JP2001210572A - Method for forming alignment marking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which will not cause the trouble of forming an alignment mark for a device part in an upper interlayer film, in a separate production process, and which can precisely determine the location for forming the device part. SOLUTION: A method includes the steps of forming on the bottom of a lower interlayer film 3B, an auxiliary mark 6 along with an alignment mark 2B for forming a device part 5B in the bottom interlayer film 3B, and setting the dimensions of the supporting mark 6 so as to have the same size as an alignment mark 2A for forming a device part 5A in an upper interlayer film 3A, so that the ruggedness, which appears on the bottom of the upper interlayer film 3A, is laminated on the bottom interlayer film 3B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for forming an alignment mark when a multilayer element is manufactured.

[0002]

2. Description of the Related Art In a multilayer film element such as a thin film magnetic head or a thin film integrated circuit, an insulating interlayer such as alumina or silica is laminated on a substrate and a circuit element is formed in the interlayer by a photolithography process. Has been done. Then, alignment marks are used for accurate positioning of the substrate and the photomask in such a process.

For example, when manufacturing a thin film magnetic head, a ceramic substrate 1 made of AlTiC or the like as shown in FIG.
After forming a separation layer such as a Cu material on the entire surface of the substrate, devices forming yokes of a NiFe material, coils and lead wires of a Cu material, wiring connection pads of an Au material, etc. are formed in a large number of shot areas 11 on the substrate 1. The portions are sequentially formed by a photolithography process using step-and-repeat exposure, and each device portion is laminated while being appropriately insulated from each other by an insulating interlayer film of alumina.

At this time, it is necessary to align the substrate 1 and the photomask so that the device pattern already formed on the substrate 1 and the projection pattern of the photomask accurately match each other. As shown, an alignment mark forming area 13 is secured separately from the device forming area 12. In the alignment mark forming area 13, for example, a plurality of alignment marks 2 are formed at left and right symmetric positions, and a pair of alignment marks 2 which are usually at left and right symmetric positions are used for alignment. As shown in FIG. 5, an example of the alignment mark 2 has a cross-shaped recess capable of positioning in the X and Y directions in a square area of 200 μm in a width of about 2 to 5 μm and a depth of about 0.1 to 0.1 μm. 5 μm
Is formed. In the cross-sectional views of the laminated film described below, the thickness of the device portion or the interlayer film and the depth of the alignment mark are drawn differently from the actual ratio for easy understanding.

By the way, device parts such as a yoke and a coil are formed by plating. In this case, prior to forming a new device part 5A in the upper interlayer film 3A as shown in FIG. The lower surface of interlayer film 3A (that is,
A plating seed layer 4A is formed on the entire surface (upper surface of the lower interlayer film 3B) (FIG. 6 shows the plating seed layer after removing unnecessary portions). Since the plating seed layer 4A does not transmit alignment light, its lower surface (that is, the lower interlayer film 3C) for forming the device portion 5B in the lower interlayer film 3B is formed.
Cannot be used for forming a new device portion 5A, and a new alignment mark 2A needs to be formed on the lower surface of the upper interlayer film 3A as shown in FIG.

[0006]

However, the upper interlayer film 3
The alignment mark 2A formed on the lower surface of A keeps a predetermined relative positional relationship with the alignment mark 2B on the lower surface of the lower interlayer film 3B (FIG. 6 shows a state after being crushed by the deposition of the plating layer). Therefore, there is a problem that the number of steps increases accordingly. The upper interlayer film 3 formed with reference to the alignment mark 2A (FIG. 6 shows a state after being crushed by the deposition of the plating layer).
The position of the device section 5A in A is the alignment mark 2
There is also a problem that a cumulative error for the device portion 5B in the lower interlayer film 3B formed with reference to B through the alignment mark 2A occurs.

In view of the above, the present invention has been made to solve such a problem, and does not require the trouble of forming an alignment mark for a device portion in an upper interlayer film in a separate step. An object of the present invention is to provide a method of forming an alignment mark that can be accurately determined without causing an error.

[0008]

According to the present invention, there is provided an alignment mark used for positioning a substrate when a multilayer film element is formed by laminating an interlayer film on a substrate by a photolithography process. The auxiliary mark (6) is formed on the lower surface of the lower interlayer film (3B) together with the alignment mark (2B) for forming the device portion (5B) in the lower interlayer film (3B). The size of the auxiliary mark (6) is formed, and the unevenness of the auxiliary mark (6) appears on the lower surface of the upper interlayer film (3A) laminated on the lower interlayer film (3B) and the device in the upper interlayer film (3A) is formed. Alignment mark (2A) for forming part (5A)
Set the size so that

In the present invention, on the lower surface of the lower interlayer film,
An auxiliary mark is formed in addition to an alignment mark for forming a device portion in the lower interlayer film, and irregularities of the auxiliary mark appear on a lower surface of the upper interlayer film to form a device portion in the upper interlayer film. Since it becomes an alignment mark, the trouble of forming the alignment mark on the upper interlayer film in a separate step can be omitted. In addition, this makes it possible to accurately position the device portion without causing a cumulative error when positioning the device portion in the upper interlayer film by passing through the two alignment marks as in the related art.

