KR101620395B1 - Pressure control method of automatic pressure controller values - Google Patents

Abstract

The present invention relates to a pressure control method according to conductance of a plurality of pendulum type automatic pressure control valves, comprising: inputting an opening degree of a step motor of a pendulum type automatic pressure control valve; Presetting a minimum effective open area that can be controlled from the open degree for the input step; Calculating a minimum effective conductance C ₀ by measuring flow rate and pressure in the minimum effective open area; Receiving a pre-input process recipe; Calculating a process conductance C of the process from the input process recipe; Calculating a maximum number k of the automatic pressure control valves to be actually operated to perform the input process recipe, wherein k satisfies C / k> C ₀ and k is a natural number within a range of 1 ≦ k ≦ n -; And operating the predetermined automatic pressure control valve based on the obtained maximum number k of automatic pressure control valves to be actually operated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure control method for a plurality of pincushion type automatic pressure control valves,

The present invention relates to a pressure control method in accordance with the conductance of a plurality of pendulum type automatic pressure control valves, and more particularly, to a vacuum pressure control method in a vacuum chamber used in a vacuum deposition or vacuum etching process which is a core of semiconductor, LCD, To a pressure control method for a plurality of pendulum type automatic pressure control valves.

In general, the PENDULUM VALVE or BUTTER FLY VALVE automatic pressure control valve increases the flow rate according to the open degree from 0 point and controls the pressure using the flow rate. The vacuum self-priming pressure control valve is mounted on the turbo pump in the vacuum deposition or vacuum etching process which is the core of semiconductors, LCD, OLED, etc., and in case of a large vacuum device equipped with several turbo pumps, To maintain the vacuum, several pendulum automatic pressure control valves are synchronized to adjust the total displacement to maintain a vacuum suitable for forming the plasma.

Specifically, FIG. 1 is a view schematically showing the structure of a vacuum processing chamber using such a pendulum type automatic pressure control valve. 1, a mounting table 11 for mounting an object to be processed, for example, an FPD substrate S, is provided inside the vacuum chamber 1, and plasma is generated so as to face the mounting table 11 A processing gas supply unit 12 constituting an upper electrode for the plasma processing apparatus 1 is provided. The processing gas is supplied from the processing gas supply unit 12 into the vacuum chamber 1 and the inside of the vacuum chamber 1 is vacuum-sucked by the vacuum pump 14 through the exhaust path 13 while the high frequency power source 15 The plasma of the processing gas is formed in the space above the substrate S by applying high frequency electric power to the processing gas supply unit 12 from the processing gas supply unit 12 to thereby perform the etching processing on the substrate S. [

However, when the size of the substrate S is increased and the apparatus is also enlarged, and a process of performing a process at a low pressure of about 2 Pa, for example, while supplying a large amount of process gas into the vacuum chamber 1, Ability is required. For this reason, it is necessary to provide a plurality of exhaust lines in one vacuum chamber (1).

2 is a view showing an example of the arrangement of a pressure control valve when a plurality of pendulum automatic pressure control valves are used. As shown in Fig. 2, in the bottom portion of the vacuum chamber 1, there are provided exhaust lines of, for example, eight systems from six systems along the periphery of the vacuum chamber 1, A pump 14 and a pendulum automatic pressure control valve (APC valve) 16 are provided. This pendulum automatic pressure control valve 16 is configured to detect the pressure in the vacuum chamber 1 and automatically control its opening degree based on the detected value and the pressure set value.

On the other hand, in executing the predetermined process in the above-described processing apparatus, the vacuum chamber 1 is exhausted by using all the vacuum pumps 14, and at this time, the exhaust valves 13 are opened by the pneumatic pressure valves 16, So that the pressure in the vacuum chamber 1 is controlled to a predetermined pressure.

