JPH11135487A - Apparatus for removing photosensitive film from semiconductor wafer using plasma - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide an apparatus for removing a photosensitive film on a semiconductor wafer, which can prevent generation of impurity particles when removing the photosensitive film from the semiconductor wafer. SOLUTION: The present invention provides a photosensitive film removing apparatus in which a ceramic protective ring is mounted on a surface of a flange exposed inside a plasma reaction chamber. The ceramic guard ring protects the aluminum flange from the effects of plasma and prevents the generation of impurity particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing a photosensitive film from a semiconductor wafer using plasma, and more particularly to an apparatus for removing impurity particles by plasma used for oxidizing and removing a photosensitive film by installing a ceramic protective ring. The present invention relates to a photosensitive film removing device capable of preventing the occurrence of occurrence.

[0002]

2. Description of the Related Art Generally, a semiconductor product manufacturing process includes wafer processing, package assembly and test. Of these, wafer processing in particular is a series of operations for providing circuits and elements in or on a thin, round plate of semiconductor material, called a wafer. In other words, diffusion to the wafer,
This is a step of providing an electric circuit on the wafer by repeatedly performing photolithography, etching and thin film formation.

Various layers such as a metal layer or an insulating layer are formed on a semiconductor wafer in a predetermined pattern.
In order to perform such an operation, a step of applying and removing a photosensitive film is required.

A typical patterning process will be described with reference to FIGS. First, a semiconductor layer 1 to be formed in a predetermined pattern on a semiconductor substrate 11 of a wafer 10
2 are coated. Further, a photosensitive film 13 is applied thereon (see FIG. 1A). A mask 14 on which a predetermined pattern is provided is located above the photosensitive film 13. When light is applied to the photosensitive film 14 through the mask 14, the chemical property of the photosensitive film portion 13a that has received the light changes (FIG. 1B). FIG. 2 shows a developing / etching step. The photosensitive film portion 13a whose properties have changed in this way is removed by the developer to form a photosensitive film 13 having a predetermined pattern.
Is formed (FIG. 2A). Subsequently, when an etching process is performed using the photosensitive film 13 as a mask, the semiconductor layer 12 having a predetermined pattern is obtained (FIG. 2B). The patterning process is completed by removing the remaining photosensitive film (FIG. 2C).

Similarly to the etching step, the photosensitive film 12 can be removed by a wet method or a dry method. The wet method uses chemicals, and the dry method uses plasma. In particular, in the dry method, a wafer is put into a reaction chamber, and a plasma is generated inside the reaction chamber by injecting an oxygen gas while applying a high frequency,
The photosensitive film is oxidized and removed so that oxygen atoms are excited to a high energy level. This dry method is more expensive than the wet method, but reduces the need for chemicals. Also, no washing step is required.

FIG. 3 is a perspective view of a conventional photosensitive film removing apparatus 20 using plasma. Referring to FIG. 3, the photosensitive film removing apparatus 20 includes a reaction chamber 21, a flange 22, a shielding tunnel 23, an opening / closing gate 24, opening / closing means 25, and a wafer support beam 26. The cylindrical reaction chamber 21 is supported by being connected to the flange 22. The reaction chamber 21 has a semiconductor wafer 10 coated with a photosensitive film.
And oxygen gas are supplied. In this reaction chamber 21, the photosensitive film is removed by plasma. Reaction chamber 21
A plurality of holes 23a are opened in the cylindrical shielding tunnel 23 inserted into the inside and surrounding the periphery of the wafer 12. The opening / closing gate 24 is connected to the flange 22 by opening / closing means 25 and can open and close the reaction chamber 21. The reaction chamber 21 is made of quartz, the gate 24 and the wafer support beam 26 are made of ceramic, and the flange 22 and the shielding tunnel 23 are made of aluminum.

The plurality of wafers 10 loaded on the wafer cassette 15 are introduced into the reaction chamber 21 by the wafer support beam 26. After the wafer 10 is supplied, the inside of the reaction chamber 21 is evacuated. Further, the inside of the reaction chamber 21 is filled with oxygen gas, and a high-energy radio frequency (RF; Ra
When dio-frequency is applied, the inside of the reaction chamber 21 is in a plasma state. Molecules inside the reaction chamber 21 are excited to a very high energy state by the plasma, and the photosensitive film (C _x H _y ) reacts with oxygen to react with carbon monoxide (CO), carbon dioxide (CO ₂ ) and water vapor. (H ₂ O) and is discarded and removed in a gaseous state.

