JPS60192332A - Semiconductor substrate with positioning mark and method for detection of marked position on substrate - Google Patents

Abstract

PURPOSE:To detect the reference position without fail even when the position of a scanning charged beam is shifted as well as to enable to perform a position detection smoothly even when different exposing methods are used in combination by a method wherein a pattern-line- combined positioning mark, having the line width differentiated in proportion to the distance in X-Y axis direction with the reference position as the center point, is provided. CONSTITUTION:A mark 11 is constituted by combining three pattern lines, for example, in X and Y axial directions having a different line width respectively in accordance with the distance between the reference position P and the X-Y axial direction. Pertaining to the width of said pattern lines in the X-axis direction lines, for example, the center pattern line 11a which passes the reference position is formed at 15mum in width, the pattern line 11b located at the lower part parting 70mum from the pattern line 11a, is formed at 10mum in width, the pattern line 11c located at the upper part parting 70mum from the pattern line 11a is formed at 20mum in width, and the lines in Y-axis direction are also formed in the same manner as above. A charged beam 6 is scanned in X and Y axis direction on the positioning mark 11, the width of the pattern lines is detected by the obtained mark signal, and the reference position P of the positioning mark 11 is detected.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an alignment method in which an alignment mark is formed on a semiconductor substrate such as a semiconductor wafer, and the reference position of the mark is detected by scanning a charged beam. 0 Regarding semiconductor substrates with marks and methods for detecting mark positions on such substrates [Prior art] In the manufacturing process of semiconductor substrates, there are cases in which very fine circuit patterns of approximately 1 μm or less are required, and in cases where small-scale production of a wide variety of products is required. Charged beam exposure such as electron beam exposure and ion beam exposure has come to be frequently used in development and manufacturing.

In such charge beam exposure, a dedicated alignment mark is used to precisely overlap the circuit pattern to be exposed with the circuit pattern formed in the previous process.

Alignment marks are attached to the circuit pattern or to the semiconductor wafer (hereinafter referred to as "wafer"), and these marks are scanned during charged beam exposure, and the reflected beam, secondary electrons, and other signals obtained are used to I try to set the reference position of the mark.

Such a wafer with alignment marks is shown in plan view in FIG. The wafer (1) has many chip parts (2
) are classified. (3) are alignment marks (hereinafter referred to as "marks"), which are placed at three locations A, B, and C.

Prior to charged beam writing, move marks A and B over the mark (3).

Scan in the order of 0, find each coordinate, and set the X of the coordinate system to be exposed.
, the conventional marks on the 0 wafer (1) that determine the gain and rotation in the Y-axis direction are shown in an enlarged view in FIG. (4) is a mark, which is formed in a cross shape with the same line width. (6) represents a charged beam scanning over mark (4). P indicates the reference position of mark (4).

Another example of the conventional mark is shown in an enlarged view in FIG. 3, and the mark (7) is formed in an L-shape with the same line width.

In the case of the wafer (1) with the conventional marks described above, if the coordinate system of the exposure apparatus and the coordinate system of the wafer (1) are largely misaligned, the reference position P of the marks (4) and (71) cannot be found. is shown in Fig. 4, the scanning charged beam (6) deviates significantly from the mark (4), and the reflected signal from the mark (4) cannot be obtained.Also, even if it is obtained, it will be an incorrect signal, There was a problem in that the reference position P of the mark (4) could not be set.

