JPH02158128A - Plasma generator - Google Patents

Abstract

PURPOSE:To enable plasma treatment to be carried out with greater degree of freedom by providing a means which introduces plasma in one generator among plural plasma generators, wherein generation of each plasma can be controlled independently, into another generator. CONSTITUTION:A chamber 35b is provided with a first plasma generator 330 and a second plasma generator 331. And the plasma generators 330 and 331 can be controlled independent of each other. And since the plasma of the plasma generator 331 is attracted through a chamber 356 by a vacuum pump attached to the pipe 355 of the plasma generator 330, it comes to be affected by a parameter which is set in the plasma generator 330. Accordingly, the process gas from a supply part 318 is attracted near the vicinity of the plasma generator 330 after being adjusted and is mixed with the process gas from a supply part 308, and further it is adjusted according to the parameter of the plasma generator 330. Accordingly, the operational condition of each plasma generator can be adjusted without affecting the operational condition of another plasma generator, and the degree of freedom of process increases, and the etching efficiency also becomes large.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Application on Industrial Beams The present invention relates to improvements in plasma generation devices, and more particularly to improvements in plasma generation devices suitable for use in active ion etching and deposition.

BACKGROUND OF THE INVENTION Conventionally, apparatuses such as plasma processing apparatus 100 shown in FIG. 1 have been used for semiconductor processing such as reactive ion etching (RIE) and material deposition. A typical such processing apparatus 100 includes a chamber 102, typically made of an aluminum alloy, and has a grounded top electrode 106. By means of a gas supply (not shown), via the pipe 108 and the gas introduction plenum 101,
Process gas is then supplied to chamber 102 through gas distribution holes 110 in upper electrode 106 .

High frequency power is applied to the lower electrode 103 in the chamber 102 from the high frequency oscillator 105 through the matching network 104.
This matching network 1
04 matches the impedance of the oscillator to the plasma discharge.

In operation, for example, in an application where the apparatus 100 is operated for reactive ion etching, a process gas, such as a mixture of sulfur fluoride and fluorocarbon, is supplied from a gas supply to the chamber 102 and the upper electrode 106 is When a voltage is applied between the lower electrode 103 and the lower electrode 103, plasma discharge occurs. The process gas is ionized by this voltage, and plasma 107 containing various radicals and ions is generated.

The plasma 107 near the lower electrode 103 acts to selectively etch the semiconductor wafer 109 placed on the lower electrode 103. By using a patterned resist on the wafer 109 or 9I plasma control technology, high-speed etching and notching of fine patterns with high precision can be achieved.

Nevertheless, in such plasma processing equipment, the etching variables such as supply power, gas flow rate, pressure, and temperature influence each other, and this interaction limits the degree of freedom in executing a specific process. It will be done. For example, it is an object of the present invention to provide a plasma processing apparatus that can perform plasma processing with a greater degree of freedom than was previously possible. .

Another object of the invention is to provide a plasma processing apparatus of the type described above which increases the efficiency of plasma etching and deposition.

These and other objects, features, and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the appended claims and accompanying drawings.

Generally, the present invention provides a plasma processing apparatus having multiple plasma generators, each of which can independently control the generation of plasma. A means is provided for introducing the plasma of one generator into another, and a means is provided for independently controlling the process gas and excitation power applied to the resulting plasma of each generator.

The invention is illustrated in the accompanying drawings.

2. Embodiment As generally shown in FIG.
30, and on the other side a second plasma generator 3
There are 31. Each generator communicates via a communication space 357. Process gases 308 and 318 are separately supplied to plasma generators 330 and 331, respectively.

The second plasma generator 331 has electrodes 321 and 320 connected to the first radio frequency power source 315 through a matching network 314; similarly, the first plasma generator 330 has a matching network 30.
There are electrodes 324 and 323 connected through 4 to a second radio frequency power source 305. Therefore, plasma generators 330 and 331 can be controlled independently of each other. The plasma of the second plasma generator 331 is drawn through the second plasma generation chamber 356 of the first plasma generator 330, so that the plasma of the second plasma generator 331 is drawn through the second plasma generation chamber 356 of the first plasma generator 330. This is influenced by the parameters set in step 330.

Thus, the process gas from the supply 318 is excited and adjusted according to the parameters present in the second plasma generator 331 before being drawn into the vicinity of the first plasma generator 330 . There it is mixed with the process gas from the supply 308 and further adjusted according to the parameters of the first plasma generator 330. Accordingly, the semiconductor wafer 309 above the electrode 324 can be desirably processed when the plasma moves therewith.

Referring now to FIG. 3, a preferred embodiment of the present invention is shown in which two separate plasma chambers, namely main chamber 2 and connected to main chamber 2 through communication 10, are shown. There is a sub-chamber 12 which is provided. This main chamber 2 fundamentally transfers the plasma from the slave chamber 12 to the main chamber 2, as explained below.
The configuration is similar to that of the conventional plasma generator described above in connection with FIG. 1, except for the modifications that allow it to be introduced into the main chamber 2 and mixed with the gas in the main chamber 2. One or more gases, such as CZ F&, C(
22, S Fb, HB r, etc. can be supplied to the main chamber 2 from the gas supply section 8, and S
A suitable gas such as F is supplied from the second gas supply section 118 to the pipe 1.
8 into the secondary chamber 12.

Although gas supplies 8 and 118 may preferably be identical in suitable applications, in the described embodiment they are shown as being controlled separately and independently of each other.

As shown, the gas in the secondary chamber 12, ie, the plasma, passes through the opening 35 of the secondary chamber 12 and enters the main chamber.
The slave chamber 12 can be moved when necessary for the second chamber.
is mounted vertically on the upper part 39 of the main chamber 2. Here, Figure 4A and Figure 4 will be additionally explained.
The pipe 21 has one end connected to the opening 3 of the chamber 12.
Hole 38 in the top of main chamber 2 aligned with S
It is provided in conjunction with. The other end of this pipe 21 extends through the center of the upper electrode assembly 6. The upper electrode assembly 6 itself includes a top portion 24, a bottom portion 26 and sidewall portions 25.
As shown, they provide a gas introduction plenum 34 and a gas distribution plenum through the center of the bottom 26 and top 24, so that gas directed from the slave chamber 12 through the pipe 21 is directed to the center of the main chamber. ,
It is introduced approximately on top of the semiconductor wafer 9 to be processed.

Additionally, a plurality of gas distribution holes 22 are formed in the upper portion 24 surrounding the pipe 21 through which gas is routed from the gas warm-up plenum 34 to the distribution plenum 37. A number of curved protrusions 63 formed concentrically outward on the underside of the upper part 24 within the gas distribution plenum 37 direct the gas uniformly into the distribution plenum 37 along the channels 62;
It is introduced into the main chamber 2 through the hole 23 in the bottom 26 (see FIG. 48). In this way, the main chamber is
The gas introduced into electrode 2 is uniformly distributed surrounding the periphery, but the maximum is near the center of electrode 4.
It can be seen that there is a distribution of density gradients that decreases radially toward the outside.

The distribution from the outlet part of the pipe 21 to the main chamber 2 results in an area of maximum density of gas from the supply section 8;
Mix these gases.

As best seen by referring again to FIG. 3, a lower electrode 3 is supported at the bottom of the chamber 2, for example about 110 degrees from the upper electrode 6, and receives a wafer 9 to be processed. This lower electrode 3 is connected to a high frequency oscillator 5 and an associated impedance matching network 4, e.g. 13.56 MHz at 100 OW.
A gas such as He is provided from a source 43 to cool the lower electrode 3 and its support.

The gas in the main chamber 2 is exhausted from the vicinity of the lower electrode 3 by pumps 29 and 30. The pumps 29 and 30 may be of commercially available types, such as the Booster Pump Model EH500 and the Rotary Pump Model E 2 M2O manufactured by Edwards High Vacuum International.

Secondary chamber 12 may be any suitable plasma vessel as is generally known. Through experiments conducted by the present inventor, it was found that, for example, quartz Pelger is suitable. The electrodes 13 and 16 are attached to the entire outer side of the slave chamber 12 so as to surround it, and are fixed with Teflon wires (not shown). One electrode 16 connects the matching network 14 and the high frequency oscillator 15.
The other electrode 13 is connected to ground. This high frequency oscillator 15 may be of a commercially available type and may have an adjustable output power of up to approximately 500 W at 13.56 Mtlz, for example. Matching network 14 may likewise be of any suitable commercially available type. In this way, the power generated by the high frequency oscillator 15 passes through the matching network 14 to the electrodes 13 and 16.
, a plasma is generated within the slave chamber 12.

As described above, the plasma generated in the secondary chamber 12 is guided to the main chamber 2 via the pipe section 21 and mixed with the plasma in the main chamber 2.

This increases the degree of freedom that can be realized in the process, because by changing the parameters of the secondary chamber 12, the amount of radicals generated can be increased without changing the parameters of the main chamber 2. be. That is, by being able to separately adjust the parameters of the main chamber and the sub chamber, desired process conditions can be easily achieved.

Furthermore, since the main chamber 2 and the slave chamber 12 can be independently controlled, damage to the resist (ie, resist burn, etc.) caused by increasing the power supply to the main chamber is prevented.

Therefore, the range of selection of resist materials is also widened.

Next, the advantages of the device according to the invention will be explained with reference to experimental data revealed by the inventor. The experimental data is shown in Tables 1, 2 and 3.

Table 3 Table 1 shows the change in etching uniformity in response to various levels of power applied to the electrodes in the main chamber 2 and the secondary chamber 12 for a semiconductor wafer etched with tungsten (W) formed thereon. show.

This data shows that when both the main chamber and the slave chamber are used, both the deviation from the etching target value and the etching uniformity are better than when only the main chamber is used. The etching uniformity was lower than that when the power of the slave chamber was increased to 100W.
It is clear that 0W is better, but this is because the structure in this experiment is to introduce the plasma from the slave chamber 12 into the center of the main chamber 2. It seems that too much plasma was introduced, and as a result, the plasma density in main chamber 2 became high. Even so, the etching rate can be improved by controlling the power to the slave chamber 12 without changing the etching conditions of the main chamber 2.

Tables 2 and 3 show gas selection, flow rate and power.
The etching rate of tungsten is shown when various combinations of are used.

As can be seen from Table 2, the change in the etching rate of tungsten becomes thicker when the etching gas is introduced into the slave chamber 12, and further increases when the power of the slave chamber is increased.

Of course, the conditions of the main chamber remain unchanged for comparison, except that the etching gas is introduced into the main chamber when the slave chamber 12 is not used.

Thus, by simply introducing etching gas into the secondary chamber 12 with the same power applied to the main chamber, the etching and notching rate achieved can be increased by more than 30%. The results show that by mixing plasma, the energy level of the plasma increases and radicals can be generated efficiently. It has also been shown that etching efficiency is increased as well.

Furthermore, when tungsten is etched using a gas such as SF, there is a problem in that the etching rate is lowered by adding a process gas such as C12, HBr, or CH. Prior to the present invention, increasing the power seemed to be the only way to prevent this reduction in etching rate. Resolved by increasing the rate.

Table 3 shows further changes in etching rate as a result of using secondary chamber 12.

In this example, the engineering/notching rate is 451 people 7'+in
The number of participants increased by approximately 90% to 873 people/win.

Now, a second embodiment of the present invention will be described with reference to FIG. 5, in which the slave chamber 212 is connected to the main chamber 20.
It is attached to the side wall of 2. The structures of the main chamber 202 and the slave chamber 212 are the same as those of the previous embodiments, but the lying position of the slave chamber 212 and the position of its gas outlet 210 are different. In order to mix the plasma generated in the secondary chamber 212 with the plasma in the main chamber 202, the plasma generated in the primary chamber 202 is directed in the direction in which the plasma generated in the secondary chamber 212 is pulled through the main chamber 202. must exist. Therefore, it is desirable that the gas exhaust port 220 be located on an extension of an imaginary line connecting the plasma generated in the secondary chamber 212 and the plasma generated in the main chamber 202 as shown in the figure.

