JPH0315848A - Exposing method and production of mask - Google Patents

Abstract

PURPOSE:To faithfully transfer wiring circuits of a branch shape and to prevent the leakage of light to parts exclusive of a prescribed waveguide by exchanging plural sheets of masks so as to avoid the interference of light, successively executing exposing, then developing and processing. CONSTITUTION:A substrate 1 is formed by using n type InP and an InGaAsP layer is grown thereon, then an InP layer 3 is grown as a clad layer thereon. An InGaAsP layer 4 is grown as a cap layer thereon. Zn is diffused to form a shape 5 and after this part is made into a p type, a negative resist is applied thereon and is exposed by using the 1st mask 6. The resist is then exposed by using the 2nd mask 7 without being developed and is thereafter subjected to the development, by which the Y-shaped photomask having no dulling is formed in the branch part 8. The faithful transfer of the desired shape is possible in this way and the optical switch which suppresses the leakage of the light to the parts exclusive of the prescribed waveguide is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for faithfully manufacturing a required product shape or original mask shape to a desired shape in a photoresist exposure method. [Prior art] A conventional optical switch device is described in Electronics Letters,
Volume 20, Na6 (1984) No. 228-229
Page (Elaetronics Letter 1 9
8 4voQ, 20. As stated in Nn6, pp228-229), the branched waveguide width of the optical branch is the same at the branch and beyond, and this prevents light leakage at the branch. No particular measures were taken. We will describe an optical switch device that takes measures against this problem. Related to this type of device is the Journal of the Institute of Electronics and Information Engineers (1982) 967. [Problems to be Solved by the Invention] In the above-mentioned conventional technology, in the I1 method of forming the original mask pattern using photoresist and in the manufacturing method of the wiring line, the branch portions become dull due to light interference, and this causes the optical switch to become unstable when no voltage is applied to it. At the time, a problem arose in which light leaked into waveguides other than the designated waveguide. The purpose of the present invention is to provide a method for manufacturing an original mask pattern using photoresist and a method for manufacturing wiring lines.
An object of the present invention is to provide an optical switch, etc., in which wiring lines constituting a branch shape are faithfully transferred to a desired shape in order to prevent blunting of the branch portion, and development in which light leaks to areas other than the designated waveguide is suppressed. [Means for solving the problem] In order to achieve the above purpose, arrangement II that constitutes a branched shape is required.
In order to eliminate light interference, the AIvI path is achieved by performing a development process after performing multiple transfer processes. [Function] In order to prevent the shape of the branch portion from becoming blunt in the method of manufacturing the original mask pattern using photoresist and the method of manufacturing the wiring line, the layout II that forms the branch shape is used! By applying the transfer process to the line multiple times to eliminate light interference, and then applying the current process, the desired shape is faithfully transferred, suppressing the phenomenon of light leaking outside of the designated waveguide, and preventing malfunctions. This results in an optical switch without [Example] An example of the present invention will be described below. Example 1 As shown in FIG. 1, the substrate 1 has a carrier concentration of IXIO"
(Using !l''s n @ I n P. Using the LPE method, I
The nGaAsP layer 2 is made to have a certain length. Next, an InP layer 3 is grown as a clad layer, and an I layer is grown as a cap layer on top of it.
The nGaAsP layer 4 is made to have a certain length. Next, Zn is diffused using selective diffusion technology to form the shape shown in Fig. 2, making this part P-type. After applying the negative resist to the sample, the first mask is used to perform exposure as shown in Figure 2-6. Next, without developing, a second mask is used to perform exposure as shown in FIG. 7, and then development is performed to form a Y-shaped photomask with no dullness at the branch portion 8. By the way, when using a conventional mask, the branch part becomes dull due to light interference as shown in Figures 4 and 9. Next, a cap layer 4, an InP cladding layer 3 . Dry etching is performed on the optical waveguide layer 2. After that, using lift-off technology, Au-Z
An n-electrode 10 is formed. AuGeNf was vapor-deposited on the back surface to form the n-electrode 11 to complete an optical switch device.

The results of comparing and measuring the switching characteristics of the switch of the present invention shown in FIG. 3 and the conventional optical switch shown in FIG. 4 will be described. As shown in FIG. 3, when single mode light with a wavelength of 1.3 μm is input to the switch input port 6a of the present invention and no voltage is applied, the ratio of the output Px from the output port 6b to the output P2 from the output port 7a is was 120/1. In prior art switches it is 10/1. The reciprocal of this value, ie, P x / P 1, represents the amount of light leakage. Next, Px/Px when applying 3V (current 20mA)
was 1/30 for both the switch of the present invention and the switch of the prior art. According to this embodiment, the branching portion of the conventional waveguide is blunted 9 as shown in FIG. 4 due to the photolithography process, which caused a problem in the amount of light leakage. According to this embodiment, this problem can be easily solved by double exposing the photoresist in the area to prevent light interference, and the amount of leakage can be dramatically reduced. The dimensions of this device are 1 as X Q, 5 gs, the branching angle of the Y-shaped waveguide is 6 degrees, and the width of the waveguide is 5 μm.