However, a part of the flange 22 exposed inside the reaction chamber 21 is easily worn or corroded by the plasma. As a result, impurity particles are generated, which causes the electrical characteristics of the wafer 10 to be poor. Referring to FIG. 3 and FIG. 4 showing an enlarged part of the photosensitive film removing apparatus 20, when the wafer 10 is supplied to the reaction chamber 21 and the opening / closing gate 24 is closed, the photosensitive film removing process proceeds. The aluminum flange 22 for supporting the reaction chamber 21 is exposed to the plasma. Therefore, the aluminum flange 22 is worn or corroded directly by the influence of the plasma, and generates impurity particles 29. These impurity particles 29 may cause a fatal defect in the wafer 10.

FIG. 5 shows an example of a defect occurring in the semiconductor wafer 10. As shown in FIG. 5, the impurity particles 29 having a particle size larger than the distance between the circuit wirings 12b provided on the wafer 10 short-circuit the circuit wirings 12b and cause electrical failure. In order to prevent such a defect, it is usually necessary to periodically clean the inside of the photosensitive film removing apparatus to remove impurity particles. However, this method alone is not enough to solve the above-described problem, and cannot fundamentally prevent generation of impurity particles due to plasma. Further, the conventional method is cumbersome and requires low productivity because the cleaning must be performed periodically. Reference numeral 1 in FIG.
2a indicates an insulating layer.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent generation of impurity particles when removing a photosensitive film from a semiconductor wafer.

Another object of the present invention is to improve the reliability of an apparatus for removing a photosensitive film on a semiconductor wafer using plasma and to improve the productivity of the photosensitive film removing step.

Another object of the present invention is to increase the yield of semiconductor wafers.

[0013]

In order to achieve the above object, the present invention provides an apparatus for removing a photosensitive film from a semiconductor wafer, wherein a protective ring is mounted on a surface of a flange exposed inside a reaction chamber.

According to the present invention, there is provided a photosensitive film removing apparatus using a plasma, wherein a semiconductor wafer coated with a photosensitive film, an oxygen gas is supplied, and a cylindrical reaction chamber for generating plasma is combined with a part of the reaction chamber. A flange for supporting the reaction chamber, a cylindrical shielding tunnel inserted into the reaction chamber and surrounding the semiconductor wafer and having a plurality of holes formed therein, connected to the flange by opening / closing means, and And a protection ring mounted on a surface of the flange exposed to the inside of the reaction chamber for shutting off the plasma in the reaction chamber from the flange.

The reaction chamber of the photosensitive film removing device is made of quartz, and the flange and the shielding tunnel are made of aluminum. In particular, the protection ring is preferably made of ceramic.

Further, the apparatus for removing a photosensitive film according to the present invention further includes a wafer support beam coupled to the opening / closing gate, and the wafer is supported by the wafer support beam and supplied into the reaction chamber. At this time, a plurality of wafers are loaded on a wafer cassette and supplied into a reaction chamber by a wafer support beam.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same reference numerals indicate the same components throughout the drawings.

FIG. 6 is a perspective view showing an embodiment of an apparatus 30 for removing the photosensitive film of the semiconductor wafer 10 using plasma according to the present invention. FIG. 7 is an exploded perspective view showing a relationship between main components of the apparatus shown in FIG. FIG. 8 shows FIG.
3 is a partially cutaway perspective view showing a part of the device shown in FIG. Referring to FIG. 6 to FIG.
In the above, the cylindrical reaction chamber 31 is connected to and supported by the flange 32. A cylindrical shielding tunnel 33 having a plurality of holes 33a is inserted into the reaction chamber 31. The opening / closing gate 34 is connected to the flange 32 by the opening / closing means 35.
And the reaction chamber 31 can be opened and closed. The wafer support beam 36 connected to the opening / closing gate 34 projects in the direction of the reaction chamber 31 so that the wafer 10
Can be supplied into the reaction chamber 31.

In the reaction chamber 31, the semiconductor wafer 10
A reaction for removing the photosensitive film (not shown) is performed. When the plurality of wafers 10 loaded on the wafer cassette 15 are supplied into the reaction chamber 31 by the wafer support beam 36, the inside of the reaction chamber 31 is evacuated, and then oxygen gas is injected through the injection pipe 37. You. Subsequently, when a high-energy high frequency is applied to the reaction chamber 31,
A plasma state is generated inside the reaction chamber 31, and the molecules in the reaction chamber 31 are excited to an extremely high energy state by the plasma. Therefore, the photosensitive film reacts with oxygen and is removed. Carbon monoxide, carbon dioxide, and water vapor generated by oxidizing the photosensitive film are discharged through the exhaust pipe 38 in a gaseous state.

The wafer 10 inserted into the reaction chamber 31 and
Is formed of aluminum. Since a plurality of holes 33a are formed in the shield tunnel 33, ions or radicals in a plasma state can uniformly exist around the wafer 10, and the removal of the photosensitive film can be made more uniform.

