JPH0878994A - Impedance matching circuit - Google Patents

Abstract

PURPOSE: To remarkably reduce the capacitance of a first variable capacitor and to remarkably reduce voltage of a second variable capacitor across terminals by connecting the first and second variable capacitors and a compound transformer. CONSTITUTION: A first variable capacitor 203 is connected between an input terminal 221 and ground E, and the one end of a second variable capacitor 204 is connected with the input terminal 221. The one end of the primary winding 233a of the compound transformer 233 where a secondary winding 233b is connected between an output terminal 222 and the ground E is connected with the other end of a second variable capacitor 204, and the other end of the primary winding 233a of the compound transformer 233 is grounded. Thus, the capacitance of the capacitor 203 can be remarkably reduced and the voltage of the capacitor 204 across terminals can be remarkably reduced by connecting the first and second variable capacitors 203 and 204 and the compound transformer 233. As a result, the volume and weight of the both capacitors 203 and 204 can be remarkably reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impedance matching circuit incorporated in a plasma processing apparatus for performing a predetermined process on a material such as a wafer when a semiconductor element is formed using plasma excited by a high frequency. It is about improvement.

[0002]

2. Description of the Related Art FIG. 1 is a block diagram of a plasma processing apparatus. In the figure, E is a ground, 100 is a high frequency oscillation source, 111 and 311 are high frequency transmission lines, and 200 is an impedance matching circuit. 34
Reference numeral 0 is a semiconductor processing chamber, 321 is a high frequency applying electrode, 322 is a ground electrode, and 323 is a wafer.
Reference numeral 331 is a reaction gas inflow pipe, and reference numeral 332 is an exhaust pipe.

In FIG. 1, one of the high frequency oscillation sources 100 is grounded to the earth E, and the other is connected to the impedance matching circuit 200 by the high frequency transmission line 111. Impedance matching circuit 2 installed directly above the processing chamber 340
00 by the high frequency transmission line 311
It is connected to a high-frequency applying electrode 321 installed inside 40. The inside of the semiconductor processing chamber 340 is set to a vacuum state,
A high frequency applying electrode 321 and a ground electrode 322 are installed inside the semiconductor processing chamber 340 as a pair of electrodes facing each other. The ground electrode 322 is grounded to the earth E, and the wafer 323 to be processed is placed on the upper surface of the ground electrode 322. The reaction gas inflow pipe 331 is connected to the high frequency application of the semiconductor processing chamber 340, and the exhaust pipe 332 is connected to the lower portion of the processing chamber 340.

A reaction gas supply device (not shown) supplies the reaction gas to the semiconductor processing chamber 340 through the reaction gas inflow pipe 331, and the high frequency oscillation source 100 supplies high frequency power to the high frequency application electrode 321 through the impedance matching circuit 200. To do. As a result, plasma is generated between the high-frequency applying electrode 321 and the ground electrode 322 to perform various processes such as etching process, ashing process or thin film deposition process for forming a semiconductor element.

In the block diagram of the plasma processing apparatus shown in FIG. 1, in order to efficiently and reproducibly perform the various processes described above, a stable and uniform plasma is generated in the high frequency applying electrode 321 and the ground electrode 322. Need to occur during. For that purpose, it is necessary to efficiently supply stable high frequency power to the plasma.

In order to efficiently supply stable high frequency power to the plasma, the high frequency transmission line 11 in FIG.
It is a necessary condition that there is no reflection school in 1. For that purpose, it is necessary to match the input impedance of the impedance matching circuit 200 with the characteristic impedance of the high frequency transmission circuit 111. Here, the input impedance of the impedance matching circuit 200 is all impedances seen from the input side of the impedance matching circuit 200, and is a value obtained by combining the following impedances. Impedance of the impedance matching circuit 200. Impedance of the high frequency transmission line 311. High frequency applying electrode 321, plasma between the high frequency applying electrode 321 and the ground electrode 322, and impedance of the ground electrode 322. The high frequency transmission line 311, the high frequency applying electrode 321, the plasma between the high frequency applying electrode 321 and the ground electrode 322, and the floating impedance around the ground electrode 322.

Of the above impedances,
Are referred to as load impedances, which are impedances that the operator cannot arbitrarily operate from the outside, and only the impedance of the impedance matching circuit 200 can be operated by the operator from the outside. Therefore, in order to eliminate the reflected wave existing in the high frequency transmission line 111, the input impedance of the impedance matching circuit 200 must be matched with the characteristic impedance of the high frequency transmission line 111 by operating the circuit element of the impedance matching circuit 200. I have to. This operation is called "matching impedance", and impedance matching circuit 2
00 is for impedance matching.

FIG. 2 is a diagram showing a prior art impedance matching circuit 200. In the figure, 221 is an input terminal, 201 is a first variable capacitor, 2
Reference numeral 02 is a second variable capacitor, 231 is a first inductor, and 232 is a second inductor. E
Is a ground and 222 is an output terminal. The first variable capacitor 201 is connected between the input terminal 221 and the ground E,
One end of the second variable capacitor 202 is connected to the input terminal 221. The first inductor 231 is connected between the other end of the second variable capacitor 202 and the ground E, and the second inductor 232 is connected between the other end of the second capacitor 202 and the output terminal 222.

