JP2535586B2 - Plasma processing device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a plasma gas phase reaction method for performing plasma treatment with a sputtering effect, and a plasma treatment apparatus for performing plasma treatment on a large number of substrates at one time. Regarding

As an example of application of the plasma processing method, the present invention uses a plasma CVD method to obtain a Vickers hardness of 2000 kg / mm ²
By coating the surface of the substrate on which carbon is formed, or a film containing carbon as a main component or a film such as silicon nitride or boron nitride, a reinforcing material for these solid surfaces and a protective material against mechanical stress are obtained. It's a surprise.

The present invention relates to a method of performing reactive ion etching on multiple substrates.

“Prior Art” Generally, in the plasma CVD method, it is said that a method of forming a film without spattering (damaging) the surface to be formed is effective. They are the case of forming a film of amorphous silicon or the like. On the other hand, on the other hand, on the contrary, though it is the plasma CVD method,
A method of forming a film with a sputtering effect is also known. Regarding the coating of a carbon film, which is a typical example thereof, a patent application “Composite having a carbon film and a method for producing the same” filed by the present inventor (Japanese Patent Application No. 56-146936, Showa 56).
Application dated September 17, 2012) is known. However, in these, the substrate is arranged on one electrode (cathode side) of the parallel plate type,
This is a method of forming a carbon film on the upper surface thereof, and the relationship between the reaction space and the funnel / unroat space is not discussed at all.

“Conventional problems” In the conventional method of forming a film with such a sputtering effect, not only can a large number of films be formed on a large-area substrate such as 20 cm □, 15 cm × 120 cm at the same time, but also a substrate having irregularities or It is not possible to form a large amount of film on the substrate, for example, a hard carbon film. Furthermore, no method has been proposed in which a large amount of substrates are arranged in a large capacity space and plasma processing is performed on them all at once. In this reaction space, a certain space is provided between each holder. Was completely useless in funnel or unroth spaces, wasting floor space.

"Means for Solving the Problem" In the present invention, a plurality of holders holding a plurality of substrates in a reaction space having a hexahedral structure are arranged with a one-dimensional interval or a substantially constant interval between the holders. However, the plasma treatment on each holder is to be made equal throughout. And in the funnel or unroth space, this space is made narrower.

According to the present invention, a pair of first and second electrodes are arranged on the pair of front and rear surfaces so as to be separated from each other. Further, a third electrode of the substrate or the holder is provided, and an alternating voltage, particularly the first alternating voltage, is applied between the third electrode and the pair of first and second electrodes on the substrate or holder side on the cathode side (which has a sputtering effect. Side) is applied as much as possible.

The holder and the base are arranged along the electric field from one of the pair of electrodes to the other so that the plasma uniformly processes all the substrates, and the intervals between the holders are arranged to be equal to each other. The holders and substrates in such a reaction space are pre-stored in the funnel chamber, where the spacing between the holders is made smaller to save floor space.

In the present invention, the plasma in the reaction space is held in the cylindrical space, and the plasma treatment is simultaneously performed on all the surfaces of the substrate arranged at a certain distance between the pair of electrodes and separated from each other.

Then, as an example of the plasma treatment, a thin film is formed by a plasma CVD method. Further, as an example thereof, a hydrocarbon gas such as ethylene or methane or a carbon fluoride gas such as carbon fluoride is used as a first medium frequency alternating electric field, For example, by introducing an alternating voltage of 50 KHz and a second alternating electric field, for example, a high frequency electric field of 13.56 MHz, into the atmosphere in which plasma is generated and causing the plasma to decompose, C-C similar to diamond having SP ³ orbits Make a bond. As a result, rather than making a non-translucent conductive or poorly conductive carbon like graphite, the optical energy bandwidth (called Eg) is
It is characterized in that it forms an insulating carbon having 1.0 eV or more, preferably 1.5 to 5.5 eV. Further, the carbon of the present invention has an hardness of 2000 Kg / mm ² or more, preferably 4500 Kg / mm ² or more, and is ideally 6500 Kg / mm ² amorphous (amorphous) or 5Å having a hardness similar to DIAMONT. Carbon having crystallinity of up to 2 μm or hydrogen or halogen element in this carbon is 25 atomic% or less or II
5 atomic% or less of I- or V-valent impurities and N / C of nitrogen
Carbon whose main component is so-called carbon added to a concentration of ≦ 0.05 (5%) (hereinafter, simply referred to as carbon in the present invention).
Is provided on a solid body.

