig. 4, the control unit 295 includes: a signal processing module 2951 and an a/D conversion module 2952. The signal processing module 2951 is electrically connected to the output end of the wheatstone bridge, and amplifies and filters the voltage signal output by the wheatstone bridge. The a/D conversion module 2952 converts the amplified and filtered voltage signal into a corresponding digital signal.
The calculating unit 294 is also connected to the A/D conversion module 2952, and the calculating unit 294 generates a corresponding air pressure value P based on the digital signal 0 (this is the prior art and will not be described in detail here). The calculation unit 294 also compensates the air pressure value P based on the calibrated temperature value Tc 0 Finally, a calibrated pressure value P is obtained 1 。
In the present embodiment of the present invention,. Wherein Tj is a set reference temperature value, and p is a compensation coefficient.
As shown in fig. 2, a control valve 298 is disposed on fluid line 280 upstream of branch line 281. As shown in fig. 2 and 4, the control valve 298 is connected to the control unit 295 via a wireless or wired signal. The control unit 295 is also electrically connected (either wired or wireless) to the calculation unit 294, based on the calibrated pressure value P generated by the calculation unit 294 1 The pressure value of the fluid pipeline required by the process generates a driving signal, and the opening of the control valve 298 is regulated by the driving signal, so that the flow of helium gas supplied to the back of the wafer is controlled, the wafer W is kept at a set temperature in the process, and the wafer processing quality is improvedAnd (5) the yield. In the present invention, the control unit 295 adjusts the valve opening of the control valve 298 by a proportional-integral-derivative adjustment method.
As shown in fig. 2 and 4, the flow sensor 299 is electrically connected (either wired or wireless) to the control unit 295. The amount of air flow in the fluid line 280 is measured by the flow sensor 299 and the measurement result is provided to the control unit 295. Based on the measurement of flow sensor 299, pressure gauge 290 may be monitored for faults. For example, when the calibrated pressure value output by the calculation unit 294 is small and the air flow volume measured by the flow sensor 299 is large, the pressure gauge 290 is generally considered to be malfunctioning.
As shown in fig. 2 and 4, the communication module 220 is connected and disposed between the control unit 295 and the upper computer 230, and is used for implementing wired/wireless transmission of data between the control unit 295 and the upper computer 230.
In one embodiment, the temperature sensor 293 that simultaneously measures the contact area a and the first temperature measurement area B may be split, with two temperature sensors for separate measurements of the contact area a and the first temperature measurement area B.
In another embodiment, temperature sensor 293 may also have a first temperature probe 2931 and a second temperature probe 2932. As shown in fig. 9, the first temperature probe 2931 is opposed to the first temperature measurement region B on the branch pipe 281, and the temperature value Ta of the first temperature measurement region B is acquired by the first temperature probe 2931. The second temperature probe 2932 is opposed to the manometer thermometric outer surface 2901, and the temperature value Tb of the manometer thermometric outer surface 2901 is acquired by the second temperature probe 2932. In the invention, the weighting processing of the temperature signals is convenient by respectively collecting the temperature values Ta and Tb, so that the obtained calibrated temperature valuesMore accurate.
In order to improve the measurement accuracy, the first temperature probe 2931 is set to have a first distance (in the X-axis direction in fig. 9) from the first temperature measurement region B, and the second temperature probe 2932 is set to have a second distance (in the Y-axis direction in fig. 9) from the manometer temperature measurement outer surface 2901. Due to the temperature of the outer surface 2901 measured by the pressure gauge and the output voltage U 0 And thus the first distance is greater than the second distance, thereby obtaining a more accurate calibration temperature valueThe accuracy of measuring the air pressure in the fluid pipeline 280 is further improved, and the safety of wafer processing is guaranteed.
The calculating unit 294 is connected to the first temperature probe 2931 and the second temperature probe 2932 in a signal manner, and calculates a calibration temperature value based on the temperature values Ta and Tb measured by the first temperature probe 2931 and the second temperature probe 2932Wherein、The weight coefficients of the temperature values Ta, tb, respectively. Then, the calculation unit 294 based on the calibration temperature valueThe air pressure value P measured by the pressure gauge 290 0 Compensating to obtain a calibrated pressure value。
According to another aspect of the present invention, there is provided a pressure controller, as shown in fig. 10, the pressure controller in this embodiment further includes a heating unit 2907. Heating unit 2907 is disposed around pressure gauge 290.