The first variable capacitor 201 and the second variable capacitor 202 shown in the figure are respectively adjusted to have optimum capacitances, and the first inductor 231 and the second inductor 232 are connected by, for example, selection of taps. The input impedance of the impedance matching circuit 200 is matched with the characteristic impedance of the high frequency transmission line 111 by adjusting the inductance to an arbitrary value by changing the terminals.

Therefore, in order to match the input impedance of the impedance matching circuit 200 with the characteristic impedance of the high frequency transmission line 111 in response to the change in the load impedance when impedance matching is performed, the first impedance shown in FIG. The first variable capacitor 201, the second variable capacitor 202, the first inductor 231 and the second variable capacitor 202.
The inductor 232 is an indispensable element.

The impedance matching circuit 200 is
In addition to the circuit shown in FIG. 2, various types of circuits such as L-type, π-type and T-type are used, but the principle of impedance matching is the same and is based on the adjustment of the variable capacitor and the inductor.

[0020]

When the impedance matching circuit 200 shown in FIG. 2 performs impedance matching and the second variable capacitor 202 connected in series to the load has a small capacity, the second variable capacitor 202 When the resistance component of the impedance when the load side is viewed from is small, the current between the terminals of the second variable capacitor 202 may increase significantly because the current increases in order to cause the load to consume the same power. . Further, depending on the value of the voltage between the terminals, the second variable capacitor 202 may be damaged by dielectric breakdown.

As a means for avoiding the above-mentioned dielectric breakdown, it is conceivable to use a capacitor having a large dielectric strength such as a vacuum variable capacitor as an element of the impedance matching circuit 200, but it is costly, and the volume and weight of the plasma processing apparatus are large. Cause increase.

In the plasma processing apparatus shown in FIG. 1, where the impedance matching circuit 200 is installed, considering the loss of high frequency power due to the high frequency transmission line 311,
It is necessary to be extremely close to the high frequency applying electrode 321.
However, in the vicinity of the high-frequency applying electrode 321, that is, directly above the semiconductor processing chamber 340, the reaction gas inflow pipe 331 and pipes such as a cooling water supply pipe (not shown) and measuring devices such as a pressure monitor (not shown). Due to the existence of the impedance matching circuit 200, when the volume of the impedance matching circuit 200 is large, the impedance matching circuit 200 interferes with them. Therefore, in order to avoid this interference, there is a problem that the plasma processing apparatus itself becomes large.

The present invention is an impedance matching circuit 200.
It is an object of the present invention to provide an impedance matching circuit 200 in which the variable capacitor of the impedance matching circuit 200 is prevented from causing dielectric breakdown without increasing the volume and weight of the impedance matching circuit 200.

[0029]

As shown in FIG. 1, the impedance matching circuit of claim 1 is connected between a high frequency oscillation source 100 in a plasma processing apparatus and a high frequency applying electrode 321 in a semiconductor processing chamber 340. In the impedance matching circuit for impedance matching, as shown in FIG. 3, the first variable capacitor 203 is connected to the input terminal 221.
Is connected to the ground E, one end of the second variable capacitor 204 is connected to the input terminal 221, and the second variable capacitor 2
04, the other end of the secondary winding 233b is connected between the output terminal 222 and the ground E.
a and the primary winding 233 of the compound-winding transformer 233.
It is an impedance matching circuit in which the other end of a is grounded.

In the impedance matching circuit of claim 2, as shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340.
In an impedance matching circuit that is connected between the first variable capacitor 205 and the first variable capacitor 205 to perform impedance matching, one end of the first variable capacitor 205 is connected to the input terminal 221 as shown in FIG.
The second variable capacitor 206 is replaced by the first variable capacitor 2
No. 05 and the ground E, and the secondary winding 233b is connected between the output terminal 222 and the ground E.
Of one end of the primary winding 233a of the first variable capacitor 20
5, the primary winding 233 of the compound-winding transformer 233.
It is an impedance matching circuit in which the other end of a is grounded.

In the impedance matching circuit of claim 3, as shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340.
In the impedance matching circuit that is connected to the input terminal 221 to perform impedance matching, as shown in FIG. 7, the variable inductor 236 is connected between the input terminal 221 and the ground E, and one end of the variable capacitor 207 is connected to the input terminal 221. Then
The other end of the variable capacitor 207 has the secondary winding 233b connected between the output terminal 222 and the ground E and is a multi-winding transformer 233.
Connected to one end of the primary winding 233a of the multi-winding transformer 233
Is an impedance matching circuit in which the other end of the primary winding 233a is grounded.

The impedance matching circuit according to a fourth aspect of the present invention is, as shown in FIG. 1, a high frequency oscillation source 100 in a plasma processing apparatus and a high frequency applying electrode 32 in a semiconductor processing chamber 340.
In an impedance matching circuit that is connected to the input terminal 221 to perform impedance matching, as shown in FIG. 8, one end of the variable inductor 237 is connected to the input terminal 221, and the variable capacitor 208 is connected to the other end of the variable inductor 237 and the ground E.
The primary winding 233a of the compound-winding transformer 233, which is connected between the secondary winding 233b and the output terminal 222 and the ground E.
Is an impedance matching circuit in which one end is connected to the other end of the variable inductor 237 and the other end of the primary winding 233a of the compound-winding transformer 233 is grounded.

