JPS62171112A - Manufacture of semiconductor substrate material - Google Patents

Abstract

PURPOSE:To eliminate limitation on thickness in growth of hetero epitaxial growth of foreign substance such as growth of GaAs onto a substrate by forming a plurality of grooves orthogonally crossing each other to the rear surface of a semiconductor substrate and then stacking a semiconductor single crystal layer, different from a semiconductor substrate, to the surface of semiconductor substrate. CONSTITUTION:The narrow grooves 2 are formed in parallel and in vertical to the orientation flat surface 3 at the rear surface of substrate for epitaxial. A semiconductor substrate material is manufactured allowing a single crystal layer 4 in different quality to growth by the MOCVD method or MBE method directly or through the buffer layer to the surface, where the narrow grooves 2 are not formed, of the substrate 1 for epitaxial. Since the epitaxial substrate 1 is partly thin, stress is alleviated and any crack is not generated even during the thick epitaxial growth. Thickness of substrate is usually 200mum-250mum and narrow grooves are formed by the etching in the depth of 100-150mum or the dicing saw. For the substrate of large diameter of 3 or 4 inch, the grooves are formed in the remaining thickness of 100mum-150mum.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a semiconductor substrate composed of a plurality of different semiconductor layers.

(Prior Art) Conventionally, this type of semiconductor substrate for epitaxial growth has been made of a silicon (hereinafter referred to as Si) substrate or a gallium arsenide (hereinafter referred to as G) substrate.
aAs) substrate etc. are used, and the Si substrate is St
,, GaAs substrate is a combination of GaAs, the same type or very similar type, for example, GaAs substrate and GaAt
Epitaxial growth was performed using a combination of As. In addition, recent metal organic chemical vapor deposition (MOCV)
D) method or molecular beam epitaxial growth (hereinafter referred to as M
By using the BE method, so-called heteroepitaxy growth using a combination of different materials such as GaAs, which have completely different thermal properties and crystal lattice constants, on a Si substrate or a rumanium substrate has been reported in the literature, ELECTRONIC8L.
ETTER8 (1984-10-25) Vol.

20, A 22. pp916-918, YaJap
anese Journal of Applied P
hysics Vol, 23. A 11. (19
84-11)pp.

This has been made possible by the methods described in L843-L845 and the like.

(Problems to be Solved by the Invention) However, in the conventional methods as described above, for example, a GaAs layer is formed on a 2-inch Si substrate to a thickness of 3 μm to 4 μm using MOCVD (metal-organic chemical vapor deposition) or M
When laminated by BE (molecular beam epitaxial growth) method, the substrate is 50 μm to 60 μm thick with the GaAs surface inside.
When grown even thicker, cracks occur, which becomes a problem when forming fine patterns such as LSIs and high-frequency devices.

The purpose of this invention is to eliminate the limit on the thickness of layers such as GaAa that are stacked by epitaxial growth as described above, and to eliminate the limitations on the thickness of layers such as GaAa that are stacked by the epitaxial growth described above. The goal is to eliminate thickness restrictions. Another purpose is to enable heteroepitaxial growth on large Si substrates of 4 inches and 5 inches.

(Means for Solving the Problem) In order to solve the above problem, the present invention forms a plurality of grooves perpendicular to each other on the back surface of a semiconductor substrate, for example, parallel or perpendicular to the orientation flat surface of the semiconductor substrate. However, a semiconductor body is manufactured by laminating a semiconductor single crystal layer different from this semiconductor substrate on the surface of this semiconductor substrate.

(Function) As explained above, according to the present invention, a plurality of mutually orthogonal grooves are formed on the back surface of the semiconductor substrate, so that a single crystal layer of a semiconductor different from that of the semiconductor substrate is formed on the surface of the semiconductor substrate. Even when laminated, thermal stress is relaxed and no cracks occur in the substrate, and even if the substrate is deformed flat by mechanical force during the manufacture of semiconductor devices such as LSIs, no cracks will occur.

(Example) Fig. 1 shows an epitaxial substrate 1 showing an example of the present invention.
FIG. 2 is an enlarged cross-sectional view of the back side of FIG. The explanation will be given below along with the drawings.