The control unit 295 based on the integrated temperature measurement result Tc (or the calibration temperature value) The heating power of the heating unit 2907 is controlled so that the absolute value of the difference between Tc and the preset temperature value (i.e., the reference temperature value Tj) is smaller than the set temperature difference threshold (at this time)). It is easy to understand that,by heating the pressure gauge 290 by the heating unit 2907 so that the integrated temperature measurement result Tc is equal to the reference temperature value Tj, the air pressure value P is not required to be changed 0 Performing temperature compensation calculation; or the temperature fluctuation can be in a smaller range, so that the temperature compensation is more accurate.
As shown in fig. 10, a heat insulating layer 2908 is provided outside the heating unit 2907 in the present embodiment. The portion of the insulating layer 2908 proximate to the fluid line 280 has a first thickness, and the portion of the insulating layer 2908 distal to the fluid line 280 has a second thickness, with the first thickness being greater than the second thickness. The thicker insulation layer 2908, the less heat loss is transferred to housing 291 by heating unit 2907 and the better the heating effect on pressure gauge 290. The portion of pressure gauge 290 that is closer to fluid line 280 has a lower temperature than the portion of pressure gauge 290 that is farther from fluid line 280, thus requiring more heat to heat. The variation in thickness of the insulating layer 2908 helps to reduce the temperature gradient of the pressure gauge 290 and to improve the accuracy of the calibrated pressure value.
Meanwhile, it should be emphasized that the temperature control of the wafer W is sensitive to the temperature of the cooling gas in the gas channel, and the heating unit 2907 inevitably releases heat to the end of the fluid pipeline 280 near the gas channel, so that the temperature control of the cooling gas in the gas channel by the temperature control system is disturbed, which is unfavorable for the temperature control of the wafer.
Accordingly, the portion of the insulating layer 2908 proximate to the fluid line 280 has a first thickness, the portion of the insulating layer 2908 distal to the fluid line 280 has a second thickness, and the first thickness is greater than the second thickness. Heating of the fluid line 280 by the heating unit 2907 is effectively avoided, while at the same time reducing the temperature gradient of the pressure gauge 290, with a dual effect.
As the process changes, the desired air pressure in the fluid line changes, and thus the temperature field around the manometer 290 changes. This will result in a temperature of the first temperature measuring region B and an output voltage U 0 The degree of association between the two changes. In another embodiment, as shown in fig. 11, a driving device 2934 may be further disposed in the temperature measuring hole of the side wall of the mounting seat, and the driving device 2934 is based on the instruction of the control unit 295The signal drives the temperature sensor 293 to move towards and away from the branch pipeline 281, and the temperature and the output voltage U of the first temperature measuring area B are adjusted by adjusting the first distance 0 Degree of association between the two.
In another embodiment, as shown in fig. 12, a space cavity 282 is provided between the mounting seat 296 and the mounting groove of the fluid line 280, and the space cavity 282 may be supported by a space boss (not shown) in the mounting groove, which may be disposed on the mounting groove, on the mounting seat 296, or may be a separate heat insulating member. The spacer cavity 282 forms a cushion to separate the mounting seat 296 from the mounting groove so that the cushion does not contact the mounting seat, thereby providing thermal insulation and inhibiting heat transfer between the walls of the fluid conduit 280 and the mounting seat 296 to prevent the mounting seat 296 from being overcooled by the walls of the cryogenic fluid conduit 280.
In one embodiment, the upper end surface of the spacing cavity 282 is sealed by a seal 283 and a vacuum is provided within the spacing cavity 282. This can further reduce heat transfer between the mount 296 and the fluid line 280, reducing the temperature gradient of the mount 296 and thus the pressure gauge 290.
