Method and system for controlling vacuum degree of semiconductor equipment

Abstract

The invention discloses a method and a system for controlling the vacuum degree of semiconductor equipment. The control method comprises the following steps: S1, setting a first air pressure threshold value and a second air pressure threshold value, and inputting a set air pressure value; s2, setting the operation time of the vacuum pump, and setting the interval time measured by the vacuum gauge; and S3, fully opening the butterfly valve, starting the vacuum pump, and reading the current air pressure value, measured by the vacuum gauge, of the reaction cavity according to the set interval time. And S4, according to the difference value between the current air pressure value and the set air pressure value, the air flow passing through the butterfly valve is adjusted. And S5, when the gas flow is adjusted until the vacuum degree of the reaction cavity reaches the set air pressure value, the current butterfly valve gas flow value is maintained. A gradually-increasing gas flow adjusting system is established to achieve the vacuum degree required by the specific process, and the application requirements in different scenes can be met.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, in particular to a method for controlling the vacuum degree of semiconductor equipment, and also to a vacuum degree control system for realizing the control method. Background Art

[0002] like Figure 1 As shown, semiconductor deposition, etching, oxidation, heat treatment and other equipment are usually provided with a reaction chamber, the reaction chamber is provided with an air inlet and an air outlet, the air inlet is connected to the gas source, and a stop valve and a mass flow controller are connected in sequence between the gas source and the reaction chamber, while the air outlet is connected in sequence with a butterfly valve, a stop valve and a vacuum pump, and the semiconductor equipment is also provided with a vacuum gauge for detecting the vacuum degree of the reaction chamber, and a control module. The control module determines the switch angle of the butterfly valve according to the measured value and the target value of the vacuum gauge to achieve the control of the gas flow. The time to reach the predetermined vacuum degree is usually set according to the specific requirements of the process. At present, the usual way is to output the current measured value obtained by the vacuum gauge to the control module, the control module compares the target value and the current measured value according to the process requirements, and then controls the switch angle of the butterfly valve according to its own control algorithm to achieve the control of the gas flow, thereby achieving the vacuum degree required by the process.

[0003] Although the vacuum degree required by a specific process can be achieved through the control module's own algorithm, the vacuum degree change curve is a fixed slope during specific implementation. However, in actual applications, some special application scenarios of some processes do not want the vacuum degree to change with a fixed slope. In particular, during chemical vapor deposition or etching, due to the presence of particles produced by the reaction on the reaction chamber wall, if the airflow in the reaction chamber changes too much, gas turbulence will occur, causing particles on the reaction chamber wall to fall off and onto the substrate or wafer, thereby affecting the yield of the substrate or wafer. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a semiconductor device vacuum control method and system to accurately control the vacuum degree of a reaction chamber and reach a predetermined vacuum degree in a shorter time.

[0005] A method for controlling the vacuum degree of a semiconductor device, wherein the semiconductor device comprises a reaction chamber, a vacuum pump, a vacuum gauge and a butterfly valve, and the control method comprises the following steps:

[0006] S1 sets the first air pressure threshold and the second air pressure threshold, and inputs the set air pressure value;

[0007] S2 sets the running time of the vacuum pump and the interval time of the vacuum gauge measurement;

[0008] The S3 butterfly valve is fully opened, the vacuum pump is started, and the current pressure value of the reaction chamber measured by the vacuum gauge is read at the set interval;

[0009] S4: adjusting the gas flow through the butterfly valve according to the difference between the current air pressure value and the set air pressure value;

[0010] S5 When the gas flow rate is adjusted until the vacuum degree of the reaction chamber reaches the set pressure value, the current butterfly valve gas flow rate value is maintained.

[0011] In one embodiment, the first air pressure threshold is less than the second air pressure threshold.

[0012] In one embodiment, the calculation formula of the difference is: ΔX=X-X'; wherein ΔX indicates the difference, X indicates the set air pressure value, and X' indicates the current air pressure value measured by the vacuum gauge.

