CN103399465B - Method for realizing dual-face alignment photoetching by utilization of one-face exposure machine - Google Patents

Abstract

A method for realizing double-sided alignment photolithography by using a single-side exposure machine, belonging to the field of photoelectric technology and micro-nano processing technology, designing a mask plate A and a mask plate B, respectively corresponding to the required graphics on the surface a and surface b of the substrate, Design a center-symmetric inner and outer two-layer alignment mark on the mask A, the inner alignment mark is within the size range of the substrate, first use the mask A to perform photolithography on the surface a of the substrate, and then use the mask A to The surface of the transparent substrate is photoetched, and the surface of the transparent substrate with the photoetched pattern is opposite to the surface a of the substrate with the photoetched pattern. After the substrate and the substrate are bonded, use the mask plate B The surface b is subjected to photolithography, and finally the substrate is separated from the transparent substrate by heating or dissolving to obtain a substrate with double-sided alignment patterns. By means of the transparent substrate to complete the double-sided alignment, the problem of using an ordinary single-sided exposure machine to realize double-sided lithography is realized, and the cost of the double-sided lithography process is reduced.

Description

A method for realizing double-side alignment photolithography by using a single-side exposure machine

technical field

The invention belongs to the field of photoelectric technology and micro-nano processing technology, and relates to a method for realizing double-side alignment photolithography by using a single-side exposure machine.

Background technique

Double-sided lithography technology is a widely used micro-nano processing technology for manufacturing semiconductor devices and optical devices. The manufacture of devices such as pressure sensors, quartz crystal oscillators, microelectronic machining, hybrid circuits, power semiconductor devices, bulk acoustic wave devices, and discharge diodes requires the use of double-sided lithography to precisely map the front and back sides of the substrate. Align the exposure. At present, the double-sided lithography process is mostly completed by double-sided exposure machines. According to the different alignment principles, it can be roughly divided into two types: one is to use an infrared microscope to align the substrate with the mask on the other side. One method is helpless for substrates that are not transparent to infrared light, and requires a special infrared imaging device to achieve, and the accuracy is low; the other is to use two sets of objective lenses to simultaneously observe and align the upper and lower surfaces of the substrate and the mask. This method is currently being used more often. However, these two methods rely on complex and expensive equipment to complete, and the process cost is relatively high. For some small laboratories or production workshops that cannot afford to purchase or develop double-sided exposure machines, they cannot use the double-sided lithography process. Conduct scientific research or production. Therefore, it is of great practical significance to find a simple and low-cost method for double-sided lithography using a common single-sided exposure machine.

Contents of the invention

In order to reduce the cost of double-side lithography process and solve the problem that ordinary single-side exposure machine cannot realize double-side lithography, a simple method of double-side alignment lithography with the help of a transparent substrate is proposed.

The technical solution adopted by the present invention to solve technical problems is as follows:

A method for realizing double-side alignment photolithography by using a single-side exposure machine.

Consists of the following steps:

1. Make the first mask and the second mask. The first mask has center-symmetric inner alignment marks and outer alignment marks, which are located inside and outside the substrate pattern respectively. The second mask has Outer alignment marks consistent with the first mask;

2. Perform photolithography and etching on the upper surface of the substrate with the first mask to make graphics;

3. The first mask is photolithographically and etched on the surface of the transparent substrate to make graphics;

4. Align and bond the surface of the transparent substrate with graphics and the upper surface of the substrate 3-1 through the alignment mark of the inner layer;

5. Make the alignment mark on the outer layer of the transparent substrate coincide with the alignment mark on the outer layer of the second mask, and use the second mask to perform photolithography and etching on the lower surface of the substrate to produce the required graphic structure;

6. Separating the substrate from the transparent substrate to obtain a substrate with double-sided alignment patterns.

The beneficial effects of the present invention are:

The simple and novel double-side alignment photolithography process method of the present invention completes double-side alignment with the help of a transparent substrate (such as glass, etc.), does not rely on expensive and complicated double-side exposure machines, and solves the problem of using ordinary single-side exposure machines. The problem of realizing double-sided photolithography reduces the cost of double-sided photolithography process.

Description of drawings

FIG. 1 is a schematic diagram of a first mask 1;

FIG. 2 is a schematic diagram of a second mask 2;

FIG. 3 is a schematic diagram of a transparent substrate 4 fabricated using a first mask;

4 is a schematic diagram of performing photolithography on the upper surface 3-1 of the substrate using the first mask 1;

FIG. 5 is a schematic diagram of performing photolithography on the surface of a transparent substrate by using the first mask 1;

Fig. 6 is a schematic diagram of aligning and bonding the patterned surface of the transparent substrate and the upper surface 3-1 of the substrate under a microscope;

FIG. 7 is a schematic diagram of performing photolithography on the lower surface 3 - 2 of the substrate by using the second mask 2 .

