Impurity adding apparatus, impurity adding method, and semiconductor element manufacturing method

Patent metadata

Field	Value
Publication number	US-10658183-B2
Application number	US-201615174468-A
Country	US
Kind code	B2
Filing date	Jun 6, 2016
Priority date	Jun 12, 2014
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

An impurity-doping apparatus is provided with: a supporting plate which supports a semiconductor substrate; a wall-like block disposed above the supporting plate floating away from the semiconductor substrate, the wall-like block implements a recess inside so as to establish a space for a solution region containing impurity elements, the solution region is localized on an upper surface of the semiconductor substrate, the upper surface being opposite to an bottom surface facing to the supporting plate; and a laser optical system, configured to irradiate a laser beam onto the upper surface of the semiconductor substrate, through the solution region surrounded by the wall-like block, wherein the impurity elements are doped into a part of the semiconductor substrate by irradiation of the laser beam.

First claim

What is claimed is:

1. A method for doping impurities, comprising:
disposing a wall-like block, having a recess, above a semiconductor substrate, so that the wall-like block is suspended above the semiconductor substrate and the recess is facing the semiconductor substrate so as to form a space between the wall-like block and the semiconductor substrate, the wall-like block including
a first feeding canal connected to the recess and located on a first side of the wall-like block,
a second feeding canal connected to the recess and located on a second side of the wall-like block opposite to the first side,
a first ejecting canal located on the second side, the first ejecting canal extending vertically from an upper surface to a lower surface of the wall-like block, and
a second ejecting canal located on the first side, the second ejecting canal extending vertically from the upper surface to the lower surface of the wall-like block;

forming a solution region where a layer of solution containing impurity elements is localized, inside the space, on a surface of a portion of the semiconductor substrate defined by the recess so that the impurity elements are selectively in contact with the semiconductor substrate, the space between the wall-like block and the semiconductor substrate being selected such that the surface tension does not allow the solution to leak beyond the wall-like block;
moving the solution on the surface of the semiconductor substrate, the moving the solution including
flowing the solution out of the first feeding canal and collecting the solution into the first ejecting canal while maintaining the flow of the solution between the first feeding canal and the first ejecting canal, while the semiconductor substrate is being moved in a first direction and a valve controlling flow of the solution out of the second feeding canal is closed, and
flowing the solution out of the second feeding canal and collecting the solution into the second ejecting canal while maintaining the flow of the solution between the second feeding canal and the second ejecting canal, while the semiconductor substrate is being moved in a second direction and a valve controlling flow of the solution out of the first feeding canal is closed; and
irradiating a laser beam to the surface of the semiconductor substrate through the solution region so that the impurity elements are doped into a part of the semiconductor substrate.

2. The method of claim 1 ,
wherein in the irradiating the laser beam, the laser beam is irradiated in a direction intersecting with the moving direction of the solution.

3. The method of claim 2 , further comprises:
moving the semiconductor substrate in X and Y directions, which are defined in a plane parallel to the surface of the semiconductor substrate,
wherein a pattern in which the impurity elements are doped into a part of the semiconductor substrate is directly delineated.

4. The method of claim 3 ,
wherein in the irradiating the laser beam, the semiconductor substrate is moved in the same direction as the moving direction of the solution.

5. The method of claim 1 ,
wherein in the moving the localized solution, a bottom surface of the wall-like block has a water-repellent portion so as to prevent the localized solution from leaking out of the space.

6. The method of claim 1 , wherein the moving the solution further includes collecting the solution in the recess of the wall-like block by the first ejecting canal and the second ejecting canal when the moving direction of the semiconductor substrate is switched between the first direction and the second direction.

7. A method of manufacturing a semiconductor device, comprising:
disposing a wall-like block, having a recess, above a semiconductor substrate of a first or second conductivity type so that the wall-like block is suspended above the semiconductor substrate and the recess is facing the semiconductor substrate so as to form a space between the wall-like block and the semiconductor substrate, the wall-like block including
a first feeding canal connected to the recess and located on a first side of the wall-like block,
a second feeding canal connected to the recess and located on a second side of the wall-like block opposite to the first side,
a first ejecting canal located on the second side, the first ejecting canal extending vertically from an upper surface to a lower surface of the wall-like block, and
a second ejecting canal located on the first side, the second ejecting canal extending vertically from the upper surface to the lower surface of the wall-like block;
forming a solution region where a layer of solution containing impurity elements of a first conductivity type is localized, inside the space, on a part of a surface of the semiconductor substrate defined by the recess so that the impurity elements are selectively in contact with the semiconductor substrate, the space between the wall-like block and the semiconductor substrate being selected such that the surface tension inhibits the solution from leaking beyond the wall-like block;
moving the solution on the surface of the semiconductor substrate, the moving the solution including
flowing the solution out of the first feeding canal and collecting the solution into the first ejecting canal while maintaining the flow of the solution between the first feeding canal and the first ejecting canal, while the semiconductor substrate is being moved in a first direction and a valve controlling flow of the solution out of the second feeding canal is closed, and
flowing the solution out of the second feeding canal and collecting the solution into the second ejecting canal while maintaining the flow of the solution between the second feeding canal and the second ejecting canal, while the semiconductor substrate is being moved in a second direction and a valve controlling flow of the solution out of the first feeding canal is closed; and
irradiating a laser beam onto the semiconductor substrate through the solution region to form a first semiconductor region of the first conductivity type in the surface of the semiconductor substrate.

8. The method of claim 7 ,
wherein in the irradiating, to form the first semiconductor region, the laser beam is irradiated in the direction intersecting with the moving direction of the solution.

9. The method of claim 8 ,
wherein in the irradiating, to form the first semiconductor region, the semiconductor substrate is moved in the same direction as the moving direction of the solution.

10. The method of claim 9 ,
wherein at the surface of the semiconductor substrate, a second semiconductor region of the first conductivity type is formed beforehand, and
the first semiconductor region is formed in the second semiconductor region so that the first semiconductor region is doped at higher concentration than that of the second semiconductor region.

11. The method of claim 10 , further comprises:
forming an ohmic electrode layer in the first semiconductor region.

12. The method of claim 7 ,
wherein in the moving the localized solution, a bottom surface of the wall-like block has a water-repellent portion so as to prevent the localized solution from leaking out of the space.

13. The method of claim 7 , wherein the moving the solution further includes collecting the solution in the recess of the wall-like block by the first ejecting canal and the second ejecting canal when the moving direction of the semiconductor substrate is switched between the first direction and the second direction.

Assignees

• Fuji Electric Co Ltd

Inventors

• Iguchi Kenichi
• Nakazawa Haruo
• Ogino Masaaki

Classifications

• H10P32/19

  Diffusion sources · CPC title

• H10P72/0402

  Apparatus for fluid treatment (H10P72/0441, H10P72/0448 take precedence) · CPC title

• H10P34/42

  with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20) · CPC title

• H10P32/172

  being crystalline silicon carbide · CPC title

• H10P32/16 Primary

  between a solid phase and a liquid phase · CPC title