KR0119275B1 - Substrate fabrication method with soi structure using dielectric wafer bonding - Google Patents

Abstract

A fabrication method of SOI(silicon on insulator) substrate having each different thickness of an active layer using substrate-joining technique is disclosed. The method comprises the steps of: forming patterns(3, 5) having different step coverage on a substrate A(8); sequentially forming an oxide layer(9) and a polysilicon layer(10); joining the substrate A(8) and a substrate B(13); thinning the back-side(14,15) of the substrate A(8) by polishing or etching; CMP(chemical mechanical polishing) the back-side(14,15) using the oxide layer(9) as a stopper, thereby forming a silicon thin film(16) having high aspect ration and a silicon thin film(17) having low aspect ratio.

Description

Substrate manufacturing method of SOI structure with different active layer thickness using substrate bonding technology

1 shows the a-e process according to the invention.

2 shows an SOI substrate having different active layer thicknesses having a concavo-convex composite structure.

3 shows a substrate of the SOI structure having the thicknesses A and B of the silicon active layer in which the wiring electrodes are buried.

4 shows a wiring electrode formation process.

* Explanation of symbols for main parts of the drawings

1,8 substrate A 2 mask A

2 ': mask A' 3, 6: pattern with step A

4: Mask B 4 ': Mask B'

5,7: pattern having step B 9,21: oxide film

10 polysilicon 11: mirror surface

12: preprocessed substrate A 13: substrate B

14,15 back surface of substrate A16 silicon thin film layer with step A

17: silicon thin film layer having a step B 18,19: active region

20: wiring electrode 22: junction interface

23: P-epi layer

The present invention relates to a method of manufacturing a substrate having an SOI structure having different silicon active layer thicknesses using a substrate bonding technique in a semiconductor substrate manufacturing process.

An object of the present invention is to provide a method for manufacturing a substrate having a silicon-on-insulator (SOI) structure having different silicon active layer thicknesses.

In order to achieve the above object will be described in detail based on the accompanying drawings.

First, Figure 1 shows a substrate manufacturing process (a ~ e) according to the present invention, the process is as follows.

A shape is defined on the silicon substrate A (1) using the mask A (2) (a), and the silicon layer is etched by dry etching to form a pattern 3 having a step A (b). The pattern 5 having the step B is formed on the pattern 3 having the step A using the mask B 4 in the same manner as above (c, d). The steps A and B may be formed using the method of forming them separately as described above and using the masks A '(2') and the masks B '(4') in which the masks A and B are modified. A pattern 6 having a step A is formed using the mask A '(2') (a ', b'), and a pattern 7 having a step B is formed using a mask B '(4'). (C ', d) (step (a)). After the oxide film 9 is grown or coated on the substrate A 8 having the steps A and B, the polysilicon 10 is thickly deposited (step (b)). Then, the surface of the polysilicon 10 is mirror polished (11) and then the substrate A (12) and the substrate B (13) which are pre-processed are bonded by using a substrate bonding method. Bonding strength between the pre-processed substrate A 12 and substrate B 13 is increased by high temperature heat treatment (step c). After adhering the substrates, if the pre-processed substrate A 12 is a 5-inch substrate (thickness ˜625 μm) through the polishing process, the back surface 14 of the substrate A is ground about 550 μm and thinned (substrate). If the thickness of A is different, the grinding thickness may be different) (a in process (d)). On the other hand, when the substrate A 8 is an epi substrate (P-epi layer / P + substrate), the back surface 15 of the substrate A is further thinned through selective wet etching (b of step d).

After the exposed surface of the substrate A (8) is polished to make a mirror surface, it stops when it encounters the oxide film (9) formed at the top of the tablet by the selective polishing.

The process (e) of FIG. 1 shows a SOI substrate having different thicknesses finally formed. The silicon thin film layer 16 having a step A and the silicon thin film layer 17 having a step B are surrounded by an oxide film 9. Completely isolated from the silicon layers (step e).

Next, FIG. 2 shows an SOI substrate having different active layer thicknesses having an uneven composite structure.

FIG. 2 is a modified form of FIG. 1, using masks A and B, which have no gaps between the patterns, and have irregularities (FIG. 2 (a), SOB substrates having different active layer thicknesses 18 and 19 having a composite structure of (b)). 3 illustrates the formation of the wiring electrode 20 by using ion implantation, refractory metal silicide, or the like in the step forming process of FIG. Steps (b) to (e) of FIG. 1 may be performed and manufactured, and may be manufactured after the processes of FIG. 4 illustrates a process of forming the wiring electrode 20 according to FIG. 3, and illustrates a process of forming the wiring electrode 20 after the process of FIG. 1 (a). First, the process (A) of growing or applying the oxide film 9 is shown in FIG. Then, a part of the oxide film 9 of the protruding portion is removed (B), the wiring electrode 20 is formed using ion implantation, refractory metal silicide, or the like (C), and the oxide film 21 is again applied thereon. Then, polycrystalline silicon 10 is formed (C) and the surface thereof is mirrored (D).

Subsequent processes are the same as process (c)-process (e) of the said FIG.

As described above, different types of SOI devices may be fabricated on a single substrate. For example, a hybrid device can be fabricated on one substrate by fabricating a MOS device on the thinner side of the thin film and a dipole, JFET, etc. on the thinner side of the thin film.

Claims (1)

A step (a) of forming a pattern (3) (5, 7) having a step A and a step B of different heights on the silicon substrate A (1) using a predetermined mask (2, 2 '), and the step After formation, an oxide film 9 is formed on the substrate A 8, and the wiring electrode 20 is formed using a refractory metal silicide or the like in the removed portion of the oxide film 9 by removing a predetermined portion of the protruding oxide film. Subsequently, the step (b) of depositing the oxide film 21 and the polycrystalline silicon 10 thereon, and the polycrystalline silicon 10 is mirror- mirrored (11), and then the substrate A (12) pre-processed by a substrate bonding method. And (d) adhering the substrate B 13 and thinning the rear surfaces 14 and 15 of the substrate A to a predetermined thickness by polishing and etching the rear surfaces 14 and 15 of the substrate A ( D) and the back surface 14 and 15 of the substrate A are polished by selective polishing until the oxide film 9 comes out, and then the silicon thin film layer 16 having a step A and the silicon B having a step B thereon. But form a 17, a method of producing a SOI substrate structure using a substrate bonding technique including a step (e) for isolated by the oxide film (9).