TWI743565B - Method for detecting surface of photomask used in EUV lithography process and photomask component thereof - Google Patents

Abstract

A photomask surface detection method for EUV lithography process and photomask assembly thereof, wherein the photomask assembly includes a photomask body, a photomask test unit, and a photomask protection unit, and is detected on the surface of a DUV photomask Inside the machine, the reticle test unit can be fixed on the surface of the reticle body, and detect whether there is any foreign matter on the surface of the reticle body at a wavelength of 193 nm, and then transport the detected reticle body to An EUV lithography process machine, and inside the EUV lithography process machine, the mask test unit on the mask body is replaced with the mask protection unit, and the EUV lithography process machine uses 13.5 The EUV lithography process is performed at the wavelength of nanometers, so that it is possible to detect whether there are foreign objects on the surface of the mask body before the EUV lithography process.

Description

Method for detecting surface of photomask used in EUV lithography process and photomask component thereof

The present invention relates to a method for detecting the surface of a photomask and a photomask assembly for EUV lithography process, in particular to a method for detecting whether the surface of the photomask body has foreign matter before the EUV photolithography process, and the photomask assembly .

According to the current semiconductor device manufacturing technology, the circuit pattern of the semiconductor device is transferred to the surface of the silicon wafer through a lithography process, specifically, a light source of a specific wavelength is used to project through a photomask. In this way, the circuit pattern is transferred to the surface of the silicon wafer. In order to double the number of semiconductor elements such as transistors per unit area, reducing the line width of semiconductor circuits is the main technical solution. Currently, deep ultraviolet light (DUV) with a wavelength of 193 nm is used as the exposure light source for the lithography process.

Nowadays, in order to obtain a smaller line width, it is necessary to use a light source with a shorter wavelength for exposure. Therefore, in order to make a finer line width structure, the extreme ultraviolet light source with a wavelength of 13.5 nanometers, referred to as EUV, is the only one in the next stage. Application of light sources, according to estimates, the maximum physical limit of the current argon-fluorine (ArF) 193nm light source is a line width of 10nm. If it progresses below 7nm, it is not an EUV extreme ultraviolet light source.

Due to the miniaturization of semiconductor components, in the manufacturing process of semiconductor components, the defects of the photomask will cause the distortion or deformation of the circuit pattern on the surface of the silicon wafer. Even the defects of only nanometer size such as 20nm~200nm will cause the semiconductor circuit pattern to be distorted. damage.

It is known that one of the reasons for the defects of the photomask is that the surface of the photomask is contaminated by contamination particles; in order to maintain the quality of the photomask during use, a conventional method is to provide a photomask on the surface of the photomask. The frame of the protective film (pellicle) is used to prevent pollutants from falling on the surface of the mask to form pollutant particles.

However, even if the above frame is used, it will inevitably cause pollution on the surface of the mask. Therefore, there are currently DUV mask surface inspection machines that use deep ultraviolet light (DUV) with a wavelength of 193nm as the detection light source, with a wavelength of 193nm. The deep ultraviolet light passing through the film on the frame can be irradiated on the surface of the mask for detection.

However, because there is currently no EUV mask surface inspection machine for the extreme ultraviolet light source with a wavelength of 13.5 nm, and the deep ultraviolet light with a wavelength of 193 nm cannot penetrate the film on the frame used in the EUV lithography process. Therefore, it is impossible to use a DUV mask surface inspection machine with a wavelength of 193nm to inspect the surface of the mask. In this way, only after the EUV lithography process can it be found whether there are pollution particles on the surface of the mask.

Therefore, in order to overcome the above problems, two different frames corresponding to 193nm and 13.5nm can be prepared, and the frame and the mask body can be combined with a snap assembly. When the surface of the mask is to be inspected, it can be In the DUV mask surface inspection machine, the frame corresponding to 193nm is combined on the surface of the mask body, and then the inspected mask body is transported to an EUV lithography process machine, and then the The mask test unit on the mask body is replaced with the mask protection unit, and the EUV lithography process is performed in the EUV lithography process machine at a wavelength of 13.5 nm, so that it can be performed before the EUV lithography process It is detected whether there are foreign objects on the surface of the mask body, so the present invention should be an optimal solution.

The method for detecting the surface of the photomask used in the EUV lithography process of the present invention includes the following steps: (1) Provide a photomask body, a photomask test unit, and a photomask protection unit, wherein the photomask test unit or the photomask protection unit can be selectively combined on the surface of the photomask body; (2) The photomask The mask test unit is combined and fixed on the surface of the mask body, and a DUV mask surface inspection machine detects whether there are foreign objects on the surface of the mask body at a wavelength of 193 nm; and (3) the detected mask body Transport to an EUV lithography process machine, and replace the mask test unit on the mask body with the mask protection unit, and perform EUV lithography in the EUV lithography process machine at a wavelength of 13.5 nm Process.