Although a Y-branch type optical switch has been described above, the present invention is equally applicable to an X-branch type optical switch. Furthermore, the present invention is similarly applicable to multiple branch type optical switches other than the X branch type optical switch. Although this embodiment has been described using InGaAsP as an example of the optical waveguide, it is also possible to use Si, GaAs, and other semiconductor materials. Example 2 An example in which the original mask pattern manufacturing method is applied will be described. As shown in FIG. 6, a body resist 14 is applied to a substrate on which Crl3 is deposited on a glass or synthetic quartz plate 12. No. 7, as shown in 16, a straight line pattern was closely exposed using mask 15, or a reduced projection @ was used to perform double exposure of a straight line pattern as shown in Figure 8, 17 without development after exposure. Afterwards, when development is carried out, an X-shaped original mask photoresist pattern with no dull branching parts as shown in FIG. 8 is obtained. Next, by etching the Cr vapor deposited film, an original mask with no blunted X-branched portions can be obtained. Using this original mask, we completed an optical switch device with no dullness at the branching part, as shown in the example work. Although Example 2 uses a positive type resist, similar results can be obtained using negative type resists 1 to 1. Example 3 An example of application to microfabrication of products will be shown. As shown in FIG. 9, SiOzl9 is deposited on the Si substrate 18. Next, a negative resist 20 is applied to a thickness of 0.5 .mu.m, and after pre-baking, a straight line pattern 22 is exposed through an original mask 21 as shown in FIG. 10 by contact or reduction projection exposure. A fine photoresist pattern 23 as shown in FIG. 11 was obtained by exposing and developing using the following mask without performing development. Thereafter, as shown in FIG. 12, SiOd4 was etched using the photoresist as a mask. Similar results were obtained even when the original mask pattern was moved slightly parallel or perpendicular. Similar results were obtained for BosiResist. Example 4 As shown in Fig. 13, 300% SiOz was deposited on a Si substrate.
After depositing 0.5μm of negative resist, prebaking is performed. Next, as shown in the figure, S! A 0.5 .mu.m stripe pattern 25 is exposed through an original mask using f-printing or reduction projection exposure to form a latent image without development. Next, by exposing the stripe pattern as shown in Step 4, Figure 26, at right angles and developing it, a 0.5 μm contact hole with rounded corners as shown in Figure 15, 27 was obtained. Similar results were obtained for original mask pattern production. [Effects of the Invention] According to the present invention, it is possible to prevent the branch portion from becoming dull in the method of manufacturing the original mask pattern using photoresist and the method of manufacturing the wiring line, so that a desired shape can be faithfully transferred, and a predetermined waveguide Furthermore, it is possible to provide an optical switch that suppresses the phenomenon of light leakage.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a wafer of an optical switch, FIG. 2 is a top view of a photoresist latent image of the first exposure of an optical switch waveguide according to an embodiment of the present invention, and FIG. 3 is a double exposure development according to the present invention. Top view of branch part of optical switch waveguide without dullness after copying process,
Figure 4 is a top view of the branch part of a conventional optical switch waveguide with a dull shape, Figure 5 is a cross-sectional view of the optical switch, Figure 6 is a cross-sectional view during exposure when manufacturing an original mask pattern, and Figure 7 is a cross-sectional view of the optical switch during exposure. A top view of latent copying of photoresist during the second exposure during the production of the original mask pattern, Figure 8 shows the second exposure during the production of the original mask pattern.
Top view after development and Cr film etching, Figures 9 to 12
The figure is a sectional view showing the pattern forming process of another embodiment of the present invention, and FIGS. 13 to 15 are top views showing the pattern forming process of still another embodiment of the present invention. 6...Latent image of first exposure mask, 7... Branch without dullness after second exposure, development, and dry etching, 9...
Conventional blunt branch, 16... Photoresist latent image after first exposure during original mask pattern production, 17...
X-branched original mask pattern without dullness. Condolence S Fig. 7th Taku 3rd ``fIa No. 14 Fig. 5 Fig. 2z θ, 57ytt S} La 4 ゜゜冫W I9hi 27 θ5Pπ Hmph 1 hole

Claims (1)

[Scope of Claims] 1. An exposure method for photoresist, which is characterized in that a plurality of masks are exchanged to prevent light interference, and development is performed after sequential exposure. 2. A method for manufacturing a mask, which comprises replacing a plurality of masks to prevent light interference, sequentially exposing the masks, and then developing them. 3. An exposure method for photoresist, which is characterized by moving a mask in parallel or perpendicularly multiple times to prevent light interference, and sequentially exposing and then developing. 4. A method for manufacturing a mask, which comprises moving the mask multiple times in parallel or perpendicularly to prevent light interference, sequentially exposing the mask, and then developing it. 5. A method for producing an original mask pattern for a wiring circuit having a branched shape, characterized in that the wiring line constituting the branched shape is transferred multiple times using a photoresist and then developed. . 6. The method for manufacturing a branched original mask pattern according to claim 5, characterized in that a positive resist is used as the photoresist. 7. In the original mask pattern manufacturing method for a wiring circuit having a branched shape, the angle of the wiring circuit to be branched is 1 degree or more45
7. The method for manufacturing a branched original mask pattern according to claim 5 or 6, wherein the original mask pattern has a branched shape. 8. A method for manufacturing a branched shape, which comprises performing a plurality of transfer processes on the wiring lines constituting the branched shape using a photoresist, and then developing the lines. 9. The method for manufacturing a branched shape according to claim 8, wherein a negative resist is used as the photoresist. 10. The method for manufacturing a branched shape according to claim 8 or 9, wherein the angle of the branched portion of the branched shape is 1 degree or more and 45 degrees or less. 11. A method of manufacturing a semiconductor circuit, wherein the branch shape according to any one of claims 8 to 10 is a part of a semiconductor circuit. 12. A method of manufacturing an optical circuit, wherein the branch shape according to any one of claims 8 to 10 is a part of an optical circuit. 13. A method for manufacturing an optical waveguide, characterized in that the branch shape according to claims 8 to 10 is a part of the optical waveguide.