JPH08262251A - Film forming device for optical waveguide - Google Patents

Abstract

PURPOSE: To provide an efficient film forming device for an optical waveguide in which a desired optical waveguide pattern can be formed without etching processing. CONSTITUTION: In this device, an IR laser genrator 57 emits laser light of <=1μm wavelength, which is made uniform by an optical system 59. The uniform laser light beams transmit a mask 55 in which the optical waveguide pattern is plotted to project the waveguide pattern on a wafer 23. The wafer 23 is mounted on a stage 21 in a chamber 3 the inside of which is sealed. The laser beams irradiates the wafer 23 through a light entrance window 11 of the chamber 3. The stage 21 where the wafer 23 is mounted is equipped with a cooling device 25 to cool the wafer 23. Plasma is generated by supplying at least two kinds of gasses to the wafer 23 through two or more groups of gas supply pipings 31, 35 and applying high frequency power to an antenna 41 from a high frequency power supply 51 for generation of plasma and through a matching box 49.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide film forming apparatus, and more particularly to an optical optical waveguide film forming apparatus using a laser beam.

[0002]

2. Description of the Related Art A conventional optical waveguide manufacturing method will be described with reference to FIG. First, a substrate 101 such as a silicon wafer or quartz is prepared (step SA1), and a SiO ₂ film having a thickness of about 20 μm is deposited on the entire surface of the substrate 101 to form the lower clad layer 1
03 is formed (step SA2). This deposition method will be described later.

Next, a Ge-SiO ₂ film containing several mol% of Ge is deposited on the entire upper surface of the lower clad layer 103 by 5 μm to form a core layer 105A which is an optical waveguide through which light passes ( In step SA3), the resist 107A is applied to the entire upper surface of the core layer 105A with an appropriate thickness (step SA4). The thickness of the core layer 105A and the thickness of the lower clad layer 103 are determined by the wavelength of light passing through the core layer 105A.

After the resist 107A is applied, the resist 107 is applied through a mask 109 on which an optical waveguide pattern is drawn.
The upper surface of A is irradiated with UV light 111 (step SA
5). The resist 107A has a positive type and a negative type,
For example, in the case of a positive type, UV light 1 is generated by the mask 109.
The portion irradiated with 11 is exposed to light and becomes soluble in the alkaline solution. That is, the exposed portion is removed by immersing it in an alkaline solution, and the unexposed portion 107B remains on the core layer 105A (step SA).
6).

Next, RIE (reactive ion etching)
The dry etching process as described above is performed. As a result, a part of the core layer 105A is removed, and the core layer 1 having the same pattern as the mask 109 is formed on the lower clad layer 103.
05B is formed (step SA7), and the resist 107 is formed.
B is removed (step SA8). Finally, the core layer 10
5B, a SiO ₂ film is deposited on the upper clad layer 11
3 is formed (step SA9). The upper clad layer 113 has a thickness of 20 μm, like the lower clad layer 103 described above.
It has a film thickness of m 3, and this thickness is largely related to the wavelength of light passing through the core layer 105B.

Further, the core layer 105B contains Ge as compared with the upper and lower clad layers 113 and 103, so that the refractive index is increased by that amount, and the light traveling in the core layer 105B does not leak, so that an optical signal is transmitted. It will propagate faithfully.

Next, the formation of the above-mentioned cladding layers 113, 103 and core layers 105A, 105B will be described separately for the film forming step and the etching step.

[0008] There is no method for forming a film, which has not been fixed yet. The method most often used is the flame deposition method (referred to as FHD method) shown in FIG.

Referring to FIG. 3, this method uses a multi-tube nozzle 119 having an outer nozzle 117 around an inner nozzle 115. The inner nozzle 115 ejects a mixed gas of H ₂ and O ₂ , and the outer nozzle 117 ejects SiCl ₄ gas and GeCl.
₄ Eject gas.

