JP5094307B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus, and more particularly, to a plasma processing apparatus that collectively processes a plurality of substrates.

  In order to increase the productivity of the etching process, an attempt is made to arrange a plurality of substrates in a large etching apparatus, etch each substrate in a lump, and produce the same quality with a high yield.

FIG. 8 shows a conventional plasma processing apparatus 101 used in such an etching process, and a large electrode plate 120 is arranged inside a vacuum chamber 111.
A gas introduction device 115 is arranged on the electrode plate 120, a plurality of substrates 107 are arranged on the electrode plate 120 at predetermined intervals, the evacuation system 109 is operated, and the inside of the vacuum chamber 111 is evacuated, When an etching gas is introduced from the gas introduction system 116 and an AC voltage is applied between the gas introduction device 115 and the electrode plate 120, an etching gas plasma is generated on the electrode plate 120, and activated etching gas molecules are generated. The light enters the surface of the substrate 107 and the surface of the substrate 107 is etched.

According to such an etching method, the size of the insulating film and wiring film formed by etching and the matching between the planar substrates are high, but the outer peripheral portion of the substrate 107 is within the plane of one substrate 107. However, it is easier to etch than the central portion, and the etching dimension distribution in the surface of the substrate 107 is non-uniform.
JP-A-8-181114 JP 2001-308073 A JP 2004-79918 A

  The present invention was created to solve the above-described problems of the prior art, and provides an etching apparatus capable of uniformly etching the in-plane distribution of a plurality of substrates.

In order to solve the above problems, the present invention includes a vacuum chamber and an electrode plate disposed in the vacuum chamber, a plurality of substrates are disposed on the electrode plate, and a voltage is applied to the electrode plate. A plasma processing apparatus for forming plasma on the electrode plate and treating the surface of each substrate with the plasma, wherein an insulating member is disposed at a position where each substrate of the electrode plate is disposed, The surface of the insulating member is exposed so that an outer peripheral portion of each substrate is positioned on the insulating member, and a magnet is disposed on a portion of the insulating member positioned inside the outer peripheral portion of the substrate. The magnetic lines of force penetrate through the surface of each substrate disposed on the electrode plate by the magnet, the magnet is annular, and the magnets on the back surface of each substrate have magnetic poles of the same polarity. Directed in the direction in which the substrate is located It is a plasma processing apparatus.
Further, the present invention is pre-SL has an etching gas introducing system for introducing an etching gas into the vacuum chamber, wherein a plasma is formed of an etching gas into the vacuum chamber, each of said substrate surface in a plasma processing apparatus for etching is there.

  The present invention is configured as described above, and an insulating member is provided on the electrode plate, and the substrate disposed on the electrode plate includes an edge, and an outer peripheral portion located at a certain distance from the edge is positioned on the insulating member. Therefore, the electrode plate surface located below the inner part of the outer periphery of each substrate is surrounded by an insulating member.

  Since the surface of the insulating member disposed under the outer peripheral portion of the substrate is exposed and the surface of the electrode plate is exposed inside the outer peripheral portion of the substrate, when a voltage is applied to the electrode plate The electric field on the outer peripheral portion of the substrate is weaker than that in the case where a conductive electrode plate is disposed, and the plasma density formed on the substrate surface is lowered. Therefore, compared with the case where the electrode plate is arranged in the outer peripheral portion, the etching rate in the outer peripheral portion is slow in the etching process, and the film forming speed is slow in the film forming step.

  An annular magnet is disposed on a portion of the electrode plate surrounded by the insulating member. The annular magnet is made parallel to the electrode surface, and the magnet located on the back surface of each substrate has the same magnetic pole of the N pole and S pole directed to the substrate side, and a magnetic pole of the opposite polarity to the substrate. It is directed to the other side. The lines of magnetic force formed by this magnet penetrate the inner portion of the outer periphery of the substrate, trap electrons, and increase the plasma density of the inner portion of the outer periphery of the substrate as compared with the case where there is no magnet.

When the insulating member is disposed at a position in contact with the bottom surface of the peripheral portion of the substrate, the etching rate at the peripheral portion of the substrate is slowed down, and the in-plane distribution of etching becomes uniform.
When the magnet is arranged in the central portion of the substrate, the etching rate in the central portion of the substrate is increased, and the in-plane distribution of etching becomes uniform.

Referring to FIG. 1, reference numeral 1 denotes a plasma processing apparatus according to an embodiment of the present invention, and an electrode plate 20 is disposed inside a vacuum chamber 11.
A partial planar shape of the electrode plate 20 is shown in FIG. The cross-sectional view of the electrode plate 20 in FIG. 1 corresponds to the cross-sectional view taken along the line AA in FIG.

The electrode plate 20 has an electrode main body 21 formed by forming a metal into a plate shape. A groove extending vertically and horizontally is formed on the surface of the electrode main body 21, and an insulating member 22 is disposed inside the groove.
The grooves extending in the vertical direction intersect with the grooves extending in the horizontal direction. Therefore, the surface of the electrode plate 20 located between the grooves is surrounded by the insulating member 22 inside the groove. A substrate 7 is disposed on each of the regions surrounded by the insulating member 22 of the electrode plate 20.

An annular magnet 25 is embedded in the portion of the electrode plate 20 surrounded by the insulating member 22 in parallel with the surface of the electrode plate 20. Therefore, the annular magnet 25 is disposed on the back surface of each substrate 7. ing.
In the annular magnet 25, the same magnetic pole of the N pole and the S pole is oriented in the direction in which the substrate 7 on the electrode plate 20 is positioned, and the magnetic pole of the opposite polarity is directed to the opposite side of the substrate 7. The magnetic flux penetrates through the central portion inside the insulating member 22 of each substrate 7.

A vacuum exhaust system 19 is connected to the vacuum chamber 11, and the inside of the vacuum chamber 11 is in a vacuum atmosphere.
A gas introduction device 15 connected to a gas source 16 is provided inside the vacuum chamber 11. Here, an etching gas is disposed in the gas source 16, and the etching gas disposed in the gas source 16 is introduced from the gas introduction device 15 into the vacuum chamber 11.

  The electrode plate 20 is connected to a power supply device 28, and the vacuum chamber 11 and the gas introduction device 15 are connected to a ground potential. After the inside of the vacuum chamber 11 is stabilized in an etching gas atmosphere of a predetermined pressure, when an AC voltage is applied to the electrode plate 20 by the power supply device 28, plasma is formed on the electrode plate 20.

The surface of the insulating member 22 is exposed, and the surface of the electrode body 21 is exposed at a portion surrounded by the insulating member 22.
The edge of the substrate 7 is located on the insulating member 22. Therefore, the outer peripheral portion of the substrate 7 faces the insulating member 22, and the inner side of the outer peripheral portion facing the insulating member 22 faces the electrode body 21. Yes.

  Since the insulating member 22 is exposed, the electric field strength at the outer peripheral portion of the substrate 7 is lower when the insulating member 22 is disposed on the back surface than when the electrode body 21 is disposed on the back surface. The plasma density on the outer peripheral portion located on the insulating member 22 of the substrate 7 is lower than that without the insulating member 22.

  Further, a ring-shaped magnet is embedded in the electrode body 21 surrounded by the insulating member 22. The central portion inside the outer peripheral portion of the substrate 7 faces the surface of the electrode body 21, and the magnetic lines formed by the magnets 25 pass through the surface portion of the electrode plate 20 and the central portion of the substrate 7. .

As a result, in the central portion of the substrate 7, electrons move around the magnetic flux and move, and as a result, the plasma density in the central portion becomes higher than when the magnet 25 is not provided.
As a result, the plasma density on the surface of the substrate 7 becomes uniform, and the surface of the substrate 7 is etched uniformly.
If the annular magnet 25 is used and embedded in parallel with the surface of the electrode plate 20, the magnetic flux penetrates the surface of the substrate 7 in an annular shape, and the plasma density becomes more uniform.

According to the plasma processing apparatus 1 of the present invention, a thin film source gas is introduced into the vacuum chamber 11 instead of the etching gas, and a thin film is formed on the surface of the substrate 7 disposed on the electrode plate 20, The plasma on the surface of the substrate 7 becomes uniform, and a thin film having a uniform in-plane film thickness distribution can be formed.
In each of the above embodiments, the electrode plate 20 is horizontally disposed with the mounting surface of the substrate 7 facing upward, but the electrode plate 20 may be erected so that the mounting surface is vertical. Good.

  Further, the substrate 7 that is the object to be processed of the present invention is not limited to a square substrate such as a glass substrate, but is a circular substrate 8 such as a semiconductor wafer as shown in FIG. 3, and the edge of the circular substrate 8 is an insulating member. 22 should just be arrange | positioned.

  Moreover, in the said Example, although the insulating member 22 was arrange | positioned in the groove | channel formed in the surface of the electrode main body 21, and the electrode main body 21 was not parted, as shown in FIG. Even if it is divided into a plurality of small electrodes by 22, each small electrode may be connected to the power supply device 28. In this case, a magnet 25 having a ring shape or the like may be embedded in each divided small electrode, and the magnetic lines of force similar to those in the above embodiment may be formed.

  In the above embodiment, an AC voltage is applied to the electrode plate 20, but a case where a DC voltage is applied is also included. Moreover, the case where a ground potential is applied to the electrode plate 20 and the vacuum chamber 11 and an AC voltage is applied to the gas introducing device is also included.

