JP2002313692A - Alignment mark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesive strength of an alignment mark. SOLUTION: The alignment mark is positioned on a scribe line formed on a semiconductor wafer in order to arrange chips in matrix, and the mark is longer in the extending direction of the scribe line than the widthwise direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an alignment mark. More specifically, the present invention relates to an alignment mark formed on a semiconductor wafer in which a plurality of chips are arranged in a matrix through scribe lines using a stepper.

[0002]

2. Description of the Related Art FIGS. 3A to 3D are schematic views of alignment marks according to the prior art. FIGS. 3A and 3C are views of the alignment marks 3 and 4 formed on the Si substrate 1 or on the insulating film 5 made of the oxide film 2 or the polyimide film on the Si substrate 1 as viewed from above. is there. FIGS. 3B and 3D are AA in FIGS. 3A and 3C.
It is a schematic sectional drawing of a line.

In the prior art, as shown in FIGS. 3A and 3B, a scribe line 6 having a width of 80 to 100 μm is formed.
The oxide film formed in the diffusion and oxidation steps is patterned by a photolithography step to form a width of 5-1.
An alignment mark 3 having a length of about 0 μm and a length of about 60 μm is formed. Alternatively, as shown in FIGS. 3C and 3D, on the oxide film 2 or the insulating film 5 made of a polyimide film,
An alignment mark 4 having the same shape as that of FIG. 3A is formed by metal.

[0004]

SUMMARY OF THE INVENTION Among the above prior arts,
When forming an alignment mark with an oxide film on a scribe line, the alignment mark may be damaged in a process after the formation of the alignment mark. For example, in the electrode forming step, an electrode is formed by forming a metal layer once and etching it. At this time, the alignment mark is etched and peeled off, or the metal (for example, AlSi or the like) is aligned as a residue. In some cases, damage such as sticking to marks occurred. Particularly, in the multi-layer metal process, the metal layer is formed twice and etched twice, so that the number of times of damage is increased. Therefore, there has been a problem that alignment cannot be performed in a photolithography process as a final process such as formation of a cover film. Further, even when the alignment mark is formed of metal on the oxide film 2 or the insulating film 5, there is a problem that the adhesion of the alignment mark is deteriorated at the time of etching the metal layer and the alignment mark is peeled off.

[0005]

Thus, according to the present invention, a plurality of chips are arranged on a scribe line formed on a semiconductor wafer for arranging a plurality of chips in a matrix,
An alignment mark is provided that is longer in the direction in which the scribe line extends than in the width direction of the scribe line.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. Embodiment 1 FIG. 1A is a schematic plan view of the most basic alignment mark. In FIG. 1A, reference numeral 4 denotes an alignment mark, and reference numeral 6 denotes a scribe line. The scribe line 6 extends in the left-right direction, and the alignment mark 4
Is longer in that direction. Here, the extent of the alignment mark is not particularly limited as long as it is longer in the direction in which the scribe line extends than in the width direction of the scribe line. For example, the ratio between the width direction and the extending direction is preferably in the range of 1.5 to 3, where 1 is the width direction. Although FIG. 1A illustrates an example of a “+” type alignment mark, the present invention is not limited to this shape, and any shape such as an ellipse or an irregular shape may be used as long as it has the above-described length relationship. Shape may be used. When the shape is “+” type, the length of the scribe line in the extending direction is generally 80 to 100 μm, but in the present invention, it is 150 to 30 μm.
It is preferable to further extend the thickness by 0 μm. The width is 5 to 1
It is about 0 μm.

The alignment mark may be made of any material such as a metal (for example, the same material as the electrode) or an insulator (for example, oxide) as long as it can be used for alignment. The method of forming the alignment mark
It comprises a laminating step, a photolithographic step, and an etching step in which conditions are selected according to the material used. The laminating step includes a thermal oxidation, vapor deposition, CVD step or the like when the alignment mark is made of an insulating material, and a vapor deposition step or the like when the alignment mark is made of metal. The thickness of the alignment mark is
Although not particularly limited, it is usually about 1 to 3 μm. The scribe line is formed on the substrate or on an oxide film or a resin film (for example, a polyimide film) on the substrate. Here, examples of the substrate include a semiconductor substrate such as a Si substrate and a GaAs substrate, and an insulating substrate such as a glass substrate and a resin substrate. FIG. 1A is a schematic sectional view taken along line AA of FIG.
(B). In FIG. 1B, the alignment mark 4
Are formed on an oxide film 2 formed on a substrate 1.

