JPH0621023A - Manufacture of thin film device - Google Patents

Abstract

(57) [Abstract] [Purpose] By speeding up the formation of the photo-modified layer, not only the above-mentioned steps can be greatly simplified and the yield can be improved, but also the work time can be shortened. A method of manufacturing the thin film device is provided. A surface treatment step of roughening the surface of the processed film (3) so as to substantially increase the surface area of the surface of the processed film (3), and a reforming gas for the surface of the processed film (3). A patterning step of irradiating a desired pattern with light in an atmosphere to form a photo-modifying layer (6), and the film to be processed (3) using the photo-modifying layer (6) as a protective film. And an etching step of etching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film device in which a desired pattern is formed on a device to be processed by using an etching process.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a thin film device, a step of finely processing a desired pattern on a substrate of a device to be processed is necessarily included. In recent years, in this fine processing, as represented by a semiconductor memory device, with the demand for high capacity of the device and high performance of the function, along with the miniaturization of the circuit pattern and the complicated structure of the circuit, Many treatment methods have been developed. Especially recently
For example, in a photolithography process that requires steps such as resist coating, pattern exposure, development, etching, and resist stripping, a wet process using a solution for a film forming step and an etching step on a substrate of a device to be processed. Since then, the transition to a dry process using a plasma or an excited gas in a vacuum or a reduced pressure gas is active.

[0003]

However, since a solution is used for the above resist coating, developing and resist stripping steps, the entire process cannot be a dry process. Then, with the use of the resist, the peeled resist adheres to the product as dust, which causes a reduction in yield.

Therefore, the applicant of the present invention has already formed a photo-modifying layer by irradiating the surface of the film to be processed with light in a desired pattern in a reforming gas atmosphere to form the photo-modifying layer. As a protective film, a dry process of etching the film to be processed was proposed. This simplifies the manufacturing process of thin film devices,
Further, it has become possible to avoid the generation of dust due to resist peeling and improve the product yield.

[0005]

It is an object of the present invention to further speed up the formation of the photo-modified layer in the above-mentioned process, so that not only the above-mentioned steps are greatly simplified and the yield is improved, but also the work time is increased. An object of the present invention is to provide a method of manufacturing a thin film device which can obtain a shortening effect.

[0006]

Therefore, in the present invention,
A surface treatment step of roughening the surface of the film to be processed so as to substantially increase the surface area of the film to be processed, and irradiating the surface of the film to be processed with light in a required pattern in a modified gas atmosphere. Then, a thin film device having a required pattern is manufactured by a patterning step of forming a photo-modified layer and an etching step of etching the processed film using the photo-modified layer as a protective film. .

In this case, in the surface treatment step, a bombardment treatment may be performed in which the surface of the film to be processed is roughened by using ions accelerated at an acceleration voltage of 3 KV or more. Wet etching treatment may be used.

[0008]

EXAMPLES The production method of the present invention will be described in detail below with reference to the illustrated examples. In FIG. 1A, reference numeral 1
Is a device to be processed in which the film 3 to be processed is formed on the substrate 2. The film 3 to be processed is bombarded with ions 4 or wet-etched as shown in FIG. The surface of the film 3 to be processed is roughened so that the surface area of the surface of the film 3 to be processed is substantially increased. For surface treatment, ion bomber
When carrying out the doping treatment, it is necessary to use an acceleration voltage of the ions 4 of 3 KV or more. The device 1 to be processed having the increased surface area is patterned in the next process step as shown in FIG. 1 (c). That is, the surface of the processed film 3'after the surface treatment is irradiated with light 5 in a modified gas atmosphere in accordance with a required pattern, and the irradiated film 3'is irradiated with the light 5. The modified layer 6 is formed. In this case, since the surface area of the film to be processed 3'is substantially increased as described above, the amount of the reformed gas adsorbed on the surface is increased, the reaction is promoted, and the photo-modified layer is more quickly formed. The formation of 6 is made. Then, using the photo-modifying layer 6 as a protective film (etching mask), FIG.
As shown in FIG. 3, dry etching 7 is performed to obtain a desired pattern.

