JPS60158450A - Contact exposing method - Google Patents

Abstract

PURPOSE:To perform surely and precisely pattern transfer without drop-out and to eliminate the need for high-temp. processing by interposing a photomask, an object to be transferred provided with photoresist and a water molecule layer and performing contact exposing and transfer. CONSTITUTION:Steam 12 is sprayed from a humidifier 11 into an enclosure 80 in which a substrate 1 formed therein with a pattern 6 is held to a support 90 to adsorb a water molecule layer 13 on the pattern forming surface of a photomask 7 and the rear thereof, by which a photomask 14 is obtd. The photomask 14 and a photomask blank 4 are installed via cushion sheets 21, 27 to pedestals 16, 23 and are attracted thereto by evacuating the inside of chambers 15, 22 through through-holes 17, 24. Frame bodies 19, 25 are brought into tight contact therwith and the mask 14 and the blank 4 are brought into tight contact therewith via the layer 13 by evacuation through a through-hole 18. Mercury-arc lamp light 28 is irradiated to transfer the pattern 6 to the blank 4. The pattern is surely and precisely transferred without drop-out and the need for high-temp. processing is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact exposure method for transferring a photomask pattern onto a substrate in the manufacturing process of semiconductor integrated circuits, high-density integrated circuits, and the like.

This photomask is manufactured according to the steps shown in FIG. That is, a light-shielding thin film 2 of metallic chromium or the like is deposited by sputtering or the like on a transparent substrate 1 made of quartz glass or the like whose surface has been precisely polished and cleaned, and a photoresist 3 (this example; American 5hipley company A
Z-1350 positive type -) 1 resist, film thickness 5000 mm) is coated using a spray method or the like to produce a photomask blank 4 (Fig. 1(a)). Next, use an appropriate exposure device. Photoregime 1 to obtain a predetermined pattern using
After exposing 3 to 3, it is developed to form a -C resist pattern 5 on the light-shielding thin film 2 (Figure (b)). Next, using this resist pattern 5 as a mask, the exposed portion of the light-shielding thin film 2 is exposed. The resist pattern 5 is removed by etching.
]. The pattern 6 of the light-shielding thin film is formed on the same figure (C).
), and the resist pattern 5 is removed with a stripping solution to produce a photomask 7 in which a predetermined pattern 6 is formed on the transparent substrate 1.

Such a photomask 7 is used as a transfer target plate for pattern transfer by closely exposing a semiconductor substrate with a photoresist. Since this photomask 7 is a consumable item, the above-mentioned photomask blank 4 is secretly exposed to produce a photomask for the 11/star or submaster, and this photomask blank 4 is In some cases, a photomask for a mask or a submaster is used as a substrate to be transferred, and in this case, the photomask for pattern transfer to a conductor substrate without photoresist is used as the photomask for the mask or submaster.
used as. Further, as a photomask for transfer or to be transferred, an IC (so-called emulsion mask), which uses a silver emulsion film as a light-shielding thin film, is sometimes used due to cost considerations.

However, when such a photomask 7 is closely exposed to a photoresist and transferred to a substrate such as a semiconductor substrate to transfer a pattern, static electricity is generated due to mutual contact, and a discharge phenomenon occurs between the patterns 6 of the photomask 7. In particular, when the pattern 6 is formed in an island shape, the pattern 6
A gap occurs around the periphery. Such omission of the pattern 6 results in the loss of the -C entry in the photomask for transfer, which becomes a fatal defect.

As a means to eliminate such drawbacks, the method shown in Fig. 2 is proposed.
A first mask 9 has been proposed in which a transparent conductive film 8 made of tin oxide or the like is deposited on the exposed surface 93 of the transparent substrate 1 and on the pattern 6 to a thickness of about 50 mm.

However, Noah II to Mask 9 according to this proposal,
Regarding the above-mentioned drawbacks, even if it is possible to prevent static electricity charging, the thickness of the transparent conductive film 8 ensures transparency.
Because it is relatively thin and has an uneven surface, when it is closely exposed to a transfer substrate such as a semiconductor substrate with a photoresist, a part of the transparent conductive film 8 may peel off.
However, the resist of A1 on the plate 75' had a disadvantage in that it was impossible to transfer a predetermined pattern to the resist on A1 of the substrate to be transferred.

Furthermore, the photomask 9 according to this proposal has a transparent conductive film 8
Although the predetermined pattern 6 was formed with an accuracy on the order of μm before being deposited, in the subsequent process,
In order to increase the transmittance of the transparent conductive film 8 by 90% or more, a high temperature treatment of about 400 to 500° C. is usually required, and this high temperature treatment causes thermal deformation, which is disadvantageous.