As described above, by extending the alignment mark in the direction in which the scribe line extends, the area in which the alignment mark is in close contact with the layer below the alignment mark can be increased, so that peeling of the alignment mark can be prevented. The alignment mark can be used as a positioning target of an alignment device based on image recognition.

Second Embodiment In a second embodiment, as shown in FIG. 1C, a pair of restraining patterns 2a are provided at the ends of the alignment marks of the first embodiment in the direction in which the scribe lines extend. Thus, by providing the suppression pattern, it is possible to prevent the alignment mark from peeling off. The shape of the suppression pattern is not particularly limited, and other than the square in FIG.
Any shape such as a circle, a triangle, and an irregular shape may be used.
Further, the suppression pattern may be made of the same material as the alignment mark, or may be made of a different material. Specifically, a metal (for example, the same material as the electrode), an insulator (for example, an oxide), and the like are given. The formation method can be appropriately selected depending on the material to be used. The above-mentioned suppression pattern can be used alone or together with the alignment mark as a positioning target of an alignment apparatus by image recognition.

Third Embodiment FIGS. 1D and 1E are a schematic plan view and a cross-sectional view taken along the line AA of a third embodiment. Reference numeral 1 denotes a substrate, 4 denotes an alignment mark, 5 denotes an insulating film such as a polyimide film, 7 denotes a through hole, and 8 denotes a base layer. In this embodiment, the alignment mark 4 is in contact with the base layer 8 at the through hole 7, and such a structure is referred to as a through hole chain structure. Here, as a material of the base layer 8, a metal (for example, the same material as the electrode), an insulator (for example, an oxide), or the like can be used. Further, if the base layer 8 and the alignment mark 4 are made of the same material, the adhesion between the base layer 8 and the alignment mark 4 is further improved, and the alignment mark can be prevented from peeling off.

[0011] The size of the through hole is not particularly limited as long as the alignment mark can be prevented from being peeled off.
It is preferably about 80%. The number of through holes can be appropriately set so as to be within the above-mentioned size range. A suppression pattern as in Embodiment 2 may be formed on the alignment mark. FIG. 2 (e)
An example of a method for forming an alignment mark having a through-hole chain structure will be described with reference to FIGS. In this example, a Si substrate is used for the substrate 1, a polyimide film is used for the insulating film 5, and a metal layer (for example, AiSi) is used for the alignment marks 4 and the base layer 8. First, FIG.
1A, an oxide film 2 is formed on a Si substrate 1 and a base layer 8 is formed by a sputtering method or the like. next,
As shown in FIG. 2B, the base layer 8 is patterned by using a photolithography technique. Next, as shown in FIG. 2C, an insulating film 5 covering the base layer 8 is formed by a known method.

Further, as shown in FIG.
Is patterned using a photolithography technique. Through this patterning, a through hole 7 is formed. next,
As shown in FIG. 2E, an alignment mark 4 is formed on the entire surface.
A material layer for formation is formed. Next, as shown in FIG. 2F, the alignment mark 4 is formed by patterning the material layer for forming the alignment mark 4 using a photolithography technique. Since the alignment marks 4 obtained in the above steps are in contact with the base layer made of the same material, they have excellent adhesion. In addition, each of the above steps is
By using the manufacturing process of the semiconductor device formed on the semiconductor wafer, the alignment mark can be formed without increasing the manufacturing process of the semiconductor device.

[0013]

According to the present invention, since the adhesion of the alignment mark is improved, the alignment in various steps can be stably performed.

[Brief description of the drawings]

FIG. 1 is a schematic view of an alignment mark of the present invention.

FIG. 2 is an example of a method for manufacturing an alignment mark according to the present invention.

FIG. 3 is a schematic view of a conventional alignment mark.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Oxide film 2a Suppression pattern 3, 4 Alignment mark 5 Insulating film 6 Scribe line 7 Through hole 8 Base layer

Claims (6)

[Claims] 1. An alignment mark which is located on a scribe line formed on a semiconductor wafer for arranging a plurality of chips in a matrix and is longer than a width direction of the scribe line in a direction in which the scribe line extends. 2. The alignment mark according to claim 1, wherein a suppression pattern for improving the adhesion of the alignment mark is further formed. 3. The alignment mark is formed on an insulating film on a scribe line, and the alignment mark is connected to a first-layer metal formed on the insulating film via a through hole. Alignment mark described in. 4. The alignment mark according to claim 3, wherein the through hole has a mesh pattern. 5. The alignment mark according to claim 1, wherein the alignment mark is used as a positioning target of an alignment apparatus based on image recognition. 6. The alignment mark according to claim 2, wherein the suppression pattern is used as a positioning target of an alignment device based on image recognition.