More specifically, the surface of the mask body is provided with one or more buckle parts, and the mask test unit is provided with a first buckle corresponding to the buckle part, the buckle The part can be combined with the first buckle for fixing the photomask test unit on the surface of the photomask body.

More specifically, the surface of the mask body is provided with one or more buckle parts, and the mask protection unit is provided with a second buckle corresponding to the buckle part, the buckle The part can be combined with the second buckle for fixing the photomask protection unit on the surface of the photomask body.

More specifically, the EUV lithography process machine has at least one set of robotic arms inside to be able to remove the mask test unit on the surface of the mask body, and install the mask protection unit on the surface of the mask body. On the surface of the mask body.

A photomask assembly for EUV lithography process, which includes: a photomask body with a surface, the surface of the photomask body has one or more buckle parts; a photomask test unit, which includes A first frame and a transparent film attached to the first frame, the first frame is provided with a first fastener, and the fastener portion on the surface of the mask body can interact with the first fastener Combine, In a DUV mask surface inspection machine, the mask test unit is combined and fixed on the surface of the mask body to perform mask surface inspection, and the DUV mask surface inspection machine can detect at a wavelength of 193 nm Whether there are foreign objects on the surface of the mask body; a mask protection unit includes a second frame and a non-transparent film attached to the second frame, and the second frame is provided with a second fastener, And the buckle part on the surface of the mask body can be combined with the second buckle, so as to fix the mask protection unit on the surface of the mask body and perform lithography in an EUV lithography process machine. The EUV lithography process machine can perform the lithography process at a wavelength of 13.5 nm.

More specifically, the transparent film of the mask test unit is made of a fluorine-containing polymer compound material.

More specifically, the non-transparent film of the photomask protection unit is made of an inorganic film material whose main body is silicon.

1: Mask body

11: surface

12: buckle part

2: Mask test unit

21: The first frame

211: The first fastener

22: Transparent film

3: Mask protection unit

31: The second frame

311: The second clip

32: non-transparent film

[Figure 1] is a schematic diagram of the photomask surface inspection method and the method of the photomask assembly used in the EUV lithography process of the present invention.

[Figure 2A] is an exploded implementation schematic diagram of the photomask body and the photomask test unit of the photomask surface detection method and photomask assembly used in the EUV lithography process of the present invention.

[Figure 2B] is a schematic diagram of the combination of the photomask body and the photomask test unit of the photomask surface detection method for EUV lithography process and the photomask assembly of the present invention.

[Figure 3] The present invention is a schematic diagram of the decomposition and implementation of the photomask body and the photomask protection unit of the photomask surface detection method and photomask assembly for EUV lithography process of the present invention.

Other technical content, features and effects of the present invention will be clearly presented in the following detailed description of the preferred embodiment with reference to the drawings.

Please refer to Figure 1, which is a schematic diagram of the method for detecting the surface of the mask and the method of the mask assembly used in the EUV lithography process of the present invention. A mask test unit and a mask protection unit, wherein the mask test unit or the mask protection unit can be selectively combined on the surface of the mask body (step 101); (2) the mask test unit is combined and fixed to the On the surface of the mask body, a DUV mask surface inspection machine is used to detect whether there are foreign objects on the surface of the mask body at a wavelength of 193 nm (step 102); and (3) the detected mask body is transported to a EUV lithography process machine, and replace the mask test unit on the mask body with the mask protection unit, so as to perform EUV lithography process with a wavelength of 13.5 nm in the EUV lithography process machine (step 103).

The decomposition and combination of the mask body and the mask test unit are implemented as shown in Figures 2A and 2B. The mask test unit 2 includes a first frame 21 and a transparent film 22 attached to the first frame 21. (The transparent film 22 is made of a fluorine-containing polymer material), the first frame 21 has a first fastener 211, and the fastener portion 12 on the surface 11 of the mask body 1 can interact with the first frame 21. A buckle 211 is combined to combine and fix the photomask test unit 2 on the surface 11 of the photomask body 1 in a DUV photomask surface inspection machine to perform photomask surface inspection, and the DUV photomask surface The inspection machine can detect whether there are pollution particles on the surface 11 of the mask body 1 at a wavelength of 193 nm.

The above-mentioned DUV mask surface inspection machine can penetrate the transparent film 22 with a wavelength of 193 nm and detect the surface 11 of the mask body 1, and the mask body and the mask test unit are combined It can be combined externally or inside the DUV mask surface inspection machine. If it is combined internally, a mechanical arm must be installed inside the DUV mask surface inspection machine so that the mask test unit 2 can be clamped. It is held on the top of the mask body 1 and then snap-fixed on the surface 11 of the mask body 1.