First, the substrate 101 is placed on the heater 123 driven by the power supply 121, and the power supply 121 is turned on. When the substrate 101 reaches a predetermined temperature, the inner nozzle 11
A mixed gas of H ₂ and O ₂ is ejected from 5 to ignite. Then the outer nozzle 117 is ejected with SiCl ₄ gas, SiCl ₄
And O ₂ react in a flame. This makes suit 1
A cloudy film called 25 is deposited on the substrate 101.
The substrate 101 on which the soot 125 is deposited is heated to 1000 ° C.
When heated to the vicinity, the cloudy soot 125 is vitrified and transparent clad layers 113 and 103 are obtained.

In addition, when depositing the core layer 105, GeCl ₄ is added from the outer nozzle 117 in addition to SiCl ₄ gas.
Eject gas. At this time, if the amount of GeCl ₄ gas jetted is set to an appropriate amount, the core layer 1 containing a small amount of Ge in the SiO ₂ film 1
05 is formed.

However, the above FHD method has the following problems. That is, the workability is poor because the process has two processes, the soot 125 deposition process and the vitrification process.

If the substrate 101 made of silicon, for example, is heated to around 1000 ° C. in the vitrification step, tensile stress may be generated in the film due to the difference in the coefficient of thermal expansion and the film may be damaged.

As is generally known, the strength of the silicon substrate 101 drastically decreases at around 800 ° C., so unless the temperature distribution is kept within a few ° C., a crystal defect called slip due to thermal stress occurs. There is a problem of causing.
Furthermore, the distribution becomes more severe as the wafer diameter increases.

In the future, it is desired that the optical waveguide has an electric element such as a transistor and an optical element housed in one substrate, but Al or the like is used for wiring of the transistor or the like. At a temperature of 400 ° C. or higher, this Al or the like may react with the silicon substrate 101.

Due to the above problems, the FHD method is not generally used for such a device.

Therefore, the utilization of the plasma CVD method used in the semiconductor manufacturing process has been studied in recent years.

Hereinafter, generally used plasma CV
The D method will be described.

FIG. 4 shows a parallel plate type plasma CVD apparatus 127 which is the most general apparatus used in the plasma CVD method. Here, the upper and lower clad layers 11
A case where the SiO ₂ films of 3 and 103 are formed on the wafer 129 will be described as an example.

A pair of parallel plate type electrodes 133U and 133L facing each other are provided inside a plasma CVD chamber 131 for blocking the outside air during crystal growth, and a wafer 129 is placed on the lower electrode 133L. Is posted. The upper electrode 133U is connected to the matching box 139 through an insulator 137 provided so as to penetrate the chamber upper lid 135, and is further connected to the high frequency power supply 14
Connected to 1. This matching box 139
Is for efficiently supplying the power supplied from the high frequency power supply 141 into the chamber 131. Further, the lower electrode 133L is provided with a rotating device 143,
The wafer 129 is rotated by rotating the lower electrode 133L.
This is for ensuring the uniformity of the SiO ₂ film formed on the substrate.

The chamber lower lid 145 is provided with a high vacuum exhaust system 147 for exhausting back pressure after completion of CVD and a low vacuum exhaust system 149 for exhausting supply gas during CVD. The high vacuum exhaust system 147 for vacuuming the back pressure is provided with an exhaust valve 151 for intermediate exhaust, and is connected to a high vacuum exhaust device 153 such as a turbo molecular pump.

On the other hand, a low vacuum exhaust system 149 for exhausting the supply gas
The exhaust valve 155 and the chamber 13
Throttle valve 1 for keeping the pressure inside 1 constant
57 is provided and is connected to a relatively low vacuum exhaust device 159 such as a rotary pump, a dry pump, or a mechanical booster pump.

Gas supply pipes 161 and 163 are attached to the chamber upper lid 135. here,
The gas supply pipe 161 is dichlorosilane (SiH ₂ Cl ₂ ).
The gas supply pipe 163 is for oxygen (O ₂ ). Therefore, the gas supply pipes 161 and 1
63 is a valve 1 for supplying dichlorosilane gas
65, a valve 167 for oxygen supply is provided.

The chamber 131 is provided with a loading / unloading port 169 for the wafer 129, and the loading / unloading of the wafer 129 is possible by opening / closing the valve 171.

Inside the chamber 131, the lower electrode 133L
Heater block 17 for heating the upper wafer 129
3 are provided, and the heater block 173 is connected to the heater power supply 141. The temperature at this time can be confirmed by a thermometer 175.

Next, the operation of the above plasma CVD apparatus 127 will be described. First, port 1 for loading / unloading
The valve 171 of 69 is opened to introduce a predetermined number of wafers 129 into the chamber 131, and then the valve 171 is closed. The exhaust valve 151 is opened, and the exhaust device 153, that is, the exhaust system 147 for high vacuum is evacuated to a vacuum degree of about 10 ⁻⁶ Torr. At the same time, the heater block 173 is heated to heat the lower electrode 133L and the wafer 129. At this time, the pressure inside the chamber 131 is checked at any time by a vacuum switch or an ionization vacuum gauge, and is usually 30
Heat to 0-400 ° C. Also, in order to heat the lower electrode 133L uniformly, the lower electrode 133L is installed in the rotating device 1.
It is rotationally driven by 43.

Subsequently, the dichlorosilane gas supply valve 165 of the gas supply pipe 161 is opened to supply the dichlorosilane gas into the chamber 131, and then the oxygen supply valve 167 of the gas supply pipe 163 is supplied.
Oxygen gas is supplied into the chamber 131 by opening. The exhaust of the chamber 131 at this time is performed by using an exhaust system 149 for low vacuum.

The normal gas supply amount is about several hundred SccM in total, and the pressure is on the order of 0.1 Torr to several Torr. The final pressure adjustment is performed by adjusting the opening of the throttle valve 157.

After supplying a predetermined gas at a predetermined flow rate and adjusting the pressure in the chamber 131 to a predetermined pressure as described above, the high frequency power supply 141 is turned on to supply electric power through the matching box 139 to the upper electrode. Supply to 133U. The electric power is generally about several hundred W. At this time, the matching box 139 is adjusted in advance, and the reflected power to the high frequency power source 141 is suppressed to zero or as small as possible.

As a result, plasma 177 is formed between the upper and lower electrodes 133U and 133L, and dichlorosilane gas and oxygen gas are decomposed and synthesized in the plasma 177 to form a SiO ₂ film on the wafer 129. . At this time, particularly when a gas containing Cl such as dichlorosilane is used, an intermediate product (chloride) of SiCl _X is generated in the electrode 133.
U, 133L and the inner wall of the chamber 131,
During the process, it adheres on the wafer 129 and causes deterioration of the film quality, and when the chamber 131 is opened to the atmosphere, it reacts with moisture in the air to generate HCl, which may impair the safety of the operator. In particular, the deterioration of the film quality due to chloride has a great influence.

Finally, when the above process is completed, the valves 165 and 167 are closed, the exhaust system 147 evacuates to a high vacuum, and the unprocessed wafer 129 is purged to remove the processed wafer 129 from the chamber 131. Take out. At the same time, the unprocessed wafer 129 is transferred to the chamber 13
1 and repeat the above process.

According to such a method, the vitrification step as in the FHD method is unnecessary, and the manufacturing process is simplified. Further, since the treatment can be performed at a heating temperature of 300 to 400 ° C., the problem of slippage and cracking due to the difference in thermal expansion from the substrate can be solved.

Next, a conventional plasma etching apparatus 179 will be described with reference to FIG. The plasma etching apparatus 179 is similar to the plasma CVD apparatus 127 described above, except that the gas to be used, the electrodes 181U and 181L for applying a high frequency, and the wafer 129 are cooled.

Here, patterning etching of the core layer 105 will be described as an example.

Inside the plasma etching chamber 183, a pair of parallel plate type electrodes 181U, 1 facing each other are provided.
81L is provided, and the wafer 129 is placed on the lower electrode 181L. This lower electrode 181L
Is connected to the matching box 189 through an insulator 187 provided through the chamber lower lid 185, and is further connected to a high frequency power source 191. Also,
The lower electrode 181L is provided with a rotating device 193, and by rotating the lower electrode 181L, the wafer 1
This is for ensuring the uniformity of the etching rate of the SiO ₂ film formed on the film 29.

The chamber lower lid 185 is provided with a back pressure evacuation exhaust system 195 and a supply gas exhaust exhaust system 197. An exhaust valve 199 is provided in the middle of the exhaust system 195 for vacuuming the back pressure.
Connected to 1.

On the other hand, the exhaust system 197 for exhausting the supply gas is provided with a midway exhaust valve 201 and a throttle valve 203 for maintaining a constant pressure in the chamber 183, such as a rotary pump, a dry pump or a mechanical booster pump. Is connected to the exhaust device 207 for relatively low vacuum.

Gas supply pipes 211 and 213 are attached to the chamber upper lid 209. here,
The pipe 211 is, for example, a pipe for carbon tetrafluoride (CF ₄ ) gas, and the pipe 213 is for argon (Ar) gas. Therefore, each of the pipes 211 and 213 has carbon tetrafluoride.
A (CF ₄ ) gas supply valve 215 and an argon (Ar) gas supply valve 217 are provided.

The chamber 183 is provided with a loading / unloading port 219 for the wafer 129,
The wafer 129 can be loaded / unloaded by opening / closing the valve 221.

A cooling unit 22 is provided inside the chamber 183.
3 is provided, and the cooling water is supplied from the cooling water inlet 225 and drained from the cooling water outlet 227. Thereby, the wafer 129 on the lower electrode 181L is cooled. The temperature at this time can be confirmed with a thermometer 229.

Next, the operation of the plasma etching apparatus 179 will be described. First, the valve 221 is opened and a predetermined number of wafers 129 are loaded from the loading / unloading port 219.
Is introduced into the chamber 183, the valve 221 is closed. The exhaust valve 199 is opened, and the exhaust device 201, that is, the exhaust system 195, evacuates to a vacuum degree of about 10 ⁻⁶ Torr. At this time, the pressure inside the chamber 183 is checked at any time by a vacuum switch or an ionization vacuum gauge.

At the same time, the cooling unit 223 is cooled by the cooling water supplied from the cooling water inlet 225 to cool the lower electrode 181L and the wafer 129 to a predetermined temperature. The temperature at this time is checked with a thermometer 229 from time to time, but normally 30
Cool to a temperature of 0-400 ° C. Further, in order to ensure the temperature uniformity of the lower electrode 181L, the lower electrode 181L is rotationally driven by the rotating device 193.

Next, carbon tetrafluoride (C
F ₄ ) ₄ by opening the valve 215 for gas supply
A fluorocarbon (CF ₄ ) gas is supplied into the chamber 183,
Then, the valve 217 for supplying argon (Ar) gas in the gas pipe 213 is opened to supply the argon (Ar) gas into the chamber 183. The exhaust of the chamber 183 at this time is performed using the exhaust system 197.

The normal gas supply amount is about several hundred SccM in total, and the pressure is on the order of 0.1 Torr to several Torr. The final pressure adjustment is performed by adjusting the opening of the throttle valve 205.

After the predetermined gas is supplied at the predetermined flow rate ratio and the pressure inside the chamber 183 is adjusted to the predetermined pressure as described above, the high frequency power source 191 is turned on and the power is supplied through the matching box 189 to the lower electrode. Supply to 181L. The electric power is generally about several hundred W. At this time, the matching box 189 is adjusted in advance, and the reflected power to the high frequency power source 191 is suppressed to zero or as small as possible.

As a result, the upper and lower electrodes 181U, 181L
Plasma 231 is formed between them, and this plasma 231
Carbon tetrafluoride (CF ₄ ) gas and argon (Ar) gas are decomposed therein to etch the SiO ₂ film on the wafer 129.

Finally, when the above process is completed, the valves 215 and 217 are closed, the exhaust system 195 is evacuated to a high vacuum, and the unprocessed wafer 129 is purged by the purging means (not shown). Take it out. At the same time, the unprocessed wafer 129 is the chamber 1
It is loaded into 83 and the above process is repeated.

[0048]

However, such a conventional technique has the following problems. That is, in the parallel plate plasma CVD method, the plasma CVD device 12 used in the semiconductor process is used.
The film-forming speed of No. 7 is at most about 5000Å / min,
It takes 20 minutes to form a 10 μm thick oxide film.
Therefore, it takes 40 minutes to form the upper cladding layer 113, 40 minutes to form the lower cladding layer 103, and 10 minutes to form the core layer 105, for a total of 90 minutes. This is a problem in terms of productivity, assuming that the future optical waveguide device production will be comparable to that of semiconductor devices.

The SiO ₂ film formed by the plasma CVD apparatus 127 of the above technique is a pore film as compared with the thermal oxide film.

There is a problem that it is difficult to maintain the ratio of Si and O because it is a porous film, and therefore it is difficult to make the refractive index, which is important for an optical waveguide, to its original value.

Further, the above-mentioned parallel plate type plasma etching method has the following problems. That is,
Plasma etching rate is at most 10,000Å / min
It takes about 10 minutes to etch an oxide film having a thickness of 10 μm. Therefore, assuming that the future optical waveguide device production volume will be comparable to that of semiconductor devices, productivity will be a problem.

An object of the present invention was made in view of the above-mentioned conventional techniques, and it is an object of the present invention to provide an efficient optical waveguide film forming apparatus.

[0053]

In order to achieve the above object, an optical waveguide film forming apparatus of the invention according to claim 1 has a thickness of 1 μm.
An infrared laser generator that irradiates laser light with a wavelength of m or less, and an optical device that is provided to uniformly irradiate the laser light from this infrared laser generator onto a flat work on which an optical waveguide is formed. A system, a mask provided for projecting an optical waveguide pattern on the flat work by the laser light from the optical system, a high frequency power source for plasma generation and a matching box, and a light introduction window for introducing the laser light. And a chamber for maintaining airtightness inside, wherein the chamber has a stage for mounting and fixing the flat work, a cooling means for cooling the stage, and at least two types of facing the flat work. It is characterized by comprising two or more sets of gas supply pipes for supplying gas and an antenna for generating plasma by the high frequency power supply.

An optical waveguide film forming apparatus according to a second aspect of the present invention is characterized in that the infrared laser generator according to the first aspect is an Ar + laser generator.

The optical waveguide film forming apparatus of the invention according to claim 3 is characterized in that the infrared laser generator according to claim 1 is a combination of an Ar + laser generator and a CO ₂ laser generator.

The optical waveguide film forming apparatus of the invention according to claim 4 is characterized in that the laser light according to claims 1, 2 and 3 is periodically irradiated.

According to a fifth aspect of the invention, there is provided the optical waveguide film forming apparatus, wherein the antenna according to the first aspect is provided inside the gas supply pipe.

The optical waveguide film forming apparatus of the invention according to claim 6 is characterized in that the antenna according to claims 1 and 5 is covered with a SiO ₂ film.

The optical waveguide film forming apparatus of the invention according to claim 7 is characterized in that the light introduction window according to claim 1 and the mask are integrally provided.

[0060]

In the optical waveguide film forming apparatus according to claim 1, the infrared light laser generator irradiates laser light having a wavelength of 1 μm or less,
An optical system makes the irradiated laser light uniform. The uniformized laser light passes through the mask on which the optical waveguide pattern is drawn and projects the optical waveguide pattern on the flat work. The flat plate-shaped work is placed on a stage in a chamber that maintains airtightness inside, and the laser light is emitted from a light introduction window of the chamber. The stage on which the flat work is placed is provided with a cooling device, which cools the flat work. Further, two or more sets of gas supply pipes supply at least two types of gas toward the flat work, and a high frequency power source for plasma generation and an antenna supplied with high frequency power by a matching box generate plasma to generate gas. Decompose or synthesize.

In the optical waveguide film forming apparatus according to the second aspect, the infrared laser generator generates the Ar + laser.

In the optical waveguide film forming apparatus according to the third aspect, since the infrared laser generator is a combination of the Ar + laser generator and the CO ₂ laser generator, both laser lights can be selectively irradiated.

In the optical waveguide film forming apparatus according to the fourth aspect, since the laser light is periodically irradiated, the range of heat conduction from the portion where the temperature is raised by the irradiation of the laser light can be reduced.

In the optical waveguide film forming apparatus according to the fifth aspect, since the antenna is provided inside the gas supply pipe,
The temperature rise due to the laser light can be prevented.

In the optical waveguide film forming apparatus according to the sixth aspect, since the antenna is covered with the SiO ₂ film, it is possible to prevent sputtering when plasma is formed.

Further, in the optical waveguide film forming apparatus according to the seventh aspect, the light introducing window and the mask are integrally provided,
The laser light passes through the light introduction window to project the optical waveguide pattern.

[0067]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an optical waveguide film forming apparatus 1 according to the present invention. In FIG. 1, an upper lid 5 and a lower lid 7 are attached to a chamber 3 which is a reaction chamber so that the inside can be kept airtight.

An opening 9 is provided in the center of the upper lid 5, and the light introducing window 1 for transmitting the laser beam is provided in the opening 9.
1 is attached by an O-ring 13 in a state where airtightness is maintained. Since the heat resistance of the O-ring 13 is about 200 ° C., the upper lid 5 is provided with a cooling chamber 15 for cooling the O-ring 13. The cooling chamber 15 is for cooling the upper lid 5 by injecting cooling water from the water supply port 17 and discharging it from the drainage port 19.

A stage 21 is provided in the central portion of the upper surface of the lower lid 7, that is, inside the chamber 3, and a silicon wafer 23, for example, is mounted on the stage 21 as a flat work. In this case, a stage such as an electrostatic chuck is used as the stage 21 in order to obtain the adhesion of the silicon wafer 23.

A cooling chamber 25 is provided inside the stage 21. Cooling water is injected from a water supply port 27 and a drain port 29 is provided.
The stage 21 is cooled by discharging from the stage. The stage 21 is provided with temperature measuring means such as a thermocouple, which is not shown.

A ring-shaped dichlorosilane gas supply pipe 31 is provided above the stage 21, and gas is ejected toward the silicon wafer 23 from a plurality of nozzles 31A. A dichlorsilane gas branch pipe 33 is attached to the dichlorsilane gas supply pipe 31 and extends vertically through the lower lid 7 in an airtight state. The dichlorsilane gas branch pipe 33 supplies dichlorsilane gas. It Further, a quartz oxygen gas supply pipe 35 having a ring shape is provided above the dichlorosilane gas supply pipe 31, and gas is ejected toward the silicon wafer 23 from the plurality of nozzles 35A. An oxygen gas branch pipe 37 is attached to the oxygen gas supply pipe 35 and extends vertically through the lower lid 7 while maintaining airtightness, and oxygen gas is supplied from an oxygen gas inlet 39.

Inside the oxygen gas supply pipe 35, a copper ring-shaped antenna 41 is provided in consideration of the cooling property, and this antenna 41 is used to prevent spatter when plasma is formed in the surroundings. Is wrapped in quartz 43. The cooling water is supplied from the supply port 45 that is separated from the oxygen gas branch pipe 37. Further, the antenna 41 is connected to a high frequency power source 51 via a matching box 49 by a thin copper plate 47 in consideration of the high frequency skin effect.

Further, the lower lid 7 is provided with an exhaust pipe 53 for exhausting the inside of the chamber 3.

On the other hand, a mask 55 on which an optical waveguide pattern is drawn is provided near and above the light introducing window 11 located right above the silicon wafer 23. The mask 55 is formed by drawing a desired shape on a material that transmits laser light, and by projecting this shape onto the wafer 23, the portion of the wafer 23 irradiated with the laser light is not formed. .