[0013] Furthermore, the method for controlling the gas flow through the butterfly valve according to the difference is specifically performed as follows:

[0014] S41 sets the linear adjustment value D and the proportional adjustment value K;

[0015] S42 determines whether ΔX is less than a first air pressure threshold;

[0016] If not, execute S43; if so, adjust the gas flow through the butterfly valve to the current flow + D;

[0017] S43 determines whether ΔX is greater than a first pressure threshold but less than a second pressure threshold;

[0018] If not, execute S44; if so, adjust the gas flow through the butterfly valve to the current flow*K;

[0019] S44 determines whether ΔX is greater than the second pressure threshold, and if so, adjusts the gas flow through the butterfly valve to the current flow*K+D;

[0020] S42 to S44 are repeatedly executed until X'=X.

[0021] Furthermore, the linear adjustment value D and the proportional adjustment value K are adjustment values ​​determined through testing according to the required reaction time and vacuum degree requirements, and the proportional adjustment value K>1.

[0022] In one embodiment, the method for controlling the gas flow through the butterfly valve according to the difference is specifically performed as follows:

[0023] Step 1: Determine the proportional coefficient Kp, integral coefficient Ki, and differential coefficient Kd;

[0024] Step 2: Adjust the gas flow through the butterfly valve to the current flow + Kp×△X5+Ki×(△X1+△X2+△X3+△X4+△X5)+Kd×△X5 / △t, until X'=X.

[0025] Furthermore, △X1+△X2+△X3+△X4+△X5 are the first five deviations; △t is the interval time of vacuum gauge measurement.

[0026] A vacuum control system is provided in cooperation with a reaction chamber having an air inlet and an air outlet, the control system comprising:

[0027] Air intake module;

[0028] An air outlet module, comprising a butterfly valve, an angle valve and a vacuum pump installed at the air outlet end;

[0029] A vacuum gauge, used to measure the vacuum degree of the reaction chamber;

[0030] A control module, wherein a first air pressure threshold and a second air pressure threshold are set;

[0031] The control module controls the gas flow through the butterfly valve according to the difference between the measured value of the vacuum gauge and the target value.

[0032] In one embodiment, the air intake module includes a stop valve and a mass flow controller installed at the air intake end; the mass flow controller is located between the stop valve and the reaction chamber; the angle valve is located between the butterfly valve and the vacuum pump, and the butterfly valve is arranged close to the reaction chamber.

[0033] Furthermore, the control system adopts the semiconductor equipment vacuum control method to adaptively adjust the airflow changes to achieve the vacuum required by the specific process.

[0034] Compared with the prior art, the beneficial effects of the present invention are: a gradually increasing gas flow regulation system is established to achieve the vacuum degree required by a specific process, which can meet the application needs in different scenarios, and overcomes the current use of butterfly valves in the vacuum control process. The fixed slope change, the existing gas flow change cannot be adaptively adjusted, resulting in the problem of being unable to better adapt to specific scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 The figure shows the connection diagram of the reaction chamber in the semiconductor equipment and its matching devices.

[0037] Figure 2 Shown is a flow chart of a semiconductor device vacuum degree control method provided by the present invention.

[0038] Figure 3 The flowchart shown is for controlling the gas flow through the butterfly valve according to the difference in Example 1 of the present invention.

[0039] Figure 4 The flowchart shown is for controlling the gas flow through the butterfly valve according to the difference in Example 2 of the present invention.

[0040] Figure 5 Shown is an oscillation curve of the present invention as a prior art.

[0041] Figure 6 The figure shows the adjustment curve of the vacuum degree in Example 2 of the present invention.

[0042] Figure 7 The figure shows a module block diagram of a vacuum control system provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Example 1

[0046] See also Figure 2 , this embodiment provides a method for controlling the vacuum degree of a semiconductor device, which comprises the following steps:

[0047] S1 sets a first air pressure threshold and a second air pressure threshold, and inputs a set air pressure value, wherein the first air pressure threshold is less than the second air pressure threshold.

[0048] S2 sets the running time of the vacuum pump and the interval time of the vacuum gauge measurement.

[0049] The S3 butterfly valve is fully opened, the vacuum pump is started, and the current air pressure value of the reaction chamber measured by the vacuum gauge is read at the set interval.

[0050] S4 adjusts the gas flow through the butterfly valve according to the difference between the current air pressure value and the set air pressure value. The calculation formula of the difference is: ΔX=X-X'. Among them, ΔX indicates the difference, X indicates the set air pressure value, and X' indicates the current air pressure value measured by the vacuum gauge.

