JPH04372163A - Manufacture of laminated substrates - Google Patents

Abstract

PURPOSE:To form a pattern aligned in high accuracy on a pattern disposed on an intermediate laminating surfaces after semiconductor substrates are laminated, on a polished surface. CONSTITUTION:After a pattern 2 is formed on a surface 1a of a first semiconductor substrate 1, a pattern 3 is formed in alignment with the pattern 2 on a rear surface 1b by a photolithography using a both-side mask aligner. Then, after a second semiconductor substrate 5 is laminated on a front surface 1a side of the substrate 1, a pattern 6 is again formed in alignment with the pattern 3 on the surface of the substrate 5 by a photolithography using the both-side mask aligner. Thereafter, after the substrate 1 is polished and etched to a predetermined thickness, a pattern 7 is further formed in alignment with the pattern 6 on the polished surface by a photolithography using the both-side mask aligner.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bonded substrate, and is suitable for application to, for example, manufacturing a three-dimensional semiconductor device.

0002

2. Description of the Related Art In recent years, a technique for manufacturing a three-dimensional semiconductor device by bonding a plurality of semiconductor substrates together has been attracting attention. Such a bonded substrate is usually manufactured by the following method.

That is, as shown in FIG. 3A, first
The surface (principal surface that is the element forming surface) 1 of the semiconductor substrate 101 of
After forming a pattern 102 constituting an element on 01a and forming the element by a method such as ordinary diffusion or ion implantation,
Adhesive material or polycrystalline silicon (Si) is applied to this surface 101a side.
A second semiconductor substrate 104 via an adhesive layer 103 such as a film.
Paste them together. Note that reference numeral 101b indicates the back surface (principal surface that is a non-element forming surface) of the first semiconductor substrate 101. Next, the first semiconductor substrate 101 or the second semiconductor substrate 1
04 is polished and etched to an appropriate thickness.

After that, the surface 1 of the first semiconductor substrate 101 is
The first semiconductor substrate 101 or the second semiconductor substrate 104 is patterned in accordance with the pattern 102 on 01a. That is, as shown in FIG. 3B, the first semiconductor substrate 1
01 into a predetermined shape, pattern the second semiconductor substrate 104 into a predetermined shape as shown in FIG. 3C, form an insulating film 105 on the first semiconductor substrate 101 as shown in FIG. 3D, An opening 10 in this insulating film 105
5a, 105b, and these openings 105a, 10
A diffusion layer 106 is formed by diffusing impurities into the semiconductor substrate 101 through the semiconductor substrate 101.

[0005]

[Problems to be Solved by the Invention] However, in the above-described conventional method for manufacturing a bonded substrate, since the pattern 102 on the intermediate bonding surface after bonding is not visible from the outside, the As described above, it has been difficult to pattern the first semiconductor substrate 101 or the second semiconductor substrate 104.

As a method of solving this problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 185930/1982, a hole is made at an appropriate location in the first semiconductor substrate 101 or the second semiconductor substrate 104, and the hole is utilized. There is also a method of aligning the patterns by using the following methods, but this method is not practical.

An object of the present invention is to provide a method for manufacturing a bonded substrate that can form a pattern on a polished surface that is aligned with high precision with respect to a pattern on an intermediate bonding surface after bonding. It is about providing.

[0008]

[Means for solving the problem] An exposure device (hereinafter referred to as "
There is a double-sided mask matching device). Unexamined Japanese Patent Publication 1986-
Examples include those described in Japanese Patent Application Laid-open No. 65443 and Japanese Patent Application Laid-Open No. 2-3070. The present inventor has devised the present invention by paying attention to the fact that the above-mentioned problems of the conventional technology can be solved by applying such a double-sided mask aligning apparatus to the production of bonded substrates.

That is, in order to achieve the above object, the method for manufacturing a bonded substrate of the present invention includes a first substrate (1
) is formed on the second main surface (1b) of the first substrate (1) by lithography using a double-sided mask alignment device. forming a second pattern (3) in accordance with the first pattern (2);
) side of the second substrate (5).

0010

[Operation] According to the method for manufacturing a bonded substrate of the present invention configured as described above, the second main surface (1b) of the first substrate (1) is formed by lithography using a double-sided mask aligning device. Since the second pattern (3) is formed in accordance with the first pattern (2), the intermediate bond between the first substrate (1) and the second substrate (5) after bonding is Even if the first pattern (2) on the mating surface is not visible from the outside, the first substrate (1) or the second substrate (5) can be polished by using the second pattern (3). Later, a pattern aligned with the first pattern (2) with high accuracy can be formed on this polished surface.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A to 1F show an embodiment of the present invention. In this example, as shown in FIG. 1A, a pattern 2 constituting an element is first formed on the surface 1a of a first semiconductor substrate 1. Reference numeral 1b indicates the back surface of the first semiconductor substrate 1.

