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Showing papers on "Proximity effect (electron beam lithography) published in 1982"


Patent
Fletcher Jones1
03 Nov 1982
TL;DR: In this article, a lithographic exposure pattern is modified by moving or setting back the edges of each central part away from the perimeter part which surrounds it (similar to reducing the size of the central part).
Abstract: Proximity effect is reduced or eliminated by breaking each shape of a lithographic exposure pattern into two parts, a perimeter part having a width on the order of the lithographic exposure pattern minimum linewidth and the remaining central part or parts (if any) which are completely surrounded by the perimeter part. The lithographic exposure pattern is then modified by moving or setting back the edges of each central part away from the perimeter part which surrounds it (similar to reducing the size of the central part) to form a nominally unexposed band separating each central part from the perimeter part which surrounds it. The width of the nominally unexposed band in the modified exposure pattern is preferably chosen as large as possible so long as the condition is met that upon developing a radiation sensitive layer directly exposed to the modified exposure pattern, the nominally unexposed band develops (i.e., dissolves, resists dissolution, or is otherwise modified) substantially as if it were also exposed. The nominally unexposed band is exposed, in fact, by electrons scattered from the directly exposed part(s) of the shape (the perimeter part plus the central part, if any). The width of the nominally unexposed band is preferably about twice the edge bias applied to outside edges of each shape.

37 citations


Journal ArticleDOI
TL;DR: In this article, an EB Lithographic system using an FE electron gun and steered-beam vector scan was used to fabricate submicron resist patters with line width larger than 0.5 µm and gap spacing 1.0 µm.
Abstract: This paper describes the advantages of an EB Lithographic system using an FE electron gun and steered-beam vector scan to fabricate submicron patterns. Application of this system to submicron pattern writing is studied through exposure intensity distribution (EID) and exposure dosage for submicron patterns. The system can carry out submicron pattern writing with high resolution and small proximity effect. For example, the system provides submicron resist patters with line width larger than 0.5 µm and gap spacing 1.0 µm without proximity effect correction. The application of this system to VLSI submicron pattern writing is also demonstrated.

11 citations


Patent
24 May 1982
TL;DR: In this article, the authors proposed a method for simplification and high speed operation of the titled electron beam exposure by a method wherein a measure correction on the patterns which affect on proximity effect is performed by a pattern which represents the others, and then an irradiation dose is calculated in proportion to the size of the patterns.
Abstract: PURPOSE:To contrive simplification and high-speed operation of the titled electron beam exposure by a method wherein a measure correction on the patterns which affect on proximity effect is performed by a pattern which represents the others, and then an irradiation dose is calculated in proportion to the size of the patterns. CONSTITUTION:When the amount of measure correction pertaining to the side X of an oblong pattern P0 is going to be calculated, the pattern P3 which is in the shortest distance is extracted from among oblong patterns P1, P2 and P3 that are located in close vicinity to the side X opposing to it. This is done because the scattering intensity distribution of electron beam is reduced exponential functionally against the increase in distance from the beam center. Also, in the case where two or more of patterns are located in the same distance from the side X, the sizes of the patterns are compared, and the largest pattern among them is extracted. Then, the exposure intensity distribution 10 on the center line of the pattern is observed, and when there exists the influence of proximity effect, the slope is steep and when there is little proximity effect, the slope is gentle. The amount of measure correction required to have the slope less than the threshold value is calculated. Through these procedures an operation, wherein the amount of measure correction for each side will be determined, is repeatedly performed for each unit of oblong patterns, and the necessary amount of irradiation is calculated in proportion to the corrected size of the patterns.

