Apparatus for forming a thin layer and method of forming a thin layer on a substrate using the same

Patent metadata

Field	Value
Publication number	US-9892983-B2
Application number	US-201514975706-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Dec 22, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

An apparatus and method of forming an epitaxial layer are provided. The apparatus includes a process chamber in which an epitaxial process is performed to form epitaxial layer on a substrate. A first supplier supplies source gases for the epitaxial layer into the process chamber. A second supplier supplies dopants into the process chamber. A detector detects a composition ratio of the epitaxial layer and a concentration of the dopants in the epitaxial layer during the epitaxial growth process. And a controller controls a mass flow of at least one of the source gases and a mass flow of the dopants in-line with the epitaxial growth process. Accordingly, the layer thickness of the epitaxial layer can be accurately controlled in real time in line with the epitaxial process.

First claim

What is claimed is:

1. An apparatus for performing an epitaxial process, comprising:
a process chamber in which an epitaxial layer is formed on a substrate using an epitaxial process;
a first supplier supplying source gases for the epitaxial layer into the process chamber during the epitaxial process;
a second supplier supplying dopants into the process chamber during the epitaxial process, the dopants being different from the source gases and reducing a band gap of the epitaxial layer;
a detector detecting a composition ratio of the epitaxial layer and a concentration of the dopants in the epitaxial layer during the epitaxial process; and
a controller controlling a mass flow of the source gases and a mass flow of the dopants in-line with the epitaxial process.

2. The apparatus of claim 1 , wherein the detector includes:
an irradiator radiating continuous x-rays onto the epitaxial layer while performing the epitaxial process in the process chamber;
a diffractometer detecting diffraction spectrums of diffraction rays diffracted from the epitaxial layer and determining the composition ratio and a layer thickness of the epitaxial layer from a peak angle of the diffraction spectrums; and
a fluorescence spectrometer detecting fluorescent x-rays resulting from the dopants of the epitaxial layer being exposed to the continuous x-rays and calculating the concentration of the dopants in the epitaxial layer using the fluorescent x-rays.

3. The apparatus of claim 2 , wherein the irradiator includes an x-ray generating unit from which the continuous x-rays are generated using one or more of an aluminum (Al) plate and a magnesium (Mg) plate as a target metal plate, and further includes an irradiating unit radiating the continuous x-rays to the epitaxial layer at an irradiation angle.

4. The apparatus of claim 2 , wherein the epitaxial layer is arranged on a plurality of test patterns, said plurality of test patterns being arranged on peripheral regions of dies defined by scribe lines, wherein the continuous x-ray has a beam size that is smaller than a surface of the test pattern, and wherein a respective test pattern is individually irradiated by a corresponding continuous x-ray beam.

5. The apparatus of claim 2 , wherein the epitaxial layer is arranged on a plurality of test patterns, said plurality of test patterns arranged on peripheral regions of dies defined by scribe lines, wherein the continuous x-ray has a beam size corresponding to a unit shot covering a plurality of the dies, and wherein the continuous x-ray is radiated onto the dies by the unit shot such that a plurality of the test patterns are substantially simultaneously exposed to the continuous x-ray.

6. The apparatus of claim 2 , wherein the controller includes a first operator, a second operator, a flow controller, and a central processing unit;
said first operator having a reference ratio that is a reference composition ratio of the epitaxial layer, wherein said first operator compares the reference ratio with a detected ratio that is the composition ratio detected by the diffractometer;
said second operator having a reference concentration that is a reference concentration of the dopants, wherein said second operator compares the reference concentration with a detected concentration that is the concentration of the dopants detected by the fluorescence spectrometer;
said flow controller individually controlling the mass flow of the source gases based on a comparison result from the first operator, and individually controlling the mass flow of the dopants based on a comparison result from the second operators; and
said central processing unit connected to the first and the second operators and transferring control signals to the process chamber, the first supplier, the second supplier, and the detector to control the epitaxial process.

7. The apparatus of claim 6 , wherein the first supplier includes a source reservoir holding the source gases, a first supply tube through which the source gases are supplied from the source reservoir to the process chamber, and a first valve arranged on the first supply tube to control the mass flow of the source gases to the process chamber,
wherein the second supplier includes a dopants reservoir holding the dopants, a second supply tube through which the dopants are supplied from the dopants reservoir to the process chamber, and a second valve arranged on the second supply tube to control the mass flow of the dopants to the process chamber,
wherein the first valve is controlled by a first flow control signal generated from the flow controller based on the comparison results of the first operator, and
wherein the second valve is controlled by a second flow control signal generated from the flow controller based on the comparison result of the second operator.

8. The apparatus of claim 6 , wherein the central processing unit is configured to generate a check signal that indicates to an operator the need to check process environments of the epitaxial process when a ratio of a variation of the detected concentration with respect to a variation of the mass flow of the dopants is negative.

9. The apparatus of claim 1 , wherein the epitaxial layer includes at least one of a gallium arsenide indium (InGaAs) layer and a silicon germanium (SiGe) layer and wherein the dopant includes at least one of carbon (C) and boron (B).

10. A method of forming an epitaxial layer on a substrate, the method comprising:
setting process conditions for an epitaxial process performed in a process chamber in which the substrate is arranged, the process conditions including:
a mass flow of source gases for the epitaxial layer,
a mass flow of dopants that is different from the source gases and reduces a band gap of the epitaxial layer,
a reference composition ratio of the source gases, and
a reference concentration of the dopants for the epitaxial layer;
performing an epitaxial process under the process conditions, thereby forming the epitaxial layer on the substrate;
detecting a composition ratio of the source gases and a concentration of the dopants in the epitaxial layer by analyzing the epitaxial layer, and providing a detected ratio and a detected concentration;
obtaining a ratio difference between the detected ratio and a reference ratio, wherein the reference ratio is a reference value of the composition ratio of the epitaxial layer, and obtaining a concentration difference between the detected concentration and a reference concentration, wherein the reference concentration is a reference value of the concentration of the dopants; and
changing the mass flow of the at least one of the source gases and the dopants in response to the ratio difference and the concentration difference during the epitaxial process when at lest one of the ratio difference and the concentration difference is outside an allowable range.

11. The method of claim 10 , wherein the detected ratio is obtained using x-ray diffractometry, in which continuous x-rays are radiated to the epitaxial layer and diffraction spectrums of diffraction rays that are diffracted from the epitaxial layer are measured to detect a peak angle of the diffraction spectrums, and wherein the composition ratio is determined using the peak angle of the diffraction spectrums together with a layer thickness of the epitaxial layer; and
wherein the detected concentration is obtained using x-ray fluorescent spectrometry, in which the concentration of the dopants in the epitaxial layer is determined by detecting fluorescent x-rays resulting from the dopants of the epitaxial layer in response to the continuous x-rays.

12. The method of claim 11 , where

Assignees

• Samsung Electronics Co Ltd

Inventors

• Kim Min Kook
• Kim Bang Won
• Yang Yu Sin
• Yoon Young Jee
• Lee Sang Kil
• Jang Yoo Seok
• Jun Chung Sam

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/238 Primary

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• C30B29/40

  AIIIBV compounds {wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi} · CPC title

• H01L22/26 Primary

  Electricity · mapped topic

• H01L22/12

  Electricity · mapped topic