JPS60111245A - Manufacture of mask - Google Patents

Abstract

PURPOSE:To enhance yield and efficiency by preparing a large number of duplicated masks from a common pattern mask having the light intercepting layer on which only a common pattern is formed, and forming individual patterns on the duplicated masks by the quantum ray exposure system. CONSTITUTION:A light intercepting layer is divided into a common pattern part A and an individual pattern part 3, and a light intercepting layer 10a corresponding to the part A is patternwise formed on a transparent base 9 to form a common pattern mask 8. A large number of duplicated masks 20 on each of which the light intercepting layer of the pattern A is patternwise formed and the pattern part B is left in a blank state are formed by using the common mask 8 as an original. The face of the mask 20 on the side of a light intercepting layer 16 is coated with a quantum ray sensitive resist layer 21. The desired part of the resist layer 21 is exposed to quantum rays 22, and developed to form a resist pattern 23 corresponding to a desired individual pattern is formed on the pattern part B. The light intercepting layer 16 of the part B not covered with the resist layer 21 is etched off to form a pattern, and the resist layer 23 is removed and a mask 24 having the light intercepting layers 16a, 16b on the parts A and B, respectively, on a transparent base 15 is thus completed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for manufacturing a photomask or reticle mask used in manufacturing semiconductor integrated circuits, solid-state image sensors, and the like.

(Technical Background of the Invention) It can be said that semiconductor integrated circuits and solid-state image sensing devices usually consist of a common (general-purpose) pattern and subdivided patterns. Corresponding to this situation, the mask also naturally has a common pattern section and an individual pattern -7 section.

To explain this point with reference to Figures 1 and 2 of the drawings, Figure 1 shows an enlarged view of the mask pattern area corresponding to the chip of a solid-state image sensor or an integrated circuit element, and the surrounding area is shown in an enlarged manner. In part (1), there tends to be a pattern that is large and specified for that type, such as the bonding pad part 2), and therefore has a fixed pattern. On the other hand, in the central portion (3), a unique pattern is formed by the element.

That is, in this case, the peripheral part (1) is considered to be a common pattern part, and the central part (3) is considered to be equivalent to an individual pattern part. Regarding Fig. 2, if an integrated circuit chip is viewed as one functional element, for example, 1% O
The read only memory (M) portion (4) may vary individually depending on the role of each functional element, whereas the other portions (11) may be commonly used for general purposes. There are many.

(Objective of the invention) As shown above, when we consider one integrated circuit chip,
In many cases, it is possible to distinguish between a common pattern part and an individual pattern part, and the present invention provides a method for manufacturing a photomask or reticle mask (hereinafter simply referred to as a mask) that is suitable for this situation. It is made of wood.

(Summary of the Invention) That is, in manufacturing a mask, the present invention first creates a common pattern mask having a light-shielding layer in which only the common pattern portion is patterned, and then converts it into a mask to obtain a mask.

The mask of the present invention is formed by forming a light-shielding layer of photoresist that is opaque to the photosensitive area in a pattern on a transparent substrate, and its manufacturing method includes the following steps (a) to (f). It is safe to say that it is equipped.

(a) A step of separating the light-shielding layer into a common pattern portion and an individual pattern portion, and forming a light-shielding layer corresponding to the common pattern portion in a pattern on a transparent substrate to create a common pattern mask; (b) the common pattern mask; A step of creating a large number of double-acid masks based on a patterned mask, in which the light-shielding layer of the common pattern part is formed in a pattern while the individual pattern parts are blank; (C) the surface of the above-mentioned double-acid mask with the light-shielding layer; forming a quantum beam-sensitive resist layer on the side; (d) exposing desired portions of the quantum beam-sensitive resist layer on the individual pattern portions of the above-mentioned double acid mask to quantum beams and developing;
forming a resist layer corresponding to a desired individual pattern on the individual pattern portion; (e) etching away the light-shielding layer of the individual pattern portion that is not covered by the resist layer of the double acid mask to remove the light shielding layer of the individual pattern portion; (f) Step of removing the resist layer of the double acid mask.

(Detailed Description of the Invention) The present invention will be specifically described below with reference to FIGS. 4(A) to 4(N) of the drawings.

FIG. 4(a) is a schematic cross-sectional view showing the common pattern mask (8). In the figure, a transparent substrate (9) is made of quartz glass, low expansion glass, ordinary glass, etc., and a light shielding film 00) made of metal, metal compound, etc. is formed on its upper surface. However, in the light-shielding film α0) at this time, only the light-shielding film (10a) of the common pattern portion (5) shown in FIG. The light shielding film (10b) of the individual flat pattern portion (B) may not be patterned at all or may not exist at all. Patterning of the light shielding film (10a) of the common pattern portion (5) of the common pattern mask is performed by conventionally known means.

