JPS63159853A - Reticle - Google Patents

Abstract

PURPOSE:To improve the throughput of a semiconductor device, and to reduce manufacturing cost by providing a light transmission control part using a liquid crystal, on an area to be transferred of a reticle, and dividing the light transmission control part into plural segments so that they can be driven selectively. CONSTITUTION:A light transmission control part 20 using a liquid crystal is provided on the center (area to be transferred) of a reticle 4. The light transmission control part 20 consists of segments 20a provided in a matrix shape, and each segment 20a is placed in accordance with each memory of a ROM to be formed. By driving a common driver 22 and a segment driver 23 by a multiplexing driving system, the selected segment 20a becomes opaque, and a desired pattern is obtained. Subsequently, by driving the drivers 22, 23 which function as a P/G 3 by a ROM data 1, a pattern 4a is formed on the reticle 4. In such a way, a working mask 6 is prepared by a step and repeater 5.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a technique that is particularly effective when applied to a reticle used for reduction projection exposure.
The present invention relates to a technique effective for use in a reticle used for forming a mask pattern for writing cell information in an OM (read-only memory).

[Prior Art] Conventionally, in a mask ROM, cell information is stored by varying the threshold voltage of the MOSFET by changing the thickness of the gate oxide film or changing the impurity concentration by ion implantation into the channel region. There are methods for writing cell information, and methods for writing cell information depending on whether or not a data line contact hole is formed to the source or drain region. In any case, writing to the mask ROM is performed during the wafer process, and a mask for selective oxidation, a mask for ion implantation, or a mask for forming contact holes is formed according to the data written in the ROM, and this mask is used. Then, the cell information will be written.

The outline will be explained based on FIG. 3 as follows.

That is, ROM data 1 is obtained from the customer, and the ROM data is edited by the artwork processing device.

The data is converted into data for driving the pattern generator 3 and stored in the pattern generator machine tape (PG/MT) 2. Next, a reticle 4 is created by the pattern generator 3. The reticle 4 in this case is created through the steps shown in FIG. That is, first, the chromium thin film 12 formed on the surface of the glass substrate 11 is
A photoresist 13 is applied thereon (FIG. 4(a)).

Next, the photoresist 13 is selectively exposed to an electron beam or the like and developed to form a resist pattern (FIG. 4(b)). Next, the chromium thin film 12 is selectively etched using the remaining photoresist 13 as a mask (FIG. 4(C)). Thereafter, the photoresist 3 is removed to form a mask pattern (FIG. 4(d)).

Once the reticle 4 has been created in this manner, a reticle (working mask) 6 for reduction exposure is created using the step-and-repeater 5. That is, as shown in FIG. 5, light from a mercury lamp 14 is projected onto a reticle 4 through a condenser lens 15, and a mask pattern 4a formed on this reticle 4 is passed through a reduction lens 16 to become a working mask 6. Transfer to photoresist coated on a glass substrate. Then, a working mask 6 is created through substantially the same process as above, and this working mask 6 is
Writing to the mask ROM is performed using the .

For information on the reticle creation technology used for reduction projection exposure, see 1. For example, please refer to the 1984 edition 15th edition of the Electronic Materials Special Edition "Ultra LSI Manufacturing and Testing Equipment" published by the Kogyo Kenkyukai.
It is described on pages 8 to 164.

[Problems to be solved by the invention] However, in recent years, the amount of ROM data has become enormous due to high integration, miniaturization, and diversification.
It takes a long time to edit the ROM data and to form the mask pattern 4a by the pattern generator 5, which has been a bottleneck in improving the throughput in the semiconductor device manufacturing line. Also,
Since the mask pattern 4a on the reticle 4 is formed of a thin chrome layer, it is difficult to change the pattern.

It is necessary to create a reticle each time the content of the ROM data differs, resulting in a problem of increased manufacturing costs.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a reticle that can improve the throughput of semiconductor devices and reduce manufacturing costs.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving the Problems] Representative inventions disclosed in this application will be summarized as follows.

That is, the transfer area of the reticle is composed of a transmissive LCD (liquid crystal device) in which segments are arranged in a matrix, and each segment is driven independently using the same dot matrix driving method as in a liquid crystal display device. so that only the segment to which voltage is applied transmits the exposure light (
or shut off).

[Operation] According to the above-described means, for example, by performing reduction exposure while independently driving each segment of the matrix liquid crystal reticle according to ROM data, a mask pattern having an opening for forming an oxide film at a desired position is formed. etc. are created, so the ROM is created by the artwork processing device.
There is no need for a data editing process, and since the mask pattern can be changed simply by changing the segment to which voltage is applied on the liquid crystal reticle, there is no need to create a separate reticle for each different ROM data. In other words, by converting the ROM pattern of the reticle into liquid crystal, a large number of ROM masks with various patterns can be created from one reticle using liquid crystal. As a result, the above objectives of improving the throughput and reducing manufacturing costs of semiconductor devices are achieved.