Next, as shown in FIG. 1B, by photolithography and etching using a double-sided mask alignment device (not shown), a pattern is formed on the back surface 1b of the first semiconductor substrate 1 in accordance with the pattern 2 on the front surface 1a. Form pattern 3. Here, the pattern 3 on this back surface 1b is the first
It may be formed by directly etching the semiconductor substrate 1, or it may be formed by forming a film such as a SiO2 film on the back surface 1b and etching this film.

Next, as shown in FIG. 1C, a second semiconductor substrate 5 is bonded to the surface 1a of the first semiconductor substrate 1 on which the pattern 2 is formed, with an adhesive layer 4 interposed therebetween. For example, when a polycrystalline Si film is used as the adhesive layer 4, this bonding is performed as follows. That is, polycrystalline S is formed on the entire surface 1a of the first semiconductor substrate 1 by the CVD method.
After forming the i film and polishing this polycrystalline Si film, heat treatment is performed at a temperature of, for example, about 1100° C. with the second semiconductor substrate 5 bonded to the surface of the polished polycrystalline Si film. Thereby, the first semiconductor substrate 1 and the second semiconductor substrate 5 can be bonded together.

Next, as shown in FIG. 1D, the first semiconductor substrate 1 is formed on the surface of the second semiconductor substrate 5 opposite to the adhesive layer 4 by photolithography and etching using a double-sided mask alignment device. Pattern 3 on the back side 1b of
Pattern 6 is formed in accordance with the above. Next, as shown in FIG. 1E, the first semiconductor substrate 1 is polished and etched to a predetermined thickness from its back surface 1b side.

Next, as shown in FIG. 1F, a pattern is formed on the polished surface of the first semiconductor substrate 1 and on the back surface of the second semiconductor substrate 5 by photolithography and etching using a double-sided mask alignment device. According to pattern 6,
A pattern 7 constituting the element is formed.

As described above, according to this embodiment, even if the pattern 2 on the intermediate bonding surface after bonding is not visible from the outside, it is visible on the side opposite to the polished surface of the first semiconductor substrate 1. By further performing photolithography and etching using a double-sided mask alignment device using the pattern 6 on the surface of a certain second semiconductor substrate 5, the pattern 6 on the bonding surface is aligned with high precision. A pattern 7 can be formed on the polishing surface. The method for manufacturing a bonded substrate according to this embodiment is suitable for application to manufacturing a three-dimensional structured semiconductor device, for example, a three-dimensional LSI.

Next, another embodiment of the present invention will be described. In this other embodiment, first, the steps shown in FIGS. 1A to 1C are performed in the same manner as in the above embodiment, and then FIG.
As shown in A, the second semiconductor substrate 5 is polished and etched to a predetermined thickness. Next, by photolithography and etching using a double-sided mask alignment device, elements are formed on the polished surface of the second semiconductor substrate 5 in accordance with the pattern 3 formed on the back surface 1b of the first semiconductor substrate 1. A constituting pattern 6 is formed.

According to this other embodiment, as in the above-described embodiment, the pattern 2 on the intermediate bonding surface is aligned with high precision on the polished surface of the second semiconductor substrate 5. A pattern 6 can be formed. Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the case where the first semiconductor substrate 1 and the second semiconductor substrate 5 are bonded together has been described, but the present invention can also be applied to the case where three or more semiconductor substrates are bonded together. Needless to say, it can be applied. Furthermore, the present invention can be applied not only to the case of bonding semiconductor substrates together, but also to the case of bonding various types of substrates other than semiconductor substrates, and even to the case of bonding different types of substrates.

[0020]

[Effects of the Invention] As described above, according to the present invention,
A pattern can be formed on the polished surface that is aligned with high precision with respect to the pattern on the intermediate bonding surface after bonding.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention in the order of steps.

FIG. 2 is a cross-sectional view for explaining another embodiment of the present invention in the order of steps.

FIG. 3 is a cross-sectional view for explaining a conventional method for manufacturing a bonded substrate.

[Explanation of symbols]

1 First semiconductor substrate 1a Surface 1b Back side 2, 3, 6, 7 pattern 4 Adhesive layer 5 Second semiconductor substrate

Claims (1)

[Claims] 1. After forming a first pattern on a first main surface of a first substrate, the first pattern is formed on a second main surface of the first substrate by lithography using a double-sided mask alignment device. A method for manufacturing a bonded substrate, comprising: forming a second pattern in accordance with the first pattern; and bonding a second substrate to the first main surface side of the first substrate.