JPH01321637A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To remove generation of a pin hole and side etch and to prevent enlargement of the pin hole produced in a film in the preceding process by using a printed film instead of a resist film when covering the part except recesses with corrosion resistant mask material for removing, by etching, a film adhering inside a plurality of recesses formed from one main face side of a semiconductor substrate. CONSTITUTION:A recess 2 is formed in a silicon substrate 1 by stop etching, and then a metallic film 3 is deposited, and next screen printing is performed, and mask material 6 is dropped sufficiently on a screen 5. And by shifting a squugee 7 along the upper face of the screen 5, the film of the mask material 6 is printed on the surface of a substrate 1, and the mask material 6 does not adhere to the inner face of the recess 2. Hereafter, when etching is performed, a metallic film 3 inside the recess 2 is removed completely, and neither pin hole nor side etch occurs at the metallic film 3 on the surface of the substrate 1. Hereby, the film at the inner face of the recess can be removed completely, and the film on the surface of the semiconductor board 1 other than the recess 2 can be maintained as it stands in the favorable condition.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention, for example, when manufacturing a semiconductor pressure sensor, processes a plurality of recesses at predetermined intervals from one main surface side of a semiconductor plate, and forms a diaphragm portion. A semiconductor device in which a film made of metal, inorganic material, or organic material deposited on the entire surface is covered with a mask of a predetermined pattern except for at least the inside of the recesses, and the film in the parts not covered by the mask is removed by etching. Relating to a manufacturing method.

[Conventional technology]

In order to manufacture a semiconductor pressure sensor, a process is performed in which a resist pattern is provided on one surface of a semiconductor board, and recesses are processed in a regular array using a method such as stop etching to form a thin diaphragm part. After that, when a metal film such as Cr, Au, Au, etc. for forming wiring etc. on the semiconductor board is deposited on the entire surface, the metal film deposited on the above-mentioned recesses, or other than that, is deposited on the entire surface of the semiconductor board. The portion of an inorganic film such as a nitride film or an organic film such as a resist film deposited on the recess must be removed in order to stabilize the deformation characteristics of the diaphragm portion due to pressure. For this reason, conventionally, for example, as shown in FIG. 2, a plurality of recesses 2 are formed on a silicon substrate 1 by a stop etching method, although only one is shown in the figure, and then a photoresist is applied on top of the deposited metal film 3. If it is a negative resist, it is exposed to light using a mask that has a light shielding part above the concave part 2, and then developed to form a resist film 4 in a predetermined pattern with a thickness of 1 to 3-3 on the surface of the silicon substrate 1. After that, etching is performed to pattern the metal film 3 and remove the portion 31 of the metal film on the inner surface of the recess 2.

[Problem to be solved by the invention]

However, if there is uneven coating during resist application, thin portions 41 and 42 of the resist film 4 will occur during development. Further, if the recess is deep, the corners of the bottom surface are difficult to expose, resulting in resist residue 43. When the metal film 3 is etched in this state, the metal ll! is etched as shown in FIG. 3 pinhole 31
．． There is a drawback that side etching 32 or etching residue 33 occurs.

An object of the present invention is to provide a method for manufacturing a semiconductor device that eliminates the above drawbacks, completely removes the film on the inner surface of the recess, and maintains the film on the surface of the semiconductor board other than the recess in a good condition. It is in.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention forms recesses arranged at predetermined intervals from one main surface side of a semiconductor substrate, and then After forming a film on the entire main surface, when removing the film on the inner surface of the recess, print a paste-like printing material on the main surface using a member that contacts only the flat part of the main surface, and then use the printed film as a mask for etching. The film on the inner surface of the recess shall be removed.

[Effect]

If you print paste-like printing material only on the flat part of the main surface and use it as a mask and perform etching, the viscous printing material will not adhere to the inner surface of the recess, so the film on the inner surface can be removed uniformly and no residue will remain. Moreover, a mask that can be formed into a predetermined pattern by printing is less likely to cause defects, and the film on the main surface is maintained in good condition with the desired pattern after the etching process.

〔Example〕

Figure 1 fat ~ (C1 shows one embodiment of the present invention,
゜The same parts as in Fig. 3 are given the same reference numerals.

After forming a recess 2 in a silicon substrate 1 by stop etching, a metal film 3 is deposited (Figure a).

