JPH04258109A - Device and method for x-ray exposure - Google Patents

Abstract

PURPOSE:To prevent electrification at the time of X-rays exposure and at the same time eliminate photoelectrons and Auger electrons which are generated at the time of exposure effectively and then a resist pattern to be formed with an improved accu racy by forming a substrate which is subjected to exposure of X rays of an X-rays exposure device and a means for fixing it in a specific structure. CONSTITUTION:Photoelectrons, Auger electrons, etc., which are generated in a substrate 2 when exposed to X rays pass through a conductive portion 22, a ground spring 26, and a substrate check 25 after being absorbed by a conductive film 23, and then flow to a chamber 1. Also, electrons which are generated from an X-ray mask 5 pass through a mask conductive film, a block 7, and a mask check 6, and then flow to the chamber 1. In this case, since a ground spring 26 whose pin tip is smaller than a thickness of a substrate 21 is used, X rays can be exposed with a proximity gap between a mask surface and a substrate to be exposed 2 being equal to a certain value and at the same time electrification of a resist film surface which is generated at the time of exposure of X rays can be prevented. Also, an excessive exposure of the resist can be prevented, thus forming a resist pattern with an improved dimension accuracy.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an X-ray exposure apparatus and an X-ray exposure method used in X-ray lithography, and more specifically, to preventing charging during X-ray exposure and reducing photoelectrons and Auger electrons generated during exposure. The present invention relates to an X-ray exposure apparatus and an X-ray exposure method that can effectively remove .

0002

[Background Art] In recent years, with the increase in density and speed of semiconductor integrated circuits, the pattern line width of integrated circuits has increased to 70% in about 3 years.
% tends to be reduced. Furthermore, with further integration of large-capacity memory elements (for example, 4MDRAM), 16Mbi
For devices with a capacitance of t, device design has come to be based on the 0.5 μm rule. Along with this, even higher performance is required for printing equipment, and the minimum line width that can be transferred is 0.5
High performance of micrometers or less is beginning to be required. For this reason, steppers using light in the X-ray region (2 to 20 Å) as the exposure light source wavelength are being developed. In the process using these X-ray exposure devices, a resist pattern is formed on the X-ray exposed substrate to which metals, ceramic oxides, etc. have been added, and the material directly below the resist may be a conductor. It may be a non-conductor, and its shape may be various, such as one with or without steps. In addition, in processes that use X-ray exposure equipment, high resolution,
Since a high aspect resist pattern is required, the resist used is polymethyl methacrylate (P
Polymers such as MMA) and chemically amplified resists (main polymer is novolak) are used.

0003

[Problems to be Solved by the Invention] However, although the resist as described above satisfies high resolution, etc., it is a material with high electrical insulating properties, and the substrate on which the resist is applied is also electrically insulating. The resist may be made of a highly insulating material (for example, silicon oxide), and the resist and the substrate, that is, the substrate to be exposed, may have high electrical insulation. Furthermore, since the X-ray exposure apparatus uses X-rays having higher energy than conventional light as a light source, photoelectrons and Auger electrons are generated from the exposed substrate. Furthermore, X
Line exposure equipment may have a helium atmosphere to prevent the intensity of the X-rays from decreasing, but if X-ray exposure is performed in such a dry atmosphere, static electricity may be generated due to friction between the exposed substrate and the gas during exposure. occurs. On the other hand, during X-ray exposure,
The gap between the line mask surface and the exposed substrate is 10 to several 1
It is necessary to maintain a constant value in the range of 0 μm. Therefore, in the above-mentioned X-ray exposure equipment, when X-ray exposure is performed, the resist surface is charged, and on the other hand, because there is a small gap between the mask surface and the exposed substrate, the mask surface and the resist surface are in contact with each other. This causes a problem in that the mask surface or resist surface is scratched or damaged due to discharge. Furthermore, the resist is overexposed due to the influence of emitted photoelectrons, Auger electrons, and the like, resulting in problems such as deviations in dimensional accuracy and the like when forming fine patterns. Therefore, the object of the present invention is to
It is an object of the present invention to provide an X-ray exposure apparatus and an X-ray exposure method that solve the above-mentioned problems of the prior art and have excellent antistatic properties and dimensional accuracy.