In the impedance matching circuit of claim 5, as shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency application electrode 32 in the semiconductor processing chamber 340.
In an impedance matching circuit for connecting impedance between the first variable capacitor 209 and the input terminal 221 and the ground E, one end of the variable inductor 238 is connected to the input terminal 221 as shown in FIG. 221 to connect the second variable capacitor 210 to the variable inductor 2
38 and the secondary winding 233b connected between the output terminal 222 and the ground E, and the compound winding transformer 233.
Is an impedance matching circuit in which one end of the primary winding 233a is connected to the other end of the variable inductor 238 and the other end of the primary winding 233a of the compound-winding transformer 233 is grounded.

In the impedance matching circuit of claim 6, as shown in FIG. 1, the high frequency oscillating source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340.
In an impedance matching circuit that is connected between the first variable capacitor 211 and the input terminal 221 and the ground E, one end of the second variable capacitor 212 is connected as shown in FIG. Input terminal 2
21 and the other end of the second capacitor 212 is connected to one end of the primary side of the autotransformer 239, the secondary side of which is connected between the output terminal 222 and the ground E. 1
This is an impedance matching circuit in which the other end on the secondary side is grounded.

In the impedance matching circuit of claim 7, as shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340 are used.
In the impedance matching circuit which is connected to the input terminal 221 to perform impedance matching, one end of the first variable capacitor 213 is connected to the input terminal 221, and the second variable capacitor 214 is connected to the first variable capacitor 214 as shown in FIG. One end of the primary side of the autotransformer 239, which is connected between the other end of the variable capacitor 213 and the ground E and whose secondary side is connected between the output terminal 222 and the ground E, is connected to the other end of the first variable capacitor 213. It is an impedance matching circuit in which the other end of the primary side of the autotransformer 239 is grounded by being connected.

In the impedance matching circuit of claim 8, as shown in FIG. 1, the high frequency oscillating source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340.
In an impedance matching circuit that is connected between the input terminal 221 and the ground terminal E, the variable inductor 240 is connected between the input terminal 221 and the ground E as shown in FIG.
One end of the variable capacitor 215 is connected to the input terminal 221, and the other end of the variable capacitor 215 is connected to one end of the primary side of the autotransformer 239 whose secondary side is connected between the output terminal 222 and the ground E. It is an impedance matching circuit in which the other end of the primary side of the autotransformer 239 is grounded.

In the impedance matching circuit of claim 9, as shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency applying electrode 32 in the semiconductor processing chamber 340 are used.
In an impedance matching circuit that is connected to the input terminal 221 to perform impedance matching, one end of the variable inductor 241 is connected to the input terminal 221 as shown in FIG.
Of the variable capacitor 216 is connected between the other end of the variable inductor 241 and the ground E, and the secondary side is connected to the output terminal 222 and the ground E.
This is an impedance matching circuit in which one end of the primary side of the autotransformer 239 connected between them is connected to the other end of the variable inductor 241, and the other end of the primary side of the autotransformer 239 is grounded.

The impedance matching circuit of claim 10 is
As shown in FIG. 1, the high frequency oscillation source 100 in the plasma processing apparatus and the high frequency application electrode 3 in the semiconductor processing chamber 340.
In the impedance matching circuit which is connected between the first and second terminals to perform impedance matching, as shown in FIG.
Of the variable inductor 242 is connected between the input terminal 221 and the ground E, and one end of the variable inductor 242 is connected to the input terminal 221.
, The second variable capacitor 218 is connected between the other end of the variable inductor 242 and the ground E, and the secondary side is connected between the output terminal 222 and the ground E. One end of the primary side of the autotransformer 239. Is connected to the other end of the variable inductor 242, and the other end on the primary side of the autotransformer 239 is grounded.

The impedance matching circuit according to claim 11 is
15. The impedance matching circuit according to claim 6, wherein a cylinder 243 made of a conductor is mounted around the autotransformer 239 as shown in FIG.

The impedance matching circuit according to claim 12 is
16. The impedance matching circuit according to claim 1, wherein a cylinder 243 made of a conductor is mounted around the compound transformer 233 as shown in FIG.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an impedance matching circuit 2 of the present invention.
It is a figure which shows the 1st Example of 00. In the figure, the same reference numerals as those in FIG. 2 are the same as those in FIG.
The difference will be described.

In FIG. 3, reference numeral 203 is a first variable capacitor, and 204 is a second variable capacitor. Two
33 is a compound winding transformer, 233a is a primary winding, and 233b is a secondary winding.

The first variable capacitor 203 is connected to the input terminal 2
21 and the ground E, and the second variable capacitor 204
Is connected to the input terminal 221. Secondary winding 23
3b is connected between the output terminal 222 and the ground E. One end of the primary winding 233a of the compound winding transformer 233 is connected to the other end of the second variable capacitor 204, and the primary winding of the compound winding transformer 233 is connected. The other end of 233a is grounded.

FIG. 4 is a diagram showing a compound-winding transformer 233 used in the impedance matching circuit 200 of the present invention. In the figure, the same reference numerals as those in FIG. 3 are the same as those in the description of FIG.