Applying such a process to a practical case is as follows. That is, a device to be processed is a Si substrate on which a Cr film is formed with a thickness of 3000 Å by an electron beam vapor deposition method, and the surface treatment is performed using an Ar ⁺ ion beam with an acceleration voltage of 3 KV or more. -Irradiate As a result, the device to be processed 1 becomes the film to be processed 3'having a rough surface. The training process for the film to be processed 3 ', in an O ₂ atmosphere, the required pattern - - next pattern by emission of KrF excimer - The - irradiated with,
A photo-modifying layer (CrO _x ) as a protective film in the irradiation area
To form. Then, after that, dry etching is performed with a chlorine plasma flow using the above-mentioned photo-modified layer as a mask.

The apparatus used for carrying out the manufacturing method of the present invention is, as shown in FIG. 2, a surface treatment chamber 12a,
It is provided with a light modification processing chamber 12b and an etching processing chamber 12c, and the atmosphere in each chamber is controlled independently. The processing chambers 12a to 12c are in communication with each other via gate valves 10a to 10c. For this reason,
Since the device to be processed is processed without being exposed to the atmosphere from the time it is first introduced into the surface treatment chamber 12a until the end of etching, there is no contamination by dust and deterioration of the device performance is avoided. , Yield is improved.

Each of the processing chambers is equipped with holding bases 9a to 9c for holding the device to be processed, and is located above the holding bases 9a to 9c. In the surface processing chamber 12a, there are counter electrodes for bombardment processing. 27, the light reforming chamber 12b is equipped with a translucent window 23, and the etching chamber 12c is equipped with a plasma generating means 13.

The plasma generating means 13 guides the microwave generated by a microwave generator (not shown) to the microwave transmitting window 17c using a waveguide, and the plasma chamber 13
The electromagnetic coil 14c surrounding c accelerates the plasma in the direction of the magnetic force lines of the divergent magnetic field applied to the plasma chamber, and irradiates the plasma flow on the surface of the film to be processed of the device to be processed on the holding table 9c. ing.

The light from the excimer laser 19, which is a KrF light source, is passed through the illumination window 20 of the light reforming chamber 12b and the holding table 9b through the illumination optical system 20 and the projection optical system 22. The surface of the film to be processed of the device to be processed above is irradiated, and a mask 21 is arranged between the both optical systems for patterning at this time. .

Each of the processing chambers is evacuated, and the processing chambers 12a, 12b and the plasma chamber 13c are provided with gas inlets 11a, 11b, 11c for introducing an atmospheric gas. is there.

In the figure, reference numerals 15c and 16c denote
A cooling water inlet and outlet of a cooling passage for cooling the electromagnetic coil 14c. Further, reference numeral 24 is an insulator, and 26 is a DC power supply.

The method of manufacturing the thin film device of the present invention using the apparatus having such a configuration will be specifically described below. First, the surface treatment chamber 1 is operated through the gate valve 10a.
The device to be processed 1 introduced into 2a is placed on the holding table 9a. Then, the surface treatment chamber 12a is set to 10 ⁻⁸ to
It is evacuated (decompressed) until it reaches rr, then Ar gas is introduced from the gas inlet 11a at a flow rate of 50 sccm, and the vacuum exhaust device is controlled so that the internal pressure becomes 0.05 torr.
Then, the DC power supplies 26 to 7 are connected to the holding table 9a.
A DC voltage of KV is applied to cause glow discharge with the counter electrode 27. This voltage accelerates Ar ions, collides with the surface of the Cr film, and roughens the surface. At this time, the ion current density is 1.2 A / cm ² , and the treatment time is 2 minutes. When the surface of the Cr film thus obtained was observed with an STM (scanning tunneling microscope), the difference between peaks and valleys was 1
It was found that unevenness of about 0 to 30Å was observed, and the surface area was almost 3.5 times that of the case where no treatment was applied. After this treatment, the supply of the gas is stopped, and the gas is evacuated until the internal pressure becomes 10 ^-8 torr or less.