The purpose of the present invention is to eliminate the above-mentioned drawbacks. In other words, in the contact exposure process with the substrate to be transferred, (1) the pattern of the photomask is completely covered (no defects occur;
■ Transferring a predetermined pattern reliably and precisely to the A-regis of the transfer substrate9, and ■ Increasing the transmittance of the transparent conductive film to make it undefeated by high-temperature processing such as means. The aim is to provide an A mask that satisfies all three items at the same time.

In order to achieve such an object, the present invention provides a method for transferring a pattern made of light-shielding all formed on a photomask to a transfer target substrate with a photoresist by contact exposure. and the photoresist-coated transfer substrate with a water molecule layer interposed between -C
This is a contact exposure method characterized by the following.

The present invention will be described below with reference to the drawings.

FIG. 3 shows an apparatus for adsorbing a layer of water molecules on the entire surface of the photomask of this example.
As shown in Fig. 1), a metal chromium pattern 6 (in this example; line width 2 μm) is formed on a quartz glass substrate 1, and near its four corners, four wires are suspended from the ceiling of an enclosure 80. The supports 90 are aligned and installed on the four supports 90.

A humidifier 11 is attached to a section 10 of this enclosure 80, and water vapor 12 is blown from this humidifier 11 into the interior of the enclosure 80. A water molecule layer 1 is formed on the surface of the mask 7 on the side where the pattern 6 is formed.
Adsorb 3. Note that the water molecule layer 13 is also adsorbed on the other surface and each end face of the photomask 7 at the same time. enclosure 8
The part 14 between the J parts 0 and 0 is an exhaust port for the water vapor 12.

This photomask 14 was left in a water molecule layer adsorption device for about 10 minutes to adsorb a water molecule layer 13 on the surface on the pattern formation side as shown in FIG. 4.
4! , Iru. This water molecule layer 13 has a relative temperature of about 97%
About 90 molecular layers are formed under the surface type S t! f
lt&! , the temperature inside the device is approximately 200 °C (mohos
x 1012), then remove the equipment from the clean room (phase λ
・Take out the photomask 14 to 1 humidity 50%) C10
Approximately 100 within minutes (mohos x 1012)
It seems to be a little earlier than that.

As mentioned above, Figure 5 shows the water molecule Bi? ) 13 was used as a transfer mask, and Noah I
l-';r' A contact exposure method when manufacturing a saw 1 master photomask from mask blanks 4 to A1 using mask blank 4 (FIG. 1(a)) as a transfer substrate. show. The density exposure apparatus of this example includes a transfer transfer chamber 15, a transfer receiving chamber 22, a transfer booth 17, and a transfer transfer chamber 22.
The chamber 15 includes a pedestal 16 on which the photomask 14 is placed, a frame 19 (material; material, etc.) having through holes 17 and 18, and a transparent sealing plate 20 (material; material;
quartz glass, etc.) and a shoe sheet 21 (4J material: rubber, etc.) interposed between the photomask 14 and the pedestal 16. A frame body 25 having a through hole 24 (
A cushion sheet 2 interposed between the blank 4 and the pedestal 23.
7 (material: rubber, etc.).

The photomask 14 and the blank 4 are placed on the pedestals 16 and 23 via the cushion sheets 21 and 27, and the insides of the bumpers 15 and 22 are evacuated through the through holes 17 and 24, so that the photomask 14 and the blank 4 are placed in the above installation state. It is placed in an adsorption state. (Figure 5(a)). Next, after bringing the head surfaces of the frames 1-9 and 25 of each chamber 15 and 22 into contact with each other, the photomask 14 and the blank 4 are inserted through the through hole 18.
When the facing space of
)), the photomask 14 and the blank 4 are brought into close contact with the water molecule layer 13 interposed therebetween. In this close contact state, the mercury lamp light 28
is exposed to the photoresist 3 of the blank 4 through the photomask 14 from the transparent sealing plate 20 side, and the photomask 1
Transfer pattern 6 of 4 onto blank 4. Thereafter, the photomask 14 and blank 4 are removed from each chamber 15 and 22 by performing the vacuum and leakage procedures in reverse as described above.

Therefore, in the present invention, when the surface of the photomask 14 on the pattern 6 side and the surface of the 77+1- resist 3 of the blank 4 are brought into close contact, the water molecule layer 13 is interposed between them. Type conductivity (approximately 100 to 2001+10
11 (13X 1012) 'aA, '7 Teilko and Kara, static rr7 Can prevent Ki destruction. The effectiveness of preventing the destruction of the city air will be evaluated based on the following experimental results.