In this case, conventionally, the operator had to move the wafer (1) and search for the mark (4) position, which hindered automation. , or different exposure methods (e.g. electron beam exposure method and light exposure method)
[Summary of the Invention] This invention was made to eliminate the drawbacks of the above-mentioned conventional products.
An alignment mark that combines multiple pattern lines in the X-axis and Y-axis directions with different line widths depending on the distance in the axis and Y-axis directions is made on the semiconductor substrate, and the alignment mark is The charged beam is scanned in the X-axis and Y-axis directions, and the pattern line width is detected using the obtained mark signal.The reference position of the alignment mark is detected from this, and the scanned charged beam is scanned from the alignment mark. Semiconductor substrates with alignment marks that can reliably detect the reference position even if the position is misaligned, and enable position detection without any problems even in the exposure process that combines different exposure methods, making automation possible. The present invention also aims to provide a method for detecting a mark position on this substrate.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to an enlarged view of the alignment mark portion shown in FIG. α→ is the wafer (1
), which is a pattern line for three lines in the Y-axis and It consists of a combination of The line width of each of these pattern lines is, for example, in the X-axis direction line, the center pattern line (lla) passing through the reference position P is 15 μm, and the line width is 7 μm downward from this line.
The pattern line (11b) which is 0 .mu.m apart is 10 .mu.m, and the pattern line (llc) which is 70 .mu.m away from the pattern line (lla) on the upper side is 20 .mu.m. Still, in the Y-axis direction line, the center pattern line (lld) passing through the reference position P is 15
μm, pattern line (11
θ) is 10 μm, the pattern line (11f) is 70 μm to the right from the pattern line (1, 1111), and the pattern line (11f) is 20 μm apart.

We will explain the position detection method when the coordinate system of the wafer (1) using such mark 01) and the coordinate system of the exposure device are largely misaligned. Scanning with the beam (6) is performed with a scanning width of 60 μm. If no mark signal is obtained, shift the scanning position by 10 μm and scan the mark again. By repeating this operation, as shown in Figure 5, Then, a mark signal is obtained by scanning the mark αη.

In this way, if the mark α→ is scanned even slightly, from this mark signal, the mark 01 scanned by the electronic computer
) pattern line width. In the example shown, the X direction is 20
μm, Y direction is 20 μm 0 From this value, it can be seen that the coordinates determined by the current scan by the electronic computer are +70 μm in both the X direction and Y direction from the reference position P, and the reference point of the mark aη The position P can be detected and the wafer (1) position can be automatically corrected.

In this way, even if the coordinate system of the exposure apparatus is shifted by the formed mark αη, position detection can be performed without any problem and automation can be achieved.

In the above example, a mark 0η made of pattern lines for three trees in the Y-axis and X-axis directions is used, and its size is 160μ.
Although the case of m x 160 μm is shown, the shape is not limited to this, and it is preferable to use a mark having a size similar to the maximum deviation that can actually occur.

〔Effect of the invention〕

As described above, (1) according to the present invention, multiple trees in the Y-axis and An alignment mark made by combining the older brother's pattern lines is made on a semiconductor substrate, and a charged beam is scanned over this alignment mark in the X-axis and Y-axis directions, and the pattern line width is determined by the mark signal obtained. The reference position of the alignment mark is detected, and even if the position of the scanning charged beam deviates from the alignment mark, the reference position can be reliably detected and the semiconductor substrate can be exposed. Further, even in a process that combines different exposure methods, position detection can be performed without any problem and automation can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a semiconductor wafer with alignment marks, FIGS. 2 and 3 are enlarged plan views showing each side of conventional alignment marks, and FIG. 4 is a plan view of a semiconductor wafer with alignment marks. FIG. 5 is an enlarged plan view of an alignment mark portion of a semiconductor wafer showing an embodiment of the present invention. 1... Semiconductor wafer, 6... Scanning charged beam, 1
1... Alignment mark, 11a-llf... Pattern line Note that the same reference numerals in the drawings indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A plurality of lines in the Y-axis and A semiconductor substrate with alignment marks made from a combination of pattern lines. (2) The semiconductor substrate according to claim 1, wherein the alignment mark is in the form of a print. and a positioning mark formed by combining multiple pattern lines in the Y- and X-axis directions, each having a different line width depending on the distance in the Y-axis direction, is applied to the semiconductor substrate,
A charged beam is scanned over this alignment mark in the X-axis and Y-axis directions, and the line widths of the scanned pattern lines in the Y-axis and X-axis directions are detected using the obtained mark signals, and these line width values are detected. A method for detecting a mark position on a board, wherein a reference position of the alignment mark is detected from the reference position of the alignment mark. (4) The method for detecting the position of a mark on a substrate according to claim 3, wherein the alignment mark is in the form of a print.