JPS62224946A - Manufacture of semiconductor substrate - Google Patents

Abstract

PURPOSE:To permit the manufacture of a semiconductor element, which has a thick compound semiconductor single crystal layer and has a large diameter, without inflicting bad effect on such semiconductor devices as an LSI and a high-frequency device, which are formed on this single crystal layer, even though cracks are generated in the semiconductor substrate by a method wherein grooves intersecting orthogonally to one another are formed in the surface of the semiconductor substrate and the compound semiconductor single crystal layer consisting of a material different from that of this semiconductor substrate is grown on this surface. CONSTITUTION:Fine grooves 2 are worked in the surface of a substrate 1 for epitaxial growth in parallel and vertically to an orientation flat surface 3. It is desirable that the longitudinal and lateral grooves 2 are worked in bilateral and vertical symmetries and also, the interval between each groove is formed into an interval corresponding to the size of a dice to be used at the time of dicing of this substrate. When the dice is of larger than 10mm square, the interval is formed at the prescribed interval of 5-10mm. Then, a single crystal layer 4 consisting of a material different from the material of the substrate is grown directly or through a buffer layer on the surface with the fine grooves 2 worked therein by an MOCVD (metal organic chemical vapor deposition) method or an MBE (molecular beam epitaxial growth) method. Thus, a crack 5 is securely caused in the interior only of the fine groove 2 and this elements is formed into a flat semiconductor element. Accordingly, no trouble is generated even in a close contact exposure and so on in the following process.

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 Sl substrate is made of Si,
Epitaxial growth has been performed on a GaAs substrate using a combination of GaAAa, and using the same type or a very similar type, for example, a combination of GaAAAs on a GaAs substrate. Furthermore, by using the recent metal organic chemical vapor deposition (hereinafter referred to as MOCVD) method or molecular beam epitaxial growth (hereinafter referred to as MBE) method, it is possible to deposit completely thermal properties of GaAs on a Si substrate or damanium substrate with a crystal lattice constant. The so-called heteroepitactic growth due to the combination of different and different materials has been reported in the literature, Nikkei Microdevices (1,98
This has been made possible by the method described in P, P, 113-127, etc.

(Problems to be Solved by the Invention) However, in the conventional method as described above, for example, a GaAs layer is formed on a 2-inch Si substrate with a thickness of 3 μm to 411 μm.
When laminated to a certain thickness using MOCVD (metal-organic chemical vapor deposition) or MBE (molecular beam epitaxial growth), the substrate warps by 50 to 60 μm with the GaAs surface inward, and if it is grown even thicker, cracks occur, causing problems such as LSI and This becomes a problem when forming fine patterns such as in high-frequency devices.

The purpose of this invention is to eliminate the limit on the thickness of layers such as GaAs that are stacked by epitaxial growth as described above, and to avoid the difference in thermal properties in heteroepitaxial growth in which a different material, such as GaAs, is grown on a Si substrate. 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 Problems) In order to solve the above-mentioned problems, the present invention provides a structure in which the surface of the semiconductor substrate is parallel to and perpendicular to the orientation flat surface of the semiconductor substrate, and is parallel to and perpendicular to the size of the die. After forming a plurality of grooves with corresponding intervals or predetermined intervals of 5 to 10 TIrm, a compound semiconductor single crystal layer made of a material different from that of the semiconductor substrate is laminated on the surface of the semiconductor substrate.

(Function) According to the present invention, as described above, since a plurality of grooves are formed on the surface of the semiconductor substrate, a compound semiconductor single crystal layer made of a material different from that of the semiconductor substrate is grown on the surface of the semiconductor substrate. However, when this semiconductor substrate is used to form a compound semiconductor single crystal layer, L
When forming a semiconductor device such as an SI, even if a physical force is applied to deform the device into a flat shape, cracks will surely form only inside the narrow grooves, and no cracks will have a negative impact on the semiconductor device.

(Example) FIG. 1 is a view showing the surface of an epitaxial growth substrate 1 showing an example of the present invention, and FIGS. 2 and 3 are enlarged cross-sectional views thereof. The explanation will be given below along with the drawings.