[0051] Please refer to Figure 3 The method for controlling the gas flow through the butterfly valve according to the difference is specifically operated as follows:

[0052] S41 sets a linear adjustment value D and a proportional adjustment value K. The linear adjustment value D and the proportional adjustment value K are adjustment values ​​determined by testing according to the required reaction time and vacuum degree requirements, and the proportional adjustment value K>1.

[0053] S42 determines whether ΔX is less than the first air pressure threshold. If not, execute S43. If yes, adjust the gas flow through the butterfly valve to the current flow + D.

[0054] S43 determines whether ΔX is greater than the first pressure threshold and less than the second pressure threshold. If not, execute S44. If yes, adjust the gas flow through the butterfly valve to the current flow*K.

[0055] S44 determines whether ΔX is greater than the second pressure threshold, and if so, adjusts the gas flow through the butterfly valve to the current flow*K+D.

[0056] S42 to S44 are repeatedly executed until X'=X.

[0057] When ΔX is less than the first air pressure threshold, only the linear adjustment value D is used to adjust the air intake flow rate, so that the gas flow rate through the butterfly valve in the next time period is the current flow rate + D, and then the current air pressure value of the reaction chamber measured by the vacuum gauge at the end of the next time period is obtained, until the first air pressure threshold is less than ΔX and less than the second air pressure threshold.

[0058] When the first air pressure threshold < ΔX < the second air pressure threshold, only the proportional adjustment value K is used for adjustment, so that the gas flow through the butterfly valve in the next time period is the current flow × K, and then the current air pressure value of the reaction chamber measured by the vacuum gauge at the end of the next time period is obtained until ΔX> the second air pressure threshold.

[0059] When ΔX>the second pressure threshold, the linear adjustment value D and the proportional adjustment value K are used simultaneously to make adjustments so that the gas flow through the butterfly valve in the next time period is the current flow×K+D. Then, the current pressure value of the reaction chamber measured by the vacuum gauge at the end of the next time period is obtained until the current pressure value is equal to the set pressure value, indicating that the reaction chamber has reached the vacuum degree required by the process. At this time, the current gas flow value of the butterfly valve is maintained.

[0060] The next time period mentioned above is the interval time when the vacuum gauge performs the next measurement. The air flow rate is regulated by operating the butterfly valve, such as closing the butterfly valve to 1 / 2 or 1 / 3, which will not be described in detail.

[0061] S5 When the gas flow rate is adjusted until the vacuum degree of the reaction chamber reaches the set pressure value, the current butterfly valve gas flow rate value is maintained.

[0062] The vacuum control method of this embodiment has the following advantages: according to the difference between the current pressure value of the reaction chamber and the set pressure value, and the comparison between the pressure thresholds, the gas flow rate of the butterfly valve is first adjusted by linear adjustment, that is, the flow rate of the butterfly valve is increased slightly at the beginning, and then the flow rate of the butterfly valve is increased by proportional adjustment. Finally, the flow rate of the butterfly valve is adjusted by combining linear adjustment and proportional adjustment at the same time, and a gradually increasing gas flow rate regulation system is established to achieve the vacuum degree required by the specific process, which can meet the application requirements in different scenarios. It overcomes the current problem that the fixed slope change of the butterfly valve in the vacuum control process cannot be adaptively adjusted, resulting in the inability to better apply to specific scenarios.

[0063] Example 2

[0064] This embodiment provides a method for controlling the vacuum degree of a semiconductor device, which comprises the following steps:

[0065] S1 sets a first air pressure threshold and a second air pressure threshold, and inputs a set air pressure value, wherein the first air pressure threshold is less than the second air pressure threshold.

[0066] The S3 butterfly valve is fully opened, the vacuum pump is started, and the current air pressure value of the reaction chamber measured by the vacuum gauge is read at the set interval.

[0067] S4 adjusts the gas flow through the butterfly valve according to the difference between the current air pressure value and the set air pressure value. The calculation formula of the difference is: ΔX=X-X'. Among them, ΔX indicates the difference, X indicates the set air pressure value, and X' indicates the current air pressure value measured by the vacuum gauge.