Detailed ways

Below in conjunction with accompanying drawing this method is described in further detail:

As shown in Figure 1-2, the first mask 1 and the second mask 2 are designed to correspond to the required patterns on the upper surface 3-1 and the lower surface 3-2 of the substrate respectively, and the center is designed on the first mask 1 Symmetric inner layer alignment mark 1-1 and outer layer alignment mark 1-2, inner layer alignment mark 1-1 is within the size range of substrate 3, and outer layer alignment mark 1-2 is designed within the size range of substrate 3 Outside the range, less than the size of the transparent substrate 4, through the inner layer alignment mark 1-1 and the inner layer alignment mark 4-3 of the transparent substrate 4, the transparent substrate surface 4-1 and the substrate with graphics will be made The surface 3-1 is used for alignment and bonding, and the outer layer alignment marks 1-2 are used to make patterns on the second mask plate 2 and the transparent substrate 4 when performing photolithography on the lower surface 3-2 of the substrate. Alignment of the transparent substrate surface 4-1. On the second mask 2 , the same outer layer alignment marks 2 - 1 as those of the first mask 1 are designed. Considering that the graphics on the transparent substrate 4 and the upper surface 3-1 of the substrate are all made by the first mask plate 1, and the surface 4-1 with the graphics on the substrate is face-to-face with the substrate surface 3-1 when bonding the chips , the graphics of the two are in a mirror image relationship, so the alignment marks of the mask must be designed to be symmetrical to the center, so as to ensure that the alignment marks can still play an alignment role under the mirror image condition.

As shown in Figure 3-4, first use the first mask 1 to perform photolithography on the upper surface 3-1 of the substrate to make the required pattern structure, and transfer the pattern from the photoresist by wet or dry etching On the upper surface 3-1 of the substrate, then use the first mask 1 to carry out photolithography on the surface of the transparent substrate 4, and transfer the pattern to the surface of the transparent substrate by etching. 1 is a mirror image, but the alignment marks are consistent.

As shown in Figure 5, the transparent substrate surface 4-1 that is made on the transparent substrate 4 and the upper surface 3-1 of the photolithographic pattern of the substrate 3 are opposite to each other, and the transparent substrate 4 is on the top, because the substrate It is transparent, so it can be aligned under the microscope using the inner layer alignment marks 1-1 on both sides, and then use the transparent curing glue 6 to bond the two together. This step can be carried out in two ways: 1. One way is to first complete the alignment through the microscope 5, and then drip the transparent curing glue 6 from the edge of the contact surface between the substrate 3 and the transparent substrate 4, and use capillary action to naturally penetrate between the two surfaces, and complete the bonding after curing; One way is to drop transparent curing glue 6 on the substrate 3 first, then press the transparent substrate 4 on the substrate 3, and complete the alignment before the glue is cured. The choice of transparent curing adhesive 6 is relatively wide, such as ultraviolet curing adhesives, various instant adhesives, etc., but two conditions must be met: one must have a certain degree of light transmission, that is, transparency, which is to ensure alignment and Observation is not affected during the curing process; second, it is convenient to remove, such as heating, dissolving and other simple methods can be used to remove, so as to ensure that the substrate 3 and the transparent substrate 4 can be separated smoothly after the entire double-sided photolithography process is completed.

As shown in FIG. 6, after the substrate 3 is bonded to the transparent substrate 4, photolithography is carried out on the lower surface 3-2 of the substrate by using the second mask 2, and at this time, the outer layer of the second mask 2 is utilized. Alignment marks 2-1 and outer layer alignment marks 4-2 on the transparent substrate 4 are used to complete the alignment, and the alignment of the upper surface 3-1 of the substrate and the lower surface 3-2 of the substrate is also realized. Then make required patterns on the lower surface 3-2 of the substrate by etching. Finally, the substrate 3 is separated from the transparent substrate 4 by heating or dissolving, thereby obtaining the substrate 3 with double-sided alignment patterns. It can be seen that we only need to use a transparent substrate 4 as an intermediate medium, so that the double-sided photolithography process that can only be completed by relying on expensive double-sided exposure machines can now only be completed by using ordinary single-sided exposure machines Complete, greatly reducing the process cost.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (2)

1. utilize single-side exposure machine to realize a method for double-sided alignment photoetching, realized by following steps:

One, the first mask plate (1) and the second mask plate (2) is made, first mask plate (1) has centrosymmetric internal layer alignment mark (1-1) and outer alignment mark (1-2), lay respectively in substrate figure and outside substrate figure, the second mask plate (2) has the outer alignment mark (2-1) consistent with the first mask plate (1);

Two, utilize the first mask plate (1) to carry out photoetching and etching at substrate upper surface (3-1), make figure;

Three, utilize the first mask plate (1) to carry out photoetching and etching on transparent substrates (4) surface, make figure;

Four, by the internal layer alignment mark (4-3) of internal layer alignment mark (1-1) and transparent substrates 4, the transparent substrates surface (4-1) and substrate upper surface (3-1) that are manufactured with figure are carried out aiming at and bonding die;

Five, transparent substrates (4) outer alignment mark is made to overlap with the second mask plate (2) outer alignment mark (2-1), utilize the second mask plate (2) to carry out photoetching and etching at substrate lower surface (3-2), make the figure needed;

Six, substrate (3) is separated with transparent substrates (4), obtains the substrate (3) with double-sided alignment figure.

2. a kind of method utilizing single-side exposure machine to realize double-sided alignment photoetching according to claim 1, it is characterized in that: by relative with the upper surface (3-1) that litho pattern carried out by substrate for the surface (4-1) of transparent substrates (4) upper making figure, under microscope (5), utilize the internal layer alignment mark in two faces to aim at, the two is bonded together by recycling transparent cured glue (6), this step can be undertaken by two kinds of modes: a kind of mode first can complete aligning by microscope (5), then from substrate (3) and transparent substrates (4) surface of contact edge instillation transparent cured glue (6), capillary action is utilized naturally to infiltrate between two faces, bonding is completed after solidification, another kind of mode is first at substrate (3) upper upper transparent cured glue (6), then transparent substrates (4) is pressed on substrate (3), and completed aligning before colloid solidification.