However, as can be seen from the graph of the correlation between the pressure in the vacuum chamber 1 shown in Fig. 3 and the opening degree of the pressure valve 16, the pressure curve falls sharply, and then the inclination becomes small and gentle, I draw a curve like approaching. In this case, the degree of change of the opening degree of the pendulum type pressure valve 16 with respect to the degree of the pressure change is small in the pressure range where the inclination of the curve is large, so that the resolution of the valve 16 is low. On the other hand, in the pressure range in which the inclination of the curve is small, the degree of change in the degree of opening of the pendulum type pressure valve 16 with respect to the degree of the pressure change is large, so that the resolution of the valve 16 is high. Although the resolution of the pendulum type pressure valve 16 is different depending on the pressure range, it is difficult to perform minute adjustment of the opening degree in the pressure range of low resolution, so that the pressure fluctuation of the vacuum chamber 1 becomes large .

In order to solve such a problem, Korean Patent Laid-Open Publication No. 2009-0004596 discloses a processing vessel in which a vacuum is applied to an object to be processed in the processing vessel, one end is connected to the processing vessel, (N is an integer of 2 or more) exhaust passages for evacuating the vacuum, vacuum exhaust means connected to the other end side of these exhaust passages, pressure detecting means for detecting the pressure in the processing vessel, (1 ≤ k ≤ n-1) exhaust passages and fixing the conductance of the exhaust passage to a selected value; and an exhaust passage And constantly varying control means for automatically controlling the conductance of the exhaust passage based on the detected value of the pressure detecting means and the pressure set value. It discloses the ball processing apparatus. However, in this patent document, since the constantly variable control means is provided for a few of the plurality of exhaust paths connected to the processing vessel and the semi-fixed control means is provided for the remaining exhaust path, It is necessary for the operator to create a combination of the variable control means and the semi-fixed control means for each recipe, which requires experience and effort of the operator, Therefore, it is difficult to find a suitable pressure control method in the program only by the data of the normal flow rate and the degree of vacuum.

(Prior art document) 10-2009-0004596

The present invention is based on the above-described problems, and it is an object of the present invention to provide a vacuum control apparatus for controlling at least two identical pendulum type automatic pressure control valves installed in a vacuum chamber, which predicts a vacuum conductance according to an opening degree, Automatic control of the automatic pressure control valve, which automatically determines the closed quantity and the quantity of the automatic pressure control valve required for the control, and also the opening of the automatic pressure control valve used for the control can be performed in a stable range .

In order to achieve the above object, according to a first aspect of the present invention, there is provided a control method for an n-pendent automatic pressure control valve including n exhaust passages in a processing container, Inputting an opening degree of the step motor of the child automatic pressure control valve; Presetting a minimum effective open area that can be controlled from the open degree for the input step; Calculating a minimum effective conductance C ₀ by measuring flow rate and pressure in the minimum effective open area; Receiving a pre-input process recipe; Calculating a process conductance C of the process from the input process recipe; Calculating a maximum number k of the automatic pressure control valves to be actually operated to perform the input process recipe, wherein k satisfies C / k> C ₀ and k is a natural number within a range of 1 ≦ k ≦ n -; And operating the predetermined automatic pressure control valve based on the obtained maximum number k of automatic pressure control valves to be actually operated.

In this embodiment, the minimum effective open area is preferably set such that the opening degree of the pendulum type automatic pressure control valve is set to 5% or more of the total opening degree, (S _{n + 1} -S _n ) / S _n of the opening area S (?) Of the valve with respect to one step of the opening area ratio is 0.5 or less.

In addition, when n is 8, it is preferable that the automatic pressure control valve is selected so as to operate with 1, 2, 4, 6, 8 symmetry, and the input recipe includes the kind of gas required for the process, The pressure in the vessel, and the treatment temperature.

In addition, if the K satisfying the C / k> _0, C 0 is not present in the range 1 to n, it is preferred that the warning to the operator that improper recipe or to switch to manual operation.

According to the present invention, it is possible to stably improve the effect of the automatic pressure control function of a plurality of pendulum type automatic pressure control valves provided in the chamber, to minimize the external parameters necessary for the reproducibility of the process, and to improve the repetitive reproducibility of the process .

1 is a view showing the structure of a vacuum processing chamber using such a pendulum type automatic pressure control valve.
2 is a view showing an example of arrangement of a pressure control valve when a plurality of pendulum automatic pressure control valves are used.
3 is a graph showing the correlation between the pressure in the vacuum chamber shown in FIG. 3 and the opening degree of the pressure valve.
4 is a view showing the arrangement relationship of the chamber, the automatic pressure control valve, and the turbo pump.
5 is a view showing an open area changed by a circular opening of a pendulum type automatic pressure control valve and a circular graduated plate.
6 is a diagram for explaining overlapping areas between two objects;
7 is a view for explaining an overlapping area change according to a rotation center angle.
8 is a view showing a change in area according to an angle change;
9 is a view showing an open area according to an angle;
10 is a view showing an open area according to a step change of the step motor.
11 is a view showing a change amount (slope) according to a step change of the step motor.
12 is a graph corresponding to an opening rate change amount ((Sn + 1-Sn) / Sn) corresponding to Table 1. Fig.
13 is a view showing a change in pressure due to a step change of the step motor.
14 shows an example of the use of a pendulum automatic pressure control valve operated symmetrically in correspondence with the number of valves used when eight pendulum automatic pressure control valves are installed in the chamber.
15 is a flowchart of a pressure control method for a plurality of pendulum automatic pressure control valves according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, but may be embodied in various forms.

The present embodiments are provided so that the disclosure of the present invention is thoroughly disclosed and that those skilled in the art will fully understand the scope of the present invention. And the present invention is only defined by the scope of the claims. Accordingly, in some embodiments, well known components, well known operations, and well-known techniques are not specifically described to avoid an undesirable interpretation of the present invention.

Like reference numerals refer to like elements throughout the specification. Moreover, terms used herein (to be referred to) are intended to illustrate embodiments and are not intended to limit the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. Also, components and acts referred to as " comprising (or comprising) " do not exclude the presence or addition of one or more other components and operations.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless they are defined.

Hereinafter, technical features of the present invention will be described in detail with reference to the accompanying drawings.

4 is a view showing the arrangement relationship of the chamber 100, the automatic pressure control valve 200, and the turbo pump 300 in order to explain a method of controlling the pressure of a plurality of pendulum automatic pressure control valves according to the present invention.

4, the turbo pump 300 vacuum-sucks the inside of the chamber 100 while the automatic pressure control valve 200 is disposed between the pump 300 and the chamber 100, 200 are configured to automatically control the degree of opening thereof in accordance with the pressure in the vacuum chamber 100.

4, when the upper pressures of the automatic pressure control valve 200 are p ₁ and p ₂ and the lower pressure of the automatic pressure control valve 200 is P ₀ , the automatic pressure control valve 200 ) is the pressure difference Δp = p ₁ -p ₀ (or p ₂ -p ₀₎ of the upper and lower ends through the. At this time, assuming that p ₁ and p ₂ are close to the degree of vacuum of the chamber 100, most of them are maintained at several tens of mtorr, and P ₀ is in the range of 10 ^-5 to 10 ^-6 mtorr Lt; / RTI > Therefore, the pressure of the refrigerant flowing through the automatic pressure control valve 200

The upper and lower pressure difference Δp ≒ p can be approximated assumed to be ₁ (or Δp ≒ p _2).

In order to simplify the explanation, assuming that two exhaust passages are formed in the chamber 100, the flow quantities q ₁ and q ₂ in the respective passages can be defined as follows.

q ₁ = C ₁ x p ₁

q ₂ = C ₂ x p ₂

₍ Where C is the conductance, p is the pressure, and q is the flow rate)

If the installed pressure control valves are the same, C ₁ = C ₂ when measured in the same step.

Where the measurable total pressure of the chamber is p ≒ p ₁ (or p ₂ ) and the flow q = q ₁ + q _2, so the overall conductance C is C ₁ + C ₂ .

On the other hand, the vacuum conductance C in a commonly used unit system is defined by the following equation (1).

식(1)

Equation (1)

In the embodiment shown in Fig. 4, the conductance is controlled by the opening degree of the two automatic pressure control valves 200 (here, pendulum valves) at the right and left sides. And the rate of change of the open area according to the following equation.