0004

[Means for Solving the Problems] The above objects are achieved by the present invention as described below. That is, the present invention provides an X-ray exposure apparatus comprising an X-ray light source section, an X-ray mask section, a substrate to be exposed to X-rays, and means for fixing the substrate, in which the outermost periphery of the substrate to be exposed to X-rays is a conductive part. and has at least one highly electrically conductive film on the substrate, and at least a part of the means for fixing the substrate in a predetermined position has a conductive part smaller than the thickness of the substrate, and these conductive parts An X-ray exposure apparatus and an X-ray exposure method using the same are characterized in that the X-ray exposure apparatus and the X-ray exposure method are formed such that they are in electrical contact with each other.

[0005]

[Function] In the X-ray exposure apparatus of the present invention, photoelectrons and Auger electrons generated from the substrate to be exposed due to the generation of static electricity during exposure and high-energy X-rays are absorbed by the conductive film on the substrate to be exposed to X-rays. After that, the current flows to the outside through a conductive part provided on the outermost periphery of the substrate and a conductive part provided on the substrate fixing means, and the thickness of the substrate fixing means is smaller than the thickness of the substrate to be exposed. Because the conductive part provided on the surface is small, it is possible to expose X-rays while keeping the proximity gap between the X-ray mask surface and the substrate to be exposed at a constant value, and the resist film surface generated during X-ray exposure can be electrification is prevented, and as a result, the X-ray mask and the substrate will not come into contact with each other to cause discharge, and damage to the X-ray mask and the substrate can be prevented. Furthermore, it is possible to prevent the resist from being overexposed due to the influence of emitted photoelectrons and Auger electrons, so that a resist pattern can be formed with high dimensional accuracy.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a diagram illustrating a cross section of an X-ray exposure apparatus according to the present invention. As shown in FIG. 1, this exposure apparatus has an electrical contact point 4 between a substrate to be exposed 2 and a substrate chuck 3 which is a means for fixing it, and furthermore, the substrate chuck 3 has a chamber 1. It is conducting. Further, there is an electrical contact point between one side of the X-ray mask 5 and a block 7 for positioning the X-ray mask that constitutes a part of the mask chuck 6, and furthermore, there is an electrical contact between the block part 7 and the chamber 1. is conductive, and the chamber 1 is at ground potential. The inside of chamber 1 is a helium atmosphere, and the pressure is 100 tons.
It is about orr.

FIG. 2 is a partially enlarged view of the substrate to be exposed 2 shown in FIG. 1 and the substrate chuck 3 which is a means for fixing it. The substrate to be exposed 21 is a Si wafer having a conductive portion 22 on the outermost periphery. The conductive portion 22 is formed by partially depositing copper to a thickness of 10 μm. Exposure substrate 21
The Si wafer used in this example is often used as the forming material, but other materials include GaAs substrates, glass substrates, or Si wafers on which metals, ceramics, oxides, etc. are attached and processed. Can be used. Also, 2
4 is an X-ray resist, and here a chemically amplified resist RAY-PN (trade name: manufactured by Hoechst) was used. However, the resist 24 is removed by edge rinsing at the outermost periphery where the conductive portion 22 is located. Conductive film 2 laminated thereon
3 is formed using an alkali-soluble conductive polymer. Here, a polymer consisting of a tetracyanoquidimethane (TCNQ) complex and a methacrylate resin was used. Reference numeral 25 denotes a substrate chuck, which is made of Al, but metals such as stainless steel and ceramics such as alumina can also be used. There is an earth spring 26 on this substrate chuck 25,
As shown in FIG. 2, it is formed in contact with the conductive portion 22. The material for forming the earth spring 26 may be phosphor bronze, stainless steel, or the like. Further, as shown in FIG. 2, the contact end of the contact portion is curved so as not to damage the conductive portion 22. However, the material and shape of the earth spring 26 are not limited to this, and the material and shape of the earth spring 26 are conductive and the conductive part 22
This does not apply unless the resist is damaged. Further, although 26 is referred to as an earth spring, it may be a pin or the like without spring properties. However, since the X-ray exposure is a proximity exposure, the distance between the X-ray mask 5 and the exposed substrate 2 must be fixed at a fixed value of about 10 to 50 μm. For this reason, the size of the earth spring 26 is
It must be smaller than the thickness of Therefore,
If a standard Si wafer is used to form the X-ray exposure substrate 21, the thickness is usually 525 μm for a 4-inch wafer and 67 μm for a 6-inch wafer.
Since it is 725 μm for a 5 μm, 8 inch wafer, the size of the earth spring 26 may be as long as the diameter of the ball at the tip of the pin is 0.5 mm or less. Also, the substrate 2 to be used
The pins can also be replaced depending on the thickness of 1.

