JPS6210010B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing integrated circuits and the like using electron beam exposure, and in particular improves the method of detecting the position of an electron beam in aligning an electric wire and a pattern during pattern production. be.

BACKGROUND ART Conventionally, a method has been used in which a pattern of an integrated circuit or the like is exposed using an electron beam. In this case, when exposure of a pattern is repeatedly performed on the same substrate, it is necessary that the mutual alignment of the electron beam and the pattern is performed accurately.

To this end, it has been conventional practice to attach irregularities to the substrate as position reference marks, and scan the area containing the position reference marks with an electron beam to detect the positional relationship between the electron beam and the substrate. There is.

Therefore, the present inventor has proposed the use of protrusions with burrs formed by re-deposition during etching as marks as a high-speed and highly accurate positioning method.

This will be explained in detail with reference to the process sectional view of FIG.

(1) A film 2 on which element patterns and marks are to be formed is deposited on a substrate 1, and then a resist 3 is spin-coated to form a resist pattern of position reference marks and element patterns.

(2) Appropriately select the film thicknesses of the film 2 and the resist 3, and ion-etch the film 2 using the resist pattern as a mask to form a burr 5 around the position reference mark 4 (About the formation of burrs) (See Proceedings of the 11th Semiconductor/Integrated Circuit Technology Symposium (1976), p. 38).

(3) After peeling off the resist 3, apply an electronic resist 7, scan the area including the position reference mark 4 with an electron beam, and detect the relative position of the mark 4 and the electron beam to form the element pattern 6. A pattern of electronic resist 7 is formed in a desired positional relationship.

By doing so, high-speed and highly accurate positioning is possible.

However, as shown in FIG. 1, this method has the disadvantage that burrs are also formed on the element pattern 6, and these burrs have an adverse effect on the film deposited on the element pattern, such as by cutting off steps. are doing.

The electron beam position detection method according to the present invention solves the drawbacks of the above methods, does not create burrs on the element pattern,
By creating burrs only on the marks, high-speed, high-precision electron beam position detection is possible.

According to the present invention, by arranging the position reference mark in the recess, high-speed and highly accurate electron beam position detection can be performed without affecting the element pattern.

Hereinafter, steps related to electron beam exposure in the method for manufacturing an integrated device according to the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a cross-sectional view of the electron beam position detection step in the present invention.

(1) A recess 21 is formed on the substrate 1 at a location where a position reference mark is to be placed. (The depth is assumed to be D) (2) A film 2 on which element patterns and marks are to be formed is deposited on the substrate 1, and then a resist 3 is spin-coated. The concave portion 21 of the substrate 1 remains as it is for the film 2.
However, since the resist 3 is a fluid during film formation, almost no recesses remain. The lower the viscosity of the resist, the smaller the difference in the unevenness of the resist surface between areas corresponding to the recesses on the substrate and other areas. Furthermore, even if the resists have the same viscosity, the smaller the width of the recesses, the smaller the difference in unevenness on the resist surface. The small unevenness of the resist surface means that the resist film thickness above the recesses 21 on the substrate is thicker than at other parts.

(3) This resist 3 is positioned so that the position reference mark is located at the recess 21, and a resist pattern of the position reference mark and the element pattern is formed.

(4) The resist film thickness H at the flat area should be determined in consideration of the film thickness of the film 2 and the etching speed so that no burrs appear on the pattern at the flat area. When ion etching is performed with such a resist film thickness to form the element pattern 6 and the position reference mark 4, the element pattern 6 has the optimum resist film thickness H, so there is no burr, but the resist of the position reference mark is Since the film thickness is approximately H+D, which is thicker than the optimum value H, burrs 5 can be created.

(5) After peeling off the resist 3, apply an electronic resist 7, scan the area including the position reference mark 4 with an electron beam, and detect the relative position of the mark 4 and the electron beam to form the element pattern 6. A pattern of electronic resist 7 is formed in a desired positional relationship.

By doing so, high-speed and highly accurate electron beam position detection can be performed without creating burrs on the element pattern.

Next, the present invention will be explained in detail using examples.

Alumina (Al ₂ O ₃ ) is deposited to a thickness of 3300 Å on the garnet. Next, a resist is applied, exposed and developed to form a pattern with windows opened only in the vicinity of the positions where position reference marks are to be placed, and recesses are formed in the alumina film by etching. Next, 3300 Å of Permalloy is deposited. next
AZ1350J resist (trademark; Shipley, USA) is applied to a thickness of 3300 Å on the flat area. At this time, the thickness of the recess is approximately 6600 Å. Next, the element pattern and position reference mark are exposed and developed to perform patterning. Next, using this resist pattern as a mask, ion etching is performed for 15 minutes at an acceleration voltage of 500V. By peeling off the resist,
A clean permalloy element pattern with no burrs and a permalloy position reference mark with burrs are formed. Then electronic resist PMMA
(Polymethyl methacrylate) is applied to a thickness of 6000 Å, the area including the position reference mark is scanned with an electron beam, the relative position of the mark and the electron beam is determined, and alignment with the existing pattern is performed. Ta. This was high-speed and highly accurate positioning. Also, in the subsequent lamination process, since there are no burrs at the edges of the device pattern, there is no problem of step breakage, and a good device can be obtained.

In the above embodiment, the etching method was used to form the concave portion of the substrate, but the same effect can be obtained by using the lift-off method.

As explained above, according to the present invention, it is possible to remove the burrs at the end of the element pattern that adversely affect the process after mark formation, and it is possible to apply burrs only to the marks, making it possible to use marks with burrs. This makes it possible to perform high-speed and highly accurate positioning.

[Brief explanation of the drawing]

FIG. 1 is a process cross-sectional view for explaining an electron beam position detection method using a protrusion with burrs, in which 1 shows a state in which a film and a resist pattern are formed on a substrate, 2
3 shows a state where ion etching has been performed, and 3 shows a state where a resist has been applied. FIG. 2 is a process cross-sectional view for explaining the electron beam position detection process in the present invention, 1 is a state in which a recess is formed on the substrate, 2 is a state in which a film and a resist film are formed, and 3 is a state in which a resist pattern is formed. 4 shows a state in which ion etching was performed, and 5 shows a state in which a resist was applied.

Claims (1)

[Claims] 1. In an integrated device manufacturing process that includes an electron beam exposure process in which unevenness provided on the surface of the object to be processed is used as an electron beam positioning mark, the positioning mark is a protrusion having burrs made of redeposited matter during etching. , and the protrusion is arranged in a recessed part of the substrate.