JPS6048901B2 - Photomask manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to photomask manufacturing technology.

In the manufacture of semiconductor devices, photolithography technology that uses photomasks is indispensable. The method of manufacturing a photomask is to receive a drawing from the design department, create a reticle with the final size of 1000 yen using an artoire or pattern generator, and create a master mask with multiple patterns arranged in a pattern reduced to 1 size using a repeater. A common method is to form a work mask (photomask) by forming a work mask (photomask) and directly exposing it to light through or without using this master mask. A required pattern corresponding to a plurality of chips is printed on the surface of the semiconductor wafer through this work mask, and after final wafer processing, each chip is separated by scribing. When creating a master mask from a reticle, it is necessary to burn a pair of target patterns for pattern positioning together with a main pattern corresponding to the element pattern of each chip.

The conventionally used target pattern is, for example, the first target pattern.
Using a reticle chip 1 having the same target pattern as shown in the figure, the same target pattern is placed in one section (for one or several chips) on the left and right on the substrate 2 that will become a photomask as shown in Figure 2. I got 3a and 3b. However, with this method, the target pattern itself cannot distinguish between right and left, so there is a risk of misreading the target in a later process and causing misalignment. On the other hand, as shown in FIGS. 3a and 3b, two reticles 5a each have two different target patterns 4a and 4b.
, 5b is proposed, and a method is proposed in which a photomask is obtained by burning on the right and left sides of 5, respectively.

According to this method, it is clear to distinguish between right and left, so there is no misreading of the target, but (1) two types of reticles 5a and 5b must be created for the target, (2) repeater When setting the reticle on the target pattern, there is a drawback that there is a possibility that accuracy may be lowered due to positional deviation of the target pattern due to deviation of the reticle frame. The present invention was made to eliminate the drawbacks of the prior art described above, and its purpose is to obtain highly accurate left and right target patterns with a single reticle, streamline heater work, and reduce photomask production costs. The objective is to provide a cost-saving photomask manufacturing technology.

In order to achieve the above object, the present invention uses a reticle having two different target patterns in one reticle section, and prints the two target patterns over two adjacent sections at two separate positions. included,
The gist is to overlay this pattern on the patterns of one section and the other section at each position.

The present invention will be specifically described below with reference to Examples.

First, as shown in FIG. 4, two different target patterns (positive patterns) 4a, 4 are placed within one reticle section.
A reticle 6 having a shape b is prepared.

When setting this reticle 6 on a heater (not shown) and performing reduction printing on, for example, a positive resist film on a substrate 7 serving as a master mask, two positions A,
In step B, the two tunny target patterns 4a and 4b of the reticle 6 are burned into two adjacent sections, respectively. The portions surrounded by dashed lines in the figure correspond to the reticle 6, respectively. Next, the reticle having the main pattern is set on a heater, and the main patterns 8a, 38b, . . .
Burn it. The printing of this main pattern extends to all sections of the target pattern that are not burned, and among the two adjacent sections at the two positions A and B, the target pattern 4a is on the left in A, and the target pattern on the right is in 4b. 4b so as to overlap each burned section. As a result, the target pattern 4b at position A (!:. Only the target pattern 4a at position B remains, and the other target patterns disappear. After this, the resist film is developed and baked, and the master mask is According to the present invention described in the above embodiments, (1) one reticle is used to print the left and right target patterns, so there is no movement of the reticle in the heater during that time, and the positional accuracy of the pattern is improved. (2) For the same reason as (1) above, the operating efficiency of the heater improves.

(3) As described in (1) above, (the manufacturing cost of a two-beam photomask can be reduced (the unit price of the photomask increases by 5% for an increase of one reticle). The present invention is not limited to the above embodiments.

For example, the pattern may be printed using a heater first for the main pattern and then for the target pattern.

[Brief explanation of the drawing]

1 to 3 show conventional examples, of which FIGS. 1 and 3A and 3B are plan views of a reticle, and FIG. 2 is a partial plan view of a photomask. 4 and 5 show an embodiment according to the present invention, FIG. 4 being a plan view of a reticle, and FIG. 5 being a partial plan view of a photomask. 1...Reticle, 2...
・Photomask, 3a, 3b...Target pattern, 4a, 4b...Target pattern,
5a, 5b...Reticle, 6...Reticle, 7...Photomask, 8a, 8b...
...This pattern.

Claims (1)

[Claims] 1. In a photomask manufacturing method in which a reticle having a main pattern and a reticle having a target pattern for pattern positioning are used, and a target pattern is burned into a plurality of main patterns arranged, two different patterns are printed in one reticle section. Using a reticle having a target pattern, burning the two target patterns into two adjacent sections at two separate positions on a substrate that will become a photomask, and using a reticle having this pattern. The process includes a process of arranging and burning a plurality of identical patterns on a substrate that will become a photomask, and one of the two adjacent sections at the two positions where the two target patterns are printed, one on the right side. A method for manufacturing a photomask, characterized in that a target pattern, on the other hand, a left target pattern and the above-mentioned main pattern are overlapped and exposed.