5, the pendulum type automatic pressure control valve 200 includes a circular disk 210 having a diameter larger than the diameter of the opening to open and close the circular opening 210 and the circular opening 210, The central portion of the vacuum plate 220 is fixed to the rotational center axis R of the automatic pressure control valve 200 via the arm 221 and rotates around the rotational axis, The area is determined.

If the open area for the opening angle? Is S (?), It can be approximated using a design program, but it is not easy to program the pressure controller using a PLC (programmable logic controller) Therefore, it is desirable to obtain a mathematical solution as follows and to reflect it in the program as a function.

5, the opening radius of the opening 210 of the pendulum type automatic pressure control valve is 132 mm and the radius of the retarder 22 is 142 mm, and the retarder 220 moves from the rotation center R to the opening 210 ) Is a pressure control valve that rotates around a point 200 mm away from the center of the pressure control valve.

Since the open area S ([theta]) can not be directly obtained, if the mathematical method is used first, the intersection area of two different circles can be expressed by the distance of two sources as shown in FIG. In FIG. 6, R1 (or R) is 142 mm in radius of the retarder 220 and R2 (or r) is 132 mm in radius of the opening 210.

The area A in FIG. 6 is represented by the following equation (2).

식(2)
A =

Equation (2)

When r = 132 mm R = 142 mm is substituted for this equation,

The open area S (θ) is πr ² - A (hitting area), which is calculated by equation (3).

식(3)

Equation (3)

The following equation (4) is obtained.

식(4)

Equation (4)

Here, d is the distance between the centers of the two sources. Referring to FIG. 7, the distance d can be expressed by a function d (?) According to the angle?, And can be expressed by the following equation (5).

식(5)

Equation (5)

The following equation (6) is obtained by substituting the equation (5) into the equation (4)

식(6)

Equation (6)

The equation (6) is summarized by the following equation (7).

식(7)

Equation (7)

The S (θ) to be obtained is shown in FIG.

As can be seen from the graph shown in FIG 8, when the opening angle is above a predetermined angular area of the opening it can be seen from becoming constant at π · 132 ² = 54739.11mm ^2.

FIG. 9 is a graph of a table obtained by making a change by an opening area S (?) According to an opening angle, and FIG. 10 is a graph after forming an opening angle table by changing the area change per step, which is a characteristic of the step motor. As can be seen in FIGS. 9 and 10, it can be seen that the open area S (θ) does not show an area change from about 2.8 to 514 steps. This is because the size Is more likely to occur.

Next, for stable control, it is necessary to recognize an effective control period of the open area S (&thetas;). 11 is a diagram showing an increase amount of S with respect to the movement per one step in order to judge the effectiveness with respect to the pressure control. From this data, the open area for each motion increases suddenly from a certain point (about 514 steps starting to open the opening), gradually becomes a slope at about 1000 steps, and after about 2500 steps, It can be seen that the increase in the open area is reduced.

As shown in Equation 7, the open area S (&thetas;) is an accurate method for obtaining the derivative with respect to [theta], but in this case, mathematical complexity increases. Therefore, in the present invention, Quot; S change per step [slope] "or" opening rate change amount (Sn + 1-Sn) / Sn [%] "

Actually, the opening degree S is 0 before 514 steps (2.8626 degrees), and then the opening degree is rapidly increased. As can be seen from Table 1, the steps of the step motor showed only from 0 to 2329, and in particular, it can be seen that the rate of change of the opening rate was 0.752 in step 699, and stably changed to about 0.514 in step 777.

(Table 1)

Fig. 12 shows a graph corresponding to the opening ratio change amount ((Sn + 1-Sn) / Sn) corresponding to the above-mentioned Table 1. Fig. As shown in Fig. 12, it can be seen that the area is opened rapidly in the area with small opening degree and the area in which the nose is not controllable, and the area with minimum control is approximately equal to or larger than step 777 .