The present invention is further applied to glass, ceramics, metal, magnetic material, plastics (also called organic resin), and oxide superconducting material as the substrate material to be subjected to the plasma treatment. In addition, as the shape of the substrate, a plate shape,
It is also possible for plate-shaped, containers, tweezers, wafer holder cassettes, jigs, and rod-shaped materials.

Further, in the present invention, particularly as plastics, there are organic resin substrates such as PET (polyethylene terephthalate), PES, PMMA, Teflon, epoxy and polyimide.

The plasma processing method used in the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 shows the outline of a plasma processing apparatus for carrying out the plasma processing method of the present invention. Further, FIG. 2 shows a state in which the vertical cross section taken along the line AA ′ in FIG. 1 is viewed from the right.

In the drawing, the reaction vessel (7) of the plasma processing apparatus has a loading spare material (7-1) and an unloading spare chamber (7-2), and a gate valve (14-2), Gate valves (14-1), (14-4) or (1
It is divided by 4).

In the reaction space (6), the substrates (1-), (1-2), ... (1-
m) That is, (1) is the holder (2-1), (2-2), ... (2-
n), that is, on (2). This substrate (1) has a structure in which plasma processing is performed only on one surface. However, when plasma treatment is to be performed on the front surface and the back surface of the substrate at the same time, holes may be formed in the holder (2) and the substrate may be sandwiched between the holes.

In this embodiment, since the first voltage is an alternating voltage, the holder is a plate-shaped conductor made of aluminum, nickel, etc., and both sides of the holder are made of an insulating substrate such as glass, silicon substrate, ceramics, etc. It can be arranged. Space between these holders (31-1), (31-2), ... (31-n
-1) should be equal or roughly equal to each other, 5 to 15 cm
For example, it has 10 cm. Then, the degree of treatment on each substrate was made to be the same (the film thickness and film quality were the same in film formation) (variation within ± 20% of the average value).

If this interval is as wide as 10 to 15 cm when the pressure is 0.01 to 0.05 torr, the density of radical species in this interval is sufficient,
We were able to obtain a high deposition rate (800-2000A / min) and film thickness uniformity. On the other hand, when the pressure was 0.07 to 0.1 torr, the film formation rate increased, but the film thickness uniformity became insufficient. When the pressure is 0.005 to 0.02 torr, the interval is narrow and 5 to 10 cm because of good uniformity, but the film forming rate becomes insufficient and only 20 to 50 A / min can be obtained.

In the load chamber (17-1) and the unload chamber (17-2), the space between the base body and the holder (32-
1), (32-2) ... (32-n-1) are narrower than the space in the reaction space. This interval is 0-5 cm, for example 1-2 cm
And 0 cm indicates that the substrates are in contact with each other. Further, these holders are hung (hanged) on the guide rails (9) to be held, and a current is passed through the guide rails (9) to the holders so that the holders or the electrodes can be moved to the third position.
It is configured so that it can be used as an electrode of.

In the gas system (10), hydrogen or argon gas as a carrier gas is supplied from (10-1), and a hydrocarbon gas such as methane or ethylene is supplied as a carrier gas from (10-1).
I-valent impurities diborane (diluted to 1% hydrogen) or V-valent impurities ammonia or foshin (diluted to 1% hydrogen)
From (10-3), and an etching gas such as oxygen or an oxide gas or a fluoride gas such as NF ₃ or SF ₆ from (10-4) to a valve (28) and a flow meter (29). It is introduced from the nozzle (25) into the reaction system (30).

The reaction system (30) has cylindrical structures (8) and (8 ') (having a square frame structure), and as shown in FIG. 2, the front side in FIG. 1 (the left side in FIG. 2). ) And rearward (on the right side in FIG. 2), a pair of first and second electrodes (3) and (3 ') are made of a metal mesh. Halogen heaters (11) and (11 ') are arranged on the outside thereof, and infrared ray reflection plates (12) and (12') are further provided on the outside thereof. The substrate was then brought to a temperature of -100 ° C (when a cooling means was provided) to 850 ° C. Further, the holder (2) constitutes a third electrode and is electrically insulated from the reaction container (7). The substrate (1-1), (1-
2), ... (1-n), that is, (1) is provided. The first alternating voltage is applied from the power source (17) between the third electrode of the holder (2) and the first and second electrodes (3) and (3 ').

In addition, the matching transformer (1
A second alternating voltage having a frequency higher than the first alternating electric field is applied to the pair of electrodes (3), (3 ') (4), via (6).
(4 ') is applied.