- For example, a resist layer sensitive to light, electron beams, and quantum beams such as Partially expose the desired area using an electron beam exposure device, remove the uncured part of the resist layer by development, and remove the light shielding film from the part not covered with the resist layer.
By removing 0) by an etching method, a patterned light shielding film (108) is obtained.

At least two or more alignment marks (5a) are formed at arbitrary locations on this common pattern mask (8).

This alignment mark (5a) is used to align the light-shielding layers of the common pattern part (8) and the individual pattern part (B) in a later process, and the details will be described later.

Since the common pattern mask (8) is used to create a large number of double acid masks (20) based on this,
It is desirable that the mask be defect-free. The common pattern mask (8) shown in FIG. 4(A) has a black defect (1) in which a light shielding layer exists where it should not exist, and a white defect (1) in which a light shielding layer does not exist in a place where it should exist. 13
) is shown schematically.

A common pattern mask (8) having such defects is
As shown in FIG. 4(b), the mask is modified to have no defects. In other words, 0' black defects! For J, unnecessary light shielding layers are removed by local etching or laser repair. In addition, the white defect 03) is corrected by filling it with a light shielding material (1(a)).

The defect-free common pattern mask obtained in this way (
8) to create a large number of double acid masks.

As shown in Figure 4 (c), common pattern mask (8)
The light shielding layer 00) side of the transparent substrate (I5), the blank uniform light shielding layer 06), the photoresist layer (1, 71)
The photoresist layer (1η plane side) of the mask blank plate 08) laminated in this order is faced, and light is irradiated from the transparent substrate (9) side of the common pattern mask (8). The pattern mask (8) and the mask blank plate (I8) are not in close contact with each other (although a close exposure method with a slight gap is used, of course, the method is not limited to this, and may be a contact exposure method or a projection exposure method). I can't help it.

The mask blank plate (+8
A latent image is formed on the first photoresist layer (17).

This is subjected to a prescribed resist development, and a resist pattern layer U wing having a desired shape as shown in FIG. 4 is formed. Subsequently, the portion of the blank light shielding layer (16) that is not covered with the resist pattern layer (19) is removed, and after that, the unnecessary resist pattern layer is also peeled off and a fourth layer is formed. A double acid mask (20
). In addition to a wet etching method using a corrosive solution, dry etching methods such as sputter etching, ion etching, and plasma etching may be used to remove the light shielding layer (16). The double acid mask (20) can be used as shown in Figure 4 (c) if there is only one common pattern mask (8).
By repeating the steps from to (e), a large number of them can be created.

As is already clear, in the example shown in the figure, the photoresist layer (1) in the area irradiated with light has been dissolved and removed by development, and in this example, the positive photoresist is in the photoresist layer (lη). When using a negative photoresist for the photoresist layer αη, the light shielding layer (10
It is appropriate that a) is a negative pattern. If the light-shielding layer (10a) of the common pattern mask (8) has a positive pattern as shown in FIG. 4(b), it is necessary to repeat the operations in FIG. 4(c) to (e) twice.

However, there is nothing that cannot be done even with this method, and it is naturally included in the present invention.

The thus obtained double acid mask (light shielding layer 06 for 20
) and (16a), a quantum beam-sensitive resist layer (2I) is formed on the surface thereof to obtain the state shown in FIG. 4(f). The quantum beam mentioned here includes light, ultraviolet light, electron beam, ion beam, laser light, etc.

Next, as shown in FIG. 4 (G), the individual pattern section (13
) on the quantum beam-sensitive resist layer (2υ), a desired portion thereof is exposed to quantum beams (22). At this time,
The resist layer (21) on the alignment mark (5b) of the double acid mask is also exposed to quantum beams. The quantum beam sensitive resist layer (2+) on which the latent image has been formed is developed to form a desired individual pattern on the light shielding layer (L6) of the individual pattern section (B) as shown in FIG. 4 (4). The corresponding resist layer (forms the second floor) Although the explanation has been mixed, it is preferable to use a positive resist layer CD as the quantum beam sensitive resist layer CD.The reason is that if it is a positive resist layer, quantum beam irradiation is possible. The patterned portion is dissolved and removed by development, and therefore the common pattern portion (5) that has already been patterned
This is because the resist layer (23) can remain after development even without irradiation with quantum beams.

This means that the common pattern portion (5) is not included as an exposure area for two quantum beams, and by reducing the exposure area, the time required for quantum beam, for example, electron beam exposure can be shortened. Become more efficient.

Next, the common pattern part (5) is completely covered by the resist layer (C) in FIG. When the layer (1e) is etched and removed, Figure 4 (
As shown in the figure, the light shielding layer (16b) of the individual pattern part (B)
) is formed. Regarding the method for partially removing the exposed light-shielding layer (le), both wet etching and dry etching can be selected, as described when creating the common pattern portion (5) of the composite mask 0@.

