JP3173402B2 - Liquid phase growth equipment for semiconductor substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly, to a liquid phase growth apparatus used for performing epitaxial growth in a liquid using a temperature gradient method or the like. is there.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the structure of a conventional liquid phase growth apparatus 90. This liquid phase growth apparatus 90 basically has a main body provided with a solution pot 91a for accommodating a solvent. 91, a bottom portion 92 provided on the bottom surface side of the main body portion 91 slidably provided with a housing concave portion 92 a for housing the semiconductor substrate, and a lid portion 93 for closing the upper surface of the solution pot 91 a of the main body portion 91. It is composed of

FIG. 4 shows a state in which liquid phase growth is performed using the liquid phase growth apparatus 90. The bottom side of a main body 91 is a bottom portion 92 in which a semiconductor substrate 11 is stored in a storage recess 92a. The solvent 1 in which the solute material 12 a is dissolved in a saturated state is closed in the solution pot 91 a of the main body 91.
2 is injected and covered with a lid 93.

In this state, when the bottom portion 92 is brought into contact with the cooling table 94 and the heater 95 is further heated from above the lid portion 93, the temperature of the solvent 12 in the solution pot 91a becomes high and the bottom becomes high. This causes a temperature gradient in the vertical direction at a low temperature, and the solute material 12a is supersaturated below. When this state is maintained for a predetermined time, a crystal having a predetermined composition grows epitaxially on the semiconductor substrate 11.

[0005]

However, in the liquid phase growth apparatus 90 having the above-mentioned conventional configuration, the heater 9
5 from the side of the side wall 9 of the solution pot 91a.
When the temperature distribution of the solvent 12 immediately above the semiconductor substrate 11 is measured in the horizontal direction, the semiconductor substrate 11 also has a high liquid temperature at the peripheral portion, , The liquid temperature tends to decrease.

Accordingly, the solute material 12a becomes more supersaturated at the center of the semiconductor substrate 11 where the liquid temperature is low, so that the crystal growth proceeds and the film thickness becomes thicker, and the supersaturation is less at the periphery and the crystal growth proceeds. First, the film thickness is reduced, and as a result, the growth thickness over the entire surface of the semiconductor substrate 11 becomes nonuniform, which causes a problem of causing a defect and lowering the yield, and solving this point is an issue.

[0007]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, there is provided a main body provided with a solution pot for accommodating a solvent, and a sliding member provided on the bottom side of the main body. In a liquid phase growth apparatus for a semiconductor substrate, comprising: a bottom portion movably provided with a storage concave portion for storing a semiconductor substrate; and a lid portion for closing an upper surface of the solution pot portion of the main body portion. Is formed of a member that withstands the temperature of the solvent and has a higher thermal conductivity than the thermal conductivity of the solvent, and has an area larger than the area of the semiconductor substrate;
A thermal equalizing plate in which a plurality of through-holes are formed in a matrix on substantially the entire surface is provided with a gap of 5 mm or more with the side wall of the solution pot, and has a depth of 5 mm or more from the liquid level of the solvent, and The problem is solved by providing a liquid phase growth apparatus for a semiconductor substrate, wherein the apparatus is suspended from the lid so as to be parallel to the semiconductor substrate at a distance of 3 mm or more from the semiconductor substrate. Things.

[0008]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 is a liquid phase growth apparatus for a semiconductor substrate according to the present invention, and the liquid phase growth apparatus 1 is roughly divided into a main body 2 provided with a solution pot 3 for accommodating a solvent 12; A housing recess 4 slidably provided on the bottom side of the main body 2 for housing a semiconductor substrate.
This is similar to the conventional example in that it comprises a bottom part 4 provided with a and a lid part 5 for closing the upper surface of the solution pot part 3 of the main body part 2.

When performing liquid phase growth, the main body 2
Of the semiconductor substrate 11 is housed in the housing recess 4a, and the solute material 12 is placed in the solution pot 3 of the main body 2.
a is dissolved in a saturated state,
After that, the bottom 4 is brought into contact with a cooling stand (not shown), and heating is performed from above the lid 5 by a heater (not shown). The same is true.

Here, in the present invention, a thermal leveling plate 6 immersed in the solvent 12 is provided, and the thermal leveling plate 6 is heated to a temperature at which the solvent 12 is heated, for example, 800 ° C.
Is formed by using a plate-shaped member such as graphite carbon, which is sufficiently resistant to heat. At this time, the thermal conductivity of the thermal leveling plate 6 is selected to be higher than the thermal conductivity of the solvent 12. Is done.

FIG. 2 shows the structure of the thermal equalizing plate 6. If the semiconductor substrate 11 on which crystal growth is to be performed has a circular shape, the thermal equalizing plate 6 also has a circular shape. As described above, it is formed as a shape corresponding to the planar shape of the semiconductor substrate 11, and its outer diameter φ1 is equal to the outer diameter φ2 of the semiconductor substrate 11.
It is formed larger than appropriate.

A plurality of through-holes 6a are formed in the thermal equalizing plate 6, for example, in a matrix form over almost the entire surface so as not to prevent the diffusion of the solute material 12a in the solvent 12. . The thermal leveling plate 6 is attached to the lid 5 by a support column 7 and is suspended at a predetermined position in the solvent 12 by covering the solution pot 3 with the lid 5 during liquid phase growth. It is made of things.

