JPH0448720A - Surface treating method and device - Google Patents

Abstract

PURPOSE:To obtain a surface treating device which has a light source section having high illuminance, high performance, high reliability, a long lifetime and low cost and into which the light source section is incorporated by installing a sheath, through which light is transmitted and which is airtight or vacuum-resistant to the inside of a reaction treatment chamber, inserting the light source into the sheath and providing a means introducing a fluid into the sheath and discharging the fluid. CONSTITUTION:An ultraviolet lamp 1 is supplied with power from a lighting power supply and lit, and ultraviolet rays are radiated from a light-emitting section 1a. Since the space of the light-emitting section 1a and a sheath 2 is filled with nitrogen introduced from a gas introducing path 1c, radiated ultraviolet rays are not sucked in the space, and are transmitted through the sheath 2, an article to be treated 6 on a stage 5 in a treating chamber 4 is irradiated with ultraviolet rays, and the article 6 is surface-treated. On the other hand, a large quantity of heat are generated from the lamp 1, and the temperature of the lamp can be adjusted properly by regulating the flow rate of nitrogen gas. Since a vacuum in the treating chamber 14 need not be broken and the treating chamber 4 be exposed to atmospheric air, the deterioration, etc., of surface treatment characteristics due to the change of the state such as the adsorption, etc., of moisture and impurities on the inwall of the treating chamber 4 can be avoided in the exchange of the lamps at a time when the lifetime of the lamp expires. The down-time of the device required for exchange can be shortened largely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention involves supplying light, a reactive gas, a cleaning liquid, etc. to the surface of a solid such as a semiconductor to cause a surface reaction, thereby forming a film.

This relates to surface treatment equipment that performs etching, ashing, cleaning, etc.

[Conventional technology]

Generally, optical ashing and optical CVD in semiconductor manufacturing process
Surface treatment methods such as these have advantages such as less damage than plasma treatment methods and the equipment used requires a simpler configuration, so their range of use is increasing. Furthermore, optical cleaning is being put into practical use in industrial fields that require precision cleaning.

These optical processing methods include processing at approximately atmospheric pressure, such as optical ashing and optical cleaning, and processing in vacuum, such as photo-CVD.

Conventional examples and problems in the case of optical CVD apparatuses will be summarized below.

``Unexamined Japanese Patent Publication No. 62-50467'' has a housing whose front surface is covered with a quartz plate and which is equipped with a diffused reflection mirror and a light source, facing the substrate to be processed. A thin film with a uniform thickness is formed on the surface of the substrate by forming a reaction gas and blowing out the reaction gas. In this example, the light source is placed in a vacuum atmosphere due to its structure. For this reason, the thickness of the quartz plate can be reduced to less than a few inches, but in this case, it becomes difficult to control the temperature of the light source, which affects the performance of the light source, and there is a problem that the performance and lifespan may fluctuate or deteriorate.

[Unexamined Japanese Patent Publication No. 63-29927] discloses a method in which a light source is placed on the atmospheric pressure side and irradiates the substrate surface in a vacuum processing chamber through a quartz plate window.

``Unexamined Japanese Patent Publication No. 62-81020 J discloses that the outside of a light source inserted into a vacuum processing chamber is perforated in order to prevent reaction products from adhering to the outside surface of the light source and deteriorating the transmission of light from the light source. The light source is surrounded by a transparent cylindrical body to form a double structure, and the surface of the light source is gas-shielded.In this example, since the inside of the perforated transparent cylindrical body is almost in a vacuum atmosphere, the light source is It is exposed to the atmosphere inside the vacuum processing chamber.

[Problem to be solved by the invention]

Among the above conventional techniques, in the case of JP-A-62-50467, JP-A-62-81020, etc., the outside of the ultraviolet lamp used as a light source is in a vacuum, so there are the following problems. Ta.

l) The airtight structure of the feedthrough for supplying power to the lamp becomes complicated, which increases manufacturing costs and tends to reduce reliability.

2) Heat transfer is reduced due to the vacuum atmosphere around the lamp, and controllability of the temperature at the coldest point of the lamp, which affects the illuminance of the lamp, becomes poor, and the illuminance fluctuates, making the reaction speed likely to become unstable.

3) Cooling of the arc tube becomes insufficient and the temperature rises.
Lamp life tends to be shortened.

4) Due to the complicated structure of the lamp, it is difficult to clean the dirt that adheres to the lamp during the treatment process.

5) It is necessary to break the vacuum in the processing equipment each time the lamp is replaced, which increases the downtime of the equipment, and the processing characteristics are likely to be affected by deterioration of vacuum performance.

On the other hand, in the case of JP-A No. 63-29927, the pressure difference between both sides of the quartz plate is about 1 atmosphere, so the thickness of the quartz plate must be about 15 mm or more to ensure strength. Since the transmittance of ultraviolet rays is generally inversely proportional to the thickness of the quartz plate, if left as it is, the amount of transmitted light would be significantly reduced5, leading to a problem that the thin film formation speed, that is, the processing speed would be significantly reduced.

The purpose of the present invention is to have a simple structure of the light source section, be able to reliably control the lamp's lowest point temperature, enable sufficient cooling, and be easy to clean, regardless of whether the light source is in a vacuum atmosphere or an atmospheric pressure atmosphere. , there is no need to break the vacuum when replacing the lamp,
Moreover, it is an object of the present invention to provide a surface treatment device that can reduce the thickness of a light transmission window to several meters or less.

[Means to solve the problem]

The above object is to provide a sheath that transmits light and is airtight or vacuum resistant to the inside of the reaction processing chamber, inserts a light source into the sheath, and includes means for introducing and discharging a fluid into the sheath. This is achieved by

[Effect]

A bag-shaped or tubular sheath is attached near the object to be treated in the processing chamber of the surface treatment apparatus, and a lamp is inserted into the sheath. As a result, the light necessary for processing is emitted from the lamp, passes through the sheath, and is irradiated onto the surface of the object to be processed within the processing chamber. Since the lamp is isolated from the atmosphere of the processing chamber, such as a vacuum, there is no need for an airtight maintenance mechanism for the lamp power supply section. In other words, the lamp structure can be almost the same as that of conventional lamps for atmospheric pressure processing.By cooling the lamp by flowing gas inside the sheath, the temperature of the lamp tube wall is prevented from rising excessively, and this reduces the lamp's lifespan. It can be prevented. In the case of an ultraviolet lamp, the purpose can be achieved by making the sheath made of synthetic quartz and flowing nitrogen into the inside of the sheath.

Furthermore, by varying the type of gas flowing inside the sheath, the wavelength of the light irradiated into the processing chamber can be controlled, so the reaction conditions can also be varied.

Since the lamp is isolated from the atmosphere of the processing chamber, there is no need to open the inside of the processing chamber to the atmosphere when replacing the lamp, and deterioration of processing characteristics due to the influence of moisture in the atmosphere can be prevented.

The simple shape of the sheath allows for easy cleaning if the outer surface becomes dirty.

〔Example〕

The configuration of one embodiment of the present invention is shown in FIGS. 1, 2, and 3 below.
This will be explained with reference to FIGS. 4 and 5.

Note that FIG. 1 shows a plan sectional view of the lamp unit portion of the surface treatment apparatus of the present invention. FIG. 2 shows a sectional view taken along the line AA in FIG. Figure 3 shows the lamp unit 4 in Figure 1.
1 shows a top view of a surface treatment apparatus incorporating a set of FIG. 4 shows a sectional view taken along line BB in FIG. FIG. 5 shows how the lamp is attached and detached.

A quartz sheath 2 is attached to a processing chamber 4, most of which is not shown in FIG. 1, through a seal 3 in a vacuum-proof manner. Scabbard 2
The light emitting part 1a of the ultraviolet lamp 1 is inserted into the inside of the holder, and the lamp base 1b is brought into close contact with the flange part 2b of the sheath 2.

The lamp base 1b is provided with a gas introduction path 1c and a gas exhaust path 1d.

Further, a reflector 2C is attached to one inside surface of the sheath 2.

3 and 4 show the workpiece 6 placed on the stage 5.
This figure shows a case in which four sets of the lamp units shown in FIG. 1 are arranged above the lamp unit.

In this embodiment, the operation of the above structure will be explained using optical CVD. The ultraviolet lamp 1 is lit by receiving power from a lighting power source (not shown), and ultraviolet light is emitted from the light emitting portion 1a. Since the space between the light emitting part 1a and the sheath 2 is filled with nitrogen introduced from the gas introduction path 1c, the emitted ultraviolet rays are not absorbed in this space and are processed by passing through the sheath 2. The object to be treated 6 on the stage 5 in the chamber 4 is irradiated with the light to perform surface treatment. Incidentally, among the ultraviolet rays emitted from the light emitting part 1a, the ultraviolet rays emitted from the object to be treated 6 and the reflection side are reflected by the reflector 2c to increase the efficiency of irradiation to the object to be treated 6 and to prevent unnecessary irradiation to unnecessary parts. By preventing the reaction, it acts to suppress the progress of the reaction in unnecessary parts.

On the other hand, the lamp generates a large amount of heat, and if left as it is, mercury oxide will form and adhere to the inner wall of the lamp's arc tube, causing the illumination intensity of ultraviolet rays to rapidly decrease, resulting in a shortened lifespan. In order to prevent the lamp from overheating, nitrogen gas is introduced into the sheath 2 through the gas introduction path 1c and is discharged through the gas exhaust path 1d while cooling the lamp. In this case, the temperature of the lamp can be appropriately adjusted by adjusting the flow rate of nitrogen gas.

When the lamp reaches the end of its life, lamp replacement is completed by removing the ultraviolet lamp 1 from the sheath 2 and inserting and fixing another ultraviolet lamp 1'. In this case, there is no need to break the vacuum inside the processing chamber 4 and expose the processing chamber 4 to the atmosphere, so it is possible to avoid deterioration of surface treatment characteristics due to changes in conditions such as adsorption of moisture and impurities to the inner wall of the processing chamber 4. . Furthermore, the downtime of the device required for replacement can be significantly reduced.

In the case of an apparatus for forming a thin film, such as a photo-CVD apparatus, the raw material gas reacts in a gas layer, so that products are deposited not only on the object to be processed but also on the inner wall of the processing chamber and the surface of the lamp. If it accumulates on the lamp surface, the illuminance of ultraviolet rays will decrease and the performance will deteriorate, so to prevent this, it is necessary to periodically clean it. In the case of this embodiment, the sheath 2 has a simple shape and can have sufficient strength, so that cleaning can be performed easily and with good workability.

Another embodiment of the invention is shown in FIGS. 6 and 7.

In this embodiment, the sheath 2 has a circular cross section, and units in which straight tube lamps are inserted inside the sheath 2 are arranged in the processing chamber 4. In the case of this configuration, by making the cross-sectional shape of the sheath 2 circular, the tube thickness of the sheath 2 can be reduced to a minimum mechanically, which has the effect of minimizing the decrease in illuminance when ultraviolet rays pass through the sheath 2. .

Another embodiment of the invention is shown in FIG. In this embodiment, the sheath 2 has a rectangular cross section, and units in which straight tube lamps are inserted inside the sheath 2 are arranged above the object to be processed 6 in the processing chamber 4. By providing a gap between each lamp unit and pouring the reaction gas in the form of a shower onto the workpiece 6 from this gap, there is an effect of improving the uniformity of the surface treatment rate on the workpiece 6. Incidentally, since the lower surface of the sheath 2 is flat, there is also the effect that the flow of the reaction gas can be easily controlled. Also sheath 2
It also has the effect of making it easier to clean when the outer surface becomes dirty. Furthermore, by rotating the ultraviolet reflector 2b inside the sheath 2 and directing the ultraviolet rays upward, it also functions as a light shutter, blocking ultraviolet rays from the object 6 to be treated, so that the surface treatment reaction can be instantaneously carried out. It also has the effect of suppressing or stopping it.

This effect is due to the characteristics of light sources such as ultraviolet lamps, which do not stabilize immediately even after power is supplied and require a warm-up period of about 30 minutes. Considering how difficult it is, this is a very useful effect.