In FIG. 4, R1 is the radius of the primary winding 233a, R2 is the radius of the secondary winding 233b, and D
Is the length of the primary winding 233a or the secondary winding 233b, and the length of the primary winding 233a and the length of the secondary winding 233b are the same. Here, the number of turns of the primary winding 233a is N1, and the number of turns of the secondary winding 233b is N2.
The Nagaoka coefficient of the secondary winding 233a is B1, and the secondary winding 233 is
When the Nagaoka coefficient of b is B2 and the magnetic permeability is μ0, the inductance L233a of the primary winding 233a and the inductance L233b of the secondary winding 233b are obtained from the equations (1) and (2), respectively.

[0048]

[Equation 1]

[0050]

[Equation 2]

FIG. 5 is a diagram showing an equivalent circuit when the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3 is used in a plasma processing apparatus. In FIG. 5, the same reference numerals as those in FIG. 1 or 3 are the same as those in FIG. 1 or 3, and therefore the description thereof will be omitted, and different points will be described.

In FIG. 5, 234 and 235 are inductors, and 300 is a load. The inductance of the inductor 234 matches the inductance of the primary winding 233a shown in FIG. 4, and the inductance of the inductor 235 matches the leakage inductance of the secondary winding 233b shown in FIG. In FIG. 5, the compound transformer 2
The resistance value of the wire 33 is ignored. Further, due to the structure of the compound-winding transformer 233, all the magnetic flux generated by the current flowing through the primary winding 233a is secondary winding 233b.
Is assumed to penetrate.

When the cross-sectional areas of the primary winding 233a and the secondary winding 233b shown in FIG. 4 are S1 and S2, respectively, these S1 and S2 are expressed by equations (3) and (4).

[0058]

(Equation 3)

[0060]

[Equation 4]

Therefore, the inductance L234 of the inductor 234 and the leakage inductance L235 of the secondary winding 233b are expressed by the equations (5) and (6), respectively.

[0064]

(Equation 5)

[0066]

(Equation 6)

Assuming that the impedance of the load 300 shown in FIG. 5 is Z300, the transformation function of the compound-winding transformer 233 converts it to the square of the turns ratio A of the compound-winding transformer 233. Impedance of 300 Z300
t is shown by Formula (7).

[0070]

(Equation 7)

In the impedance matching circuit 200 of the prior art shown in FIG. 2 and the equivalent circuit of the impedance matching circuit 200 of the present invention shown in FIG. 5, the capacitance of the variable capacitor and the voltage between terminals when impedance matching is performed are compared. The results obtained are shown in Table 1.

[0073]

[Table 1]

In Table 1, L231, L232, L2
34 and L235 are the first inductor 231, the second inductor 232, the inductor 234, and the inductor 23.
5 is the respective inductance, and W100 is the supply power of the high frequency oscillation source 100. Z111 and Z30
0 is the impedance of each of the high frequency transmission line 111 and the load 300. C201 to C204 are the first
Variable capacitor 201, second variable capacitor 20
2, V is a capacitance of each of the first variable capacitor 203 and the second variable capacitor, and V201 to V204 are the first variable capacitor 201, the second variable capacitor 202, the first variable capacitor 203, and the second variable capacitor.
Is the voltage across the terminals of the variable capacitor. The frequency is 13.
It is 56 [MHz].

As a condition for impedance matching, the primary winding 233a of the compound-winding transformer 233 of the present invention shown in FIG. 4 is used.
And the length D of the secondary winding 233b is set to 0.1 [m], and 1
The number of turns N1 of the secondary winding 233a is 5 [turns], and the secondary winding 2
The number of turns N2 of 33b is 10 [turns], and the primary winding 23
The radius R1 of 3a is 0.04 [m], and the radius R2 of the secondary winding 233b is 0.05 [m].

From these dimensions, the Nagaoka coefficient B1 of the primary winding 233a was set to 0.72, and the Nagaoka coefficient B2 of the secondary winding 233b was set to 0.75. Expressions (1) to (6) described above
Therefore, the inductance L234 of the equivalent circuit of the impedance matching circuit 200 of the present invention and the leakage inductance L235 of the secondary winding 233b have the values shown in Table 1. The inductances L231 and L232 of the impedance matching circuit 200 of the prior art are made to match the inductance L234 of the equivalent circuit of the impedance matching circuit 200 of the present invention and the leakage inductance L235 of the secondary winding 233b, respectively. Supply power W1 of the high frequency oscillation source 100
00 and the impedance Z11 of the high frequency transmission line 111
1 is set to the same value in the prior art and the present invention.
Although the same load 300 is connected in the prior art and the present invention, in the equivalent circuit of the impedance matching circuit 200 of the present invention, since it is converted to the square of the turns ratio A of the compound-winding transformer 233, It is shown in Table 1 as a power of one squared, that is, a quarter.

In the present invention, the load impedance Z30
Since 0 becomes 1/4, the first variable capacitor 2
03 and the capacitance of the second variable capacitor 204 and the voltage between terminals are calculated as shown in Table 1. Since the capacitance C203 of the equivalent circuit of the impedance matching circuit 200 of the present invention is remarkably reduced as compared with the capacitance C201, the volume and weight of the first variable capacitor 203 can be reduced. The capacitance C204 is slightly higher than the capacitance C202, but the terminal voltage V204 is significantly lower than the terminal voltage V202, so that the withstand voltage of the second variable capacitor 204 is significantly increased. It can be reduced. As a result, the volume and weight of the second variable capacitor 204 can be reduced.

