Electron beam conditioning

Patent metadata

Field	Value
Publication number	US-10384299-B2
Application number	US-201313928264-A
Country	US
Kind code	B2
Filing date	Jun 26, 2013
Priority date	Jun 26, 2013
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

The described embodiments relate generally to adjusting output or conditioning of an electron beam. More specifically various configurations are disclosed that relate to maintaining a footprint of the electron beam incident to a workpiece within a defined energy level. Such a configuration allows the electron beam to heat only specific portions of the workpiece to a superheated state in which intermetallic compounds are dissolved. In one embodiment a mask is disclosed that prevents low energy portions of an electron beam from contacting the workpiece. In another embodiment the electron beam can be focused in a way that maintains the electron beam at an energy level such that substantially all of the electron beam is above a threshold energy level.

First claim

What is claimed is:

1. A system for using electron beam processing to remove intermetallic compounds from a surface portion of a metal work piece, the system comprising:
an electron beam emitter configured to emit a beam of electrons, the beam of electrons including:
(i) a first portion corresponding to electrons characterized as having a maximum electron energy that is less than a threshold energy capable of removing the intermetallic compounds from the surface portion of the metal work piece, and
(ii) a second portion corresponding to electrons characterized as having a minimum electron energy greater than or equal to the threshold energy; and

an electron beam mask disposed between the electron beam emitter and the surface portion of the metal work piece, wherein when the beam of electrons is incident at the electron beam mask, the electron beam mask includes:
(i) an electron absorbing portion that is formed of an electron absorbing material and has a size and shape capable of absorbing most of the first portion of the beam of electrons, and
(ii) an aperture having an adjustable size and an adjustable shape that concurrently allows most of the second portion of the beam of electrons to pass through the aperture to the surface portion of the metal work piece.

2. The system as recited in claim 1 , wherein the electron absorbing portion is a shutter apparatus.

3. The system as recited in claim 2 , wherein the maximum electron energy that is less than the threshold energy is inconsistent with a pre-selected metallic phase of the metal work piece.

4. The system as recited in claim 1 , further comprising:
an active cooling apparatus for cooling the electron beam mask while the electron absorbing portion absorbs most of the first portion of the beam of electrons.

5. The system as recited in claim 1 , wherein the threshold energy corresponds to an amount of energy required to superheat the surface portion.

6. The system as recited in claim 1 , wherein an upper limit of an energy density of the electron beam is about 10 J/cm 2 .

7. The system as recited in claim 4 , wherein the electron beam mask is capable of actively removing energy at the electron beam mask that was absorbed from the beam of electrons.

8. The system as recited in claim 7 , wherein the metal work piece is coupled to an actively cooled work piece manipulator during the electron beam processing.

9. A method for removing intermetallic impurities at a surface portion of a metal work piece, the method comprising:
emitting a beam of electrons from an electron beam emitter, the beam of electrons having:
(i) a first spatial distribution of electrons having a first range of electron energy values that are less than a selected electron energy value suitable for removing the intermetallic impurities from the surface portion of the metal work piece, and
(ii) a second spatial distribution of electrons that is spatially independent of the first spatial distribution, wherein the second spatial distribution has a second range of electron energy values that are greater than or equal to the selected electron energy value; and

preventing most of the electrons corresponding to the first spatial distribution from reaching the surface portion of the metal work piece while concurrently allowing most of the electrons corresponding to the second spatial distribution to reach the surface portion of the metal work piece by using an electron shield having an adjustable aperture that corresponds to the second spatial distribution.

10. The method as recited in claim 9 , wherein the second range of electron energy values is suitable for superheating the surface portion.

11. The method as recited in claim 10 , wherein the adjustable aperture allows most of the electrons corresponding to the second spatial distribution to reach the surface portion.

12. The method as recited in claim 11 , further comprising:
actively cooling the metal work piece and the electron shield while emitting the beam of electrons at the surface portion.

13. The method as recited in claim 12 , wherein the second range of electron energy values maintains the surface portion within a temperature range that corresponds to a pre-selected metallic phase.

14. The method as recited in claim 13 , wherein the electrons of the second spatial distribution are capable of dissolving the intermetallic impurities within 20 microns of the surface portion.

Assignees

• Apple Inc

Inventors

• Lancaster-Larocque Simon R
• Chan Collin
• Uemura Kensuke
• Raharjo Purwadi

Classifications

• B23K15/02

  Control circuits therefor · CPC title

• H01J2237/05

  Arrangements for energy or mass analysis · CPC title

• B23K15/00 Primary

  Electron-beam welding or cutting · CPC title

• H01J37/305

  for casting, melting, evaporating, or etching · CPC title

• H01J37/05

  Electron or ion-optical arrangements for separating electrons or ions according to their energy {or mass}(particle separator tubes H01J49/00) · CPC title