Apparatus and a method for removing solder from an object

• US 6,435,401 B1
• Filed: 07/18/2000
• Issued: 08/20/2002
• Est. Priority Date: 07/23/1999
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Yasuhiro, Katayama, Kaoru, Miitsu, Takeshi
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): PITTMAN, ZIDIA T
• Application Number:
  US09/618,456
• Time in Patent Office: 763 Days
• Field of Search: 228/19, 228/20.1, 228/20.5, 228/264, 228/119, 228/102, 228/103
• US Class Current: 228/264
• CPC Class Codes: B23K 1/018 Unsoldering; Removal of melted solder or other residues
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection
• CPC Class Codes: H01L 21/681 using optical controlling means

Abstract

A solder-removing apparatus includes a heating portion for heating the object having the solder adhered thereto, a measuring portion for measuring the distance from the measuring portion to the object, a solder-drawing portion for drawing the molten solder on the object by suction, an X-Y moving portion for moving the object in an X-direction or a Y-direction, a Z moving portion for moving the object relative to the solder-drawing portion in a Z-direction, and a control portion for controlling the X-Y moving portion and the Z moving portion. During the time when the molten solder on the object is drawn by the solder-drawing portion, the control portion causes the X-Y moving portion to move the object, and also causes the Z moving portion to move the object relative to the solder-drawing portion in accordance with the distance, measured by the measuring portion, so that the distance between the solder-drawing portion and the object can be kept constant.

Claims

1. A solder-removing apparatus for removing solder from an object, comprising:

a heating portion for heating the object having the solder adhered thereto;

a measuring portion for measuring the distance from said measuring portion to at least two points of the object;

a solder-drawing portion for drawing the molten solder on the object by suction;

an X-Y moving portion for moving the object in an X-direction or a Y-direction;

a Z moving portion for moving the object relative to said solder-drawing portion in a Z-direction; and

a control portion for controlling said X-Y moving portion and said Z moving portion;

wherein said control portion obtains displacement of the object in accordance with measured results during the time when the molten solder on the object is drawn by said solder-drawing portion, said control portion causes said X-Y moving portion to move the object, and also causes said Z moving portion to move the object relative to said solder-drawing portion in accordance with said obtained displacement, so that the distance between said solder-drawing portion and the object can be kept constant.

2. A solder-removing apparatus according to claim 1, further comprising a chamber within which said heating portion, said solder-drawing portion, said X-Y, moving portion and said Z moving portion are received, wherein said chamber has a discharge portion for discharging gas within said chamber, and a gas-introducing portion for introducing gas into said chamber;

and

wherein an oxygen concentration of an atmosphere in said chamber is adjusted to a value lower than an oxygen concentration of the ambient atmosphere, and the heating by said heating portion and the drawing of the molten solder by said solder-drawing portion are effected in said atmosphere.

3. A solder-removing apparatus according to claim 1, in which said heating portion heats the object to a temperature below a melting point of the solder adhered to the object, and said solder-drawing portion includes a solder-melting portion for blowing high-temperature gas onto the solder to melt the same.

4. A solder-removing apparatus according to claim 1, which includes means for moving the object in the Z-direction.

5. A solder-removing apparatus according to claim 1, in which said measuring portion applies a laser beam to the object, and receives the laser beam reflected by the object, thereby measuring the distance between said measuring portion and said object.

6. A solder-removing apparatus according to claim 1, in which the object is received in a pocket formed in a uniformly-heating jig, and is heated by said heating portion.

7. A method of removing solder from an object, comprising the steps of:

placing the object, having the solder adhered thereto, in an atmosphere which is lower in oxygen concentration than the ambient atmosphere;

adjusting the position of the object;

obtaining displacement of the object by measuring a distance to at least two points of the object;

heating the object to melt the solder;

moving the object in an X-direction or a Y-direction, and

keeping the distance between the solder-drawing position and the object to a predetermined value in accordance with the displacement of the object; and

drawing the molten solder at a position spaced a predetermined distance from the object.

8. A method according to claim 7, in which said step of heating the object includes a step of heating the object to a temperature lower than a melting point of the solder, and said step of drawing the solder includes the step of blowing high-temperature gas onto the solder to melt the same.

9. A method according to claim 7, in which said step of keeping the distance includes the step of controlling the movement of the object in a Z-direction in accordance with the displacement of the object.

10. A method according to claim 7, in which said step of adjusting the position of the object includes the step of picking up an image of the object, and the step of locating a reference point of the object at the center of an image picking-up portion.

11. Apparatus for removing solder from an object, comprising:

means for receiving the object, the interior of said receiving means being controlled to an atmosphere having an oxygen concentration lower than an oxygen concentration of the ambient atmosphere;

means for adjusting the position of the object;

means for measuring a distance to at least two points of the object;

means for obtaining displacement of the object by the measured distance;

means for heating the object;

means for moving the object in an X-direction or a Y-direction;

means for keeping the distance between drawing means and the object to a predetermined value in accordance with the displacement of the object; and

means for drawing a molten solder by suction from a position spaced a predetermined distance from the object.

12. Apparatus according to claim 11, in which said heating means heats the object to a temperature below a melting point of the solder, and said solder-drawing means includes means for blowing high-temperature gas onto the solder to melt the same.

13. Apparatus according to claim 11, in which said means for keeping the distance to the predetermined value includes means for controlling the movement of the object in a Z-direction in accordance with the displacement of the object.

14. Apparatus according to claim 11, in which said means for adjusting the position of the object includes means for picking up an image of the object, and means for locating a reference point of the object at the center of said image picking-up means.