The matching transformer has symmetrical or substantially symmetrical outputs, and one end (4) and the other end (4 ') are connected to a pair of first and second electrodes (3), (3'), respectively. Has been done. The first alternating voltage (17) is applied to the output side midpoint (5) of the transformer. A high frequency electric field having a frequency of 1 to 5000 MHz, for example 13.56 MHz was applied as the second alternating voltage, and an alternating electric field having a frequency of 1 to 500 KHz, for example 50 KHz was applied as the first alternating voltage.

Thus, plasma (6) is generated in the reaction space. The exhaust system (20) exhausts unnecessary gas through the pressure control valve (21), the turbo molecular pump (22), and the rotary pump (23).

These reactive gases are 0.001 to 1.0 in the reaction space (6).
torr, for example, 0.05 torr, and this tubular structure (8),
(8 ') has a rectangular parallelepiped shape, for example, width 160cm, depth 40c
m, 160 cm in height.

Further, cylindrical structures (8) and (8 ') are provided so that plasma does not stick to the outside (60) from the reaction space (6) so as not to adhere to the inner wall surface of the reaction container (7).

Since the effective area of the pair of electrodes was 120 cm □, it was set to 150 cm □. 1.0 to 30KW in such space (per unit area
0.04 to 1.3W / cm ² ) For example, 10KW (0.44W / cm per unit area)
^{A second} high frequency voltage of (2 plasma energy) is applied.
Further, the AC bias by the first alternating voltage is set to -200 to 600V (for example, its output is 500W) on the surface to be formed.
An output of 3 KW was added at a frequency of 0 KHz.

Of course, the height of this rectangular tubular structure is 20 cm to 5 m,
Further, one side of the electrode may be 30 cm □ to 3 m □.

Example 2 This example is an example in which carbon or a coating film containing carbon as a main component is formed on a substrate by using the plasma processing apparatus described in Example 1.

For example, methane or ethylene was used as the reactive gas. A self heating system was used without heating. For this reason, argon gas was introduced first, and 0.05 torr was set to about 10
The surface of the substrate was sputtered to heat the substrate. This surface could then be at 100-500 ° C, for example 300 ° C. The outputs of the first and second voltages were 3 KW and 10 KW, respectively. Furthermore, after this, methane, which is a reactive gas, was continuously introduced to form a carbon film while preventing the temperature of the substrate from lowering. After that, the amount of methane and the amount of argon were changed little by little, and all the gas in the reaction space was changed to the nitride gas.
The alternating voltage of the same output was applied.

By changing the reaction pressure and the distance between the holders in the reaction space under such conditions, the deposition rate, the uniformity of the deposited film, and the number of processing holders per batch are greatly affected. It became clear like the result.

Therefore, the distance between the holders in the reaction space is 5 to 10 cm, for example, 8 cm, and 15 holders per batch. 0 because there is no limit on the interval in the load or unload chamber
A floor area of ~ 2 cm can be saved.

The film formation rate is 10 to 600 A / min, and particularly the reaction pressure
The plasma CVD method at 0.03-0.07 torr gave 100-200 A / min. The uniformity of the film was within ± 10%, and 24 to 12 funnel holders per batch were obtained. All of these were regarded as good products only under the condition that the Vickers hardness was 2000 Kg / mm ² or more. Of course, if graphite is the main component (50% or more), it is extremely soft and black, which is completely different from the present invention.

Contrary to the present invention, when the electric potential on the substrate side (holder side) is set to the anode (side without sputtering effect) level, the carbon film has a Vickers hardness of 300 Kg / mm ² or less, which is extremely soft and industrially applicable. Was impossible.

In the present invention, when the frequency of the alternating voltage applied to the first and second electrodes is 1 to 500 KHz, which is the same as the bias voltage, it is difficult to turn reactive gas into plasma. Therefore, in order to further improve the film forming speed, the second alternating voltage is 1
˜5000 MHz, for example, 13.56 MHz, especially C-C bond, C = C bond is decomposed, C-C bond or -C-C-
Bonds can be made and carbon unpaired bonds can be made to collide with each other to form a covalent bond, resulting in a structure locally having a diamond structure with a stable SP ³ bond.

Thus, the base body of semiconductor (eg, silicon wafer), ceramics, magnetic material, metal, oxide superconducting material or base body of electric component is temporarily attached to or placed on a conductive holder, and carbon, especially carbon It was possible to form a film containing carbon as the main component, which contains 25 mol% or less of hydrogen, or carbon having P, I or N type conductivity.

