JPH07201811A - Plasma processing device - Google Patents

Abstract

(57) [Summary] [Objective] The guiding means is moved to another space from the facing space on the surface to be processed of the object to be plasma-treated by the guiding means. Constitution: An induction means 5 for generating a plasma 13 when performing a plasma treatment on an object 3 to be treated provided in an airtight container 1 is provided on the opposite side of the object 3 to be treated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma processing apparatus.

[0002]

2. Description of the Related Art As a plasma source of a plasma processing apparatus for processing a semiconductor wafer or a liquid crystal substrate for a liquid crystal display, an induction means, for example, an induction means for applying a high frequency, for example, a radio frequency, to a planar coil to generate plasma, JP-A-2-235332, "Plasma processing apparatus", JP-A-3-79025, "Apparatus for generating magnetically coupled planar plasma and method and apparatus for processing this plasma article", JP-A-4 -29042
No. 8, “Plasma Reactor Using UHF / VHF Resonant Antenna Supply Source and Method Thereof”, Japanese Patent Laid-Open No. 5-2060
No. 72, "Plasma processing apparatus using inductive RF coupling and method thereof".

Next, the conventional techniques described in these publications will be described with reference to FIG. FIG. 6 is a vertical sectional view of a conventional plasma processing apparatus. An object 103 to be processed is provided on a mounting table 102 provided inside an airtight container 101. The wall surface of the container 101 facing the object 103 to be processed is formed by a dielectric 104.

Further, a guiding means 105, for example, a planar coil is arranged outside the container 101 so as to face the object 103 to be processed. A voltage of a high frequency, for example, a radio frequency, is applied to the induction means 105 from a high frequency power supply 107 via a matching circuit 106. A gas supply port 10 is provided inside the container 101.
A predetermined gas is supplied from the gas supply frequency 109 via the switch 8.

Through the exhaust port 110 provided at the bottom of the container 101, the exhaust means 111 allows the container 10 to be exhausted.
The inside of 1 is configured to be evacuated to a predetermined degree of vacuum. The side wall of the container 101 has a gate valve 112.
And the object to be processed 10 is provided by a transporting means (not shown).
3 is configured to be loaded and unloaded through the opening of the gate valve 112.

In the plasma processing apparatus configured as described above, the plasma 113 is generated mainly between the object 103 to be processed and the dielectric means 104, and the object is plasma-processed.

[0007]

In the plasma apparatus as described above, the guiding means is arranged to face the surface of the object to be processed, which is to be subjected to the plasma processing, and the space in which the guiding means is provided is arranged. There is a problem that the space cannot be used freely for other purposes, for example, when a gas supply shower head, a light heating means, or the like is provided.

Since the inducing means generates plasma by inductive coupling, if a part made of a conductive material is provided between the inducing means and the object to be processed, the inductive coupling is affected and the object to be processed is affected. There is a problem that it is difficult to perform uniform treatment on the surface.

More specifically, when the guiding means and the light heating means for heating the shower head or the object to be processed are simultaneously provided in the facing space on the surface to be processed of the object to be processed, the inductive coupling is achieved. There has been a problem that the processing result of the object to be processed is adversely affected by the material and the position of these materials.
In the conventional technique shown in FIG. 6, the processing gas for processing the object 103 is supplied to the gas supply port 1 by the gas supply means 109.
08, but when the gas supply port 108 is arranged near the object 103 to be supplied with an effective gas for increasing the processing speed, the material of the pipe 109 of the gas supply port 108, for example, There is a problem that the inductive coupling formed by the guiding means 5 is affected by the stainless steel and cannot be brought close to each other.

An object of the present invention is to provide a plasma processing apparatus in which the guiding means is moved from the facing space on the surface to be processed side of the object to be processed by the plasma generated by the guiding means to another space. It is in.

[0011]

According to a first aspect of the present invention, there is provided an inducing means for generating plasma in an airtight container, and an object to be treated by the plasma is provided between the inducing means and the plasma. It is characterized in that it is provided. According to a second aspect of the present invention, a dielectric forming a part of a wall surface of an airtight container, an induction unit provided outside the container, a power source for applying a high frequency voltage to the induction unit, and a gas inside the container. And a gas supply means for supplying the gas, and a processing object to be processed by the plasma is provided in a space sandwiched between the plasma in the container generated by the induction means and the induction means. . According to the invention of claim 3, a substrate to be processed provided in an airtight container, a gas supply means for supplying gas into the container, and a guiding means provided outside the container,
A plasma source for applying a high-frequency voltage to the inducing means to generate a plasma for processing the surface to be processed (front surface) of the substrate to be processed; It is characterized by being The invention of claim 4 is characterized in that the guiding means is a planar coil arranged to face the substrate to be processed. The invention of claim 5 is characterized in that the guiding means is arranged to face the substrate to be processed through a window of a dielectric material forming a part of a wall surface of the container. The invention of claim 6 is characterized in that the guiding means is a planar coil. The invention of claim 7 is characterized in that the guiding means is a spiral coil or a spiral coil. The invention of claim 8 is characterized in that the guiding means is a loop antenna. The invention of claim 9 is characterized in that the guiding means has a plurality of loop antennas arranged in the same circle. The invention according to claim 10 is characterized in that the guiding means comprises a plurality of coils arranged side by side. The invention of claim 11 is
It is characterized in that position adjusting means is provided which is capable of freely setting a relative distance between the guiding means and the object to be processed. The invention of claim 12 is characterized in that a magnetic field forming means for confining the plasma is provided outside the container.

[0012]

According to the plasma processing apparatus of the present invention, the guiding means can be eliminated from the facing space on the side of the surface to be processed by the plasma of the object to be processed. It can be used to provide a shower head or the like. Further, it is possible to provide a plasma processing apparatus capable of controlling the plasma generated by the inducing means via the object to be processed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a vertical cross-sectional view of the first embodiment of the plasma processing apparatus of the present invention.

First, the structure will be described. The airtight container 1 is made of aluminum, and its inner wall surface is polished and then an oxide film is formed. The oxide film is configured to prevent generation of dust from the aluminum, particularly contamination of heavy metals, during the processing of the object 2 to be processed in a vacuum atmosphere.

A gate valve 3 is provided on the side wall of the container 1 so as to be openable and closable, and the object 2 to be processed is conveyed through an opening of the gate valve 3 by a conveying means (not shown).
It is configured to be carried in and placed inside. On the upper wall surface (ceiling) of the container, there is provided a shower head 5 provided with a gas supply port 4 arranged to face the object to be processed 2.

The shower head 5 is opened and closed after the supply amount is adjusted by the gas supply means 6 by the processing gas mass flow controller 7 corresponding to the processing of the object 2 to be processed, for example, film forming processing or etching processing. It is designed to be supplied via a possible valve 8.

The gas supply means 6 is constructed so as to be capable of supplying a plurality of processing gases and an inert gas such as N ₂ gas according to the processing content. The shower head 5 is provided with a multi-stage diffusion plate (not shown) therein, and after mixing the plurality of process gases, a small hole, for example, 0.
By providing diameters of 1 to 3 mm at equal intervals, for example, 2 to 5 mm, over the entire opening surface, it is possible to uniformly supply gas to the object to be processed.

On the bottom surface of the container 1, there is provided a dielectric 9 which constitutes a part of the wall surface of the container 1, such as quartz, synthetic quartz or fused quartz. The material of the dielectric 9 can be selected according to the processing temperature for processing the object 2. Although synthetic quartz is expensive, it is desirable in terms of heat resistance and strength.

The size of the dielectric 9 needs to be set according to the degree of vacuum in the container 1.
If it is about x10 ^-4 Torr, the thickness may be 40 mm, and the outer diameter size is preferably 10 to 40% or more larger than the outer size of the object 2 to be processed.

For example, when an 8-inch semiconductor wafer is selected as the object to be processed 2, the outer size of the front dielectric 9 is 220 to 280 mm or more, and the liquid crystal substrate is 540 mm ×.
If it is 640 mm square, the outer size of the dielectric 9 is
About 600 mm x 700 mm square to 760 mm x 900 m
Require an external size of m square or more.

The object 2 to be processed is mounted on the dielectric 9 inside the container 1, and a mounting table made of a material such as ceramics or quartz is further provided on the dielectric 9. The object 2 to be processed may be placed on the placing table.

A guiding means 10 is provided outside the container 1 so as to be opposed to the surface 16 to be processed of the object 2 to be processed. As the guiding means 10, a flat spiral coil, a spiral coil, a one-turn coil, a plurality of coils arranged concentrically, a plurality of coils arranged in parallel, a shape of the object 2 to be processed It is possible to use various antennas according to.

The material of the guiding means 10 is preferably a metal, which is a conductive material, such as copper (Cu). As a more specific example, a copper plate having a thickness of 2 to 5 mm is punched into a spiral shape by pressing, or as another example, a copper pipe having an outer diameter of 5 mm and an inner diameter of 3 mm is bent into a spiral shape. A coil can be formed.

The outer size of the guiding means 10 is at least larger than the outer size of the object 2 to be processed,
It is desirable that the object 2 to be processed can be processed in a portion where the distribution of generated plasma is more uniform. For example, in the case of an 8-inch semiconductor wafer, the external size of the guiding means 10 is 220% to 280 which is larger by 10% to 40% or more.
It can be set to mm size or more.

A high frequency power source 11 provided outside the container 1 applies a high frequency, for example, a radio frequency, for example, a voltage of 13.56 MHz to the dielectric means 10 through a matching circuit 12. ing.
The frequency of the high frequency power source 11 can be set to a higher frequency of 40 MHz to 60 MHz, for example, depending on the processing process of the object to be processed 2. Specific examples of the dielectric means will be described later in detail. An exhaust port 13 is opened at the bottom of the container 1. From the exhaust port 13, the exhaust means 1 is connected to the container 1 via an openable / closable valve 15.
It is configured to perform vacuum evacuation so as to reach and maintain a predetermined degree of vacuum. The plasma processing apparatus of the first embodiment is constructed as described above.

Next, the operation of the first embodiment will be described. Through the gate valve 3, the object 2 to be processed is loaded and placed in the container 1 by a transporting device (not shown). When the gate valve 3 is closed and the interior of the container 1 becomes airtight, the exhaust means 14 evacuates the interior of the container 1 to a predetermined vacuum degree, for example, 1 × 10 ⁻⁷ Torr.

Next, a predetermined processing gas is uniformly supplied to the facing region of the object to be processed 2 through the shower head 5 by the gas supply means 6. Next, a high frequency voltage, for example, a voltage of 13.56 MHz is applied to the inducing means 10 from the high frequency power source 11, and plasma 13 is generated in the facing region of the object 2 to be processed 16 side.

The distribution of the plasma 13 mainly depends on the configuration of the guiding means 10, and then the spread of the distribution depends on the degree of vacuum in the container. Vacuum degree is 1 × 10 ^-4 Torr, 1 × 10 ^-5 Torr
Becomes Therefore, the plasma distribution becomes wider. That is, when the induction means 10 is a flat spiral coil, the plasma 13 having a substantially flat distribution as a whole is provided in the space inside the container 1 facing the flat spiral coil. It is caused. The distribution of the plasma 13 can be determined by measuring at a plurality of locations in the space inside the container 1 with a probe that measures the electron temperature of the plasma.

The electron temperature distribution obtained based on this probe measurement, that is, the plasma distribution, is the object 2 to be processed.
Since the plasma processing apparatus of the first embodiment is configured so as to have a more uniform distribution in the range that covers the surface 16 to be processed,
As a result of the processing, the uniform processing can be performed over the surface 16 to be processed.

When the predetermined process for the object to be processed 2 is completed, the voltage supply of the high frequency power source 11 is stopped and the plasma is extinguished. At the same time, after the supply of the processing gas by the gas supply means 6 is stopped, the residual gas in the container 1 by the exhaust means 14 is discharged to the outside of the container 1. Next, the gas supply means 6
A more inert gas such as N ₂ gas is supplied, and the inside of the container 1 is replaced with the N ₂ gas atmosphere.

Next, the valve 15 is closed, the inside of the container 1 is set to a positive pressure higher than the atmospheric pressure by the N ₂ atmosphere, the gate valve 3 is opened, and the transfer means (not shown) is used to cover the treated 21. The processing body 2 is carried out of the container 1, and a series of processing by the plasma processing apparatus of the first embodiment is completed.

According to the plasma processing apparatus of the first embodiment, which operates as described above, the guiding means 10 is provided on the side of the object 2 opposite to the surface 16 to be processed so that the surfaces to be processed face each other. It has succeeded in eliminating the guiding means from the space.
As a result, the shower head 5 that covers the surface 16 to be processed and that can supply a uniform gas can be provided at a position facing the surface 16 to be processed. Since the shower head 5 is provided outside the space sandwiched by the guiding means 10 and the plasma 13 generated by the guiding means 10, the shower head 5 is inductively coupled by the guiding means 10, and further the plasma 13 generated by the induction coupling is generated. It is provided in a space that does not adversely affect the uniformity of distribution.

The embodiment in which the shower head 5 is provided in the space facing the surface 16 to be processed of the object 2 has been described above. Instead of the shower head 5, a plurality of gas supply ports 13 are used as nozzles. Even if provided, these plural nozzles are located outside the space sandwiched between the guiding means 10 and the plasma 13, so that the adverse effect on the uniformity of the plasma 13 is less than that of the prior art configuration shown in FIG. There is.

Next, a second embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 2 is a vertical sectional view of the plasma processing apparatus of the second embodiment. The same parts as those in FIG. 1 are given the same numbers and their explanations are omitted.

In the center of the airtight container 1, a mounting table 17 made of quartz and having a flat mounting surface is provided on the dielectric 9. The processing target 2 is mounted on the mounting table 17 with the surface 16 to be processed facing upward. The surface 1 to be processed is opposed to the object 2 to be processed.
In the space opposite to the 6 side, the guiding means 10 is provided so as to be vertically movable while maintaining the facing posture. The guiding means 10 includes the surface 16 to be processed and the guiding means 1.
The distance H from 0 is provided so that it can be set freely. The elevating mechanism 18 is a mounting table 1 on which the guiding means 10 is mounted.
9, a ball screw 20 rotatably coupled to the support portion of the mounting table 19, and a rotary drive mechanism 21 for rotating the ball screw 20 to adjust the distance H. A plurality of electromagnets 21 are provided on the outer peripheral portion of the side surface of the container.

A voltage is applied from a DC power source 22 to these electromagnets, and the magnetic poles formed inside the container 1 adjacent to each other surrounding the side wall of the container are alternately different, for example, N, S, N, S, N, S are arranged.

By the action of the magnetic field formed by the plurality of electromagnets 21, the surface 16 to be processed is guided by the guiding means 10.
Of the plasma generated in the facing region of the object 16 is confined toward the facing region of the object 16 to be processed, the plasma density is increased, and the processing speed of the object 16 can be improved. Next, the upper wall surface (ceiling) of the container is provided with a plurality of openings 23 for lamps that emit light. A plurality of quartz windows 80 are provided above these openings 23, and a lamp 24 for optically heating the object 2 to be processed is provided with these quartz windows 8.
It is provided to irradiate through 0. These lamps 24 are provided with a reflecting mirror 25 that reflects light on the back side.

A digital high frequency voltage is supplied to the lamp 24 from a lamp control means 26 which supplies electric power. The lamp 24 directly irradiates and heats the object 2 to be processed, so that the object 2 can be heated to a processing temperature of about 600 ° C. in a short time, for example, 60 seconds. .