FIG. 6 is a diagram showing a second embodiment of the impedance matching circuit 200 of the present invention. In the figure,
The same reference numerals as those in FIG. 3 are the same as those in FIG. In FIG. 6, 205
Is a first variable capacitor, and 206 is a second variable capacitor. One end of the first variable capacitor 205 is connected to the input terminal 221, and the second variable capacitor 206
Is connected between the other end of the first variable capacitor 205 and the ground E. One end of the primary winding 233a of the compound transformer 233 is connected to the other end of the first variable capacitor 205.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the second embodiment shown in FIG. 6, the impedance of the load 300 is changed by the transformer function of the compound transformer 233. Since Z300 is converted to the square of the turns ratio A, the first variable capacitor 20
The volume and weight of the fifth and second variable capacitors 206 can be reduced.

FIG. 7 is a diagram showing a third embodiment of the impedance matching circuit 200 of the present invention. In the figure,
Since the same reference numerals as those in FIG. 3 are the same as those in FIG. 3, the description thereof will be omitted, and different points will be described. In FIG. 7, the variable inductor 236 is connected between the input terminal 221 and the ground E,
One end of the variable capacitor 207 is connected to the input terminal 221. One end of the primary winding 233a of the compound transformer 233 is connected to the other end of the variable capacitor 207.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the third embodiment shown in FIG. 7, the impedance of the load 300 is changed by the transformer function of the compound-winding transformer 233. Since Z300 is converted to the square of the winding ratio A, the volume and weight of the variable capacitor 207 can be reduced.

FIG. 8 is a diagram showing a fourth embodiment of the impedance matching circuit 200 of the present invention. In the figure,
Since the same reference numerals as those in FIG. 3 are the same as those in FIG. 3, the description thereof will be omitted, and different points will be described. In FIG. 8, one end of the variable inductor 237 is connected to the input terminal 221, and the variable capacitor 208 is connected between the other end of the variable inductor 237 and the ground E. Primary winding 23 of compound transformer 233
One end of 3a is connected to the other end of the variable inductor 237.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the fourth embodiment shown in FIG. 8, the impedance of the load 300 is changed by the transformer function of the compound transformer 233. Since Z300 is converted into the square of the winding ratio A, the volume and weight of the variable capacitor 208 can be reduced.

FIG. 9 is a diagram showing a third embodiment of the impedance matching circuit 200 of the present invention. In the figure,
Since the same reference numerals as those in FIG. 3 are the same as those in FIG. 3, the description thereof will be omitted, and different points will be described. In FIG. 9, the first variable capacitor 209 is connected between the input terminal 221 and the ground E, and one end of the variable inductor 238 is connected to the input terminal 221. The second variable capacitor 210 is connected between the other end of the variable inductor 238 and the ground E, and the compound transformer 2
33 is connected to one end of the primary winding 233a of the variable inductor 238
Is connected to the other end of.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the fifth embodiment shown in FIG. 9, the impedance of the load 300 is changed by the transformer function of the compound winding transformer 233. Since Z300 is converted to the square of the turns ratio A, the first variable capacitor 20
The volume and weight of the ninth and second variable capacitors 210 can be reduced.

FIG. 10 is a diagram showing a sixth embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same reference numerals as those in FIG. 3 are the same as those in the description of FIG. In FIG. 10, 2
Reference numeral 11 is a first variable capacitor, 212 is a second variable capacitor, and 239 is an autotransformer. First
Is connected between the input terminal 221 and the ground E, and one end of the second variable capacitor 212 is connected to the input terminal. The other end of the second variable capacitor 212 is connected to one end of the primary side of an autotransformer 239 whose secondary side is connected between the output terminal 222 and the ground E. The other end of the primary side of the autotransformer 239 is grounded.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the sixth embodiment shown in FIG. 10, the maximum capacitance of the first variable capacitor 211 can be reduced. The volume and weight of the first variable capacitor 211 can be reduced. Moreover, since the withstand voltage of the second variable capacitor 212 can be significantly reduced, the volume and weight of the second variable capacitor 212 can be reduced.

FIG. 11 is a diagram showing a seventh embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same symbols as those in FIG. 10 are the same as those in the description of FIG. In FIG. 11, 213 is a first variable capacitor and 214 is a second variable capacitor. First variable capacitor 21
One end of 3 is connected to the input terminal 221, and the second variable capacitor 214 is connected between the other end of the first variable capacitor 213 and the ground E. One end of the primary side of the autotransformer 239 is connected to the other end of the first variable capacitor 213.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the seventh embodiment shown in FIG. 11, the impedance of the load 300 is changed by the transformer function of the autotransformer 239. Since Z300 is converted to the square of the winding ratio A, the first variable capacitor 21
The volume and weight of the third and second variable capacitors 214 can be reduced.

