JPS58500306A - Method for manufacturing screen lens array plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Manufacturing method of screen lens array plate Background of the invention This invention relates to charged particle beam lithography systems, and more particularly to multiple charged particle beam lithography systems. A method for manufacturing a blank screen lens array for use in a camera exposure system It is related to

In recent years, the general trend in semiconductor industry technology has been as integrated circuits have become more complex. The focus has been on increasing device integration density. Device integration density Increasing the number of circuit elements per chip or reducing the chip size Surukoto is possible. Current technology concepts are to reduce this chip size as much as possible and The aim is to increase the device integration density. However, the chip size is Due to the inherent resolution limitations of currently used photolithographic graphics processes, Therefore, it cannot be arbitrarily reduced. In particular, the wavelength of light is 1 This is a fine reproducibility Q disorder in the μm region.

Many methods have been proposed to solve this resolution problem, but this It is connected to two trends in the physical industry. These solutions limit resolution. In order to overcome this limitation, lithography technology employing particles with wavelengths shorter than visible light It is based on In general, short-wavelength particles include light, that is, high-energy particles. It has been proposed to selectively use two classes consisting of photons (X-rays) and electrons. ing.

Optimized topography systems should become a valuable element in integrated circuit manufacturing is required to have certain attributes. These attributes include resolution coverage, lithograph Great for speed, matching ability and stability.

Currently, the minimum reproducible linewidth is 1 μm, but future integrated circuit structures will One would require a desired system resolution of 1/4 μm or less. exposure system is the standard type 75 and 100 rttm wave currently used in this field. wafers of larger size (125-150 wafers). 11ff). And from tens of minutes to several hours Significant wafer exposure times that can extend up to It is unacceptable. Throughput allowed for wafer exposure time The conditions are limited to several minutes for 751ff and 1ooff wafers.

International Patent Application No. PCT/US8110O4B8 filed April 10, 1981 (CP application) describes a parallel charged particle beam system, and these descriptions is quoted here for reference. In this system, a normal type of lithography system is used. The system's throughput capacity is increased by using a multiple charged particle beam exposure system. is significantly enhanced, thereby allowing one light-collecting circuit pattern to be placed at multiple locations on the target surface. This allows both to be written simultaneously and directly. This disclosure In one embodiment of the system, an electron source illuminates the objective aperture. An electron beam is generated. The screen lens, which comes out of many holes, comes from the objective aperture The emitted electron beam is interrupted to form a multi-flux beam, their focuses are aligned, and the beam is sensed. A parallel incidence is applied onto a substrate with a layer, a so-called photoresist. Each hole in the lens plate is small when a positive potential is applied to that wafer with respect to the screen lens. Acts as an aperture lens.

The method for manufacturing an optimal screen lens array is Coaxial beam-limiting apertures and aperture lenses that determine performance are extremely important in construction. It must be able to produce zualley. Specially manufactured screen lenses The Zuarray consists of two thin plates made of conductive material, with a layer of 25 μm or more on both sides. Should have a concentrated aperture array with lower spacing. Each upper aperture, i.e. diaphragm The pores have a diameter of 0.25 to 1.Off, and each lower aperture, or lenslet, ．． It should have a diameter between 0 and 2.0. Between the two sides with these openings The interval is 1. Must be within the range of ○ to 3,0ffl+. The above opening diameter is ±25μm between lens plates and ±1 within a given lens plate Must have an accuracy of 2 μm. Jagged edges should be avoided, but Even if it exists, when it protrudes toward the lens axis, it is less than 2 μm, When protruding away from the lens axis, it must be 5 μm or less.

In some applications, the lens is made of a solid material that forms a diaphragm and lens aperture. Obtainable.

For standard 10On wafers, the lens plate has a diameter of 100N or more. , equipped with a minimum of 50 small lenses and a maximum of 1000 small lenses arranged on a parallel coordinate grid. should be prepared. The closest distance between lenslets should be maintained to an accuracy of ±25 μm. be. The aperture plate and lens plate should form parallel surfaces within a range of ±12 μm. Ru.

Several methods of forming screen lens arrays are still well known today. well known.

