JPH0283924A - Method for microwave plasma treatment - Google Patents

Abstract

PURPOSE:To improve substrate treating ability without making the device larger by providing a plate electrode in parallel with the propagation direction of microwave and plasma treating a substrate disposed in parallel with the exhaust direction while applying potential. CONSTITUTION:A substrate 7, disposed on a plate electrode 9 or disposed perpendicularly to the plate electrode 9, is plasma treated while high frequency or DC potential is applied to the plate electrode 9 provided in parallel with the propagation direction of introduced microwave 5. By providing the substrate 7 in the exhaust direction 2 within a vacuum container 1 in this manner, and providing a plate electrode 10 being at earth potential in parallel with the plate electrode 9 on which the substrate 7 is disposed, stable bias potential can be applied to the substrate 7 so that etching speed and anisotropy is increased and a plurality of substrates 7 can be treated simultaneously without making the exhaust ability in the vacuum container 1 or the container volume larger.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a plasma processing method and apparatus.

In particular, it is suitable for achieving high processing efficiency and miniaturization of equipment when plasma processing a substrate using electron cyclotron resonance (ECR) to generate ions and mainly using the ions that reach the substrate. The present invention relates to a microwave plasma processing method and apparatus.

[Conventional technology]

In conventional microwave plasma processing, methods for increasing the efficiency of ion processing include a device installed on a grid at the plasma source exit as described in JP-A-55-141729, and a device as described in JP-A-56-13480. There was a device that applied high frequency waves to the substrate.

[Problem that the invention sought to solve]

The above conventional technology does not take into consideration the interaction field between the applied magnetic field and the introduced microwave, and the positional relationship between the exhaust direction of the device and the substrate, and the substrate to be processed is located perpendicular to the central axis of the device. In order to process the substrate, it was necessary to increase the inner diameter of the device.

As a result, there are problems in that the size of the apparatus is increased and that it is not possible to simultaneously process large-diameter substrates or a plurality of substrates. In addition, in methods that aim to improve the efficiency of ion processing by applying a negative potential to the grid or a high frequency to the substrate to induce a negative bias potential in the substrate, it is necessary to There is a problem in that there is a limit to the efficiency improvement of ion processing because local discharge occurs and causes significant damage to the substrate.

An object of the present invention is to solve the above-mentioned disadvantages.

[Means to solve the problem]

Regarding one of the above objects, a method of processing a plurality of substrates at the same time without requiring an increase in the size of the apparatus, the substrates are placed in a vacuum container parallel to the exhaust direction.

The microwaves introduced to generate plasma are introduced parallel to the substrate surface, and the magnetic lines of force applied for ECR excitation are perpendicular to the substrate surface so that ions in the plasma are efficiently incident on the substrate side. This is achieved by making the direction. Regarding methods for efficiently performing ion processing,
By installing a pair of parallel electrodes located parallel to the substrate surface, that is, an electrode that applies a bias potential to the substrate side and an electrode facing the electrode that has a ground potential, or perpendicular to the substrate surface, This is achieved by installing a pair of parallel electrodes at positions parallel to the microwave propagation direction, applying a high frequency to one of the electrodes, and setting the other to ground potential.

[Effect]

If you install the board in the exhaust direction inside the vacuum container,
Compared to the conventional method, the exhaust conductance can be significantly reduced, and as a result, a plurality of substrates can be installed simultaneously on the exhaust direction side without the need to increase the exhaust capacity. Furthermore, the diameter of the vacuum container can be significantly reduced. In order to excite gas by ECR and generate plasma, it is introduced parallel to the substrate surface, that is, in the exhaust direction, and magnetic lines of force are applied perpendicular to the substrate surface. The magnetic field lines cause the ion flow to be perpendicular to the substrate surface. By positioning the substrate, microwave introduction direction, and magnetic field line direction as described above, the distance to the inner diameter of the container facing the substrate surface can be shortened, without increasing the exhaust capacity inside the vacuum container or increasing the container volume. Both can process large-diameter substrates and multiple substrates at the same time.

In the above positional relationship, for example, when applying a potential to a part of the inner wall of the container where the substrate is installed or to the electrode, if the part of the inner wall facing the substrate surface or the parallel electrode is set to ground potential, the picture electrode surface Because they are parallel, the potential is not concentrated locally, and therefore the mark can increase the potential.
The speed and amount of ions reaching the substrate can be increased.

Therefore, the ion processing efficiency becomes high.

In the above positional relationship, only the position of the electrode that applies high frequency and has a ground potential is parallel to the substrate surface, the water drop, and the propagation direction of the microwave, and the fluctuating contact field caused by the high frequency electric field and the high frequency electric field The open force accelerates the ions toward the substrate.

This motion generates an inductive force through interaction with the magnetic field applied to the substrate side, further accelerating the ions (hereinafter this will be abbreviated as an inductive force). Therefore, if a high frequency application electrode is installed at the above-mentioned position, the speed and amount of ions reaching the substrate can be increased, and the ion processing efficiency can be increased.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Example 1. FIG. 1 is a schematic diagram of the main parts of a plasma processing apparatus according to an embodiment of the present invention, and the same reference numerals as in FIG. 3 represent the same or equivalent parts.

This embodiment is characterized in that the substrate 7 is positioned parallel to the propagation direction of the microwave 5, and that the substrate is placed on a parallel plate electrode 9.6 The vacuum vessel 1 is shown in FIG. The plasma generation chamber 12 and reaction chamber 13 of the conventional device shown are integrated, and the length is 800 [m+] and the height is 200 [+a].
], SO3 with a depth of 200 [m]! II. The volume of the vacuum container is almost the same as the device shown in FIG. 3, and the exhaust capacity from the exhaust port 2 is also the same. Below, using the apparatus of the present invention, 8o of AQ was deposited on a Si wafer with a diameter of 100 [m].
After O[Im] was deposited, AQIII was etched using the substrate 7 patterned with resist.
This will be explained by comparing it with the conventional microwave plasma processing apparatus shown in the figure. Boron trichloride, BCQ3, was introduced from the reaction gas supply pipe 3 at a rate of 200 n Q /In1n, and the vacuum vessel 1 or 13 was heated at a rate of 5 mtorr.
It was evacuated so that it was maintained at

In addition, the magnetic field coil 4 causes the lines of magnetic force to be positioned on the substrate in a water droplet, and the magnetic flux density inside the container satisfies the ECR condition.875 [G
aussl or higher was generated.
2.45[GI(z] microwave 5 is quartz introduction window 6
The water was introduced at 300 [W]. The ion flow 8 in the generated plasma is incident on the substrate in the same direction as the lines of magnetic force. At this time, in order to increase the amount and velocity of ions incident on the substrate, 13
, 6 [M117. ] The high frequency 11 of 200[w
] was applied to induce a bias potential. In the apparatus of the present invention, a parallel plate electrode is provided at a position facing the substrate, whereas in the conventional apparatus, the inner wall of the processing chamber 13 is at ground potential. In the conventional device, only one substrate can be installed at the same time due to the increase in exhaust conductance due to the substrate and the relationship between the exhaust capacity and the volume of the container, but in the device of the present invention.

Since the exhaust conductance is small, five boards arranged in the exhaust direction can be installed and processed at the same time.

In addition, in consideration of uniformity of processing characteristics among the substrates, the location that satisfies the ECR conditions and serves as the main generation site of plasma is located parallel to the substrate surface, as shown in FIG. The etching results are shown below. The etching speed was measured using a surface roughness meter.

The amount of dimensional shift from the resist pattern was determined by looking at the etched cross section of the substrate on the SEMI side. In the conventional equipment, the etching speed is 200 [stops/11 inch], the variation within the substrate surface is ±6 [%], and the amount of dimensional shift is 0.
．． The volume was 20 μml. On the other hand, in the apparatus of the present invention, at an etching speed of 220 [r+m/win], the variation within the substrate plane and between substrates is ±6 [%], and the amount of 1-dimensional shift is:
0.17 rμm]. These results show that although 5 times as many substrates can be processed at the same time, the etching characteristics are still very slow.

It was found that the anisotropy was excellent.

Next, in order to reduce the amount of dimensional shift 1, that is, to strengthen the anisotropy, the power of the high frequency wave 11 applied to the substrate was increased. With conventional equipment, if the mark is above power or aso [w],
A local discharge occurred between the substrate or electrode 9 and the inner wall of the device, and the substrate was significantly damaged. On the other hand, in the device of the present invention, 1
No local discharge occurred even when the voltage was applied at 000 [W] or more. The etching rate at this time was 300 [nm/m1n
l, and the dimensional shift amount was 0.10 [μm]. As can be seen from this result, by placing a flat plate electrode with a ground potential in the iV row on the electrode on which the substrate is installed, a bias potential can be stably applied to the substrate, and as a result, the etching speed and variation can be improved. It was found that the orientation was strengthened.

Example 2. In order to increase the etching rate and anisotropy, instead of using a bias potential applied to the substrate to increase the speed and anisotropy of the ions incident on the substrate, the induction force of a high-frequency electric field of a magnetic field is used to increase the speed and anisotropy of the ions incident on the substrate. We considered ways to increase the amount. FIG. 4(a) shows a front view and FIG. 4(b) a side view of the apparatus of the invention for achieving the above method.

The difference from the device shown in FIG. 1 is that the high frequency application electrode 10'
, 11' are the same except that they are oriented perpendicularly to the substrate surface. The etching conditions were the same as in Example 1. 5 and 6 show the etching speed and the amount of dimensional shift with respect to the applied high-frequency power. The solid line A shows the etching rate when a bias potential is used as shown in Example 7, and the broken line B
indicates when the induction force is used. These results show that the etching rate is higher and the anisotropy is stronger when the inductive force is used rather than the bias potential. In other words, it was found that ion processing efficiency can be increased by utilizing the interaction between a magnetic field and a high-frequency electric field.

Example 3 Using a substrate 7 on which a thermal oxide film was formed on a Si wafer of 100φ [=111], argon and Ar were introduced as one reaction gas through the reaction gas supply pipe 3 at a rate of 200 [w Q /min]. , using the device using the bias potential shown in FIG. 1 and the device using the inductive force shown in FIGS. 4(a) and (b), respectively.
An iOz film was sputtered. The amount of sputtering is shown in FIG. 7, with the results obtained using an ellipsometer and the high frequency applied power plotted on the horizontal axis. These results show that the method using inductive force is more efficient in sputtering as well.

Example 4: A thermal oxide film was formed on a 100φ [011] Si wafer, and a polycrystalline silicon film was placed on top of it.
A method in which phosphine, PH3, is introduced as a reaction gas through a reaction gas supply pipe 3 at a rate of 10 [w Q /ll1inl, and the bias potential shown in FIG. Figure 4(a), (
Doping of polycrystalline silicon with phosphorus was carried out for 20 minutes using each of the devices of the method using the induction force shown in b). At this time, the applied high frequency power was 500 [
w].

The results are shown in FIG. 8, with the phosphorus concentration profile plotted on the vertical axis and the distance in the depth direction plotted on the horizontal axis. As can be seen from this result, it can be seen that the doping efficiency is higher when the vI induction force is used. Of course, the substrate can be doped stably and significantly more efficiently than the conventional type shown in FIG.

Example 5: A thermal oxide film was formed on a Si wafer of 100 φ and a substrate 7 was patterned with AQ (thickness: 0.8 [μm]), and a supply pipe 3 was used as a reaction gas. through 80 hQ/ml of Ar and 80 h of oxygen gas.
0 [wQ/win], and then through the supply pipe 14, monosilane, SiH4, was added at 20 [wQ/l! 110]
and set the reaction pressure to 3 [mTorr].
A 5iOz film was planarized and deposited on the substrate for 10 minutes. At this time, the high frequency power applied was 500 [wl]. Figure 9(a) shows a schematic diagram of the deposition situation.

Shown in (b), (a) is a method using bias potential,
(b) shows the case of the method using inductive force.As you can see from this result, in the method using bias potential,
It can be seen that although the surface was not flattened after 10 minutes, it was sufficiently flattened using the method using the induction force.

Example 6. Using a polycarbonate plate of 100 φ as the substrate 7, Ar was applied from the gas supply pipe 3 to 80 [wQ/l]
After introducing 1 inch of Fi7 and sputtering the group Fi7 with Ar for 1 minute, ammonia and NH3 were introduced from the gas supply pipe 3.
From the gas supply pipe 14, SiH
4 was introduced at 20 [vQ/n], silicon titanide and SiN were deposited to a thickness of loo [nm] on the polycarbonate plate,
During Ar sputtering, which investigated the adhesion between polycarbonate material and SiN film, the high frequency applied power was 350[wl],
The power was 70 [wl] during deposition. For comparison, we also investigated a substrate that was subjected to Ar treatment using the apparatus shown in FIG. 4, then exposed to -degree air, and then deposited SiN, and a substrate that was deposited with SiN without Ar treatment. The adhesion strength was evaluated by heating the wafer after SiN film deposition at 60°C and 90%I.
Test 1 for accelerated deterioration up to 2000 [h] was conducted in an RH atmosphere, and peeling at that time was visually observed. After 2 hours for a substrate not subjected to Ar treatment, after 10 hours for a substrate exposed to -degree air after Ar treatment, and after surface modification in the same chamber using a method using a bias potential, S
The deposited iN film peeled off after 800 hours. From these results, it was found that the adhesion of W4 was significantly higher when the substrate was treated with Ar and when the film was continuously deposited in the same chamber. After performing Ar treatment using induction force, Si was subsequently treated in the same chamber.
The substrate on which the N film was formed did not peel off even after more than 2000 hours. Referring to these results and the doping profile shown in Example 4, it can be seen that in order to improve adhesion, it is important for ions to efficiently reach deep areas on the substrate surface by utilizing inductive force.

According to this embodiment, if the substrate is installed parallel to the exhaust direction, and the microwave introduction direction and the magnetic field line direction are respectively parallel and perpendicular to the substrate,
In the method of ion processing a substrate using a bias potential, which improves the processing capacity of a substrate without increasing the size of the device, at the above installation position, the ground potential is placed parallel to and facing the flat plate electrode to which the bias potential is applied. Installing a flat plate electrode stabilizes the application of bias potential and improves ion processing efficiency.Also, it is better to use bias potential to bring ions to the substrate by converting the magnetic field into a high-frequency electric field. Utilizing the induction force due to interaction has the effect of further increasing ion processing efficiency and processing characteristics.

〔Effect of the invention〕

According to the present invention, it is possible to improve throughput, process large area substrates, and improve ion processing characteristics without increasing the size of the device or increasing the exhaust capacity. This has the effect of reducing the cost of devices, as well as ion processing equipment for optical disks, etc., shortening processing time, and reducing processing coils.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the main parts of a plasma processing apparatus that is an embodiment of the present invention, Figure 2 is a magnetic flux density distribution diagram on the central axis of the equipment, and Figure 3 is a diagram of the main parts of a conventional plasma processing apparatus. 4(a) and 4(b) are schematic front and side views of the main parts of a plasma processing apparatus according to an embodiment of the present invention, and FIGS. 5 and 6 show the etching speed and pattern of AQ. Figure 7 is a diagram showing the amount of sputtering of SiO2, Figure 8 is a diagram showing the doping profile, and Figures 9 (a) and (b) are schematic diagrams showing the planarization deposition situation. be. 1... Vacuum container, 3, 14... Gas supply pipe, 4...
Magnetic field generating coil, 5...microwave, 7...substrate, 8...
...Ion flow, 9...High frequency application 1! Extreme, 10...
Earth electrode, A... When bias potential is applied to the substrate, B...
When applying inductive force to ions. Figure 4 (Ku) Figure 5 Front 6 Figure High Rise R Anti-Popno Power (W) 1 Ryo M; Eef'n011'') (W) My Flora Drama Introduction Figure 8. 171 distance (νm) towards Takama trench epna Figure 9

Claims (1)

[Claims] 1. Electron cyclotron resonance is achieved using a vacuum container having a microwave introduction window, a reaction gas supply system, and an exhaust system, and a device having a magnetic field generating section that applies a magnetic field to the vacuum container. In this method, a flat plate electrode is installed parallel to the propagation direction of the microwave to be introduced, and while applying a high frequency or DC potential to the electrode,
Alternatively, a microwave plasma processing method characterized in that a substrate placed perpendicular to the electrode is subjected to plasma processing. 2. A flat plate electrode is installed parallel to the propagation direction of the microwave introduced in the method of processing a substrate by causing electron cyclotron resonance due to the interaction between the microwave introduced into the vacuum container and the applied magnetic field, and the electrode It is characterized by applying an electric field perpendicular to the direction of microwave propagation, and accelerating ions in the plasma toward the substrate using the potential gradient or the interaction force between the magnetic field and the applied alternating frequency electric field. Microwave plasma treatment method. 3. Claims characterized in that a flat plate electrode is positioned substantially perpendicular to the direction of the introduced magnetic field lines, a substrate is placed on the flat plate electrode, and plasma processing is performed while creating a potential gradient in a direction perpendicular to the plane of the substrate. The microwave plasma processing method according to item 1 or 2. 4. The microwave plasma according to claim 3, wherein the potential applied to the electrode is a direct current potential, an alternating frequency potential, or a direct current potential and an alternating frequency potential. Processing method. 5. A flat plate electrode is installed parallel to the direction of propagation of the microwave to be introduced and the direction of the lines of magnetic force, and due to the interaction force between the high frequency electric field introduced from the electrode and the magnetic field in the direction of the substrate placed perpendicular to the electrode surface. 3. The microwave plasma processing method according to claim 1, wherein the plasma processing is performed while accelerating ions. 6. The magnetic flux density that satisfies the electron cyclotron resonance condition is
6. The microwave plasma processing method according to claim 1, wherein the microwave plasma processing method is positioned in front of the substrate surface and in a plane substantially parallel to the substrate surface. 7. The microwave plasma processing method according to any one of claims 1 to 6, characterized in that a plurality of substrates to be plasma processed are arranged side by side on the same plane and are processed simultaneously. 8. The microwave plasma processing method according to any one of claims 1 to 7, wherein the flat plate electrode is a part of the inner wall of a vacuum chamber in which the substrate is processed. 9. Claims 1 to 8, characterized in that the plasma treatment involves etching a desired material on the substrate.
The microwave plasma treatment method described in . 10. The microwave plasma processing method according to any one of claims 1 to 8, characterized in that the plasma treatment involves sputtering the substrate. 11. A microwave plasma processing method according to any one of claims 1 to 8, characterized in that the plasma processing involves forming a film on a substrate. 12. The microwave plasma processing method according to any one of claims 1 to 8, wherein the plasma processing is performed by combining an etching or sputtering process with a process of forming a film on a substrate. 13. The first aspect of claim 1, characterized in that the plasma treatment involves doping impurities into the constituent material on the substrate.
The microwave plasma processing method according to items 8 to 8. 14. The microwave plasma processing method according to any one of claims 1 to 8, characterized in that the plasma treatment involves modifying the surface of the substrate. 15. The microwave plasma according to claims 1 to 8, characterized in that after modifying the substrate surface, a film is formed on the modified surface in the same apparatus. Processing method.