[0068] Please refer to Figure 4 The method for controlling the gas flow through the butterfly valve according to the difference is specifically operated as follows:

[0069] Step 1: Determine the proportional coefficient Kp, integral coefficient Ki, and differential coefficient Kd.

[0070] The proportional coefficient Kp, the integral coefficient Ki, and the differential coefficient Kd are determined by testing according to the application scenario (such as the volume of the chamber, the deposition thickness, the number of substrates placed in the chamber, etc.).

[0071] The method for determining the proportional coefficient Kp is: first perform pure proportional adjustment, the set air pressure value = (60% to 70%) of the maximum value of the current air pressure value + Kp×△X, Kp is gradually increased from 0 until the feedback oscillates, and then Kp is gradually reduced until the feedback has no oscillation, then (60% to 70%) of the current Kp is taken as the proportional coefficient Kp.

[0072] The method for determining Ki is: after determining Kp, the set air pressure value = (60%~70%) of the maximum value of the current air pressure value + Kp×△X5+Ki(△X1+△X2+△X3+△X4+△X5), Ki gradually decreases from the maximum until the feedback value oscillates, and then increases Ki from a small value until the feedback has no oscillation, and takes the current Ki (140%~180%) as the integral coefficient Ki.

[0073] The method for determining Kd is: after determining Kp and Ki, the input value = (60% to 70%) of the maximum value + Kp×△X5+Ki(△X1+△X2+△X3+△X4+△X5)+Kd×△X5 / △t, Kd increases from 0 until the feedback value oscillates, and then gradually decreases to no oscillation, and 30% of the current Kd is taken as the differential coefficient Kd.

[0074] Step 2: Adjust the gas flow through the butterfly valve to the current flow + Kp×△X5+Ki×(△X1+△X2+△X3+△X4+△X5)+Kd×△X5 / △t, until X'=X.

[0075] △X1+△X2+△X3+△X4+△X5 are the first five deviations (5 of which are settable). △t is the interval time of vacuum gauge measurement.

[0076] S5 When the gas flow rate is adjusted until the vacuum degree of the reaction chamber reaches the set pressure value, the current butterfly valve gas flow rate value is maintained.

[0077] The following is a comparative analysis of the oscillation curve of the prior art and the adjustment process of the present embodiment using proportional integral differential to control the gas flow through the butterfly valve. Figure 5 The oscillation curve of the existing method is shown. Figure 6 The following is the adjustment curve of the vacuum degree of the reaction chamber using proportional integral differential. Figure 5 and Figure 6 It can be seen intuitively that Figure 5 The reaction time to reach the target vacuum degree is longer. Figure 6 The reaction time to reach the target vacuum degree is effectively shortened. The above results show that the vacuum degree control method of this embodiment can quickly reach the target vacuum degree of the reaction, is more conducive to the reaction process in the reaction chamber, and ensures the product yield.

[0078] Example 3

[0079] See also Figure 7 This embodiment provides a vacuum control system, which uses the semiconductor device vacuum control method described in Example 1 or Example 2 to adaptively adjust the airflow change to achieve the vacuum required by the specific process. The control system is arranged in conjunction with a reaction chamber having an air inlet and an air outlet. The substrate or wafer, such as chemical vapor deposition or etching processing reaction, is carried out in the reaction chamber. The air inlet is connected to the gas source, and the working gas is fed into the reaction chamber through the air inlet. The control system includes an air inlet module, an air outlet module, a vacuum gauge for measuring the vacuum of the reaction chamber, and a control module.

[0080] The air intake module includes a stop valve and a mass flow controller installed at the air intake end. The mass flow controller is located between the stop valve and the reaction chamber. In this embodiment, the opening or closing of the air intake passage is controlled based on the stop valve, and the mass flow controller plays a role in controlling the air intake flow rate.

[0081] The gas outlet module includes a butterfly valve, an angle valve and a vacuum pump installed at the gas outlet end. The angle valve is located between the butterfly valve and the vacuum pump, and the butterfly valve is arranged close to the reaction chamber. In this embodiment, the vacuum pump is operated to evacuate the reaction chamber so that the vacuum degree of the reaction chamber meets the preset value of the process. The opening or closing of the gas outlet passage is controlled based on the angle valve, and the butterfly valve plays a role in controlling the gas outlet flow rate.