[0010] The reference numerals in parentheses indicate the correspondence with specific means described in the embodiment described later.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a sectional view of a laminated film in a shot region 11 (FIG. 4) to which the method of the present invention is applied. In FIG. 1, the lower surface of the lower interlayer film 3B has a cross-shaped planar shape described in the prior art (FIG. 5), and has an alignment mark 2B at a predetermined depth and width (FIG. Is formed, and the substrate and the photomask are positioned by the alignment mark 2B to form the device portion 5B in the lower interlayer film 3B.
On the lower surface of the lower interlayer film 3B, there is further provided a concave auxiliary mark 6 having the same shape as the planar shape of the alignment mark described in the above-mentioned prior art and having an appropriate width and depth which is enlarged to a predetermined size. Is formed.

When these are covered with the lower interlayer film 3B after the formation of the device portions 5B, the upper surface of the lower interlayer film 3B has alignment marks 2B, auxiliary marks 6 formed on the lower surface, and irregularities of the device portion 5B. Irregularities 31, depending on
The concave portion 32 or the convex portion 33 appears. The uneven portion 3
1, the size of the concave portions 32 and the convex portions 33 are drawn differently from the actual ratios for easy understanding.

Thereafter, for example, a plating seed layer 4A (FIG. 2 shows a plating seed layer after removing unnecessary portions) is formed on the entire upper surface of the lower interlayer film 3B. Since the auxiliary mark 6 having a width and depth obtained by enlarging the size of a normal alignment mark is appropriately reduced and appears on the upper surface of the lower interlayer film 3B (that is, the lower surface of the upper interlayer film 3A), It has the same width and depth as a normal alignment mark. Therefore, the device portion 5A in the upper interlayer film 3A can be formed by using the recess 32 as an alignment mark 2A (FIG. 2 shows an alignment mark after being crushed by deposition of a plating layer).

As described above, according to the present embodiment, the device portion 5 in the lower interlayer film 3B is provided on the lower surface of the lower interlayer film 3B.
In addition to the alignment mark 2B for forming B, a concave auxiliary mark 6 having a size obtained by enlarging the width and depth of a normal alignment mark is simultaneously formed to form the upper surface of the lower interlayer film 3B, that is, the upper interlayer film 3A. Since the concave portion 32 that can be used as the alignment mark 2A appears on the lower surface, the trouble of forming the alignment mark 2A for positioning the device portion 5A in the upper interlayer film 3A in a separate step can be omitted, and the conventional method can be achieved. Since there is no occurrence of a cumulative positioning error due to passing through the two alignment marks, the device section 5A can be accurately positioned. In the above embodiment, the auxiliary marks 6 and the alignment marks 2 formed by the auxiliary marks 6 are used.
A is not limited to a concave shape but may be a convex shape.

[0015]

As described above, according to the method of forming an alignment mark of the present invention, it is not necessary to perform a separate step of forming an alignment mark for a device portion in an upper interlayer film, and the formation of the device portion is not required. The position can be determined accurately.

[Brief description of the drawings]

FIG. 1 is a conceptual sectional view of a laminated film, showing one embodiment of the present invention.

FIG. 2 is a conceptual sectional view of a laminated film, showing one embodiment of the present invention.

FIG. 3 is a plan view of a ceramic substrate.

FIG. 4 is a conceptual plan view of a shot area.

FIG. 5 is a plan view of an alignment mark.

FIG. 6 is a conceptual cross-sectional view of a laminated film showing a conventional example.

[Explanation of symbols]

1 ... substrate, 2A, 2B ... alignment mark, 3A, 3
B: interlayer film, 5A, 5B: device part, 6: auxiliary mark.

Claims (1)

[Claims] In a method of forming an alignment mark used for positioning the substrate when a multilayer film element is formed by laminating an interlayer film on a substrate by a photolithography step, a lower surface of a lower interlayer film is provided. Along with alignment marks for forming device parts in the lower interlayer film,
An alignment mark for forming an auxiliary mark, and adjusting the size of the auxiliary mark to form a device portion in the upper interlayer film by forming the unevenness on the lower surface of the upper interlayer film laminated on the lower interlayer film A method for forming an alignment mark, wherein the alignment mark is set to have a size such that: