阅读说明：本技术 一种多光束光掩膜板曝光系统 (Multi-beam light mask plate exposure system ) 是由 陈新晋 唐光亚 于 2019-01-09 设计创作，主要内容包括：本发明提供一种多光束光掩膜板曝光系统,在所述曝光系统中设置至少一个双折射偏光棱镜,从而可以使得一道光束被分离成具有一定分离角γ的两道光束,提高了对光掩膜板曝光和写入的速度,提高了生产效率、降低了生产成本。其中,所述双折射偏光棱镜包括渥拉斯顿棱镜。本发明还提供了一种采用上述曝光系统对光掩膜板进行写入的方法,具备上述技术效果。(The invention provides a multi-beam photomask plate exposure system, wherein at least one birefringent polarizing prism is arranged in the exposure system, so that one beam can be separated into two beams with a certain separation angle gamma, the speed of exposing and writing the photomask plate is improved, the production efficiency is improved, and the production cost is reduced. Wherein the birefringent polarizing prism comprises a Wollaston prism. The invention also provides a method for writing in the photomask plate by adopting the exposure system, and the method has the technical effects.)

1. A multi-beam photomask exposure system, said exposure system comprising:

a light source for emitting an exposure light beam;

a high-frequency modulator is arranged in the high-frequency modulator,

at least one birefringent polarizing prism having a plurality of polarizing prisms,

at least one zoom optic, and

at least two polygon mirrors;

the high-frequency modulator, the birefringent polarizing prism, the zooming optical device and the polygon mirror are sequentially arranged behind the light source, and an optical path is formed; in the optical path, the birefringent polarizing prism is disposed between the zoom optical device and the high-frequency modulator, the polygon mirror is disposed behind the zoom optical device, one light beam incident from one surface of the birefringent polarizing prism passes through the birefringent polarizing prism and becomes two light beams having a certain separation angle, and the two polygon mirrors respectively receive the two light beams having a certain separation angle and emitted from the birefringent polarizing prism.

2. The exposure system of claim 1, wherein the birefringent polarizing prism is selected from one of the following prisms: wollaston prism, double Wollaston prism, Nikel prism, Glan-Foucault prism, Glan-Thompson prism, Rochon prism, and Senymond prism.

3. The exposure system according to claim 1 or 2, wherein a reduction lens is further provided after the polygon mirror, and the reduction lens is a rotating flywheel reduction lens.

4. The exposure system according to claim 1 or 2, wherein the light source is a laser, and the laser includes a He-Ne laser or an Ar laser.

5. The exposure system according to claim 1 or 2, wherein the high-frequency modulator is an 8-channel acousto-optic modulator.

6. The exposure system of claim 1 or 2, wherein the birefringent polarizing prism comprises a double-wollaston prism comprising a first isosceles triangular prism, a second isosceles triangular prism and a third isosceles triangular prism, wherein a hypotenuse of the first isosceles triangular prism is attached to one of the waists of the second isosceles triangular prism and the other waist of the second isosceles triangular prism is attached to a hypotenuse of the third isosceles triangular prism.

7. The exposure system according to claim 1 or 2, wherein the separation angle γ is calculated by equation (1):

γ＝2sin^-1((n_o-n_e)tan) (1)

wherein n is_oDenotes the refractive index of o light in the birefringent polarizing prism, n_eThe refractive index of e light in the birefringent polarizing prism is shown, and the acute angle in a right-angled triangular prism constituting the birefringent polarizing prism is shown.

8. The exposure system according to claim 1 or 2, wherein the polygon mirror includes a polygon rotating mirror having 24 surfaces.

9. The exposure system according to claim 1 or 2, further comprising an attenuator, an stigmator, and a beam splitter, which are disposed in sequence after the light source and between the light source and the high-frequency modulator.

10. The exposure system according to claim 1 or 2, further comprising a steering mirror disposed between the birefringent polarizing prism and the high-frequency modulator, a ring mirror for placing a photomask plate to be written, and a stage mirror disposed between the stage mirror and the polygon mirror.

11. The exposure system according to claim 1 or 2, wherein a zoom optical device is further provided between the birefringent polarizing prism and the polygon mirror.

12. The exposure system according to claim 1 or 2, wherein the exposure system is further provided with an optical alignment system including a laser light source, a high power CCD and a low power CCD, wherein the high power CCD and the low power CCD receive an optical signal from the laser light source and transmit it to the image acquisition system.

13. The exposure system of claim 13, wherein the optical alignment system is further provided with a photomultiplier tube (PMT) that transmits the received light signal to the data timing sequence.

14. The exposure system of claim 11, wherein the exposure system is further provided with a laser interferometer so that the scanning action of the beam is synchronized with the movement of the stage.