First, as shown in FIG. 1, an epitaxial growth substrate 1 is prepared.
A thin groove 2 (see Fig. 2) is machined on the 0 surface parallel to and perpendicular to the orientation flat surface 3. For example, when a 2-inch 5t (100) substrate is used as the epitaxial substrate 1, the thickness of the substrate is usually 200 to 250 μm, and the narrow grooves are formed by etching or dicing saw to a depth of 100 to 150 μm. For large diameter boards of 3 inches or 4 inches, the remaining thickness is 100 μm or more.
Grooving is performed at 150 μm. The vertical and horizontal grooves 2 are preferably horizontally and vertically symmetrical, and their intervals are formed at intervals corresponding to the size of the dice when this epitaxial growth substrate 1 is diced. The dice are 10Trr! When the distance is larger than n, it is formed at a predetermined interval of 5 to 1011 m. Further, the width of the groove is sufficient if it is narrow; for example, when cutting the groove with a dicing saw, a blade with a width of about 20 μm is used.

Next, as shown in FIG. 2, an epitaxial growth substrate 1 is formed.
A semiconductor substrate is manufactured by growing a heterogeneous single crystal layer 4 by MOCVD or MBE directly or through a buffer layer on the surface where the narrow grooves 2 have been processed.

For example, when using the Si substrate 1 as the substrate 1 for epitaxial growth, the surface of the Si substrate 1 is cleaned by heat-treating it at about 900° C., and then if MOCVD is used,
00 to 450°C; in the case of the MBE method, 20 nm thick GaAs is deposited at a low temperature of 150 to 400°C, the growth is interrupted once, and 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.

In the embodiment of the present invention, M
Three to three GaAs single crystal layers are formed by OCVD method or MBE method.
When it grows by 4 μm, it deforms into a concave shape by about 50 μm. Furthermore, in the embodiment of the present invention, since thin grooves 2 are formed on the surface of the epitaxial growth substrate 1, the thicker the heteroepitaxial growth is performed, the more concave the growth surface becomes. The degree of deformation increases in proportion to the film thickness, and if there is no thin groove 2,
If GaAg is grown to a thickness of 5 μm or more on an inch-inch silicon substrate, it will crack and cannot be used as a semiconductor substrate for manufacturing semiconductor devices, but by providing the thin groove 2, the epitaxial growth substrate l will be greatly deformed. However, no cracks occur during the growth of the single crystal layer 4, and even if it is deformed flat due to physical force during contact exposure during the manufacturing process of semiconductor devices, the single crystal layer of GaAS is suitable for epitaxial growth of Si. Since the material is more susceptible to cracking than the substrate 1, cracks 5 will surely form only inside the narrow grooves 2, as shown in FIG. 3, resulting in a flat semiconductor substrate. Therefore, l-rubble does not occur even during close contact exposure in the subsequent process.

Moreover, since the grooves 2 are formed at intervals corresponding to the size of the die, there is no adverse effect on the semiconductor device formed on the semiconductor substrate thus formed.

(Effects of the Invention) According to the present invention, as described in detail above, grooves perpendicular to each other are formed on the surface of a semiconductor substrate, and a compound semiconductor single crystal layer made of a material different from that of the semiconductor substrate is grown on this surface. Therefore, even if a crack occurs in the semiconductor substrate, it will not have an adverse effect on semiconductor devices such as LSIs and high frequency devices formed on this single crystal layer. A substrate can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a plan view of a substrate for epitaxial growth showing an embodiment of the present invention viewed from the surface, FIG. 2 is an enlarged cross-sectional view of the substrate when a compound semiconductor single crystal layer is grown, and FIG. The figure is an enlarged cross-sectional view of the groove portion when the substrate is flattened. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Groove, 3...Orientation flat surface, 4...Single crystal layer, 5...Crack.

Claims (1)

[Claims] 1. Forming a plurality of grooves on the surface of the semiconductor substrate parallel and perpendicular to the orientation flat surface of the semiconductor substrate and having predetermined intervals; 1. A method for manufacturing a semiconductor substrate, comprising the step of laminating compound semiconductor single crystal layers made of a material different from that of the semiconductor substrate. 2. The method of manufacturing a semiconductor substrate according to claim 1, wherein the predetermined interval is an interval corresponding to the size of the die. 3. The method of manufacturing a semiconductor substrate according to claim 1, wherein the predetermined interval is 5 to 10 mm.