[Example] In general, a liquid crystal can perform a light blocking effect and a light transmitting effect by applying a voltage or not applying a voltage to the liquid crystal by utilizing its electric field controlled birefringence effect. 1 The present invention applies a liquid crystal having such an effect to a reticle. An embodiment of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of a reticle according to the invention. In FIG. 1, reference numeral 4 represents a reticle, and in the center (transfer area) of this reticle 4, a light transmission control section 20 using liquid crystal is provided. and,
The light transmission control unit 20 is composed of a plurality of segments 20a arranged in a matrix at appropriate intervals, and each segment 20a has an upper electrode connected to a common electrode line 21a arranged laterally. , and segment electrode A where the lower electrode is vertical? ! 21b, and can be driven using the same driving method as a known dot matrix type liquid crystal display device. moreover,
Specifically, this reticle 4 is a reticle for forming a mask for writing data into a mask ROM, and each segment 20a of the light transmission control section 20 corresponds to each memory cell of various mask ROMs. like.

That is, the segments 20 are arranged in a matrix with the same pitch as the memory array, and the segments 20 arranged in this matrix are
In a, when the common driver 22 and the segment driver 23 are driven by the multiplexing drive method, a voltage is applied to the segment (indicated by diagonal lines in the figure) located at the intersection of the selected common electrode line and the segment electrode line. applied. Then, that segment will no longer transmit light, and the others will be in a state of transmitting light. By driving each driver 22, 23 according to the ROM data, a desired mask pattern can be obtained. This first
The arrangement of each liquid crystal shown in the figure varies depending on whether the photoresist used to create the working mask 6 is a negative type or a positive type, and FIG. 1 shows the case where the photoresist is a negative type.

Next, the process of creating the working mask 6 using the reticle 4 using such a liquid crystal will be explained using the flowchart shown in FIG.

The common driver 22 and segment driver 23 functioning as the pattern generator 3 are driven by the ROM data 1 obtained from the customer, and each segment of the translucent control section 20 is selectively driven to the position corresponding to the memory cell to be written. A mask pattern having openings is formed on the reticle 4. Then, using this reticle 4, a working mask 6 is created with a step-and-repeater 5. In addition, the mask pattern can be changed using the ROM.
This can be done simply by changing the data.

According to the reticle of the embodiment configured in this way, the following effects can be obtained.

That is, since the area to be transferred is the light transmitting control section 20 using liquid crystal, the mask pattern 4a can be easily created from the ROM data.
This eliminates the need to edit ROM data using an artwork processing device to drive a pattern generator as in the conventional art, and also eliminates the need to create reticles for each type of ROM data using an electron beam or the like.

Therefore, from one reticle using liquid crystal to various ROM
You can create many ROM masks (working masks) with eyes. Accordingly, it is possible to obtain the effect that the throughput of the semiconductor device can be improved.

Similarly, a light transmitting control section 20 using a liquid crystal for the transfer area is also provided.
Therefore, the mask pattern can be easily changed by changing the ROM data, and there is no need to create a separate reticle 4 for each different ROM data, which greatly reduces the manufacturing cost and man-hours of the ROM mask. Can be reduced. As a result, it is possible to obtain the effect of reducing the cost of the semiconductor device.The invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples. It goes without saying that various changes can be made without departing from the spirit of the invention. For example, each segment in the above embodiments can have any shape other than a rectangular shape.

Furthermore, the segments may not be formed apart from each other, but may be formed close to each other.

In addition, in the above explanation, the invention made by the present inventor will be mainly referred to as the mask ROM, which is the application field that is the background of the invention.
Although we have explained the reticle for forming, it is not limited to this, for example, PLA (programmable logic array), RAM (random access memory) with redundant circuits, etc. may require changes in the wiring pattern etc. depending on the customer's request. It can also be used as a reticle for manufacturing semiconductor devices.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained below.

In other words, since the transfer area of the reticle is a light transmission control section using liquid crystal, it is easy to create and change mask patterns, and as a result, throughput and manufacturing cost reductions are achieved in semiconductor device manufacturing lines. It will be possible to achieve this goal.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the reticle according to the present invention, FIG. 2 is a flowchart showing a method for creating the reticle shown in FIG. 1 and a method for creating a working mask using this reticle, and FIG. A process diagram for explaining a method for creating a reticle and a method for creating a working mask using this reticle. FIG. 5 is a front view of a step-and-repeater used when creating a working mask using the reticle of FIG. 4. 4... Reticle, 20... Light transmission control section, 20
a...Segment. Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] 1. In a reticle used to create a working mask by reduction projection exposure, the mask pattern is a light transmission control section using a liquid crystal, and this light transmission control section is formed into a plurality of segment areas. A reticle characterized by being divided into two segments, and each segment can be selectively driven independently. 2. The reticle according to claim 1, wherein the light transmission control section is constituted by a plurality of segment areas arranged in a matrix. 3. The reticle according to claim 1, wherein the reticle is for creating a ROM mask.