In one embodiment, a lower portion of heating unit 2907 is located within spacing cavity 282, and heating unit 2907 surrounds the entire mount 296 and pressure gauge 290, heating the entire mount 296 and pressure gauge 290. By controlling the heating power of the heating unit 2907, the integrated measurement result Tc of the temperature sensor 293 reaches the reference temperature value Tj without the air pressure value P 0 And (5) performing temperature compensation calculation. Because the mounting seat 296 and the pressure gauge 290 are heated at the same time, the temperature difference between the mounting seat 296 and the pressure gauge 290 is further reduced, so that the temperature gradient of the environment where the pressure gauge 290 is positioned is reduced, and the temperature compensation is more accurate.
In one embodiment, heating unit 2907 is not in contact with the mounting groove. Thereby, contact heat exchange of the heating unit 2907 with the mounting groove is avoided, adverse effects of the mounting groove on the heating efficiency of the heating unit 2907 are avoided, and heating effects of the heating unit 2907 on the mounting groove are avoided. Because the fluid in the fluid line 280 is relatively sensitive to temperature, the wafer temperature control at the rear end is directly affected, so that the heating unit 2907 is not contacted with the mounting groove, the influence of the heating unit 2907 on the fluid temperature in the fluid line 280 can be reduced, and the stability and consistency of the wafer temperature control are ensured.
In one embodiment, an insulating layer 2908 is also provided external to the heating unit 2907. Thereby, the heat insulation between the heating unit 2907 and the mounting groove can be further enhanced, the temperature control efficiency of the heating unit 2907 to the pressure gauge 290 can be improved, the influence on the fluid temperature in the fluid pipeline 280 can be reduced, and the stability and consistency of the wafer temperature control can be ensured. Preferably, the insulating layer 2908 does not contact the mounting groove to further enhance the insulating effect.
In summary, the pressure controller of the invention can overcome the influence of complex environmental temperature on the measurement result of the wide-range pressure gauge 290, and the measurement result of the pressure gauge 290 is compensated by the measurement result of the temperature sensor 293, so that the pressure controller can remarkably improve the measurement efficiency of the wide-range strain pressure gauge in the low-pressure measurement region (smaller than that of the pressure gaugeThe maximum range) of the fluid pipeline 280 meets the actual requirements of the air pressure control of the fluid pipeline.
The present invention also provides a semiconductor processing apparatus, which may be any semiconductor processing apparatus with a chuck for holding a wafer W, comprising:
the reaction chamber is internally provided with an electrostatic chuck, and a wafer W to be processed is supported and fixed through the electrostatic chuck; the inside of the electrostatic chuck is provided with a plurality of gas channels to which cooling gas is supplied through a fluid line 280 communicating with an external cooling gas source; a plurality of gas channels are connected in parallel with the branch pipe 281, whereby the gas pressure in the gas channels can be determined by measuring the gas pressure value of the branch pipe 281;
And a pressure controller according to the present invention for controlling the value of the air pressure in the fluid line 280.
In one embodiment, the pressure controller controls the gas pressure in the gas channel to be constant when the wafer W is held on the electrostatic chuck.
In one embodiment, the flow sensor 299 of the pressure controller is also used to detect the fixed mass of the electrostatic chuck to the wafer W when the wafer W is fixed to the electrostatic chuck. When the electrostatic chuck adsorbs the wafer W, the wafer W is ideally completely attached to the upper surface of the electrostatic chuck, that is, the wafer W is completely adsorbed by the electrostatic chuck, and the fixing quality is best at this time. Because wafer W and electrostatic chuck upper surface laminate completely, then the gas channel export is shutoff by wafer W, and when pressure controller detects branch pipeline 281 atmospheric pressure and reaches the default, the accessible closes dead control valve 298 in order to realize that the cooling gas in the gas channel is non-conductive and pressure is invariable to cooling gas in the gas channel can regard as heat transfer medium, and a plurality of gas channels are equivalent heat pipe structure and outside heat transfer. It will be appreciated that the measurement of the flow sensor 299 at this point is zero, i.e., the control valve 298 is nonconductive back and forth.