However, these well-known methods are not disclosed in the above-mentioned international patent Some types of screen lens arrays are unsuitable for forming screen lens arrays. It has restrictions or determinations. For example, these conventional techniques Disclose the use of 1n-diffusion techniques However, they provide a satisfactory solution to the problem that the present invention seeks to solve. It's not a thing. In particular, the so-called 1-spin coating technology, which does not apply boron, This does not provide a satisfactory screen lens array having the above-mentioned performance characteristics. do not have. Furthermore, the disclosed boron penetration (approximately 2 μm) does not have sufficient mechanical strength. It's a good thing. Also, how can the conventional technology determine the concentration of boron atoms that can be used? There is no mention of how to configure it.

The basic object of the invention is therefore to overcome the aforementioned limitations and disadvantages of known methods. A charged particle beam that has all of the attributes necessary to comply with and meet the aforementioned requirements. A method of manufacturing a screen lens array for use in an exposure system is provided. Is Rukoto.

A specific object of the present invention is to provide a method for manufacturing a high resolution screen lens array. It is to provide law.

Other objects of the invention will become apparent in the following detailed description and examples of the invention. It will be.

Brief description of the drawing For illustrating preferred embodiments of the invention, the accompanying drawings include an aperture plate and a lens. A single screen lens array consisting of a plate is shown.

Summary of the invention In the above-mentioned or other objects and manifestations of the invention, or embodiments of the invention These will become clear in the following and can be achieved by the configuration of the invention summarized below. It will be done. That is, the method of the present invention uses a circular polished silicon wafer approximately 0.5 mm thick. - form a screen lens array plate. It is a useless method, and silicon polishing both sides of the wafer and oxidizing both sides of the silicon wafer; forming a dense, porous oxide film having a thickness of about 2 μm; A predetermined pattern is formed on both sides of the wafer using photography or electron beam lithography. and diffusively depositing boron on both sides of the wafer. so that the boron atom density is approximately 7X1019 atoms/d at a depth of approximately 10 μm. forming a boron layer of which the predetermined pattern has a thickness of the wafer; The step of anisotropically etching the silicon wafer until it is formed through It is characterized by:

Detailed description of preferred embodiments The lens plate and the aperture plate are manufactured as outlined above, and they are manufactured in one step. It is assembled as a high-performance array of electronic lenses called "clean lenses". Ru. This screen lens is a flat screen lens as described in the international patent application mentioned above. Row lighting forms an important part of the electron beam exposure system. be more specific For example, it is used to pattern electron-sensitive films with sub-micron resolution. This significantly reduces the time required.

According to the invention, the diaphragm and the lens plate are made of silicon material for photolithography or electronic printing. After pattern processing using lithography technology, boron is diffused and fixed6. It is formed by anisotropic silicon etching. these boards form a pair of mutually spaced parallel pairs, ±2 to form a full screen lens. It has seven open lower arrays arranged at intervals of 5 μm or less. Shown in relative detail in the figure. As shown, one plate is the diaphragm aperture plate α (g), and the other plate is the lens plate (200). It is. The former is a single-crystal silicon wafer <100> with a diameter of 1001 fN. A row (typically 0.5-0.7!M* in diameter) is formed. Also, the latter ( 200) in similar silicon wafers with larger holes (typically 1.5 a diameter) ).

Lithography has been learned theoretically and confirmed empirically by the inventors. Plates 00 [] and (2 00,) is as flat as possible (no unevenness of 12 μm or more throughout the wafer). ), the formed aperture should be close to a perfect circle (ellipse deviation less than 1 μm), and Their side walls must be extremely smooth (less than 0.25 μm).

Single crystal silicon wafer with a diameter of 10011 ffl and a thickness of approximately 0.5 fi wafer (100) with as starting structure for plates (9) and (200) used. Only one side (top surface) of each wafer should have an unevenness of 12 μm or less. The opposite surface (bottom surface) is polished to have an unevenness of less than 50 μm. . The wafer may be either p-type or n-type, and the resistivity should be 0.1Ω or more. shall be above. These wafers are cleaned using standard semiconductor cleaning techniques. 1. Then oxidized on both sides to form a dense porous layer 2. Q±0.3μm oxide film form.

Next, the pattern on both sides of the wafer is created using a negative photoresist and high quality chrome mask. exposed using photolithographic technology. This photoresist film was prebaked at 70℃ for 0.5 hours. ○ at 150℃. Standard KTI resist post-baked for 5 hours. Wow Since both sides should be exposed, masks for the front and back sides should be made with holes on both sides. are aligned in advance so that they correspond within a range of ±25 μm. Between the holes on both sides, If the deviation is larger than this, significant astigmatism will occur in high-resolution images. .