FIG. 12 is a diagram showing an eighth embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same symbols as those in FIG. 10 are the same as those in the description of FIG. In FIG. 12, reference numeral 240 is a variable inductor, and 215 is a variable capacitor. Variable inductor 240 is input terminal 221
And the ground E, and one end of the variable capacitor 215 is connected to the input terminal. One end of the primary side of the autotransformer 239 is connected to the other end of the variable capacitor 215.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the eighth embodiment shown in FIG. 12, the impedance of the load 300 is changed by the transformer function of the autotransformer 239. Since Z300 is converted to the square of the winding ratio A, the volume and weight of the variable capacitor 215 can be reduced.

FIG. 13 is a diagram showing a ninth embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same symbols as those in FIG. 10 are the same as those in the description of FIG. In FIG. 13, 241 is a variable inductor and 216 is a variable capacitor. One end of the variable inductor 241 is connected to the input terminal 221, and the variable capacitor 216 is connected between the other end of the variable inductor 241 and the ground E. One end of the primary side of the autotransformer 239 is connected to the other end of the variable inductor 241.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, also in the ninth embodiment shown in FIG. 13, the impedance of the load 300 is changed by the transformer function of the autotransformer 239. Since Z300 is converted into the square of the winding ratio A, the volume and weight of the variable capacitor 216 can be reduced.

FIG. 14 is a diagram showing a tenth embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same symbols as those in FIG. 10 are the same as those in the description of FIG. In FIG. 14, 217 is a first variable capacitor, 218 is a second variable capacitor, and 242 is a variable inductor. The first variable capacitor 217 is connected between the input terminal 221 and the ground E, one end of the variable inductor 242 is connected to the input terminal, and the second variable capacitor 218 is connected between the other end of the variable inductor 242 and the ground E. ing. One end of the primary side of the autotransformer 239 is connected to the other end of the variable inductor 242.

Similar to the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3, the tenth embodiment shown in FIG. 14 is used.
In the embodiment, the impedance Z300 of the load 300 is changed by the turn ratio A by the transformer function of the autotransformer 239.
The first variable capacitor 2 to be converted to the square of
The volume and weight of 17 and the second variable capacitor 218 can be reduced.

FIG. 15 is a diagram showing an eleventh embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same symbols as those in FIG. 10 are the same as those in the description of FIG. In FIG. 15, 243 is a tube made of a conductor. By mounting the cylinder 243 around the autotransformer 239, a current flowing by electromagnetic induction can be passed through the cylinder 243. As a result, it is possible to reduce the inductive coupling between the box that houses the impedance matching circuit 200 and the autotransformer 239, so that it is possible to reduce the loss of high frequency power due to the current flowing through the box.

Similar to the eleventh embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 15, the seventh embodiment shown in FIG. 11, the eighth embodiment shown in FIG. 12, and the ninth embodiment shown in FIG. Also in the embodiment of FIG. 14 and the tenth embodiment shown in FIG. 14, by mounting the tube 243 around the autotransformer 239, a box between the impedance matching circuit 200 and the autotransformer 239 is installed. Since the inductive coupling can be reduced, the loss of high frequency power due to the current flowing through the box can be reduced.

FIG. 16 is a diagram showing a twelfth embodiment of the impedance matching circuit 200 of the present invention. In the figure, the same reference numerals as those in FIGS. 3 and 15 are the same as those in FIGS. 3 and 15, and therefore the description thereof will be omitted, and different points will be described. Similar to the eleventh embodiment shown in FIG. 15, by mounting the cylinder 243 made of a conductor around the compound-winding transformer 233 in FIG. 16, a current flowing by electromagnetic induction can be made to flow through the cylinder 243. As a result, inductive coupling between the box that houses the impedance matching circuit 200 and the compound-winding transformer 233 can be reduced, so that high-frequency power loss due to current flowing through the box can be reduced.

Similar to the twelfth embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 16, the second embodiment shown in FIG.
In the third embodiment shown in FIG. 7, the third embodiment shown in FIG. 7, the fourth embodiment shown in FIG. 8 and the fifth embodiment shown in FIG. 9, a tube 243 made of a conductor is placed around the compound transformer 233. By mounting, the inductive coupling between the box that houses the impedance matching circuit 200 and the compound-winding transformer 233 can be reduced, so that the loss of high frequency power due to the current flowing through the box can be reduced.

[0120]

According to the impedance matching circuit of claim 1,
As shown in FIG. 1, in an impedance matching circuit that is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, as shown in FIG. By connecting the second variable capacitor and the multi-transformer, the capacitance of the first variable capacitor can be significantly reduced, and the voltage across the terminals of the second variable capacitor can be significantly reduced. it can. As a result,
This has the effect of significantly reducing the volumes and weights of the first and second variable capacitors.

The impedance matching circuit of claim 2 is, as shown in FIG. 1, an impedance matching circuit which is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, As shown in FIG. 6, the first variable capacitor, the second
By connecting the variable capacitor and the multi-transformer, the load impedance is converted to the square of the turns ratio by the transformer function of the multi-transformer, so that the first variable capacitor and the second variable transformer are connected. The volume and weight of the capacitor can be reduced.

As shown in FIG. 1, the impedance matching circuit according to claim 3 is an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, As shown in FIG. 7, by connecting the variable inductor, the variable capacitor and the compound transformer, the impedance of the load is converted to the square of the turns ratio by the transformer function of the compound transformer. The volume and weight of the capacitor can be reduced.