However, in actual use, there may be situations that the wafer W is warped due to heat or particles exist on the contact surface of the wafer W and the electrostatic chuck, so that the wafer W is not completely attached to the electrostatic chuck, and the fixing quality at this time is poor. Because the wafer W is not completely attached to the electrostatic chuck, the outlet of the gas channel is not completely blocked by the wafer W, and there is a leakage gap, so that the gas pressure in the gas channel is reduced, and in order to keep the gas pressure in the gas channel constant, the pressure controller opens the control valve 298 to replenish the gas channel, at this time, the control valve 298 is turned on back and forth, and the measurement value of the flow sensor 299 is not zero. Thus, the fixed mass of the electrostatic chuck to the wafer W is detected by the flow sensor 299.
The present invention also provides a pneumatic control method for the semiconductor processing apparatus according to the present invention, as shown in fig. 13, comprising the steps of:
s1, driving a temperature sensor to reach a designated position in a temperature measuring hole based on a process in a reaction cavity;
s2, a calculation unit generates a corresponding air pressure value based on a measurement result of the pressure gauge, and compensates the air pressure value based on a measurement result of the temperature sensor to obtain a calibration pressure value;
and S3, the controller adjusts the opening degree of the control valve based on the calibration pressure value.
In one embodiment, as shown in fig. 14, step S1 further includes:
the controller controls the heating power of the heating unit based on the measurement result of the temperature sensor, so that the absolute value of the difference value between the temperature value measured by the temperature sensor and the preset temperature value is smaller than the set temperature difference threshold value.
While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims (30)

1. A pressure controller disposed on a fluid line for delivering a process fluid having a maximum delivery pressure of a first pressure, the pressure controller comprising:
a housing that is provided to cover the fluid line, and that forms an installation space for the pressure controller, the fluid line having a branch line that extends toward the housing;
the pressure gauge is arranged in the shell and arranged at the tail end of the branch pipeline through a mounting seat, the mounting seat is provided with a first area, the first area is a projection area of the pressure gauge on the mounting seat, and the branch pipeline is at least partially positioned in the first area; the maximum range pressure of the pressure gauge is a second pressure which is at least 5 times the first pressure;
the temperature sensor is positioned in the temperature measuring hole and at least partially arranged in the first area, and the tail end of the temperature sensor is opposite to the branch pipeline; the side surface of the temperature sensor is opposite to the bottom surface of the pressure gauge;
the calculating unit is electrically connected with the pressure gauge and the temperature sensor, and compensates the measurement result of the pressure gauge based on the measurement result of the temperature sensor to obtain a calibrated pressure value;
A control valve disposed on the fluid line and upstream of the branch line;
and a control unit that adjusts the opening degree of the control valve based on the calibration pressure value so that the calibration pressure value is maintained constant for a certain time.
2. The pressure controller according to claim 1, further comprising a driving device provided in the mount, the driving device driving the temperature sensor to move toward and away from the branch pipe based on a command signal of the control unit.
3. The pressure controller of claim 1, wherein the pressure gauge comprises: a pressure sensing film layer and four piezoresistors; the pressure sensing film layer generates corresponding deformation based on the air pressure of the branch pipeline; the four piezoresistors are arranged on the pressure sensing film layer and form a Wheatstone bridge, and the Wheatstone bridge outputs voltage signals corresponding to the deformation.
4. A pressure controller according to claim 3, wherein two of the four piezoresistors are disposed in a positive strain region of the pressure sensing membrane layer and the remaining two piezoresistors are disposed in a negative strain region of the pressure sensing membrane layer.
5. The pressure controller of claim 3, wherein the pressure sensitive film layer is further provided with a conformal insulating layer; the four piezoresistors are arranged on the insulating layer.
6. The pressure controller of claim 3, wherein the pressure gauge further comprises a rigid base; the pressure sensing film layer is arranged on the substrate in an arch shape.
7. The pressure controller of claim 6, wherein a vacuum dome is formed between the pressure sensitive membrane layer and the substrate.
8. A pressure controller according to claim 3, wherein the distance between any two points on the pressure sensitive membrane layer is no more than 2cm.
9. The pressure controller of claim 1, wherein an outer surface of the housing is coated with a thermal insulating material.
10. The pressure controller of any one of claims 1 to 9, further comprising a heating unit disposed around the pressure gauge.
11. The pressure controller of claim 10, wherein the heating unit is externally provided with a thermal insulation layer.
12. The pressure controller of claim 11, wherein a portion of the insulating layer proximate the fluid line has a first thickness and a portion of the insulating layer distal the fluid line has a second thickness, the first thickness being greater than the second thickness.