′? However, according to the conventional contact exposure method without a water molecule layer, when producing several dozen rib master masks from the same photomask 14 (5 inch square), the first, second and third The total number of chips (the depth is formed by pattern 6, and each mask in this example has 600 chips of 1/Imm square) of the eye submaster mask due to electrostatic damage (the number of chips missing due to electrostatic damage) is Those with a length of 2 μm or more) tended to accumulate in several pieces, 50 to 60 pieces, and 70 to 80 pieces, respectively. On the other hand, according to the contact exposure method using a water molecule layer of the present invention, no chipping occurred in all chips of any submaster mask, no matter how many submaster masks were manufactured. However, due to the presence of the water molecule layer in the present invention, there is no possibility that the quality of the pattern transfer substrate and the transfer substrate will be degraded physically (heat, transmittance, etc.) or chemically. Inogu allows pattern transfer to be performed reliably and precisely.

In the above embodiment, the pattern transfer substrate is a photomask,
Use -C') A tons blank as the transfer substrate,
Although this blank karari'Bunster mask was manufactured, this book also applies when using these A1 hard disks and rib master masks as transfer substrates and a semiconductor substrate such as silicon substrate with photoresist as a transfer substrate. The effect of the invention (it works exactly the same way).

The present invention is not limited to the following embodiment, but the water molecule layer may be adsorbed onto the transfer substrate's [A1] - resist layer 11 - mask blank or semiconductor substrate side. The adsorption means may be immersion in pure water, spraying, etc.Next, regarding the transparent substrate (soda lime glass or aluminum pot), other multi-component glass substrates such as Schilling-1 and glass bonding, For light-shielding thin films, la, Ti,
These oxides including W, No, Fe and C (C
r O, etc.), carbides (CrxC, etc.), y nitrides (CrXNV, etc.), and for photoresists for pattern transfer base plates and transferred substrates, other types of positive type 7711 ~ resists (e.g. Tokyo Ohka) are used. Manufactured by 0FP
R-800), negative photoresist (e.g. 0D
tlR-, 120) or photoresist by X-ray exposure method. The film thicknesses of the light-shielding thin film and the photoresist are each appropriately selected. This light-shielding thin film is not only deposited directly on the transparent substrate, but also has a transparent conductive layer on the side of the transparent V-plate.
Either or both of Q and the back anti-reflection film may be applied as required. A vacuum evaporation method, a vapor phase growth method, an ion plating method, or the like may be used for removing these films.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the manufacturing process of a conventional photo mask, Figure 2 is a cross-sectional view of a conventional photo mask that prevents charging, and Figure 3 is a water molecule layer adsorption used in the present invention. There is a sectional view C showing the device, the same figure (a) is a front sectional view, the same figure (b) G, 11iJ1 is a side view of Ii at the x-X line in Fig. 1 (a), and Fig. 1 is a view of the present invention The water molecular layer is adsorbed by U
FIG. 5 is a 71'lli plan view of the photomask, and FIG. 5 is a 71'lli plan view showing the dense exposure process according to the present invention. 1...j4 bright substrate, 3...photoresist, 4...
・Photomask blank, 6... Light-shielding thin film pattern, 13... Moisture layer, 14... Photomask Figure 1 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Display of case 1982 patent application No. 1368082,
Title of the invention Contact exposure method 3, relationship with the person making the correction Patent applicant address 1-13-12 Nishi-Shinjuku, Shinjuku-ku, Tokyo @ 16
0 T [Ei 03 (34B) 1221 E A7 Glass name Yasutani Glass Co., Ltd. (shipped: April 24, 1980) 5. Subject of amendment (1) "Brief explanation of drawings" in the specification Column (2) Details J
1. Full text 6. Contents of amendment The full text of the specification is revised as shown in the attached sheet.

Claims (1)

[Scope of Claims] (1) When a pattern consisting of a light-shielding thin film formed on a photomask is transferred to a transfer target substrate made of a photoresist material by close contact light, the photomask on the pattern formation side and A contact exposure method characterized in that a water molecule layer is interposed between the photoresist-coated substrate and the transfer target substrate. (2. The contact exposure method as set forth in claim 1, characterized in that a water molecule layer is adsorbed in advance on the photon surface on the pattern formation side. (3) Claim 1 In the description, a contact exposure method characterized in that a water molecule layer is adsorbed in advance on the surface of the substrate to be transferred with the photoresist toy 4.