As before, the reaction chamber 31 is made of quartz, the gate 34 and the wafer support beam 36 are made of ceramic, and the flange 32 and the shielding tunnel 33 are made of aluminum. However, the reaction chamber 31
The surface of the flange 32 exposed inside has a flange 32
A protection ring 40 is provided to shut off the plasma inside the reaction chamber 31. Since the protection ring 40 is made of ceramic, the protection flange 40 can protect the aluminum flange 32 from the influence of plasma.

In the exploded perspective view of FIG.
Indicates fastening means for fastening between the protective ring 40 and the flange 32 and between the flange 32 and the reaction chamber 31.

FIG. 9 shows the results of the impurity particle test before and after the protective ring was attached to the photosensitive film removing apparatus. The tests were conducted over a one-month period from March 25 to April 25, 1997, using a batch or barrel type photoresist stripper capable of working on 20 to 25 wafers at a time. . The horizontal axis in FIG. 9 indicates the date. As a test method, a normal wafer was put together with one test wafer, and a photosensitive film removing step was performed in the usual manner. Then, the number of impurity particles attached to the test wafer was examined. The vertical axis in FIG. 9 indicates the number of impurity particles. In the test, a test wafer having a circuit wiring interval of 3 μm was used. Thus, the particle size of the impurity particles examined was 3 μm or more. The protective ring was attached on April 6. In FIG. 9, the attachment of the protection ring is simply indicated by G / R. The permissible limit of impurity particles (spec. In FIG. 9: standard) is 40.

As is clear from the test results in FIG. 9, before the protective ring was attached, for example, before April 6, five failures occurred in 12 tests, but the protective ring was attached. Later, the results of the 20 tests were all good.

[0025]

As described above, according to the present invention,
By mounting a protective ring on the surface of the flange of the photosensitive film removing device, the flange can be shielded from plasma, and the generation of impurity particles can be prevented. Therefore, the conventional problem that the semiconductor wafer is electrically defective due to the generation of impurity particles can be fundamentally solved, thereby increasing the yield of the semiconductor wafer. Further, the reliability of the photosensitive film removing apparatus using plasma and the productivity of the semiconductor manufacturing process can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a typical process of forming a circuit pattern on a semiconductor wafer using a photosensitive film.

FIG. 2 is a cross-sectional view showing a typical developing / etching process when a circuit pattern is formed on a semiconductor wafer using a photosensitive film.

FIG. 3 is a perspective view showing a conventional photosensitive film removing apparatus.

4 is a partially cutaway perspective view showing a part of the apparatus shown in FIG. 3 in an enlarged manner.

FIG. 5 is a perspective view showing an example of a defect occurring on a semiconductor wafer in a conventional photosensitive film removing apparatus.

FIG. 6 is a perspective view showing an embodiment of an apparatus for removing a photosensitive film from a semiconductor wafer according to the present invention.

7 is an exploded perspective view showing a relationship between main components of the device shown in FIG. 6;

FIG. 8 is a partially cutaway perspective view showing a part of the device shown in FIG. 6 in an enlarged manner.

FIG. 9 is a diagram showing the possibility of adhering impurities by attaching a protective ring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer 15 ... Wafer cassette 30 ... Photosensitive film removal apparatus 31 ... Reaction chamber 32 ... Flange 33 ... Shielding tunnel 33a ... Hole 34 ... Opening / closing gate 35 ... Opening / closing means 36 ... Wafer support beam 37 ... Oxygen injection pipe 38 ... Exhaust pipe 39 ... fastening means 40 ... protective ring

Claims (5)

[Claims] A semiconductor wafer coated with a photosensitive film, a cylindrical reaction chamber supplied with oxygen gas, and generating plasma; a flange coupled to a part of the reaction chamber to support the reaction chamber; A cylindrical shielding tunnel inserted into the inside of the reaction chamber and surrounding the semiconductor wafer and formed with a plurality of holes, connected to the flange by opening and closing means, and opening and closing the reaction chamber. A semiconductor using a plasma, comprising: a gate capable of being opened and closed; and a protection ring mounted on a surface of the flange exposed to the inside of the reaction chamber in order to shut off the flange and plasma inside the reaction chamber. Wafer photosensitive film removal equipment. 2. The apparatus according to claim 1, wherein the reaction chamber is made of quartz, and the flange and the shielding tunnel are made of aluminum. 3. The device according to claim 2, wherein said guard ring is made of ceramic. 4. The apparatus of claim 1, further comprising a wafer support beam coupled to the gate, wherein the wafer is supported by the wafer support beam and supplied into the reaction chamber. The device according to claim 1. 5. The apparatus according to claim 4, wherein a plurality of the wafers are loaded on a wafer cassette and supplied into a reaction chamber by the wafer support beam.