13. The pressure controller of claim 10, wherein the temperature sensor comprises a first temperature probe and a second temperature probe; the first temperature probe is opposite to the side wall of the branch pipeline, and the second temperature probe is opposite to the bottom surface of the pressure gauge; the calculating unit calculates a calibration temperature value based on the temperature value measured by the first temperature probe and the temperature value measured by the second temperature probe; the calculation unit calculates the calibration pressure value based on the calibration temperature value.
14. The pressure controller of claim 10, wherein the control unit controls the heating power of the heating unit based on the temperature value measured by the temperature sensor such that an absolute value of a difference between the temperature value measured by the temperature sensor and a preset temperature value is less than a set temperature difference threshold.
15. A pressure controller according to claim 3, wherein the control unit comprises:
the signal processing module amplifies and filters the voltage signal;
the A/D conversion module is used for converting the amplified and filtered voltage signals into corresponding digital signals; the calculation unit calculates and generates an air pressure value corresponding to the digital signal, and compensates the air pressure value based on the temperature value measured by the temperature sensor to obtain the calibration pressure value.
16. The pressure controller of claim 1, further comprising a flow sensor disposed upstream of the control valve and electrically connected to the control unit.
17. The pressure controller of claim 1, further comprising a communication module, electrically connected between the control unit and the host computer, for data transmission between the control unit and the host computer.
18. The pressure controller of claim 1, wherein the tip of the temperature sensor is a first distance from the side wall of the branch conduit, the side of the temperature sensor is a second distance from the bottom surface of the pressure gauge, and the first distance is greater than the second distance.
19. A pressure controller according to any one of claims 1 to 9, wherein a mounting groove is provided in the wall of the fluid line, the mounting seat being mounted in the mounting groove, the wall of the fluid line being submerged.
20. The pressure controller of claim 19, wherein the mounting seat and mounting groove have a spacer cavity therebetween.
21. The pressure controller of claim 20, wherein the upper end surface of the spacer cavity is sealed and blocked, and wherein a vacuum environment is provided in the spacer cavity.
22. The pressure controller of claim 20 or 21, further comprising a heating unit at least partially within the spacing cavity.
23. The pressure controller of claim 22, wherein the heating unit is not in contact with the mounting groove.
24. The pressure controller of claim 22, wherein the heating unit is surrounded by a thermal insulation layer.
25. The pressure controller of claim 24, wherein the insulating layer is not in contact with the mounting groove.
26. A semiconductor processing apparatus, comprising:
the reaction chamber is internally provided with an electrostatic chuck, and a wafer to be processed is supported and fixed through the electrostatic chuck; a plurality of gas channels are arranged in the electrostatic chuck, and cooling gas is supplied to the plurality of gas channels through a fluid pipeline communicated with an external cooling gas source; the plurality of gas channels are connected in parallel with the branch pipe;
a pressure controller as claimed in any one of claims 1 to 25; the pressure controller is used for controlling the air pressure value of the air channel.
27. The semiconductor processing apparatus of claim 26, wherein the pressure controller controls the gas pressure in the gas channel to be constant when the wafer is held on the electrostatic chuck.
28. The semiconductor processing apparatus of claim 27, wherein a flow sensor is configured to detect a fixed mass of the electrostatic chuck to the wafer while the wafer is fixed to the electrostatic chuck.
29. A gas pressure control method for a semiconductor processing apparatus according to any one of claims 26 to 28, comprising the steps of:
based on the process in the reaction cavity, driving the temperature sensor to reach a designated position in the temperature measuring hole;
the calculation unit generates a corresponding air pressure value based on the measurement result of the pressure gauge, compensates the air pressure value based on the measurement result of the temperature sensor, and obtains a calibration pressure value;
the controller adjusts the opening degree of the control valve based on the calibrated pressure value.
30. The air pressure control method of claim 29, further comprising, prior to generating the air pressure value:
the controller controls the heating power of the heating unit based on the measurement result of the temperature sensor, so that the absolute value of the difference value between the temperature value measured by the temperature sensor and the preset temperature value is smaller than the set temperature difference threshold value.
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