On the contrary, in the region of the step 2500 or more, it is understood that the opening degree per step is hardly changed, so that it is necessary to perform more steps than the previous section for the pressure control. Therefore, To 15% area and 15% or more area, and it is necessary to perform tuning for each section such as a value necessary for PID control.

Now, to determine the conductance of the actual pressure regulating valve, measure the flow-pressure and enter the pressure control table using the LEARNING function.

The following Table 2 and FIG. 13 are tables and graphs showing the angles, steps, and mtorr measured at a flow rate of 1000 SCCM.

(Table 2)

Assuming that the stable control period is 5% ~ 15% (about 800 ~ 2500step) of the opening angle as described above, if the conductance of the step motor is 800 steps,

C = 1000 (sccm) / (78.7 x 0.024 torr) = 529.44 L / S.

C = 529.44, and since two pressure regulating valves are used (C = C1 + C2)

C1 = C2 = 529/2 = 264.72 L / s (effective conductance per valve in 800 steps). Through this, the minimum controllable area of the pressure control valve used here can be determined as 529 L / s.

As a result, the pressure control method can be set by the following procedure.

1) Confirm the total pressure and flow rate - Input process conditions by RECIPE

For all 5SLPM, 50 mtorr jobs

C = (5000 [sccm]) / (78.7 x 0.050 [torr]) = 1270.65 L / s

2) Calculate the expected conductance per pressure control valve

With six pressure control valves, Cn = 211.77 L / s

With eight pressure regulating valves, Cn = 158.83 L / s

3) Judging suitability of conductance

As described above, the step value in the control area that is proper according to the design dimension of the valve is obtained, and the minimum control contractance is set to be 5% of the opening through the PRE-LEARNING under the standard condition to 264.72 L If / s is used, the maximum number of pressure control valves

1270.65 / n? 267.22

n? 4.80

That is, the number of suitable pressure control valves at an effective opening degree of 5% can be judged to be four.

4) After receiving the pressure and flow rate as recipe in the program, calculate the appropriate pressure control quantity, and set the valve more than the required quantity in STEP0 for PID control and do not use it.

5) Even when using various RECIPE, it can control the quantity of pressure regulating valve automatically by PID control.

6) Since the geometric valve positions of the chambers may be different as shown in FIG. 14, the number of valves considering symmetry at 2, 4, 6, 8, etc. is also reflected as the positional condition of the pre-valve. In this embodiment, since n? 4.80, it is preferable to use four valves, and the symmetry necessary for the process is taken into consideration to select the valve. In FIG. 14, although the open form of the square is shown as the symmetry, the open form may be changed by the symmetry of the diamond shape, and in some cases, the asymmetry may be selected.

If the maximum number of pressure control valves to be operated is 3, it is preferable to select two valves considering the symmetry, which means that if the number exceeds 4, the valve should be operated under an effective opening of 5% So that a problem of low reliability is caused.

Fig. 15 shows a flowchart for performing a process of a product using the control method according to the present invention. Although not described in the present invention, the method according to the present invention shown in Fig. 15 can be performed through a program installed in a computer or the like for controlling the processing chamber (vacuum chamber). In addition to the method according to the present invention, this program can also transmit control signals necessary for control of the processing vessel to respective parts, or can control the type of the processing gas, the flow rate of the processing gas, the pressure setting in the processing vessel , The processing temperature, and the like.

As shown in FIG. 15, the step of controlling the pressure of the automatic pressure control valve according to the present invention includes the step of inputting the dictionary data for the product in step 100. In this step, data such as the opening per step of the stepping motor is inputted in advance as a step of inputting the shipping value of the product.

Next, step 200 is a pre-learning step for calculating an effective conductance C ₀ in a controllable minimum control area (step of the step motor corresponding to the 5% open area) based on the pre-inputted dictionary data (Flow and pressure measurement in the minimum control zone).

After the preliminary data input step S100 and the free running step S200, the processing unit waits in the stand-by state at step 300 and receives user input items such as a recipe from the user side. User inputs include flow and pressure tables, other process sequences, determination of control valve numbers (1 to N), control valve use recipe settings (eg, available n = 1, 2, 4, 6, 8) .