6 citations


Patent
02 Sep 1982
TL;DR: In this paper, a fine mask pattern with high accuracy was created by fluorine containing plasma treatment two layers of high molecular bond with its upper layer patterned by charged particles and thereby making the surface layer of one of the layers resistive to dry etching.
Abstract: PURPOSE:To form a fine mask pattern with high accuracy, by fluorine containing plasma treatment two layers of high molecular bond with its upper layer patterned by charged particles and thereby making the surface layer of one of the layers resistive to dry etching. CONSTITUTION:An Az1350J layer 103 for example is coated making the surface flat on an Si substrate 101 on which an oxide film, for example is formed. After forming a pattern by electron beam exposure providing, for example, a styrene resist layer 104, an dry-etching resistive modified layer 105 is formed on the patterned surface by exposing to a plasma of, for example, CF4. Then an oxygen plasma treatment is performed by a paralled flat plate type device, and a pattern consisting of the Az1350J layer 103 is formed utilizing the difference of etching speed, followed by oxide film etching. An organic material layer having vinyl base is formed in the lower layer and a negative resist pattern of PGMA and the like is formed in the upper layer and a positive type pattern is formed in the lower layer by a similar treatment. A fine pattern is thus formed not affected by side etching or proximity effect.

3 citations



Proceedings ArticleDOI
TL;DR: In this article, the advantages of high voltage electron beam lithography in submicron VLSI fabrications have been established, and the pattern size variation due to the proximity effect is within 0.05 µm for line patterns ranging from 10 µm to 0.25 µm.
Abstract: The advantages of high voltage electron beam lithography in submicron VLSI fabrications have been established. By electron beam lithography with 50 kV acceleration voltage, vertically walled PMMA pattern is obtained at a relatively low dose, 50 µC/cm2. This fact, combined with the increase in beam current, brings about the improvement of throughput in 50 kV writing by a factor of 5 over 20 kV writing. Proximity effect is markedly reduced in 50 kV writing. The pattern size variation due to the proximity effect is within 0.05 µm for line patterns ranging from 10 µm to 0.25 µm. Vertically walled PMMA pattern of 0.25 µm space, which is equal in size to the beam spot, is obtained at 50 µC/cm2 in 50 kV writing. In addition, it is shown that radiation damage of MOSFET's due to the 50 keV beam is essentially the same as that due to 20 keV beam.

2 citations


Patent
15 Mar 1982
TL;DR: In this paper, the resist pattern was obtained by exposing a large area section and a bridge section by slightly small amount of irradiation and exposing both sides of the bridge through thin beams by a slightly large amount of radiation.
Abstract: PURPOSE:To minimize a proximity effect of electron beams, and to obtain the minute pattern by exposing a large area section and a bridge section by the slightly small amount of irradiation and exposing both sides of the bridge through thin beams by the slightly large amount of irradiation. CONSTITUTION:The large area section and the bridge section are exposed by the amount of irradiation 42 slightly less than the proper amount of irradiation, and both sides of the bridge are doubly exposed through thin beams by the amount of irradiation 41 slightly more than the proper amount of irradiation. The resist pattern 2 with the bridge section 10 according to the design is formed because the electron beams are reflected by a substrate 3 and are more than the proper amount of irradiation.

2 citations


Patent
15 Mar 1982
TL;DR: In this article, an opaque mask is attached to the top surface of a transparent substrate, which transmits light, and a resist 13 for electrosensitization is attached on the top of this mask.
Abstract: PURPOSE:To improve resolution and proximity effect by attaching an opaque mask to the surface of a transparent substrate, and forming this substrate or mask of a light element metal or its compound or alloy of a small coefft. of reflection of electrons. CONSTITUTION:An opaque mask 12 which shuts off light is attached onto the top surface of a transparent substrate 11 which transmits light, and a resist 13 for electrosensitization is attached on the top surface of this mask 12. The substrate 11 is formed on the top surface of this mask 12. The substrate 11 is formed of LiB type glass, for example, 30% lithium and 70% boron oxide, and its coefft. of reflection of electrons is extremely small. The LiB type glass forming the substrate 11 is mixed with alumina, magnesia, etc. so that its coefft. of thermal expansion is set low. The mask 12 is formed of carbon and its coefft. of reflection of electrons is extremely small as compared to chromium or the like, and the resist 13 is drawn to prescribed patterns by electron beams.

1 citations