[0082] The control module is set with a first pressure threshold and a second pressure threshold, wherein the first pressure threshold is less than the second pressure threshold. The control module controls the gas flow through the butterfly valve according to the difference between the measured value of the vacuum gauge and the target value.

[0083] The control module of this embodiment can adaptively adjust the airflow change so that the reaction chamber reaches the vacuum degree required by the process.

[0084] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for controlling the vacuum degree of a semiconductor device, wherein the semiconductor device comprises a reaction chamber, a vacuum pump, a vacuum gauge and a butterfly valve, wherein: The control method comprises the following steps: S1 sets the first air pressure threshold and the second air pressure threshold, and inputs the set air pressure value; S2 sets the running time of the vacuum pump and the interval time of the vacuum gauge measurement; The S3 butterfly valve is fully opened, the vacuum pump is started, and the current pressure value of the reaction chamber measured by the vacuum gauge is read at the set interval; S4: adjusting the gas flow through the butterfly valve according to the difference between the current air pressure value and the set air pressure value; S5 When the gas flow rate is adjusted until the vacuum degree of the reaction chamber reaches the set pressure value, the current butterfly valve gas flow rate value is maintained.

2. The semiconductor device vacuum control method according to claim 1, characterized in that: The first air pressure threshold is less than the second air pressure threshold.

3. The semiconductor device vacuum control method according to claim 1, characterized in that: The calculation formula of the difference is: ΔX=X-X'; Wherein, ΔX indicates the difference, X indicates the set air pressure value, and X' indicates the current air pressure value measured by the vacuum gauge.

4. The semiconductor device vacuum control method according to claim 3, characterized in that: The method for controlling the gas flow through the butterfly valve according to the difference is specifically operated as follows: S41 sets the linear adjustment value D and the proportional adjustment value K; S42 determines whether ΔX is less than a first air pressure threshold; If not, execute S43; if so, adjust the gas flow through the butterfly valve to the current flow + D; S43 determines whether ΔX is greater than a first pressure threshold but less than a second pressure threshold; If not, execute S44; if so, adjust the gas flow through the butterfly valve to the current flow*K; S44 determines whether ΔX is greater than the second pressure threshold, and if so, adjusts the gas flow through the butterfly valve to the current flow*K+D; S42 to S44 are repeatedly executed until X'=X.

5. The semiconductor device vacuum control method according to claim 4, characterized in that: The linear adjustment value D and the proportional adjustment value K are adjustment values ​​determined by testing according to the required reaction time and vacuum degree requirements, and the proportional adjustment value K>1.

6. The semiconductor device vacuum control method according to claim 3, characterized in that: The method for controlling the gas flow through the butterfly valve according to the difference is specifically operated as follows: Step 1: Determine the proportional coefficient Kp, integral coefficient Ki, and differential coefficient Kd; Step 2: Adjust the gas flow through the butterfly valve to the current flow + Kp×△X5+Ki×(△X1+△X2+△X3+△X4+△X5)+Kd×△X5 / △t, until X'=X.

7. The semiconductor device vacuum control method according to claim 6, characterized in that: △X1+△X2+△X3+△X4+△X5 are the first five deviations; △t is the interval time of vacuum gauge measurement.

8. A vacuum control system, which is arranged in cooperation with a reaction chamber having an air inlet end and an air outlet end, characterized in that: The control system comprises: Air intake module; An air outlet module, comprising a butterfly valve, an angle valve and a vacuum pump installed at the air outlet end; A vacuum gauge, used to measure the vacuum degree of the reaction chamber; A control module, wherein a first air pressure threshold and a second air pressure threshold are set; The control module controls the gas flow through the butterfly valve according to the difference between the measured value of the vacuum gauge and the target value.

9. The vacuum control system according to claim 8, characterized in that: The air intake module includes a stop valve and a mass flow controller installed at the air intake end; The mass flow controller is located between the stop valve and the reaction chamber; the angle valve is located between the butterfly valve and the vacuum pump, and the butterfly valve is arranged close to the reaction chamber.

10. The vacuum control system according to claim 9, characterized in that: The control system adopts the semiconductor equipment vacuum control method as described in any one of claims 1 to 7 to adaptively adjust the air flow changes to achieve the vacuum required by the specific process.

Images