Next, the surface-treated device 1 to be processed is passed through the gate valve 10b to the light reforming chamber 12 through the gate valve 10b.
It is introduced into b and placed on the holding table 9b. even here,
The inside is evacuated to 10 ^-8 torr or less, and then O ₂ gas is introduced from the gas inlet 11b until the pressure reaches 200 torr. Then, oscillate the excimer laser 19,
The laser light having a wavelength of λ = 248 nm is patterned by the mask 21.
The surface of the Cr film is selectively irradiated according to the mask (the masking portion becomes a negative pattern). In this case, the glass plate fitted into the transmission window 23 is preferably made of quartz glass that does not absorb the laser light. On the surface of the Cr film, only a portion irradiated with light causes a photochemical reaction between O ₂ and Cr, and the thickness of 80 to 100Å is modified to CrO _x from the surface of the Cr film by exposure for only 5 minutes. This is because the surface area of the surface of the film to be processed has been increased in advance by the surface treatment. After forming the modified layer, O ₂
The gas is stopped, and the internal pressure is again evacuated to 10 ^-8 torr or less.

The patterned device 1 to be processed
Is introduced into the etching chamber 12c through the gate valve 10c and placed on the holding table 9c. Again, the interior was evacuated to below 10 ^-8 torr and then
Cl ₂ gas is introduced into the plasma chamber 13c from the gas inlet 11c at a flow rate of 30 sccm, and the vacuum exhaust device is controlled so that the internal pressure becomes 200 torr. Then, a current of 154 A is applied to the electromagnetic coil 14c to generate a magnetic field of 875 Gauss in the plasma chamber. On the other hand, 2.45 GHz _Z via a waveguide, the microwave 400W was supplied to the plasma chamber to generate chlorine plasma. Cl ⁺ ions in the plasma are accelerated by the floating potential (10 to 20 V) generated between the device 1 to be processed and the plasma,
Cl or Cl excited by collision with the surface of the a-SiN film
_{In addition to 2} , the etching is performed only on the portion irradiated with the laser light. Note that here, Cr and CrO _x
Selectivity ratio (Cr / CrO
_X ) is about 100, so the mask material is CrO _x
The etching can be completed before the film is lost. Especially, in this etching, since the pressure is as low as 5 × 10 ^-4 torr, the mean free path of the ions is about 8 cm, which is much larger than the ion sheath (about 0.1 mm), and the ions have good verticality. Is incident on the surface of the a-SiN film, fine processing with good anisotropy can be realized.

Next, with reference to FIGS. 3A to 3D, an example of manufacturing an amorphous silicon photosensor using the present invention will be described. Here, first, the glass substrate 3
A Cr film 31 having a thickness of 1000 Å is vapor-deposited on the substrate 0, and the device to be processed is subjected to an ion bombardment treatment using an Al ⁺ ion beam. After that, KrF excimer laser
Light is irradiated through the mask to form a photo-modified layer made of CrO _x . Then, using this CrO _x film as a mask, etching is performed with an etching gas (Cl ₂ gas), as shown in FIG.
A lower electrode 31 'as shown in (b) is formed. Next, as shown in FIG. 3B, an a-SiN film 32 having a thickness of 3000 Å is formed by using a mixed gas of SiH ₄ , NH ₃ , and H ₂ , followed by using a mixed gas of SiH _4, H ₂ . An a-Si film having a thickness of 1.5 μm is formed on the n ⁺ -a-Si film 34 having a thickness of 2000 Å by using a mixed gas of SiH ₄ , PH ₃ , and H _2.
Are formed by the plasma CVD method, and the Al film 35 of 6000 Å is further formed by the vapor deposition method. Next, as in the previous embodiment, after performing ion bombardment using Ar ⁺ ion beam, KrF excimer laser light was selectively irradiated through a mask to obtain AlO.
A photo-modified layer made of _X is formed. And the above AlO _x
Using the etching gas (Cl ₂ ) as a mask with the layer as n
⁺ Etching is performed up to the a-Si film 34, and the light incident window 37
And the upper electrode 36 is formed.