Another embodiment of the invention is shown in FIG. In this embodiment, the sheath 2 has a rectangular cross section, and a unit in which U-shaped lamps are inserted inside the sheath 2 is arranged above the workpiece 6 in the processing chamber 4. A gap similar to that shown in FIG. 8 is provided between each lamp unit, and the reaction gas is poured into the object 6 from this gap in the form of a shower. The cross-sectional shape of the sheath 2 may be oval.

Another embodiment of the invention is shown in FIG. In this embodiment, a plurality of sheaths are integrated into a plate shape, with one side facing the processing chamber and the other side facing the atmosphere. In the case of this embodiment, since the inner surface of the light transmitting window 7 can be made completely flat, it has the effect of being able to relatively easily handle large-area objects to be processed. Furthermore, since the vacuum seal structure between the processing chamber main body and the transmission window is simplified, reliability against leakage is increased, and the manufacturing cost of the apparatus can also be reduced.

Another embodiment of the invention is shown in FIG. This embodiment is similar in form to the embodiment shown in FIG. 10, but the thickness of the light-transmitting window 7 is significantly reduced by attaching a reinforcing body 8 to the atmosphere side of the light-transmitting window. be. This can prevent a decrease in processing speed due to a decrease in the illuminance of the light emitted into the processing chamber. Note that the reinforcing body 8 is a light transmitting window 7.
Although a structure is shown in which a member made of a different material is fixed to the light transmitting window 7, it may be an integral structure of the same material as the light transmitting window 7. In the case of this embodiment, since the shape of the reinforcing body 8 can be determined to a certain extent, there are fewer restrictions on the shape and dimensions of the light source, which has the effect of facilitating the design of the device.

Next, FIG. 1 shows an example of the surface treatment method of the present invention.

This will be explained using FIG. 2 and FIG. 12. Nitrogen gas is supplied to the inside of the sheath 2 from the gas introduction path 1c in FIG. 1 to create a nitrogen gas atmosphere inside the sheath 2. Note that the nitrogen gas that has cooled the ultraviolet lamp 1 is exhausted to the outside from the gas exhaust path 1d.

In this case, the ultraviolet rays emitted from the ultraviolet lamp pass through the sheath 2 and are emitted to the outside without being absorbed by the nitrogen gas. When the gas supplied here is replaced with oxygen gas or air from nitrogen gas, the ultraviolet rays are now absorbed by the oxygen gas, so the amount of radiation emitted from the sheath 2 to the outside becomes smaller and the reaction rate decreases. An example of the relationship between the oxygen ratio and the illuminance ratio in this case is shown in FIG. This allows the reaction rate in the process to be controlled. It goes without saying that by adjusting the type and components of the gas supplied into the sheath 2, more advanced control of process conditions is possible.

Other embodiments of the surface treatment method of the present invention are shown in FIGS.
This will be explained using Figure 4. In FIG. 13, a flow rate adjusting means 10 is provided in the piping for supplying nitrogen and oxygen gas into the sheath 2. On the other hand, the intensity of the ultraviolet rays emitted from the sheath 2 is detected by the illuminance monitor 11, and the signal is taken into the control section 12. The opening degree of the flow rate adjusting means 10 is adjusted according to the signal strength of the illuminance monitor.

As a result, as shown in FIG. 14, the oxygen concentration ratio in the mixed gas of nitrogen and oxygen is successively changed so that the illuminance of the ultraviolet rays irradiated onto the object 6 to be treated is constant. This makes it possible to obtain constant illuminance, that is, processing characteristics, for a long period of time until the light source reaches the end of its lifespan, so that stable processing with good reproducibility becomes possible.

〔Effect of the invention〕

According to the present invention, the structure of the light source is simple, the temperature of the lamp's coldest point can be controlled reliably, sufficient cooling is possible, the surface treatment device is easy to clean, and there is no need to break the vacuum when replacing the lamp. Because you can get high illumination, high performance,
The effect of realizing a highly reliable, long-life, and low-cost light source section and a surface treatment device incorporating the same can be obtained.

By preventing irradiation to unnecessary parts, the effect of suppressing the reaction progress in unnecessary parts can also be obtained.