15. A method for writing to a photomask using an exposure system according to any of claims 1 to 14, comprising at least the following steps:

dividing a pattern arrangement region of a photomask plate into a plurality of writing stripe groups arranged in a staggered manner along a beam shifting direction, wherein each writing stripe group comprises a first writing stripe and a second writing stripe arranged adjacently along the beam shifting direction, and the width direction of the writing stripe group is parallel to the moving direction of a stage of the exposure system;

adjusting the direction of the beam offset to be perpendicular to the moving direction of the stage, wherein the two beams respectively correspond to the first writing stripe and the second writing stripe in one group of the writing stripe groups;

writing to the first write stripe and the second write stripe in the set of write stripes simultaneously.

16. The method according to claim 15, wherein a first column write stripe group and a second column write stripe group are provided in a moving direction of the stage, the first column write stripe group and the second column write stripe group containing the same number of the write stripe groups, and the write stripe groups in the first column write stripe group and the second column write stripe group are written alternately.

Technical Field

The invention relates to a photomask plate exposure system, in particular to a multi-beam photomask plate exposure system.

Background

Photolithography is a commonly used technique in the manufacture of integrated circuits. Photolithography refers to a technique of transferring a pattern on a photomask plate to a substrate by means of a photoresist under the action of light. FIG. 1 is a conventional lithography system, which includes the following main components: a light source 101, a lens group 102, a photomask plate 103, a condenser lens 104, and a wafer 105. The first two generations of photoetching machines adopt 436nm g-line and 365nm i-line generated by mercury lamps as photoetching light sources, and the third generation of photoetching machines adopt 248nm KrF excimer laser as a light source; and the fourth generation lithography machine employs 193nm ArF excimer laser to raise the minimum process to 65nm level at a time. The light sources used in the 1-4 generation lithography machines all belong to deep ultraviolet light, while the fifth generation EUV lithography machines use extreme ultraviolet light with a wavelength of 13.5 nm. The condenser lens 104 can reduce the pattern on the photomask 103 by several times to scribe the same pattern on the wafer 105, i.e. different lithography machines have different imaging ratios, there is 5: 1, also 4: 1.

the method for manufacturing the photomask 103 includes converting the designed circuit pattern data into a file format of an exposure tool, and performing exposure by the exposure tool according to information in the file to obtain the photomask 103. Photomask exposure is generally referred to as writing, and there are two writing methods, i.e., electron beam writing and laser writing. The laser writing mode has the advantages of high speed and efficiency, but the precision is not as good as that of an electron beam scanning mode; the pattern is written by adopting the electron beam, although the precision is high, the writing speed is slow, and the production efficiency is low. In the laser writing system, the laser light source includes a He — Ne laser, an Ar laser, or the like. Current laser writing systems typically employ a single beam raster scanning system. The photomask plate 103 generally uses high-hardness, high-light-transmittance quartz glass as a substrate, and forms Cr or an oxide of Cr thereon as a light-shielding material.

Disclosure of Invention

In view of this, the present invention provides a multi-beam photomask exposure system to solve the problems of slow writing speed and low production efficiency of the photomask exposure system in the prior art.

According to a first aspect, an embodiment of the present invention provides a multi-beam mask exposure system, including at least:

a light source for emitting an exposure light beam;

a high-frequency modulator is arranged in the high-frequency modulator,

at least one birefringent polarizing prism having a plurality of polarizing prisms,

at least one zoom optic, and

at least two polygon mirrors;

wherein the high-frequency modulator, the birefringent polarizing prism, the zoom optical device, and the polygon mirror are sequentially disposed behind the light source; in the optical path, the birefringent polarizing prism is disposed between the zoom optical device and the high-frequency modulator, the polygon mirror is disposed behind the zoom optical device, one light beam incident from one surface of the birefringent polarizing prism passes through the birefringent polarizing prism and becomes two light beams having a certain separation angle, and the two polygon mirrors respectively receive the two light beams having a certain separation angle and emitted from the birefringent polarizing prism.

Preferably, in the exposure system, the birefringent polarizing prism is selected from one of the following prisms: wollaston prism, double Wollaston prism, Nikel prism, Glan-Foucault prism, Glan-Thompson prism, Rochon prism, and Senymond prism.

Preferably, in the exposure system, a reduction lens is further provided behind the polygon mirror, and the reduction lens is a rotating flywheel reduction lens.

In the invention, the miniature lens is a rotary flywheel type miniature lens and is provided with a plurality of objective lenses with different magnifications, so that one set of exposure system has different minification magnifications, and the application range of the exposure system is greatly improved.