In this way, the process can be greatly simplified without using the conventionally used resist, and
No dust is generated by the resist, and the yield can be improved.

Further, a- is formed on a glass substrate by using the present invention.
The case of patterning the SiN _x : H film will be specifically described with reference to FIGS. 1A to 1D again. To configure the thin film device 1, first,
As shown in FIG. 1A, a 3000-Å-thick a-SiN _x : H layer is formed on the quartz glass 2 by a plasma CVD method.
Form a film. Particularly, in this embodiment, since the wet etching is used for the surface treatment, the etchant (50% H
F: 40% NH ₄ F = 1: 7) is prepared. By dipping the above device in this etchant for 1 minute, C
The surface of the r film 3'is roughened to increase the surface area. Actually, when observed by an AFM (atomic force microscope), irregularities with a difference in peaks and valleys of about 5 to 20 Å can be recognized, and the surface area is substantially larger than that when the surface treatment as described above is not performed. Has doubled. Then, on the surface of the a-SiN _x : H film 3 ′ having the increased surface area, as shown in FIG.
As shown in (c), the light of the excimer laser is selectively irradiated (using a mask), and the photo-irradiated region is photochemically reacted to form the patterned photo-modified layer 6. Form.
In this case, the atmosphere is evacuated to 10 ^-8 torr or less and then filled with O ₂ gas so that the pressure becomes 200 torr. In addition, the excimer laser has K
Laser light having a wavelength of 248 nm oscillated by an rF light source is used. On the surface of the a-SiN: H film, O ₂ and a-SiN cause a photochemical reaction only in the portion exposed to the light, and after exposure for about 5 minutes, 40 ° from the surface of the a-SiN: H film.
Approximately 50Å is modified into a SiO ₂ layer. This reforming time is half as compared with the case where the ion bombardment is not applied, and the work can be speeded up. Then, finally, as shown in FIG. 1D, etching can be performed to obtain a desired fine processed shape.

[0022]

As described above in detail, the present invention roughens the surface of the film by increasing the surface area by performing ion bombardment treatment or wet etching treatment on the surface of the finely processed film. Therefore, in the subsequent formation of the modified layer by light, the reaction surface area is large, and the reaction time can be shortened to obtain the modified layer having the same thickness. Therefore, compared to the case of using a conventional photoresist, the process is greatly simplified, and it is possible not only to avoid a decrease in yield due to dust, but also to reduce the total time more effectively. Can be achieved.

[Brief description of drawings]

FIG. 1 shows the method of the present invention in the order of work (a) to (d).
It is an explanatory view shown by.

FIG. 2 is a schematic configuration diagram of an embodiment of an apparatus for carrying out the present invention.

FIG. 3 is an explanatory diagram showing work orders (a) to (d) of a specific example in which the present invention is carried out on an actual product.

[Explanation of symbols]

 1 Thin Film Device 2 Substrate 3 Processed Film 4 Ion 5 Light 6 Modified Layer 7 Dry Etching 10a to 10c Gate Valve 11a to 11c Gas Inlet 12a Surface Treatment Chamber 12b Light Modification Treatment Chamber 12c Etching Chamber

Claims (4)

[Claims] 1. A surface treatment step of roughening the surface of the film to be processed so as to substantially increase the surface area of the film to be processed, and a pattern required for the surface of the film to be processed in a modified gas atmosphere. Of a thin film device, which comprises a patterning step of irradiating the film with light to form a photo-modified layer and an etching step of etching the film to be processed with the photo-modified layer as a protective film. Law. 2. The acceleration voltage is 3K in the surface treatment step.
2. The method of manufacturing a thin film device according to claim 1, wherein a bombardment treatment is performed so that the surface of the film to be processed is roughened by using ions accelerated at V or more. 3. The method of manufacturing a thin film device according to claim 1, wherein a wet etching treatment is used in the surface treatment step. 4. The surface treatment step, patterning step,
The etching process is performed in an independent atmosphere,
A method of manufacturing a thin film device, wherein the device to be processed is sequentially transferred into each atmosphere through a gate.