Since there is no need to break the vacuum in the processing chamber and expose the processing chamber to the atmosphere when replacing lamps, it is possible to avoid deterioration of surface treatment characteristics due to changes in conditions such as moisture and impurity adsorption on the walls of the processing chamber, improving product yield. This is a great effect. Furthermore, the downtime of the equipment required for lamp replacement can be significantly reduced, resulting in the effect of improving productivity.

By adjusting the type and component ratio of the gas flowing inside the sheath, the spectrum of the light emitted to the outside of the sheath can be changed, which also has the effect of easily controlling the processing characteristics of the object to be processed. If this function is used to an extreme, if almost all of the light is absorbed by the gas, no light will be able to pass through, so it can be used as a light shutter.

In addition, by rotating the reflector plate and making it function as a light shutter, it is possible to block ultraviolet rays from being applied to the object to be treated, which has the effect of instantly suppressing or stopping the surface treatment reaction.

By pouring the reaction gas in the form of a shower onto the object to be treated, there is an effect of improving the uniformity of the surface treatment rate on the object to be treated.

[Brief explanation of drawings]

FIG. 1 is a plan sectional view of a lamp unit portion of the surface treatment apparatus of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. Fig. 3 is a plan view of a surface treatment device incorporating the four sets of lamp units shown in Fig. 1, Fig. 4 is a sectional view taken along line BB in Fig. 3, and Fig. 5 is a lamp attachment/detachment in the embodiment shown in Fig. 3. FIG. 6 is a diagram showing another embodiment of the present invention. FIG. 7 is a plan view of the embodiment shown in FIG.
11 are diagrams showing other embodiments of the present invention, FIG.
Fig. 2 is a time chart of an embodiment of the surface treatment method of the present invention, Fig. 13 is a diagram showing an example of a system configuration of an embodiment of the surface treatment apparatus of the present invention, and Fig. 14 is a diagram showing the implementation of the surface treatment method of the present invention. It is an explanatory diagram of functions and effects in an example. 1.1'...Ultraviolet lamp, 1a...Light emitting part, 1b
...Lamp base, 1c...Gas introduction path, 1d...
Gas discharge path, 2...Sheath, 2a...Sheath part, 2b...
flange part. 2c...Reflector, 3...Seal, 4...Processing chamber, 5...
・Stage, 6... Processing object, 7... Light transmission window, 8
... Reinforcement body, 10... Flow rate adjustment means.

Claims (1)

[Claims] 1. A surface treatment device that performs a reaction treatment by bringing a reaction gas into contact with the surface of a solid and irradiating it with light, which transmits light and is airtight or vacuum resistant to the reaction treatment chamber. 1. A surface treatment device, comprising: a sheath attached thereto; a light source inserted into the sheath; and means for introducing and discharging a fluid into the sheath. 2. The surface treatment apparatus according to claim 1, wherein the light source is an ultraviolet lamp. 3. The surface treatment apparatus according to claim 1, wherein the sheath is made of quartz. 4. The surface treatment device according to claim 1, wherein the sheath is bag-shaped. 5. The surface treatment device according to claim 1, wherein the sheath is tubular. 6. The surface treatment apparatus according to claim 1, wherein the sheath has a form into which a plurality of light sources can be inserted. 7. Claim 1, wherein the fluid introduced into the sheath is a single-component or multi-component fluid.
The surface treatment device described in Section 1. 8. The surface treatment apparatus according to claim 1, wherein the fluid introduced into the sheath is a fluid having a property of controlling the wavelength of light generated by the light source. 9. The surface treatment apparatus according to claim 1, wherein the fluid introduced into the sheath is a fluid that does not absorb ultraviolet rays. 10. The surface treatment apparatus according to claim 1, wherein the fluid introduced into the sheath is nitrogen. 11. A light source unit comprising a light source, a sheath, and a gas introduction/exhaust means. 12. The surface treatment apparatus according to claim 1, wherein a reflector is provided inside the sheath. 13. The surface treatment apparatus according to claim 1, wherein the reflector has a structure that rotates or moves inside the sheath. 14. The surface treatment according to claim 1, wherein the illuminance of the light applied to the object to be treated is controlled to be constant or arbitrary by controlling the composition of the gas supplied to the inside of the sheath. Device.