Above the mask 55, an Ar + laser generator 57 as an infrared laser generator and an optical system 5 are provided.
9 are provided. This collimates the light from the laser generator 57 and irradiates the mask 55.

Next, the operation will be described. First, the silicon wafer 23 is loaded onto the stage 21 and fixed by a robot (not shown). When the inside of the chamber 3 is at atmospheric pressure, an exhaust device (not shown) exhausts the interior of the chamber 3 through the exhaust pipe 53 until the degree of vacuum in the chamber 3 becomes 10 ⁻⁶ to 10 ⁻⁷ Torr.

Next, cooling water is supplied to the cooling chamber 25 of the stage 21, and then the Ar + laser generator 57 is turned on. Therefore, the laser light is collimated by the optical system 59,
The silicon wafer 23 is irradiated through the mask 55. Therefore, the portion of the upper surface of the silicon wafer 23 that is shaded by the mask 55 and does not receive the laser light is cooled by the cooled stage 21 and has a sufficiently low temperature. On the other hand, the portion of the upper surface of the silicon wafer 23 that is irradiated with the laser light absorbs the laser light and has a temperature of 150 to 180 ° C.

Then, when gas is supplied from the dichlorosilane gas branch pipe 33, the dichlorosilane gas supply pipe 31
Gas is ejected toward the silicon wafer 23 from the nozzle 31A. Further, oxygen is supplied from the oxygen gas branch pipe 37 to supply oxygen from the nozzle 35A of the oxygen gas supply pipe 35 toward the silicon wafer 23.

When the high frequency power source 51 is turned on,
The high frequency power is supplied to the antenna 41,
A plasma is formed in the surroundings, that is, inside the oxygen gas supply pipe 35. At this time, the matching box 49 is adjusted so that the high frequency power is supplied into the chamber 3 with maximum efficiency. Further, since the temperature of the antenna 41 rises, the cooling water is supplied from the cooling water supply port 45 to flow the cooling water into the antenna 41.

As a result, the SiO ₂ film is not formed on the portion of the silicon wafer 23 where the temperature has risen due to the irradiation of the laser light, and the other portions not irradiated with the laser light are sufficiently cooled. Since the SiO ₂ film is formed, selective deposition is performed and the SiO ₂ film having the same shape as the pattern drawn on the mask 55 is formed.

That is, the optical waveguide pattern can be obtained without going through the etching process.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes. For example, although the Ar + laser generator 57 is used in the above-described embodiment, the present invention is not limited to this, and an infrared laser generator such as a lamp may be used. However, it is necessary to pass through a filter that passes only the desired wavelength. Here, the desired wavelength means a wavelength absorbed by the wafer 23, and is a wavelength of 1 μm or less.

In addition to the Ar + laser generator 57, CO
It was experimentally found that it is more effective to provide a _two- laser generator and switch to the CO ₂ laser during the process by the action of the optical system 59. This is because it is necessary to use an Ar + laser because the wavelength absorbed by the silicon wafer 23 is 1 μm or less at the initial stage of processing.
_This is because it is effective to use a CO ₂ laser having a wavelength of about 10 μm which is a wavelength absorbed by SiO ₂ when the _two films are deposited to some extent. Further, since the silicon wafer 23 allows light having a wavelength of 10 μm to pass therethrough without absorbing it, the portion where the SiO ₂ film is not deposited does not increase in temperature and is more effective.

Further, since the range in which the temperature rises due to the heat conduction of the silicon wafer 23 becomes a little wider than the range irradiated with the Ar + laser, it is effective to irradiate the laser periodically to prevent this. It can be said that there is. That is, although the temperature of the range irradiated with the laser rises, the temperature is rapidly lowered because the laser is turned off immediately. Therefore, the range of temperature rise due to heat conduction can be made extremely small as compared with the case of continuous irradiation.