After the inspection is completed, the mask body 1 combined with the mask test unit 2 can be transported to the inside of the EUV lithography process machine, and the mask test unit 2 on the mask body 1 can be replaced with the mask The protection unit 3, and the mask protection unit 3, as shown in Figure 3, includes a second frame 31 and a non-transparent film 32 attached to the second frame 31 (the non-transparent film 32 is made of silicon Is made of inorganic film material for the main body), the second frame 31 is provided with a second fastener 311, and the fastener portion 12 on the surface 11 of the mask body 1 can be connected to the second fastener 311 Combined, in an EUV lithography process machine, the photomask protection unit 3 is fixed on the surface 11 of the photomask body 1 to perform the lithography process, and the EUV lithography process machine is capable of 13.5 nanometers Wavelength for lithography process.

In addition to installing the photomask protection unit 3 inside the EUV lithography process machine, the photomask protection unit 3 can also be replaced with a robotic arm device, and the photomask protection unit 3 can be directly integrated. The photomask body 1 of 1 is sent into the EUV lithography process machine, and the lithography process is performed at a wavelength of 13.5 nm.

The aforementioned buckle portion 12, the first buckle 211, and the second buckle 311 mentioned in this case are any components on the market that can be easily combined and separated.

The advantages of the photomask surface detection method for EUV lithography process and the photomask assembly provided by the present invention are as follows when compared with other conventional technologies:

(1) The present invention can prepare two different frames corresponding to 193nm and 13.5nm, and can combine the frame corresponding to 193nm on the surface of the mask body in the DUV mask surface inspection machine. After that, the inspected mask body is transported to an EUV lithography process machine, and then the mask test unit on the mask body is replaced with the mask protection unit, and then the EUV lithography process machine The EUV lithography process is carried out at a wavelength of 13.5 nm, so that the surface of the mask body can be detected before the EUV lithography process.

(2) The present invention can detect the surface of the photomask through the DUV photomask surface inspection machine, which can solve the problem that the non-transparent film of the photomask protection unit cannot be penetrated by the wavelength of 193nm, and can also avoid the photomask The transparent film of the protection unit is deteriorated or vaporized by 13.5 nanometers to generate harmful gases.

The present invention has been disclosed above through the above-mentioned embodiments, but it is not intended to limit the present invention. Anyone familiar with this technical field with ordinary knowledge should understand the aforementioned technical features and embodiments of the present invention without departing from the scope of the present invention. Within the spirit and scope, no changes and modifications can be made. Therefore, the scope of patent protection of the present invention shall be subject to the definition of the claims attached to this specification.

Claims (7)

A method for detecting the surface of a photomask for EUV lithography process. The steps are as follows: providing a photomask body, a photomask test unit, and a photomask protection unit, wherein the photomask test unit or the photomask protection unit can be selected Combined with the surface of the mask body; the mask test unit is combined and fixed on the surface of the mask body, and a DUV mask surface inspection machine is used to detect whether the surface of the mask body has foreign matter at a wavelength of 193 nm And transport the inspected mask body to an EUV lithography process machine, and replace the mask test unit on the mask body with the mask protection unit, so as to be used in the EUV lithography process machine The EUV lithography process is performed at a wavelength of 13.5 nm. The photomask surface detection method for EUV lithography process according to claim 1, wherein the photomask body has one or more buckles on the surface, and the photomask test unit has a corresponding The first buckle part of the buckle part can be combined with the first buckle part for fixing the photomask test unit on the surface of the photomask body. The photomask surface inspection method for EUV lithography process according to claim 1, wherein the photomask body has one or more buckles on the surface, and the photomask protection unit has a corresponding The second buckle part of the buckle part can be combined with the second buckle part for fixing the photomask protection unit on the surface of the photomask body. The photomask surface inspection method for EUV lithography process as described in claim 1, wherein the EUV lithography process machine has at least one set of mechanical arms to be able to remove the surface of the mask body A photomask test unit, and the photomask protection unit is installed on the surface of the photomask body. A photomask assembly used in EUV lithography process, which contains: A mask body has a surface, and the surface of the mask body has one or more buckle parts; a mask test unit includes a first frame and a first frame attached to the first frame Transparent film, the first frame is provided with a first fastener, and the fastener portion on the surface of the mask body can be combined with the first fastener to be integrated in a DUV mask surface inspection machine The photomask test unit is fixed on the surface of the photomask body and performs photomask surface inspection, and the DUV photomask surface inspection machine can detect whether there are foreign objects on the surface of the photomask body at a wavelength of 193nm; a photomask The protection unit includes a second frame and a non-transparent film attached to the second frame. The second frame is provided with a second buckle, and the buckle part on the surface of the mask body can interact with The second buckle is combined to integrate and fix the photomask protection unit on the surface of the photomask body in an EUV lithography process machine to perform the photolithography process, and the EUV lithography process machine can be The lithography process is performed at a wavelength of 13.5 nm. The photomask assembly for EUV lithography process according to claim 5, wherein the transparent film of the photomask test unit is made of a fluorine-containing polymer film material. The photomask assembly for EUV lithography process according to claim 5, wherein the non-transparent film of the photomask protection unit is made of an inorganic film material mainly made of silicon.

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