First, as shown in FIG. 1, a narrow groove 2 (see FIG. 2) is formed on the back surface of an epitaxial substrate 1 parallel to and perpendicular to the orientation flat surface 3. As shown in FIG.

For example, when a 2-inch 5t (100) substrate is used as the epitaxial substrate 1, the thickness of the substrate is usually 200 μm.
~250μm, and narrow groove processing is 100~150μm
Perform etching or grouting to a depth of m.

For large-diameter substrates of 3 inches or 4 inches, grooves are formed so that the remaining thickness is 100 μm to 150 μm. It is preferable that the vertical and horizontal grooves be symmetrical in the horizontal and vertical directions, as shown in Figure 1.
, nm10. Arrange the pitch. The width of the groove is narrow and sufficient, for example 20μ when cutting grooves with a guising tool.
Process using a blade with a width of about m.

Next, as shown in FIG. 2, a heterogeneous single crystal layer 4 is grown by MOCVD or MBE directly or via a buffer layer on the surface of the epitaxial substrate 1 where the thin grooves 2 have not been processed. A semiconductor substrate is manufactured according to the method.

For example, when using the Si substrate as the epitaxial substrate 1, the surface is cleaned by heat-treating the Si substrate 1 at about 900°C, and then, if MOCVD is used,
~450°C, or in the case of the MBE method, a 20 nm thick GaAs layer is deposited at a low temperature of 150 to 400°C, and after the growth is interrupted, the substrate temperature is increased to 700 to 750°C.
By increasing the temperature and performing a second growth, a GaAs single crystal layer is grown.

As described above, when a GaAs single crystal layer is grown 3 to 4 μm thick on a Si substrate using MOCVD or MBE, the layer becomes 50 μm thick.
Further, in the embodiment of the present invention, since the narrow groove 2 is formed in the processed taxial substrate 1, the degree of the concave deformation increases as the thickness of the heteroepitaxial growth increases. becomes proportionally larger. However, according to the embodiment of the present invention, since the epitaxial substrate 1 is partially thin, the stress is relaxed and no cracks occur even if epitaxial growth is performed thickly.

Furthermore, according to the embodiment of the present invention, the thin groove 2 is formed on the back surface of the epitaxial substrate 1, so that it can be deformed flat by mechanical force during mask alignment during device fabrication, for example, when performing contact exposure. Also, since the epitaxial substrate 1 is partially thin, it will not break.

Since the thin grooves 2 are machined parallel to and perpendicular to the orientation flat surface 3 of the epitaxial substrate 1, stress can be uniformly relaxed during heat treatment during device fabrication, improving device yield and reliability. can improve sexual performance.

(Effects of the Invention) As described above in detail, according to the embodiments of the present invention, even if single crystal layers of a semiconductor different from the semiconductor substrate are stacked on the front surface of the semiconductor substrate, they are mutually stacked on the back surface of the semiconductor substrate. Since a plurality of orthogonal grooves are formed, thermal stress can be alleviated, and a semiconductor substrate having a thick single crystal layer and a large diameter can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the back surface of a semiconductor substrate for explaining the present invention in detail, and FIG. 2 is an enlarged cross-sectional view of the semiconductor substrate. 1... Epitaxial substrate, 2... Groove, 3...
Orientation flat surface, 4... single crystal layer. Patent applicant Oki Electric Industry Co., Ltd. Mu conductor body, N side and Hoki thousand-sided map (Text box Imon) Figure 1 % + rJJ t=, T, Lh 44 lines, JT- side ↑
Hirofu (p1 fig. 2

Claims (1)

[Claims] 1. A method comprising the steps of: forming a plurality of mutually orthogonal grooves on the back surface of a semiconductor substrate; and laminating a semiconductor single crystal layer different from the semiconductor substrate on the front surface of the semiconductor substrate. A method for manufacturing a semiconductor substrate, characterized in that: 2. The method of manufacturing a semiconductor substrate according to claim 1, wherein the mutually orthogonal grooves are formed parallel and perpendicular to the orientation flat surface of the semiconductor substrate.