[0086]

As described above, in the optical waveguide film forming apparatus according to the first aspect of the present invention, the temperature rises only in the portion of the flat plate-shaped work which is irradiated with the laser beam, and the shadow of the laser beam is formed by the mask pattern. Since the flat plate-shaped work in the portion not irradiated with light is cooled by the cooling device of the stage, the SiO ₂ film is formed only in the portion not irradiated with laser light. As a result, a desired optical waveguide pattern can be formed without performing an etching process, so that the manufacturing process of the optical waveguide is shortened and the productivity is improved. Also,
The production cost can be reduced.

In the optical waveguide film forming apparatus according to the second aspect, since the infrared laser generator generates the Ar + laser, the infrared laser generator is easily absorbed by the flat work and is effective in increasing the temperature.

In the optical waveguide film forming apparatus according to the third aspect, since the infrared laser generator is a combination of the Ar + laser generator and the CO ₂ laser generator, the Ar + laser is used in the initial stage of the process, and the SiO ₂ film A CO ₂ laser having a wavelength of about 10 μm, which is the wavelength absorbed by SiO _2, can be used when the CO ₂ is deposited to some extent. Therefore, the optical waveguide can be formed very efficiently.

In the optical waveguide film forming apparatus according to the fourth aspect, since the laser light is periodically irradiated, it is possible to reduce the range of heat conduction from the portion where the temperature rises due to the laser light irradiation. The accuracy of is greatly improved.

In the optical waveguide film forming apparatus according to the fifth aspect, since the antenna is provided inside the gas supply pipe,
The temperature rise due to the laser light can be prevented.

In the optical waveguide film forming apparatus according to the sixth aspect, since the antenna is covered with the SiO ₂ film, it is possible to prevent sputtering when plasma is formed.

Further, in the optical waveguide film forming apparatus according to the seventh aspect, the light introduction window and the mask are integrally provided,
The device is simplified because the optical waveguide pattern is projected by the laser light passing through the light introduction window.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an optical waveguide film forming apparatus according to the present invention.

FIG. 2 is a process drawing showing a conventional optical waveguide manufacturing process.

FIG. 3 is an explanatory diagram showing a conventional FHD film forming method (flame deposition method).

FIG. 4 is an explanatory view showing an apparatus used for a conventional parallel plate plasma CVD method.

FIG. 5 is an explanatory view showing an apparatus used for a conventional parallel plate plasma etching method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical waveguide film forming apparatus 3 Chamber 11 Light introduction window 21 Stage 23 Wafer (flat plate work) 25 Cooling chamber (cooling means) 31, 35 Gas supply pipe 41 Antenna 49 Matching box 51 High frequency power supply 55 Mask 57 Ar + Laser generator ( Infrared laser generator) 59 Optical system

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/3065 H01L 21/302 B

Claims (7)

[Claims] 1. An infrared laser generator for irradiating a laser beam having a wavelength of 1 μm or less, and a laser beam from the infrared laser generator for uniformly irradiating a flat work on which an optical waveguide is formed. An optical system provided accordingly, a mask provided for projecting an optical waveguide pattern on the flat work by a laser beam from the optical system, a high frequency power source for plasma generation and a matching box, and introducing the laser beam. A chamber for holding the airtightness inside and a stage for mounting and fixing the flat work, a cooling means for cooling the stage, and a chamber for facing the flat work. And at least two sets of gas supply pipes for supplying at least two kinds of gas, and an antenna for generating plasma by the high frequency power source. MichiNarumaku apparatus. 2. The optical waveguide film forming apparatus according to claim 1, wherein the infrared laser generator is an Ar + laser generator. 3. The optical waveguide film forming apparatus according to claim 1, wherein the infrared laser generator is a combination of an Ar + laser generator and a CO ₂ laser generator. 4. The optical waveguide film forming apparatus according to claim 1, wherein the laser light is periodically irradiated. 5. The optical waveguide film forming apparatus according to claim 1, wherein the antenna is provided inside the gas supply pipe. 6. The optical waveguide film forming apparatus according to claim 1, wherein the antenna is covered with a SiO ₂ film. 7. The optical waveguide film forming apparatus according to claim 1, wherein the light introducing window and the mask are integrally provided.