The rising temperature and control of this heating are achieved by the lamp control means 26 by pulse width control for controlling the ON time width of the digital voltage. Further, an inert gas that prevents the gas supplied from the gas supply means 6 and the reaction products generated by the plasma treatment from adhering to the surface of the lamp 24 is provided in the plurality of openings 23.
For example, the N ₂ gas or the Ar gas is supplied from the inert gas supply source 27 through the inert gas supply pipe 30 through the valve 29 that can be opened and closed after the flow rate is adjusted by the mass flow controller 28. Has been done. The plasma processing apparatus of the second embodiment is constructed as described above. According to the plasma processing apparatus of the second embodiment configured as described above, the distance H between the guiding means 10 and the surface 16 to be processed of the object 2 can be set by the elevating mechanism.
The distribution of the generated plasma 13 can be set to an optimum state in relation to the object 2 to be processed. Generally, the distance H from the guiding means 10 to the surface 16 to be processed is 5 to
Within the range of 150 mm, plasma can be generated to process the surface 16 to be processed. Further, if the distance H is made smaller, the processing speed by plasma is improved, but depending on the content of the processing, for example, the quality of the film formation during the film formation processing,
The optimum distance can be set. Furthermore, in order to determine the thickness of the dielectric 9 according to the degree of vacuum in the container 1, for example, if the thickness of the dielectric 9 is 40 mm, the thickness of the mounting table 17 can be adjusted by H can be set to a desired distance of 40 mm or more. First and second described above
As a process suitable for the embodiment described above, for example, in the process of manufacturing a liquid crystal substrate, an a-Si film (amorphous silicon film) and a gate insulating film are formed of a silicon nitride film on a gate insulating film formed on a glass substrate. Thin film transistor obtained by forming a film (Thin Film Transistor)
or)). 13.56 MH as high frequency
z is applied to the inducing means to decompose the raw material gas such as SiH ₄ to form a silicon nitride film which is an amorphous thin film at the temperature of the substrate to be processed of 250 to 350 ° C.

Next, the principal part of the induction means 10 used in the plasma processing apparatus described in the first and second embodiments will be described with reference to the drawings. FIG. 3 is a schematic diagram showing a spiral coil 52 having a rectangular outer shape, which is provided as a substrate to be processed so as to face a glass plate 51 for a liquid crystal substrate having a rectangular outer shape. The outer shape of the spiral coil 52 is rectangular according to the outer shape of the object to be processed. Furthermore, this spiral coil 52
The outermost circumference is larger than the outer shape of the object 51 to be processed, and the density of the generated plasma is rough at the peripheral portion, so that a more uniform central area is made wider than the object 51. Is useful for

In FIG. 4, the substrate to be processed is the semiconductor wafer 53.
Spiral coil 5 having a circular outer shape as described above, the coil forming the guiding means is circular according to the outer shape.
It is a schematic diagram which shows 4. As in FIG. 3, the spiral coil 5
The outer size of No. 4 is larger than the outer diameter size of the semiconductor wafer 53.

In FIG. 5, the guiding means arranged so that the substrate to be processed is opposed to the semiconductor wafer 53 having a circular outer shape has an inner one-turn coil 55 and an outer one-turn coil 5.
It is a schematic diagram which shows that it was formed by the several coil of 6. Voltages are supplied to the inner side and the outer side by independent high-frequency power supplies, and the respective phases can be set by shifting to arbitrary angles. The outer size of the inner one-turn coil 55 is smaller than the outer size of the substrate 53 to be processed.
The outer size of 6 is larger than that of the substrate 53 to be processed.

With the above-described structure, the density of the plasma distribution generated by the inner one-turn coil 55 becomes rough at the peripheral portion, and the processing speed becomes slower than the outer one-turn coil. By supplementing with the coil 56, it is possible to adjust the plasma density and perform the in-plane processing of the substrate to be processed more uniformly. The three different types of guiding means have been described above. However, these guiding means are not always arranged in a planar shape at positions facing the substrate to be processed, and the central portion of the planar spiral coil is not always disposed. Away from the object to be processed, and by incorporating a vertical deformation from the plane that brings the outer peripheral portion closer,
The result of the plasma treatment can be made more uniform in the central portion and the peripheral portion of the object to be treated. Needless to say, such a planar coil having a three-dimensional structure in the vertical direction is a technique in which the guiding means used in the present invention can be easily implemented.