Finally, by removing the resist layer (23) that is no longer needed, a transparent substrate (a light-shielding layer is applied to each of the common pattern area (5) and the individual pattern area (B)) as shown in Figure 4). Mask C!Yu having (16a) and (16b) is completed.

Here, to explain the alignment marks in the present invention, it is preferable to provide a plurality of alignment marks as shown in FIGS. 1 and 2 as alignment marks (5). - This is because it is difficult to recognize the amount of deviation in the angular direction. However, the position of the alignment mark (5) may be any location, such as the positioning mark (5) provided in the individual pattern section in Fig. 1 and the common pattern section in Fig. 2, for example, other than the common/individual pattern section. It may also be provided on the outer frame of.

An example of the shape of the alignment mark (5) shown in FIG. 3 is shown. The mark (6) consisting of four rectangles was drawn when patterning the common pattern section, and the cross-shaped mark (7) was drawn at the same time when patterning the individual pattern section. The alignment mark (5) shown in FIG. 3 is in an ideal state, indicating that there is no relative misalignment between the common pattern section and the individual pattern section. If a semiconductor integrated circuit is manufactured using a mask that has a significant deviation between the common pattern part and the individual pattern part, it may not function properly and the alignment mark (5
1 can be said to be a useless test.

(Effects of the Invention) The present invention is a method of manufacturing a mask as described above, in which a large number of composite masks each having a light-shielding layer in which only a common pattern part is patterned is prepared in advance, and individual pattern parts are changed according to demand. Since this is a method of patterning a mask, it is possible to keep the common two-turn portion free from defects during the production of a composite mask, which has the advantage of improving the yield of masks. Moreover, the area of the individual pattern part' is smaller than the entire mask area! ! For example, when drawing individual pattern parts using raster scan electron beam exposure, the time required is short because the drawing area is small, and the time from mask ordering to delivery is shortened. Can be shortened.

In addition, when assuming a large pattern with a relatively large area, such as a bonding butt part in a chip, as a common pattern part, it is better to use a rectangular division method to draw such a pattern than a raster scan electron beam exposure method. Drawing by a generator has the advantage of being more efficient, and it also has the advantage that an appropriate drawing method can be selected from among several types of quantum wires for drawing common pattern parts.

In addition, the AFl of the common pattern portion and the individual pattern portion can be accurately performed by providing alignment marks.

As described above, the present invention is applicable to a method of manufacturing a mask for manufacturing semiconductor integrated circuits, for example, a mask having a portion with a strong individual pattern character, such as a gate array of an aluminum wiring pattern, a ROM portion of an arithmetic circuit chip, or a bonding pattern. If used in the manufacture of a mask or the like in which the pattern density is different between a common pattern part such as a pad and an individual pattern part, it will exhibit extremely excellent effects.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view showing an example of a mask pattern corresponding to one chip of a solid-state image sensor or an integrated circuit device, and FIG. 2 is an enlarged plan view showing an example of a mask pattern suitable for the mask manufacturing method of the present invention. It is an enlarged plan view showing an example. FIG. 6 is an enlarged plan view showing an example of the alignment mark, and FIGS. 4(a) to 4(a) to 4(b) are explanatory cross-sectional views showing one embodiment of the mask manufacturing method of the present invention in the order of steps.゛(5)...Positioning mark (81...
...Common pattern mask (1 ship...Mask blank board (2o, song, mask (24J...)
・Mask (5) - Common pattern section (B)... Individual pattern section Patent applicant Toppan Printing Co., Ltd.

Claims (1)

[Claims] (1) In a method for manufacturing a mask for manufacturing a semiconductor integrated circuit, in which a light-shielding layer of photoresist that is opaque to the photosensitive area is formed in a pattern on a transparent substrate, (a) the light-shielding layer is formed in a common pattern area and in individual patterns (turns); A step of forming a turn mask by forming a light shielding layer corresponding to the common pattern part in a pattern on a transparent substrate; (common in the flink state) Step of creating a large number of composite masks each having a patterned light shielding layer in the turn portion; (C) forming a quantum diffusion sensitive resist layer on the side of the composite mask where the light shielding layer is located; (d) exposing a desired portion of the resist layer on the individual nozzle portions of the composite mask to quantum beams and developing;
forming a resist layer corresponding to a desired individual pattern on the individual pattern portion; (e) etching away the light-shielding layer of the individual pattern portion that is not covered by the resist layer of the composite mask to remove the light-shielding layer of the individual pattern portion; A method for manufacturing a mask, comprising the steps of (f) forming a light-shielding layer in a pattern; (f) removing a resist layer of a composite mask; and (a) to (f) above.