In the above embodiment, two plasma generators/vessels were connected, but
It will be appreciated by those skilled in the art that a number of generators can be linked together to sequentially introduce plasma from one generator to another, with each intermediate plasma generator having its own partial adjustment of the plasma. It would be obvious for For example, such a device is shown in FIG. 6, where the vertical device has a number of independently controlled plasma generators 600, 60.
1...610 are used to modulate the plasma transferred from each generator to the next one in turn. In this embodiment, the wafer 612 is placed in the last plasma generator 610.
included in. Multiple independent gas supplies 614.615
...620, respectively, a plurality of impedance powers aaest, eez...670 and impedance matching networks 631, 632...
... 640, so that the plasma 650 generated in the first generator 600 is moved and conditioned in each successive generator 601 until it is applied to the wafer 612 by the last generator 610. Similarly (650'
650"), the process parameters can be completely varied. Note that 680 in the figure is a vacuum pump.

Although the present invention has been described above with some specificity, the disclosure of the present invention is merely an example, and various arrangements and combinations of parts may be made without departing from the spirit and scope of the present invention as defined in the claims. It is understood that modifications may occur to those skilled in the art. For example, the plasma generator may be readily used in other applications that use plasma generation, such as ECR or microwave.

Furthermore, the present invention can be applied to glass and CDs (compact discs).
It may also be applied to equipment that performs vapor deposition or etching of thin films of materials.

Effects of the Invention The present invention has a plurality of independent plasma generators that can generate and control plasma separately, in which plasma is generated by one plasma generator and mixed with plasma generated by another plasma generator. Since the operating conditions of each plasma generator can be adjusted individually without affecting the operating conditions of other plasma generators, the process flexibility is increased. increases. Etching efficiency can be increased as well.

In connection with the above description, the following sections are further disclosed.

(1) A plasma comprising a plurality of plasma generators each capable of generating and controlling plasma, and means for moving the plasma from one of the plasma generators and controlling it by another of the plasma generators. Generator.

Device.

(2) The plasma generating apparatus according to item (1), further comprising means for independently controlling the plasma excitation power of each of the plasma generators.

(3) The plasma generating apparatus according to item (2), further comprising a plurality of gas supply sections that separately supply process gas to each of the plasma generators.

(4) In the plasma generator described in item (1), the plasma generator includes six plasma generators arranged vertically with respect to each other.

(5) The plasma generating apparatus according to item (4), further comprising mixing the plasma gas with the process gas led to the next plasma generator, and generating the plasma according to the method described above. A plasma generating apparatus including means for uniformly distributing a plasma onto a semiconductor wafer placed in the generator.

(6) The plasma generator described in item (1), wherein the plurality of plasma generators are arranged horizontally with respect to each other.

(7) In the plasma generator described in item (1), the plurality of plasma generators are two generators.

(8) A plasma generation device having a plurality of plasma generators that can independently control plasma generation.

An interconnection path generates a plasma between the chambers,
The plasma generated in one chamber is mixed with the plasma generated in another chamber.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional plasma processing apparatus, FIG. 2 is a schematic diagram showing the operating principle of an etching apparatus according to a preferred embodiment of the present invention, and FIG. 3 is a schematic diagram of a processing apparatus according to another preferred embodiment of the present invention. Schematic sectional view, Figure 4A is a bottom view of the upper part of the upper electrode of the plasma processing apparatus shown in Figure 3, Figure 4 is a plan view of the bottom of the upper electrode of the plasma processing apparatus shown in Figure 3, and Figure 5 is the main part. FIG. 6 is a schematic diagram of a plasma processing apparatus according to another preferred embodiment of the invention, in which a number of plasma generators sequentially control plasma transferred from one plasma generator to the next; FIG. 2 is a schematic diagram of another preferred embodiment of the plasma processing apparatus. In addition, in the symbols shown in the drawings, 2... Main chamber 3, 6... Electrode 4.14... Matching network 5.15...
...High frequency oscillator 8.18...Gas supply section 9...Wafer 10...Communication section 12...Sub chamber 13.16...Electrode Boo, 601... 610 - Plasma generator 612... Wafer 614, 815...-620... Gas supply unit. Agent: Patent Attorney Hiroshi AisakaFigure 3Figure 6

Claims (1)

[Claims] 1. It has a plurality of plasma generators each capable of generating and controlling plasma, and means for moving the plasma generated by one of the plasma generators and controlling it by another of the plasma generators. Plasma generator.