In the X-ray exposure method of the present invention, the above-mentioned X-ray exposure apparatus is used, and as shown in FIG. 2, that is, transferred to the resist film 24 in FIG. In the X-ray exposure apparatus of the present invention, since the exposed substrate 2 has the configuration shown in FIG. 2, photoelectrons, Auger electrons, etc. generated from the exposed substrate 2 during X-ray exposure are absorbed by the conductive film 23 Rear, conductive part 22, earth spring 26, substrate chuck 2
5 and flows into chamber 1. Further, electrons generated from the X-ray mask 5 similarly flow into the chamber 1 through the mask conductive film, the block 7, and the mask chuck 6. In this way, the X-ray exposure apparatus of the present invention uses the ground spring 26 whose pin tip is smaller than the thickness of the substrate 21 as described above, so that the proximity gap between the mask surface and the exposed substrate can be maintained at a constant value. It is possible to expose X-rays while maintaining the temperature, and prevents the resist film surface from being charged during X-ray exposure.As a result, the X-ray mask and the substrate do not come into contact with each other and discharge occurs, and the X-ray mask and It can prevent damage to the board. Furthermore, since overexposure of the resist can be prevented, a resist pattern can be formed with high dimensional accuracy. Note that since an alkaline solution is used to develop the resist film 24, the conductive film 23 is peeled off at the same time.

Embodiment 2 FIG. 3 shows a substrate 2 to be exposed and a substrate chuck 3 which is a means for fixing it in an X-ray exposure apparatus which is another embodiment of the present invention.
FIG. The substrate 31 to be exposed is a Si wafer having a conductive portion 32 on the outermost periphery, similar to the first embodiment. The conductive portion 32 is formed by ion implantation using a 100 keV Au+ focused ion beam. Ions used at this time include beryllium ions, galylium ions, germanium ions, tin ions, aluminum ions, copper ions, palladium ions, arsenic ions, boron ions, and any other ion that can be used as a focused ion beam. You may also use something. X-ray exposure device, X-ray resist 34, conductive film 33, substrate chuck 35
, the earth spring 36, etc., are the same as those in the first embodiment.

Similarly to the first embodiment, X-rays are irradiated from the back side of the mask 5 as shown in FIG. 1, and the pattern on the mask is transferred to the exposed substrate 2, ie, the resist film 34 of FIG. 3. In the X-ray exposure apparatus of the present invention, the substrate 2 to be exposed is shown in FIG.
Since it has the configuration shown in FIG. 2, photoelectrons, Auger electrons, etc. generated from the exposed substrate 2 during X-ray exposure are absorbed by the conductive film 33, and then pass through the conductive part 32, the earth spring 36, and the substrate chuck 35, and It flows into chamber 1. Further, electrons generated from the X-ray mask 5 similarly flow into the chamber 1 through the mask conductive film, the block 7, and the mask chuck 6. As described above, the X-ray exposure apparatus of the present invention uses the earth spring 36 whose pin tip is smaller than the thickness of the substrate 31 to be exposed, so that the proximity between the X-ray mask surface and the substrate to be exposed is reduced. X-ray exposure can be performed while keeping the gap at a constant value, and charging on the resist film surface that occurs during X-ray exposure is prevented, resulting in
The line mask and the board will not come into contact and cause discharge, and
This can prevent damage to the line mask and board. Furthermore, since overexposure of the resist can be prevented, a resist pattern can be formed with high dimensional accuracy. Note that the resist film 34
Since an alkaline solution is used for development, the conductive film 33 is peeled off at the same time.

Embodiment 3 FIG. 4 shows a substrate 2 to be exposed and a substrate chuck 3 which is a means for fixing it in an X-ray exposure apparatus which is another embodiment of the present invention.
FIG. The substrate to be exposed 41 is a Si wafer having a conductive portion 42 on the outermost periphery. Further, the conductive portion 42 is formed by partially plating nickel to a thickness of 100 μm. 43 is a conductive film made of carbon. Although such inorganic materials are mainly used to form the conductive film 43, organic materials such as a coated conductive polymer (for example, polyvinylbenzyltrimethylammonium chloride salt) can also be used. 44 is a resist film sensitive to X-rays;
In this example, a Si-containing resist SNR (trade name: manufactured by Toyo Soda Co., Ltd.) is used. X-ray exposure device, substrate chuck 45,
The earth spring 46 and the like are the same as those in the first embodiment.