Here, based on the results of experiments conducted by the inventor for carrying out the present invention, a preferred position of the heat equalizing plate 6 in the solvent 12 will be described. It is desirable to provide a gap A having a diameter of 5 mm or more from the side wall 3a of the solution pot 3 and to immerse the heat equalizing plate 6 in the solvent 12 to a depth B of 5 mm or more.

Here, the gap A from the side wall 3a and the solvent 1
If the depth B immersed in 2 is smaller than the above dimension, convection of the solvent 12 generated by heating by the heater is prevented, and the solute material 12a stays near the side wall 3a, for example.
This portion, that is, the crystal growth in the peripheral portion of the semiconductor substrate 11 becomes thicker, and the uniformity of the entire surface is lost.

Further, in the present invention, the semiconductor substrate 11
And the distance C between the heat equalizing plate 6 and
This interval C is preferably 3 mm or more. this is,
According to the results of the experiment by the inventor described above, if the distance C between the semiconductor substrate 11 and the thermal leveling plate 6 is too close, for example, 2 mm, the semiconductor substrate 11 after crystal growth is performed. This is because a matrix-like pattern formed by the through holes 6a is formed on the surface, and the uniformity of the entire surface is lost in the same manner as described above.

After satisfying the above conditions, the semiconductor substrate 11 and the heat equalizing plate 6 are mounted so as to be parallel to each other. Further, the liquid phase growth apparatus 1 has a structure in which a plurality of solution pots 3 are provided in a main body 2 and either one of the main body 2 or the bottom 4 is slid to continuously grow. If so, the heat equalizing plate 6 is provided for each solution pot 3 under the above-described conditions.

Next, the operation and effects of the liquid phase growth apparatus 1 of the present invention having the above-described configuration will be described. According to the present invention, the thermal leveling plate 6 having a higher thermal conductivity than the solvent 12 is immersed in parallel with the semiconductor substrate 11 at a predetermined position in the solvent 12, so that, for example, Even if a state where a horizontal temperature difference occurs in the solvent 12 due to the direct heating occurs, the temperature difference is made uniform by the thermal conductivity of the thermal leveling plate 6.

Accordingly, the temperature of the solvent 12 in contact with the semiconductor substrate 11 placed in parallel with the thermal leveling plate 6 becomes uniform over the entire surface of the semiconductor substrate 11, and the solvent 12 is supersaturated with respect to the solute material 12a. Are the same, so that crystal growth of a uniform thickness is performed over the entire surface of the semiconductor substrate 11.

If the above effects are shown as specific numerical values,
Since the crystal growth is performed uniformly, the yield of the semiconductor substrate 11 is reduced from approximately less than 80% in the past to 95% or more, and the productivity is improved by approximately 20%. . In addition, since the thickness of the crystal growth is made uniform, the wavelength characteristics are also made uniform. For example, when an LED or the like is produced, it is possible to produce a product having uniform characteristics and improve the quality.

[0020]

As described above, according to the present invention, the solution pot is formed of a member that withstands the temperature of the solvent and has a higher thermal conductivity than the thermal conductivity of the solvent. A heat equalizing plate having a larger area and a plurality of through-holes formed in a matrix on substantially the entire surface is provided with a gap of 5 mm or more with the side wall of the solution pot, and 5 mm from the liquid level of the solvent. A liquid phase growth apparatus for a semiconductor substrate suspended from the lid so as to have a depth of not less than 3 mm and to be parallel to the semiconductor substrate at an interval of 3 mm or more from the semiconductor substrate, Due to the high thermal conductivity of the leveling plate, the temperature of the solvent existing near the surface of the semiconductor substrate is made uniform, thereby making the thickness of the crystal growth uniform, improving the yield, and further enabling the uniformity of the characteristics. Improve productivity and improve quality In which it exhibits an extremely excellent effect and.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a semiconductor substrate liquid phase growth apparatus according to the present invention.

FIG. 2 is a perspective view showing a main part of the same embodiment.

FIG. 3 is a perspective view showing a conventional example.

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid phase growth apparatus 2 ... Body part 3 ... Solution pot 3a ... Side wall 4 ... Bottom part 4a ... Substrate storage recessed part 5 ... Cover part 6 ... Heat leveling plate 6a ... Through-hole 7 ... Supports 11... Semiconductor substrate 12... Solvents 12 a... Solute material A... Gap between heat equalizing plate and side wall B. Distance from semiconductor substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-28920 (JP, A) JP-A-7-215793 (JP, A) JP-A-2-208284 (JP, A) JP-A-2- 212390 (JP, A) JP-A-58-172291 (JP, A) JP-A-50-84173 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) H01L 21 / 208,21 / 368 C30B 19/00-19/12

Claims (1)

(57) [Claims] 1. A main body in which a solution pot for storing a solvent is provided, a bottom provided with a storage recess slidably provided on the bottom side of the main body for storing a semiconductor substrate, A liquid phase growth apparatus for a semiconductor substrate, comprising: a lid for closing the upper surface of the solution pot; and a member having a heat conductivity higher than that of the solvent and which withstands the temperature of the solvent in the solution pot. A heat equalizing plate having an area larger than the area of the semiconductor substrate and having a plurality of through-holes formed in a matrix on substantially the entire surface is provided with a gap of 5 mm or more from the side wall of the solution pot. And a depth of 5 mm or more from the liquid level of the solvent and 3 mm from the semiconductor substrate.
An apparatus for growing a liquid phase on a semiconductor substrate, wherein the apparatus is suspended from the lid so as to be parallel to the semiconductor substrate at an interval of at least mm.