Next, in accordance with the process start command (step S400) of the operator, the processing device reads the recipe in step 500. [ The processor calculates the C value of the corresponding process in the recipe.

Next, in step S600, the number k of valves required for actual operation is obtained by using the C value of the corresponding process obtained in step S500 and the effective conductance C0 value obtained in the free running step of step S200. At this time, It is judged whether or not the value divided by the valve number k is larger or smaller than the effective conductance C0.

C ₀ <C / k (where 1 ≤ k ≤ n, k is a natural number)

If C / k is less than C ₀ in step S600 step S610 and proceeds to step S600 to re-enter the number of k minus 1, which is repeated until the C ₀ <C / k satisfied in step 600. However, if k does not satisfy the expression C ₀ &lt; C / k in step 600 until k becomes 0, the step goes to S630 to notify the operator of the incompatibility of the recipe and to proceed with review or manual operation by the operator.

When C ₀ <C / k is satisfied If, at step S600 processing device drives the pressure control valve so as to set the k that satisfies the equation, the maximum value, and performs the pressure regulation control corresponding to the k obtained as in step S700 In step S900, it is determined whether there is a next recipe or not in step S800 by completing the process for the recipe input from the operator.

According to the present invention, it is possible to calculate and regulate the quantity of use of the pressure regulating valve automatically and separately. It is possible to automatically determine the use of the pressure regulating valve by simple information of the pressure and flow value only in the recipe according to the process (RECIPE). At this time, all the valves contributing to the pressure regulating are in the proper pressure regulating region So that the pressure control is quick and reproducible.

The foregoing description is merely illustrative of the technical idea of the present invention and various changes and modifications may be made without departing from the essential characteristics of the present invention by those skilled in the art. Therefore, the embodiments disclosed in the present invention are for illustrative purposes only and are not intended to limit the scope of the present invention, and the scope of the present invention is not limited by these embodiments.

Therefore, the scope of the present invention should be construed as being covered by the following claims rather than being limited by the above embodiments, and all technical ideas within the scope of the claims should be construed as being included in the scope of the present invention.

Claims (6)

1. A control method for n pendular automatic pressure control valves each including n exhaust passages in a processing vessel and provided in n exhaust passages,
Inputting an opening degree of the step motor of the pendulum type automatic pressure control valve;
Presetting a minimum effective open area that can be controlled from the open degree for the input step;
Calculating a minimum effective conductance C ₀ by measuring flow rate and pressure in the minimum effective open area;
Receiving a pre-input process recipe;
Calculating a process conductance C of the process from the input process recipe;
Calculating a maximum number k of the automatic pressure control valves to be actually operated to perform the input process recipe, wherein k satisfies C / k> C ₀ and k is a natural number within a range of 1 ≦ k ≦ n -;
Operating the predetermined automatic pressure control valve based on the obtained maximum number k of the automatic pressure control valves to be actually operated
And a control unit for controlling the pressure control valve. The method according to claim 1,
Wherein the minimum effective opening area is such that the opening degree of the pendulum automatic pressure control valve is 5% or more of the total opening degree.
The method according to claim 1,
Wherein the minimum effective open area that can be controlled from the opening degree with respect to the input step is determined based on an opening ratio variation amount of the automatic pressure control valve opening area S (?) According to the opening angle? Of the automatic pressure control valve for one step of the step motor S _{n + 1} -S _n ) / S _n is 0.5 or less, wherein Sn is an opening area when the step motor is in the n-th step.
The method according to claim 1,
Wherein when the n is 8, the pendulum automatic pressure control valve actuates two, four, six or eight automatic pressure control valves, wherein the operating pressure control valves are selected so that their positions are symmetrical with each other Control method of child automatic pressure control valve.
The method according to claim 1,
Wherein the process recipe includes the kind of gas required for the process, the flow rate of the process gas, the pressure in the process container, and the process temperature.
The method according to claim 1,
The control method of the C / k> C when the ₀ K is zero satisfying a warning the operator that the process recipe is not suitable recipe or to input binary characterized in that the switch to manual operation child automatic pressure control valve.

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