Higher resolution patterns use negative electron-sensitive resists; is exposed to electrons through a master plate with precisely arranged holes. can be formed more easily.

After development and post-baking, the exposed oxide film is covered with buffered oxygen to leave circular islands. During side etching, even the silicon substrate is etched. This circular island is the next life This serves as a mask for the boron diffusion step. This film (resist) is removed. and then a gas mixture at about 1,200°C (typical composition gases include diborane and The boron glass is deposited by placing the sample in a 3-hour atmosphere (containing oxygen and oxygen) for 3 hours.

This deposited glass is removed in a high frequency microwave and the wafer is heated in a 200° C. It is reheated and then placed in N2 for at least 4 hours to allow boron fixation.

In this final step, the boron layer is diffused and settled on both sides of the wafer to a depth of about 10 μm. , a coating having a density of 7X'1O19 atoms/d or more is formed.

The front side of the wafer is protected by a plastic mask such as 1 Krylon. The oxide layer is removed from the bottom surface using a buffered oxide etch. here The plastic layer shall be cleaned in isopropyl alcohol (toluene cleaning) and dried with N2 hot air.

Add p to 5.6ω ethylenediamine, and add 2.2Cr-N20 to this. completely etched in (added). This etching is caused by agglomeration under a nitrogen atmosphere. 8 at 110℃ in the condensing system Completed by placing for ~16 hours.

This anisotropic etching selectively removes silicon in orientations other than the (111) direction. However, etching is effectively stopped when only the (111) plane is maintained. completion The etched silicon wafer was removed and placed in N20 at 90°C to remove any residue. placed, further washed with isopropyl alcohol, and dried with N2 warm air. .

Finally, the remaining oxide is removed by buffered oxide etching, leaving the entire lens intact. Carefully cleaned in isopropyl alcohol and then dried with N2 hot air .

As mentioned above, a preferred embodiment of the present invention includes screen lenses each having an aperture. Plates 10G, (200) forming lenses and having larger openings are placed back to back. It is treated in a way that supports it. This assembly requires two plates (10G, (2 00) in direct surface contact to maintain the alignment of specific openings, Either maintain the flatness of the outside, or create a larger space between the diaphragm aperture plate and the lens plate. A spacer plate (300) having a large aperture is arranged to adjust the thickness of the lens plate and the diaphragm aperture plate. It is possible to form a desired aperture and lens elements with a spacing that is independent of the image quality.

As a screen lens, it is preferable to use a two-plate structure. Plate (400) of a single lens element (or diaphragm aperture element) with small optical resolution It is also possible to use A relatively small hole (410) is used as the diaphragm aperture. A relatively large hole (420) is used as the lens element. (in this case , the diameter of the lens hole is about 15 stg (about 0,75111111). Therefore, the foregoing description of the preferred embodiment of the invention Without limiting the scope of the present invention, the present invention is defined in the claims. It is limited only to

Engraving (no changes to the content) main Procedural amendment (formality) Commissioner of the Patent Office l Incident display PCTz4JS811005952, name of invention Screenrec Person who corrects movement method 3 of lens array plate 3Ji? ’l and σ・Relationship Permit applicant name (name) Heko Instruments The number of inventions will increase due to the Incoholated 6 amendment 7. Subject of amendment: clear alc, claim moving area, and translation of drawings 8. Contents of amendment Yamameishi Station 11:’; Engraving of the range of knowledge and translation of the drawings (no changes to the content).

9 Tsuyoshi Tsuyoshi♂ Vessel Catalog

Claims (1)