As a result, even if a thickness of 1 μm was applied at the end and the center, the film thickness varied only by ± 10% or less, and the film quality such as hardness was uniform.

As an example of such a substrate, when it is applied to a substrate for a thermal head, etc., it operates for 8 hours a day, and operates for 21 days a month.
The carbon film could be coated on the K thermal heads / month.

Then, as another example of such a case, it is effective to coat a carbon film as a heat sink on the back surface side of a semiconductor wafer (1), for example, a silicon wafer. Then, this carbon film has a thermal conductivity of 2.5 W / cm deg or more, typically
Since it has a value of 4.0 to 6.0 W / cm deg, local heat generation of the power transistor section in the semiconductor integrated circuit can be dissipated uniformly throughout. When the carbon film is formed on the back surface of the wafer, the carbon film has a thickness of 0.5 to 5 μm, for example, 1 μm. It is preferable that this thickness is as large as possible without impairing the adhesion.

After this coating, a wafer probe test is performed, and in order to make each IC chip, through a scribe and break process, the structure in which each semiconductor chip has a carbon film coated on the back surface is completed as die bonding and wire bonding. It was

"Example 3" As another example of the present invention, the apparatus of Example 1 is used,
Silane and ammonia were introduced as reactive gases, and silicon nitride was produced with a sputtering effect.

Boron nitride was formed by introducing diborane and ammonia as reactive gases.

Further, organic titanium and nitrogen were introduced to form titanium nitride.

Alternatively, methylaluminum or the like may be introduced to form a metallic aluminum conductor. In the method of the present invention, when the film-formed material is a conductor, a short circuit between electrodes is likely to be induced. Therefore, the film-formed material is an insulating material or a material having a sufficiently high electric resistance (oxide superconducting material (Not conductive), ceramics, magnetic materials) are preferred.

"Effects" The method of the present invention enables industrial mass production by making the substrate side an electrode that should have a sputtering effect on the cathode side and making the reaction space extremely large. In forming the thin film, a carbon film was used as an example. This carbon film has a thermal conductivity of 2.5 W / cm
Since it is more than deg, typically 4.0 to 6.0 W / cm deg and close to 60 W / cm deg of diamond, it is possible to prevent local temperature rise and accompanying characteristic deterioration of the magnetic head, wear resistance,
Many properties such as high thermal conductivity and high smoothness peculiar to a carbon film can be effectively used in combination.

As is clear from the above description, when the present invention is used as a CVD method, the thin film to be formed is not only carbon but also an insulating thin film such as silicon nitride, boron nitride, tantalum oxide, metal aluminum, oxide superconducting material. May be

When used as an etching device, anisotropic etching of silicon oxide, aluminum, silicon and carbon on the substrate can be performed by setting the same potential direction as RIE (reactive ion etching).

Further, as a base material, an organic resin or glass compounded with it, a magnetic material, a metal or a ceramic, a semiconductor or a composite thereof is formed, and a thin film is coated on the surface of the solid.

Ceramics of the present invention is alumina, zirconia, carborundum, oxide superconducting materials known in YBaCu ₃ O ₆ ~ _8, BiSrCaCuyOx like are effective. Further, the magnetic substance may be a rare earth magnet such as samarium or cobalt, an amorphous magnetic substance, iron oxide or an anisotropically shaped magnetic substance obtained by coating nickel oxide, chromium or the like.

[Brief description of drawings]

FIG. 1 shows an outline of a plasma processing apparatus manufacturing apparatus according to the present invention. FIG. 2 is a vertical cross-sectional view of the main part of the plasma processing apparatus shown in FIG.

Claims (3)

(57) [Claims] 1. A substrate having a surface to be formed is held by a plurality of holders, a reactive gas is turned into plasma between the holders, and the holders are equal or substantially equal in a reaction space for processing on the substrate. The plasma treatment, wherein the plurality of holders held by the base are held at a second interval narrower than the first interval in the load or unload space. apparatus. 2. A pair of first and second electrodes separated from each other according to claim 1, wherein a substrate and a holder are transferred between the electrodes in a direction orthogonal to the pair of electrodes. A plasma processing apparatus, wherein the substrate or the holder is operated as a third electrode. 3. The plasma processing apparatus according to claim 1, wherein the relocation is performed by suspending and holding the holder and the base from above or by holding the holder and the base from below.