The impedance matching circuit of claim 4 is, as shown in FIG. 1, an impedance matching circuit which is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, As shown in FIG. 8, by connecting a variable inductor, a variable capacitor and a compound transformer, the impedance of the load is converted to the square of the winding ratio by the transformer function of the compound transformer. The volume and weight of the capacitor can be reduced.

The impedance matching circuit of claim 5 is, as shown in FIG. 1, an impedance matching circuit which is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, As shown in FIG. 9, by connecting the first and second variable capacitors, the variable inductor, and the compound winding transformer, the impedance of the load is converted to the square of the winding ratio by the transformation function of the compound winding transformer. Therefore, the volume and weight of the first and second variable capacitors can be reduced.

As shown in FIG. 1, the impedance matching circuit according to claim 6 is an impedance matching circuit which is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, As shown in FIG. 10, by connecting the first variable capacitor, the second variable capacitor, and the autotransformer, the capacitance of the first variable capacitor can be significantly reduced, and the second variable capacitor can be significantly reduced. Since the voltage across the terminals of the variable capacitor can be significantly reduced,
This has the effect of significantly reducing the volumes and weights of the first and second variable capacitors.

According to a seventh aspect of the impedance matching circuit of the present invention, as shown in FIG. 1, the impedance matching circuit is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching. As shown in FIG. 11, by connecting the first variable capacitor, the second variable capacitor, and the autotransformer, the load impedance is converted to the square of the turns ratio by the transformation function of the autotransformer. Therefore, the volume and weight of the first variable capacitor and the second variable capacitor can be reduced.

As shown in FIG. 1, the impedance matching circuit according to claim 8 is an impedance matching circuit which is connected between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber to perform impedance matching, As shown in FIG. 12, by connecting the variable inductor, the variable capacitor and the autotransformer, the load impedance is converted to the square of the turns ratio by the transformer function of the autotransformer. The volume and weight of the capacitor can be reduced.

The impedance matching circuit of claim 9 is, as shown in FIG. 1, an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, As shown in FIG. 13, by connecting a variable inductor, a variable capacitor, and an autotransformer, the load impedance is converted to the square of the winding ratio due to the transformation function of the autotransformer. The volume and weight of the capacitor can be reduced.

The impedance matching circuit of claim 10 is
As shown in FIG. 1, in an impedance matching circuit that performs impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, as shown in FIG. By connecting the variable capacitor, the variable inductor, and the autotransformer, the impedance of the load is converted to the square of the turns ratio by the transformer function of the autotransformer. The volume and weight of the two variable capacitors can be reduced.

The impedance matching circuit according to claim 11 is
As shown in FIG. 15, by mounting a tube made of a conductor around the autotransformer, it is possible to reduce the inductive coupling between the box that houses the impedance matching circuit and the autotransformer. , It is possible to reduce the loss of high frequency power flowing through the box.

The impedance matching circuit according to claim 12 is
As shown in FIG. 16, by mounting a tube made of a conductor around the compound-winding transformer, it is possible to reduce the inductive coupling between the box that houses the impedance matching circuit and the compound-winding transformer. , It is possible to reduce the loss of high frequency power flowing through the box.

[Brief description of drawings]

FIG. 1 is a block diagram of a plasma processing apparatus.

FIG. 2 is a diagram showing a conventional impedance matching circuit 2;
It is a figure which shows 00.

FIG. 3 is an impedance matching circuit 20 of the present invention.
It is a figure which shows the 1st Example of 0.

FIG. 4 is an impedance matching circuit 20 of the present invention.
It is a figure which shows the compound winding transformer 233 used for 0.

FIG. 5 is a diagram showing an equivalent circuit when the first embodiment of the impedance matching circuit 200 of the present invention shown in FIG. 3 is used in a plasma processing apparatus.

FIG. 6 shows an impedance matching circuit 20 of the present invention.
It is a figure which shows the 2nd Example of 0.

FIG. 7 shows an impedance matching circuit 20 of the present invention.
It is a figure which shows the 3rd Example of 0.

FIG. 8 is an impedance matching circuit 20 of the present invention.
It is a figure which shows the 4th Example of 0.

FIG. 9 shows an impedance matching circuit 20 of the present invention.
It is a figure which shows the 5th Example of 0.

FIG. 10 is a diagram showing a sixth embodiment of the impedance matching circuit 200 of the present invention.

FIG. 11 is a diagram showing a seventh embodiment of the impedance matching circuit 200 of the present invention.

FIG. 12 is a diagram showing an eighth embodiment of the impedance matching circuit 200 of the present invention.

FIG. 13 is a diagram showing a ninth embodiment of the impedance matching circuit 200 of the present invention.

FIG. 14 is a diagram showing a tenth embodiment of the impedance matching circuit 200 of the present invention.

FIG. 15 is a diagram showing an eleventh embodiment of the impedance matching circuit 200 of the present invention.

FIG. 16 is a diagram showing a twelfth embodiment of the impedance matching circuit 200 of the present invention.