[Claims] 1 Thickness approximately 0. Screen lens array plate is made from a 5m circular silicon wafer. A method for forming, a) polishing both sides of the silicon wafer; b) polishing both sides of the silicon wafer; A high-density, porous oxide film with a thickness of approximately 2 μm is formed by oxidizing the C) Both sides of the silicon wafer are patterned in a predetermined pattern using photolithographic technology. d) by diffusively depositing boron on both sides of said wafer; , a boron layer with a depth of about 10 μm and a boron density of about 7×1019 atoms ZCrl was formed. Etching and drying until formed through A method for manufacturing a screen lens array plate, characterized in that: 2. Create a screen lens array plate from a circular silicon wafer 1 with a thickness of approximately 0.5 mm. A method for manufacturing, a) polishing both sides of the silicon wafer; b) polishing both sides of the silicon wafer; A high-density, porous oxide film with a thickness of approximately 2 μm is formed by oxidizing the C) Both sides of the silicon wafer are coated with a predetermined pattern using electron beam lithography. exposed in a pattern, d) Diffusely depositing boron on both sides of the wafer to a depth of approximately 10 mm. A boron layer with a boron density of about 7×1019 atoms/d in μm is formed, and e) said sheet until said predetermined pattern is formed through the thickness of said wafer/M. Anisotropically etching recon wafers A method for manufacturing a screen lens array plate, characterized in that: 3 Circular silicon wafer color screen lens array with a thickness of approximately 0.51ffff - A method for manufacturing a board, the method comprising: a) polishing both sides of the silicon wafer; b) polishing both sides of the silicon wafer; A high-density, porous oxide coating with a thickness of about 2 μm is formed by oxidizing the c) Forming a uniform layer of a thin negative photoresist film on both sides of the silicon wafer. , d) Both sides of the silicon wafer are patterned in a predetermined pattern by photolithography. e) Develop the exposure pattern of the photoresist film, and f) E-etch the exposed oxide film. g) removing the remaining photoresist film; 1]) Heat each of the wafer and oxide film surfaces at about 1.200°C for 3 hours. depositing boron; l) diffusing boron on both sides of the wafer to a depth of about 10 m; The remaining boron layer has a boron density of more than about 7×10 atoms/i in the μm range. formed within the area not protected by the oxide film, J) Remove the remaining oxide film by etching, and k) heating the silicone until the predetermined pattern is formed through the thickness of the wafer; Anisotropically etching a cone wafer and,! =1) A method for manufacturing a screen lens array plate. 4. Fabricate a circular silicon wafer color screen lens array plate with a thickness of approximately 0.5 m. It is a useless method to create a) polishing both sides of the silicon wafer; b) polishing both sides of the silicon wafer; By oxidizing, a high-density, porous oxide film with a thickness of about 2 μm is formed forming a uniform layer of a thin negative sensitive film on both sides of the silicon wafer; d) Both sides of the silicon wafer are coated with predetermined patterns using electron beam lithography. exposed in a pattern, e) developing the exposed pattern of the sensitive layer; and f) etching the exposed oxide layer. g) removing the remaining sensitive film; h) The surface of the wafer and the oxide film are each heated at 1.200°C for 3 hours. coated with urin, l) Diffusion of boron on both sides of the wafer to a depth of about 10 μm The remaining boron has a boron density of more than about 7 x 1019 atoms/i in the formed in areas not protected by the existing oxide film, J) Remove the remaining oxide film by etching, and k) heating the silicone until the predetermined pattern is formed through the thickness of the wafer; Anisotropically etching a cone wafer A method for manufacturing a screen lens array plate, characterized in that: 5. From two plates formed according to the manufacturing method described in claim 1. Each plate has an array of openings formed in a predetermined pattern, and each plate has a corresponding so that the aperture arrays are aligned with each other and their outer surfaces are substantially parallel. A screen lens array characterized by being formed by joining. 6. From two plates formed according to the manufacturing method described in claim 2. and each plate has an aperture array in a predetermined pattern, and the two plates are arranged in a predetermined pattern. bonded so that the aperture arrangements of the two are aligned with each other and the surfaces are substantially parallel. A screen lens array characterized by the following. 7 Consisting of two plates formed according to the method described in claim 3 , each of the plates has an opening array formed in a predetermined pattern, and the two plates are arranged in a predetermined pattern. The aperture arrays are aligned with each other and the surfaces are substantially parallel and in contact. A screen lens array characterized in that it is formed by combining the lenses together. 8. From two plates formed according to the manufacturing method described in claim 4. Each plate has an opening array formed in a predetermined pattern, and the two plates are The aperture arrays are aligned with each other and the outer surfaces are substantially parallel and touch each other. A screen lens array characterized in that it is formed by combining 9 Consisting of a single plate formed according to the method described in claim 1 Screen lens array. 10 Made of a single plate formed according to the method described in claim 2. screen lens array. 11 From a single plate formed according to the method described in claim 3 A screen lens array. 12. From a single plate formed according to the method described in claim 4 Screen Lens ° Array.