[0044]

According to the plasma processing apparatus of the present invention, the induction means for generating plasma can be moved from the facing space on the plasma processing surface side of the object to be processed provided in the airtight container to another. The facing space can be used for other purposes. Further, the generation and control of the plasma can be performed by the guiding means provided in the facing space opposite to the plasma processing surface.

According to the fourth aspect of the present invention, since the planar plasma can be generated, it is possible to perform the in-plane uniform treatment of the object to be treated such as the substrate.

According to the fifth aspect of the invention, the dielectric can serve to form the inductive coupling by the inductive means.

According to the seventh aspect of the present invention, a coil corresponding to the shape of the surface to be processed of the object to be processed can be formed in a spiral shape or a spiral shape to perform highly uniform processing.

According to the eighth aspect of the present invention, the induction means can be constituted by a simple loop and the plasma density can be maintained.

According to the ninth aspect of the present invention, since each loop antenna can be independently controlled by varying the power, position and frequency by the high frequency power source, the central portion and the outer edge portion of the object to be processed can be controlled. It is effective in controlling the processing speed of and.

According to the tenth aspect of the present invention, it is possible to generate the plasma which covers the entire surface to be processed of the object to be processed having a large area.

According to the eleventh aspect of the present invention, the distribution of the generated plasma and the distance between the object to be processed are adjusted according to the size of the object to be processed and the conditions of the plasma processing to obtain the optimum induction. The position of the means can be determined.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of a plasma processing apparatus of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the plasma processing apparatus of the present invention.

FIG. 3 is a schematic view showing a first embodiment of the guiding means of the plasma processing apparatus of the present invention.

FIG. 4 is a schematic diagram showing a second embodiment of the guiding means of the plasma processing apparatus of the present invention.

FIG. 5 is a schematic diagram showing a third embodiment of the guiding means of the plasma processing apparatus of the present invention.

FIG. 6 is a vertical cross-sectional view showing an embodiment of a conventional plasma processing apparatus.

[Explanation of symbols]

 1 container 2 object to be treated 9 dielectric 10 induction means 11 high frequency power supply

Claims (12)

[Claims] 1. A plasma processing apparatus comprising: an induction means for generating plasma in an airtight container; and an object to be processed by the plasma provided between the induction means and the plasma. 2. A dielectric forming a part of a wall surface of an airtight container, an induction means provided outside the container, a power source for applying a high frequency voltage to the induction means, and a gas supply into the container. And a gas supply means for controlling the plasma in the container generated by the inducing means and a space between the inducing means and an object to be processed by the plasma. apparatus. 3. A substrate to be processed provided in an airtight container, gas supply means for supplying gas into the container, induction means provided outside the container, and high-frequency voltage applied to the induction means. A plasma source for generating a plasma to apply and process a surface to be processed (front surface) of the substrate to be processed, wherein the inducing means is provided on the back surface side of the substrate to be processed. apparatus. 4. The plasma processing apparatus according to claim 3, wherein the inducing means is a planar coil arranged to face the substrate to be processed. 5. The method according to claim 3, wherein the guiding means is arranged to face the substrate to be processed through a window made of a dielectric material that forms a part of a wall surface of the container. Plasma processing equipment. 6. The plasma processing apparatus according to claim 1, wherein the inducing means is a planar coil. 7. The plasma processing apparatus according to claim 1, 2, or 3, wherein the inducing means is a spiral coil or a spiral coil. 8. The plasma processing apparatus according to claim 1, wherein the induction means is a loop antenna. 9. The plasma processing apparatus according to claim 1, 2, or 3, wherein said guiding means has a plurality of loop antennas arranged in the same circle. 10. The plasma processing apparatus according to claim 1, wherein the inducing means has a plurality of coils arranged side by side. 11. A position adjusting means capable of freely setting a relative distance between the guiding means and the object to be processed is provided. The plasma processing apparatus of item 3. 12. A plasma processing apparatus according to claim 1, wherein a magnetic field forming means for confining the plasma is provided outside the container.