The etching object to be etched by the plasma processing apparatus 1 of the present invention is not particularly limited. For example, a processing film containing SiO ₂ , SiN, Si, or the like is formed on the surface, and the processing film is etched using the substrate 7. be able to.

The constituent material of the electrode plate 20 is not particularly limited. For example, the electrode body 21 can be made of a metal such as copper, and the insulating member 22 can be made of a ceramic such as alumina.
The size and shape of the electrode plate 20 are not particularly limited. For example, when the substrate 7 is a square having a side of 150 mm, the interval between the insulating members 22 is 160 mm, the insulating member 22 is 25 mm wide, the film thickness is 4 mm, and the magnet 25 is It is a square ring shape with a side of 60 mm.

  Similar to the plasma processing apparatus 1 shown in FIG. 1, a total of 49 substrates are arranged in a matrix on the electrode plate 20 on which the edge of a square substrate with a side of 150 mm is placed, for a predetermined time. Etching was performed (first example).

  Separately, an electrode plate without an insulating member and having only a magnet is used, the entire back surface of the substrate faces the electrode plate (second example), and an electrode plate without a magnet and having only an insulating member is used. Does not penetrate the substrate (third example), uses an electrode plate without both the insulating member and the magnet, the entire back surface of the substrate faces the electrode plate, and the lines of magnetic force do not penetrate the substrate (fourth example). Except for the difference, the etching process was performed under the same conditions as the first example (the size of the substrate, the gas type, the pressure, the processing time, etc.)

  The thickness reduction amount (etching amount, unit nm) was measured at different locations (here, 9 locations) for each substrate after the etching treatment. The measurement location is indicated by “◯” in FIG. The numerical value of FIG. 7 shows the distance from the vertex when the coordinate of one vertex of the four vertices of the substrate is zero.

  FIGS. 5 (a) and 5 (b) show the average of the measurement values at the measurement points in the fourth and first examples, respectively, and FIGS. 6 (a) and 6 (b) show the measurement values at the measurement points in the third and second examples. The average of each measured value is shown. As is clear from comparison between FIG. 5A, FIG. 5B, and FIG. 6A, the fourth example in which neither an insulating member nor a magnet is arranged has a smaller etching amount in the central portion than in the edge portion. In the third and fourth examples in which the insulating member is arranged, the difference in etching amount between the central portion and the edge portion is small.

  Next, from the measurement result, the average of the etching amount is obtained for each of the first to fourth examples (average rate), and further, the distribution of the etching amount in the substrate surface (distribution within the substrate) for each of the first to fourth examples. The difference in the etching amount (distribution between the substrates) between the substrates having different positions on the electrode plate was obtained. The results are listed in Table 1 below.

The average rate of the “fourth example” was 1. As can be seen from Table 1 above, the distribution within the substrate and the distribution between the substrates are greatly improved only by disposing the insulating member without using an expensive member such as a magnet.
In particular, it was found that if both the insulating member and the magnet are used in combination, the distribution in the substrate and the distribution between the substrates are further improved, and the average rate is also increased.

Sectional drawing explaining an example of the plasma processing apparatus of this application Plan view showing the partial planar shape of the electrode plate Sectional drawing explaining the other example of the positional relationship of a board | substrate and an insulating member Sectional drawing explaining the other example of an electrode plate (A): Plan view showing measurement result of “no correction” and (b): measurement result of “insulator magnet correction” (A): Plan view showing measurement result of “insulator correction” and (b): Measurement result of “magnet correction” Plan view explaining the measurement location in detail Sectional drawing explaining the plasma processing apparatus of a prior art

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Plasma processing apparatus 11 ... Vacuum chamber 15 ... Etching gas introduction apparatus 20 ... Electrode plate 21 ... Electrode main body 22 ... Insulating member 25 ... Magnet

Claims (2)

A vacuum chamber;
An electrode plate disposed in the vacuum chamber;
A plasma processing apparatus, wherein a plurality of substrates are arranged on the electrode plate, a voltage is applied to the electrode plate to form plasma on the electrode plate, and a surface of each substrate is treated with the plasma,
An insulating member is disposed at a position where each substrate of the electrode plate is disposed,
The insulating member surface is exposed, and an outer peripheral portion of each substrate is positioned on the insulating member ,
A magnet is disposed on a portion of the insulating member located inside the outer peripheral portion of the substrate,
The magnet is configured such that the magnetic lines of force penetrate the surface of each substrate disposed on the electrode plate,
The plasma processing apparatus, wherein the magnet is annular, and the magnets on the back surface of each substrate have magnetic poles of the same polarity oriented in a direction in which the substrate is located . An etching gas introduction device for introducing an etching gas into the vacuum chamber;
Wherein forming a plasma of an etching gas into the vacuum chamber, the plasma processing apparatus according to claim 1, wherein each substrate surface is etched.

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