Further, as in the first embodiment, as shown in FIG. 1, X-rays are irradiated from the back side of the mask 5, and the pattern on the mask is transferred to the exposed substrate 2, ie, the resist film 44 in FIG. 4. In the X-ray exposure apparatus of the present invention, the substrate 2 to be exposed is shown in FIG.
Since it has the configuration shown in FIG. 2, photoelectrons, Auger electrons, etc. generated from the exposed substrate 2 during X-ray exposure are absorbed by the conductive film 43 and then passed through the conductive part 42, the earth spring 46, and the substrate chuck 45. It flows into chamber 1. Further, electrons generated from the X-ray mask 5 similarly flow into the chamber 1 through the mask conductive film, the block 7, and the mask chuck 6. In this way, since the X-ray exposure apparatus of the present invention uses the ground spring 46 whose pin tip is smaller than the thickness of the substrate 41 as described above, the proximity gap between the mask surface and the exposed substrate can be kept at a constant value. while keeping
It is possible to expose X-rays, and prevents charging of the resist film surface that occurs during X-ray exposure.As a result, the X-ray mask and the substrate do not come into contact with each other and discharge occurs, which prevents damage to the X-ray mask and the substrate. It can be prevented. Furthermore, since overexposure of the resist can be prevented, a resist pattern can be formed with high dimensional accuracy. Note that the conductive film 42 is then etched using a method most suitable for the material. In the case of carbon used in this example, oxygen plasma is used for etching. In this case, the conductive film 42 is etched along the shape of the resist pattern and is used as part of the resist film in the next process.

Embodiment 4 FIG. 5 is a partial sectional view of a substrate to be exposed in an X-ray exposure apparatus which is another embodiment of the present invention. The substrate 51 is a Si wafer having a conductive portion 52 on the outermost periphery, similar to the first embodiment. Further, this conductive portion 52 is formed by implanting a 200 keV Be2+ focused ion beam. On the substrate 51 is a layer 57 that is the lower layer of the multilayer resist. In this embodiment, 57 is made of polyimide, but polymers such as novolak resin can also be used. However, during coating, the outermost periphery where the conductive portion 52 is located is removed by edge rinsing. A conductive film 53 serving as an intermediate layer of the multilayer resist is formed on this 57. Metal such as Ti is mainly used to form the conductive film 53. Furthermore, on top of that, X-ray resist 5
4 is coated with PMMA (polymethyl methacrylate), for example. The same substrate chuck 55 and earth spring 56 as in the first embodiment are used.

Further, as in the first embodiment, as shown in FIG. 1, X-rays are irradiated from the back side of the mask 5, and the pattern on the mask is transferred to the exposed substrate 2, ie, the resist film 54 of FIG. 5. In the X-ray exposure apparatus of the present invention, the substrate 2 to be exposed is shown in FIG.
Since it has the configuration shown in FIG. 2, photoelectrons, Auger electrons, etc. generated from the exposed substrate 2 during X-ray exposure are absorbed by the conductive film 53, and then pass through the conductive part 52, the earth spring 56, and the substrate chuck 55. It flows into chamber 1. Further, electrons generated from the X-ray mask 5 similarly flow into the chamber 1 through the mask conductive film, the block 7, and the mask chuck 6. In this way, the X-ray exposure apparatus of the present invention uses the earth spring 56 whose pin tip is smaller than the thickness of the substrate 51 as described above, so that the proximity gap between the mask surface and the exposed substrate can be maintained at a constant value. while keeping
It is possible to expose X-rays, and prevents charging of the resist film surface that occurs during X-ray exposure.As a result, the X-ray mask and the substrate do not come into contact with each other and discharge occurs, which prevents damage to the X-ray mask and the substrate. It can be prevented. Furthermore, since overexposure of the resist can be prevented, a resist pattern can be formed with high dimensional accuracy. Note that the conductive film 53 is then etched using a method most suitable for the material. In the case of Ti used in this example, etching is performed using plasma using CF4 gas. Furthermore, the polymer 57 is also etched by oxygen plasma. In this embodiment, since the polymer 57 acts as a resist in the next process, the conductive film 52 may or may not be removed in the subsequent process after the polymer 57 is patterned.