However, unlike the case in FIG. 2, resist coating, exposure, and development are not performed. Next, screen printing is performed, that is, a mask material 6 is sufficiently dropped onto the screen 5. As the mask material, a paste-like material having corrosion resistance is used as described later.

Then, by moving the squeegee 7 in the direction of the arrow along the upper surface of the screen mask 5, a film of the mask material 6 is printed on the surface of the substrate 1, and the mask material 6 does not adhere to the inner surface of the recess 2 (Fig. b) In order to prevent the mask material 6 from entering the recess 2, it is necessary that the mask material has a high viscosity and the mesh of the screen mask 5 is not large so that the mask material 6 does not fall through the mesh due to surface tension. Specifically, the mesh number of screen mask 5 is set to 200 to 2.
50° The thickness t is set to 50 to 12 nm, and the mask material 6 is made of blown asphalt, straight asphalt, crystal wax, resist ink, etc., and the viscosity is adjusted to 90 ± 10 cP while stirring together with the heating material Triclean 1, Regiusa B, etc. do. During printing, by leaving a gap d of about 1 to 4 fi between the screen mask 5 and the printed surface of the silicon substrate 1, contact between the screen mask 5 and the surface of the substrate 1 can be prevented during printing. Also, squeegee 7
When applying squeegee pressure to the mask material 6 on the screen mask 5 and extruding it in parallel, the screen mask is pushed down into the recess 2 and enters from the surface of the substrate 1 by h, and since h becomes 100- or more, The depth of recess 2 is 10
If it is less than 0-, the screen mask 5 will come into contact with the bottom surface of the recess 2 and the mask material 6 will adhere.

By satisfying the above conditions, printing can be performed optimally. When forming wiring from metal wi 43, a screen mask 5 having a wiring pattern is used.

When etching is performed after this, the metal film 3 in the recess 2 is completely removed, and no pinholes or side etching occur in the metal film 3 on the surface of the substrate 1 (Figure C). When the screen mask 5 with a pattern is used, the metal film other than the wiring portion on the surface of the substrate is also removed. Similarly, the nitride film or resist film deposited within the recess 2 can be easily removed.

FIG. 4 shows another embodiment of the present invention, in which a mask material 6 is deposited on a roller 8 and rolled over a silicon substrate 1 in the direction of the arrow, so that the mask material 6 is applied onto the contacting substrate surface. The portion 61 that goes over the recess 2 remains on the roller 8 as it is.

Of course, it is necessary to adjust the viscosity of the mask material 6 so that it does not fall into the recess 2. However, this method is effective when etching is performed only for the purpose of removing the film on the inner surface of the recess.

〔Effect of the invention〕

According to the present invention, when covering areas other than the recesses with a corrosion-resistant mask material in order to remove by etching a film deposited in a plurality of recesses formed from one main surface side of a semiconductor substrate, the conventional film thickness is By using a printed film with a thickness of 10 to 50 nm instead of a resist film of 1 to 3 nm, the film that is not removed during etching is completely protected, eliminating the occurrence of pinholes and side etching, and eliminating the need for pre-processing. Since it also covers pinholes that occur in the membrane, it can prevent pinholes from expanding. Furthermore, since photoetching is not used, no resist residue remains in the recess, and the recess is kept free of deposits, which is particularly useful for improving the accuracy of the deformation characteristics of the diaphragm part of semiconductor pressure sensors in response to pressure. Extremely effective.

Note that the present invention is applicable not only to the case of complete removal of the film inside the recess, but also to the case of removing the film to leave a film of uniform thickness.

[Brief explanation of the drawing]

FIG. 1 (al to (cl) are sectional views sequentially showing the printing and etching steps of an embodiment of the present invention, FIG. 2 is a sectional view showing the conventional photoetching method, and FIG. 3 is the method of FIG. 2. 4 is a sectional view showing the printing process of another embodiment of the present invention. 1: Silicon substrate, 2: Concave portion, 3: Metal film, 5 Niscreen mask, 6: Mask material, 7: Sukiyo jf person F + Rijo Yamaguchi B, (?- ゛, -1' Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] 1) After forming recesses arranged at predetermined intervals from one main surface side of a semiconductor substrate, after forming a film on the entire surface of the main surface including the recesses, when removing the film on the inner surface of the recesses, a paste-like 1. A method for manufacturing a semiconductor device, comprising printing on the main surface using a member that brings a printing material into contact only with the flat surface of the main surface, and etching the printed film as a mask to remove the film on the inner surface of the recess.