JPS61178493A - Liquid-phase epitaxial method - Google Patents

Abstract

PURPOSE:To make the unevenness of a liquid-phase epitaxial film due to melt residue and improve the quality, by sucking and removing the melt in the form of a liquid sticking to a substrate after forming the film through a suction passage provided in a holder for tilting and supporting the substrate. CONSTITUTION:A wafer holder 18 consists of a support 22, plural annular bodies 23 closely adhered to the support at a suitable tilting angle and plural (3-4) pawls 24 having one end adhered to each annular body 23 and the support 22 closes the lower end thereof. Holes 25 are perforated above and below the part where the respective annular bodies 23 are adhered. The tip of the pawls 24 is bent to fix a wafer on the respective annular bodies 23, and dipped in a melt to apply and form a liquid-phase epitaxial film on the surface thereof. The holder 18 is pulled up from the melt,and a suction apparatus is simultaneous operated. The melt residue, sticking to the whole wafer, and filling almost half the support 22 is partially made to flow down, and the other is partially sucked up into the upper part of the holder 18 and the tubular body 19, and rapidly removed from the wafer. After removing the met 26, the aimed film having further reduced defects is obtained by applying a removing method utilizing rotational centrifugal force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a method for converting liquid melt residue into a liquid phase epitaxial film (L
PE) A novel method for rapid removal from forming substrates and improved property distribution of LPE films.

For example, in a magnetic bubble memory device/device, the element is
An LPE film made of garnet or the like is deposited on a substrate such as GGG, and a pattern is formed on it of a magnetic bubble transfer path made of a magnetic material and a magnetic bubble generator, detector, copying device, etc. made of a conductive material. has been done.

The devices are of a size that allows multiple devices to be obtained from one wafer, and in order to ensure high productivity, processes that can be performed prior to dividing into device substrates are performed in batches in the wafer state. but,.

Formation of the LPE film is one of them.

[Conventional technology]

FIG. 2 is a side view schematically showing the main structure of an apparatus for explaining the conventional technique of liquid phase epitaxial method.

In Fig. 2, 1 is a core tube, 2 is a heater surrounding the core tube 1, 3 is a crucible, 4 is the melt in the crucible 3, and 5 is a flow of gas (Ng) 6 for removing toxic gas generated by the melt 4. 7 is a wafer (GGG substrate); 8 is a holder for holding a plurality of wafers 7 at an appropriate inclination angle; 9 is a holder 8
10 is an arm that supports the support rod 9 and moves up and down, and 11 is a melt residue.

In such an apparatus, immediately after wafers 7 are immersed in the melt 4 to form an LPE film on their surfaces and then pulled up, the entire wafer 7 is left with a melt residual smell (see FIG. 1).
is attached. If the amount is kept within the range 1 for a while, approximately half of the amount will naturally run off, but a residual melt scent 11 will remain as shown in FIG.

Therefore, in order to remove the melt residual aroma 11, the conventional apparatus rotates the holder 8 and utilizes the centrifugal force thereof, so that the residual aroma 11 is blown away.

[Problem that the invention seeks to solve]

However, metal wires with sufficient resistance to melt 4 (
The rotational speed of the holder 8 made of, for example, a platinum-gold alloy wire, is limited to about 300 rpm, and since the mechanical strength of the holder 8 is low, it is necessary to gradually accelerate the rotation speed.

As a result, the LPE film grows in the area to which the residual fragrance 11 is applied, becoming thicker than the area to which the residual fragrance 11 is not applied, and traces of movement of the residual fragrance 11 are formed, impairing the uniformity of the LPE film.

That is, for example, the wafer 7 is GGG and the LPE film is a garnet film, and a magnetic bubble transfer path made of permalloy, a magnetic bubble generator made of metal such as aluminum, etc. are patterned on the garnet film. When attempting to create a magnetic bubble memory element, the distribution of the demagnetizing field of the magnetic bubble, which is affected by the thickness of the garnet film, deteriorates, and initial characteristics may not be obtained.

Therefore, the defective parts of the garnet film must be removed, but the quality of the film cannot be known until after the transfer path, generator, etc. are formed, and there is a strong desire to remove such defective parts. .

[Means for solving problems]

In order to solve the above problems, the present invention suctions the liquid melt adhering to the substrate after the film is formed through a suction path provided in a holder that tilts and supports the substrate on which the liquid phase epitaxial film is formed. This is a liquid phase epitaxial method characterized by removing.

[Effect]

According to the above means, the holder is gradually accelerated and rotated.
Since the melt residual aroma 11 is removed by suction more quickly than the conventional method of scattering and removing the melt residual aroma 11 by rotating the rotor at an insufficient rotation speed, the melt residual aroma 11 is removed by film growth on the part to which it adheres, and No traces of residual fragrance transfer remain, making it possible to homogenize the LPE film.

〔Example〕

The present invention will be described in detail below using the drawings.

FIG. 1 is a side cross-sectional view showing the configuration of a substrate holder, a wafer attached to the holder, and a melt residue on the wafer according to an embodiment of the present invention.

In FIG. 1, in which the same reference numerals are used for parts common to those in FIG. An intake pipe with one end connected to the upper end, 21 is a metal fitting that fixes the middle pipe part of the pipe body 19 to the arm 10,
The other end of the intake pipe 20 is connected to a suction device (not shown).

The holder 18, which is resistant to melting, includes a support 22 made of a pipe, a plurality of annular bodies 23 fixed to the support 22 at appropriate inclination angles, and one end of each annular body 23 for fixing the wafer 7. The support 22 is made up of a plurality of (3 to 4) fixed claws 24, and the lower end of the support 22 is closed, and through holes 25 are opened above and below the portion to which each annular body 23 is fixed.

Such a holder 18 is attached to each annular body 2 by bending the tip of the claw 24.
After fixing the wafers 7 on the melt 4, each wafer 7 is immersed in the melt 4 to form an LPB film on its surface.

Next, the holder 18 is pulled up from the melt 4 and at the same time the suction device is activated.

Then, at the moment of lifting, as shown in FIG. 1, a part of the melt residue 26 that had adhered to the entire wafer 7 and filled the middle of the support column 22 has flowed down, and the other part has fallen onto the upper part of the holder 18 and the other part. It will be sucked up into the tube 19 and quickly removed from the wafer 7.

Incidentally, in the above embodiment, the sucked up melt solidifies and becomes impossible to suction through the support column 22 by repeated use of the holder 18, but the solidified melt is immersed in a heated nitric acid solution and dissolved away.

It is also noted that after the melt residual scent 26 is removed in the present invention, a removal method that utilizes the centrifugal force of rotation is applied to obtain an LPE film with even fewer defects.

〔Effect of the invention〕

As explained above (according to the present invention, since the melt residual aroma can be removed immediately after the melt is pulled up, the non-uniformity of the LPE film due to the residual aroma can be miniaturized and the quality improved). It is extremely important to apply this method to the creation of .

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing the configuration of a substrate holder according to an embodiment of the present invention, a wafer attached to the holder, and a melt residue on the wafer, and FIG. 2 is for explaining a conventional technique of a liquid phase epitaxial method. FIG. 2 is a side view schematically showing the main configuration of the device. In the figure, 7 is a wafer, 8.18 is a wafer holder, and 11 and 26 are melt residual scents. %1 Month↑ Figure 2

Claims (1)

[Claims] A liquid phase epitaxial method characterized in that liquid melt adhering to the substrate after the film is formed is removed by suction through a suction path provided in a holder that tilts and supports the substrate on which the liquid phase epitaxial film is formed.