Preferably, in the exposure system, the light source is a laser including a He — Ne laser or an Ar laser.

Preferably, in the exposure system, the high-frequency modulator is an 8-channel acousto-optic modulator.

Preferably, in the exposure system, the birefringent polarizing prism is a double-wollaston prism, the double-wollaston prism includes a first triangular prism, a second triangular prism and a third triangular prism, a hypotenuse of the first triangular prism is bonded to one waist of the second triangular prism through an adhesive layer, and the other waist of the second triangular prism is bonded to a hypotenuse of the third triangular prism through an adhesive layer.

Preferably, in the exposure system, the separation angle γ is calculated by equation (1):

γ＝2sin^-1((n_o-n_e)tan) (1)

wherein n is_oDenotes the refractive index of o light in the birefringent polarizing prism, n_eThe refractive index of e light in the birefringent polarizing prism is shown, and the acute angle in a right-angled triangular prism constituting the birefringent polarizing prism is shown.

Preferably, in the exposure system, the polygon mirror includes a polygon rotation mirror having 24 surfaces.

Preferably, in the exposure system, the exposure system further includes an attenuator, an stigmator, and a beam splitter, which are disposed in this order after the light source and between the light source and the high-frequency modulator.

Preferably, in the exposure system, the exposure system further includes a turning mirror, an annular mirror, and a stage mirror, the turning mirror is disposed between the birefringent polarizing prism and the high-frequency modulator, the stage mirror is used for placing a photomask plate to be written, and the annular mirror is disposed between the stage mirror and the polygon mirror.

Preferably, in the exposure system, a zoom optical device is further provided between the birefringent polarizing prism and the polygon mirror.

Preferably, in the exposure system, the exposure system is further provided with an optical alignment system, and the optical alignment system includes a laser light source, a high power CCD and a low power CCD, wherein the high power CCD and the low power CCD receive an optical signal from the laser light source and transmit the optical signal to the image acquisition system.

Preferably, in the exposure system, the optical alignment system is further provided with a photomultiplier tube (PMT) that transmits the received optical signal to the data timing.

Preferably, in the exposure system, the exposure system is further provided with a laser interferometer so that a scanning action of the light beam is synchronized with a movement of the stage.

In the exposure system provided by the invention, because the birefringent polarizing prism is arranged in the light path, a single light beam is divided into two light beams with the separation angle gamma, and the writing speed of the photomask plate is greatly improved, namely the exposure system provided by the invention can improve the production efficiency and reduce the production cost.

According to a second aspect, an embodiment of the present invention provides a method for writing to a photomask, where the method uses the exposure system to write to the photomask, and the method at least includes the following steps:

dividing a pattern arrangement region of a photomask plate into a plurality of writing stripe groups arranged in a staggered manner along a beam shifting direction, wherein each writing stripe group comprises a first writing stripe and a second writing stripe arranged adjacently along the beam shifting direction, and the width direction of the writing stripe group is parallel to the moving direction of a stage of the exposure system;

adjusting the direction of the beam offset to be perpendicular to the moving direction of the stage, wherein the two beams respectively correspond to the first writing stripe and the second writing stripe in one group of the writing stripe groups;

writing to the first write stripe and the second write stripe in the set of write stripes simultaneously.

Preferably, in the method, a first column of write stripe groups and a second column of write stripe groups are provided in the moving direction of the stage, the first column of write stripe groups and the second column of write stripe groups containing the same number of the write stripe groups; writing to the write stripe group in the first column write stripe group and the write stripe group in the second column write stripe group alternately.

In the exposure system provided by the invention, the birefringent polarizing prism is arranged in the light path, so that a single light beam is divided into two light beams with the separation angle gamma, and writing in of at least two strips in the same time is realized, so that the writing speed of the photomask plate is at least doubled, and further the writing speed of the photomask plate is greatly improved, namely the production efficiency can be improved and the production cost can be reduced by adopting the exposure system provided by the invention.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

FIG. 1 is a schematic diagram of a prior art lithography system.

FIG. 2 is a schematic diagram of a prior art laser beam mask exposure system.

Fig. 3 is a schematic diagram of a laser writing method in the prior art.

Fig. 4 is a schematic diagram of an address unit of a laser beam in the prior art.

FIG. 5 is a schematic diagram of a prior art multi-beam photomask writer.

FIG. 6 is a schematic diagram of a multi-beam mask exposure system according to the present invention.

Fig. 7 is a schematic diagram of the principle of the wollaston prism in the present invention.

Fig. 8 is a schematic diagram showing a specific structure of the wollaston prism in the present invention.

FIG. 9 is a schematic diagram of a writing method of the multi-beam mask exposure system according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.