[Explanation of symbols]

 100 High-Frequency Oscillation Source 111 High-Frequency Transmission Line 200 Impedance Matching Circuit 201 First Variable Capacitor 202 Second Variable Capacitor 203 First Variable Capacitor 204 Second Variable Capacitor 205 First Variable Capacitor 206 Second Variable Capacitor 207 Variable Capacitor 208 Variable capacitor 209 First variable capacitor 210 Second variable capacitor 211 First variable capacitor 212 Second variable capacitor 213 First variable capacitor 214 Second variable capacitor 215 Variable capacitor 216 Variable capacitor 217 First variable capacitor Variable capacitor 218 Second variable capacitor 221 Input terminal 222 Output terminal 231 First variable inductor 232 Second variable inductor 233 Compound transformer 233a Compound transformer 233 Primary winding 233b Secondary winding of compound winding transformer 233 234 Inductor 235 Inductor 236 Variable inductor 237 Variable inductor 238 Variable inductor 239 Single winding transformer 240 Variable inductor 241 Variable inductor 242 Variable inductor 243 Tube 300 Load 311 High frequency transmission line 321 high frequency application electrode 322 ground electrode 323 wafer 331 reaction gas inflow pipe 332 exhaust pipe 340 semiconductor processing chamber E ground R1 radius of primary winding 233a R2 radius of secondary winding 233b D primary winding 233a or secondary winding 233b length

Claims (12)

[Claims] 1. In an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, a first variable capacitor is connected between an input terminal and ground. A primary winding of a multi-winding transformer in which one end of a second variable capacitor is connected to the input terminal and the other end of the second variable capacitor is connected to a secondary winding between an output terminal and ground Impedance matching circuit in which the other end of the primary winding of the compound-winding transformer is grounded. 2. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein one end of a first variable capacitor is connected to an input terminal,
A second variable capacitor is connected between the other end of the first variable capacitor and ground, and one end of a primary winding of a compound-winding transformer in which a secondary winding is connected between an output terminal and ground is connected to the first variable capacitor. An impedance matching circuit in which the other end of the variable capacitor of No. 1 is connected, and the other end of the primary winding of the compound winding transformer is grounded. 3. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein a variable inductor is connected between an input terminal and ground. One end of the variable capacitor is connected to the input terminal, and the other end of the variable capacitor is connected to one end of the primary winding of the compound winding transformer whose secondary winding is connected between the output terminal and ground. Impedance matching circuit in which the other end of the primary winding is grounded. 4. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein one end of a variable inductor is connected to an input terminal and a variable capacitor is connected. One end of the primary winding of the compound-winding transformer, which is connected between the other end of the variable inductor and the ground and whose secondary winding is connected between the output terminal and the ground, is connected to the other end of the variable inductor, An impedance matching circuit in which the other end of the primary winding of a compound-winding transformer is grounded. 5. In an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, a first variable capacitor is connected between an input terminal and ground. A multi-winding transformer in which one end of a variable inductor is connected to the input terminal, a second variable capacitor is connected between the other end of the variable inductor and ground, and a secondary winding is connected between the output terminal and ground 1. An impedance matching circuit in which one end of the primary winding is connected to the other end of the variable inductor and the other end of the primary winding of the compound winding transformer is grounded. 6. In an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, a first variable capacitor is connected between an input terminal and ground. , Connecting one end of the second variable capacitor to the input terminal and connecting the other end of the second capacitor to one end of the primary side of an autotransformer whose secondary side is connected between the output terminal and ground And an impedance matching circuit in which the other end of the primary side of the autotransformer is grounded. 7. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein one end of a first variable capacitor is connected to an input terminal,
A second variable capacitor is connected between the other end of the first variable capacitor and ground, and a primary side of an autotransformer whose secondary side is connected between an output terminal and ground is connected to the first variable capacitor. An impedance matching circuit, which is connected to the other end of a capacitor and whose other end on the primary side of the autotransformer is grounded. 8. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein a variable inductor is connected between an input terminal and ground. Of the variable capacitor is connected to the input terminal, and the other end of the variable capacitor is connected to one end of the primary side of the autotransformer whose secondary side is connected between the output terminal and ground. Impedance matching circuit with the other end on the secondary side grounded. 9. An impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, wherein one end of a variable inductor is connected to an input terminal and a variable capacitor is connected. One end of the primary side of the autotransformer whose secondary side is connected between the other end of the variable inductor and the ground and whose secondary side is connected between the output terminal and the ground is connected to the other end of the variable inductor,
An impedance matching circuit in which the other end of the primary side of the autotransformer is grounded. 10. In an impedance matching circuit for performing impedance matching by connecting between a high frequency oscillation source in a plasma processing apparatus and a high frequency applying electrode in a semiconductor processing chamber, a first variable capacitor is connected between an input terminal and ground. , One end of the variable inductor is connected to the input terminal, the second variable capacitor is connected between the other end of the variable inductor and the ground, and the secondary side of the autotransformer is connected between the output terminal and the ground. An impedance matching circuit in which one end of the secondary side is connected to the other end of the variable inductor, and the other end of the primary side of the autotransformer is grounded. 11. The impedance matching circuit according to claim 6, wherein a tube made of a conductor is mounted around the autotransformer. 12. The impedance matching circuit according to claim 1, wherein a tube made of a conductor is mounted around the compound transformer.