Embodiment 5 FIG. 6 is a partial sectional view of a substrate to be exposed in an X-ray exposure apparatus which is another embodiment of the present invention. substrate 61, conductive part 62,
The substrate chuck 65 and the earth spring 66 were the same as in Example 1. 63 is an X-ray resist and a conductive resist which is a conductive film. Here, polystyrene with quaternary ammonium salt was used. Further, as in Example 1, as shown in FIG. 1, X-rays are irradiated from the back surface of the mask 5, and the pattern on the mask is transferred to the exposed substrate 2, that is, the resist film 63 in FIG. In the X-ray exposure apparatus of the present invention, since the exposed substrate 2 has the configuration shown in FIG. 6, photoelectrons, Auger electrons, etc. generated from the exposed substrate 2 during X-ray exposure are absorbed by the conductive resist film 63 After passing through the conductive part 62, the earth spring 66, and the substrate chuck 65,
It flows into chamber 1. Further, electrons generated from the X-ray mask 5 similarly flow into the chamber 1 through the mask conductive film, the block 7, and the mask chuck 6. In this way, the X-ray exposure apparatus of the present invention has the substrate 61 as described above.
Since the earth spring 66 whose pin tip is smaller than the thickness of the ground spring 66 is used, X-ray exposure can be performed while keeping the proximity gap between the mask surface and the exposed substrate at a constant value.
Prevents charging of the resist film surface that occurs during X-ray exposure,
As a result, the X-ray mask and the substrate will not come into contact with each other to cause discharge, and damage to the mask and the substrate can be prevented. Furthermore, since overexposure of the resist can be prevented, a resist pattern can be formed with high dimensional accuracy.

[0017]

[Effects] As described above, in the X-ray exposure apparatus of the present invention, photoelectrons and Auger electrons generated from the exposed substrate due to static electricity and high-energy X-rays during exposure are removed from the electrically conductive film on the X-ray exposed substrate. After being absorbed in Because the conductive part provided in the fixing means is small, it is possible to expose X-rays while keeping the proximity gap between the X-ray mask surface and the exposed substrate at a constant value.
In addition, charging of the resist film surface that occurs during X-ray exposure is prevented, and as a result, the X-ray mask and the substrate do not come into contact and discharge occurs, and damage to the X-ray mask and the substrate can be prevented. Furthermore, it is possible to prevent the resist from being overexposed due to the influence of emitted photoelectrons and Auger electrons, so that a resist pattern can be formed with high dimensional accuracy.

[0015]

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an X-ray exposure apparatus of the present invention.

FIG. 2 is a partial sectional view of a substrate to be exposed to X-rays and means for fixing the substrate in the X-ray exposure apparatus according to the embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a substrate to be exposed to X-rays and means for fixing the substrate in an X-ray exposure apparatus according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a substrate to be exposed to X-rays and means for fixing the substrate in an X-ray exposure apparatus according to another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a substrate to be exposed to X-rays and means for fixing the substrate in an X-ray exposure apparatus according to another embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a substrate to be exposed to X-rays and means for fixing the substrate in an X-ray exposure apparatus according to another embodiment of the present invention.

[Explanation of symbols] 1: Chamber 2, 21, 31, 41, 51, 61: X-ray exposed substrate 3
, 25, 35, 45, 55, 65: substrate chucks 4, 2
6, 36, 46, 56, 66: Earth spring or pin 22, 32, 42, 52, 62: Conductive part 23, 33, 4
3, 53, 63: Conductive film 24, 34, 44, 54, 6
3: Resist 5: X-ray mask 6: Mask chuck 7: Block

Claims (2)

[Claims] 1. An X-ray exposure apparatus comprising an X-ray light source section, an X-ray mask section, a substrate to be exposed to X-rays, and means for fixing the substrate, wherein the outermost periphery of the substrate to be exposed to X-rays is a conductive section. and has at least one layer of highly electrically conductive film on the substrate, and at least a portion of the means for fixing the substrate in a predetermined position has a conductive part smaller than the thickness of the substrate, and these conductive parts are An X-ray exposure apparatus characterized by being formed so that they are in electrical contact with each other. 2. An X-ray exposure method in which an X-ray mask is stacked on the surface of a substrate to be exposed to X-rays and X-rays are exposed through the mask, wherein the outermost periphery of the substrate to be exposed to X-rays is a conductive portion, and the substrate at least one layer of highly electrically conductive film thereon, and at least a portion of the means for fixing the substrate in a predetermined position has a conductive part smaller than the thickness of the substrate, and these conductive parts can be attached as necessary. An X-ray exposure method characterized by electrically contacting the