Conductive ball attaching apparatus and method

• US 6,070,783 A
• Filed: 04/21/1998
• Issued: 06/06/2000
• Est. Priority Date: 04/22/1997
• Status: Expired due to Term

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company), Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakazato, Shinichi
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): ELVE, MARIA ALEXANDRA
• Application Number:
  US09/063,711
• Time in Patent Office: 777 Days
• Field of Search: 228/105, 228/246, 228/56.5, 228/245, 228/248.1, 250/559.4
• US Class Current: 228/105
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 3/0623 for shaped solder piece feeding, e.g. preforms, bumps, balls, pellets, droplets
• CPC Class Codes: H01L 21/67144 Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
• CPC Class Codes: H01L 21/681 using optical controlling means
• CPC Class Codes: H05K 3/3478 Applying solder preforms; Transferring prefabricated solder patterns

Abstract

An apparatus and a method for attaching conductive balls by which the tact time necessary for the positional recognition of a substrate before the conductive balls are attached onto a substrate can be greatly reduced. A first camera and a second camera are moved together a suction head. After the suction head picks up the conductive balls in a conductive ball supply section, the suction head is moved to a position above a flux supply section so that flux can be attached to the conductive balls 10, and concurrently the first camera recognizes a positional recognition mark on a substrate. Then, during when the suction head is moved to a position above the substrate, the second camera recognizes another positional recognition mark on the substrate. In accordance with the positional recognition conducted above, the suction head is positioned accurately with respect to the substrate, and then the conductive balls are attached onto the electrodes on the substrate.

Claims

1. A method of attaching conductive balls onto a substrate, comprising the steps of:

vacuum-absorbing and picking up conductive balls, which are accommodated in a conductive ball supply section, onto a lower surface of a suction head;

moving the suction head toward a position where the suction head is located above the substrate;

prior to accurately locating the suction head at said position, recognizing two positional recognition marks on the substrate by positioning first and second cameras simultaneously or successively at positions above the two positional recognition marks;

finding an accurate position of the substrate according to the result of the position recognition;

accurately positioning the suction head with respect to the substrate; and

moving the suction head toward and away from the substrate to attach the conductive balls onto electrodes provided on the substrate.

2. A method of attaching conductive balls onto a substrate according to claim 1, wherein said step of recognizing two positional recognition marks includes a step of moving each of said first and second cameras in at least one direction along an imaginary horizontal plane by utilizing the movement of the suction head.

3. A method of attaching conductive balls onto a substrate according to claim 1, wherein:

said first and second cameras are spaced from each other and are operable to observe a camera position reference mark to permit recognition of a mutual positional relationship between said first and second cameras.

4. A method of attaching conductive balls onto a substrate, comprising:

vacuum-attaching a plurality of conductive balls onto a lower surface of a suction head;

moving the suction head to a flux supply section;

depositing flux from the flux supply section onto the conductive balls that are vacuum-attached to the suction head;

observing a first mark formed on the substrate with a first camera during the flux-depositing step and thereby recognizing a position of said first mark;

positioning a second camera above a second mark on the substrate, observing the second mark with the second camera and thereby recognizing a position of said second mark; and

obtaining a position of the substrate based on the recognized positions of said first and second marks, positioning the suction head relative to the substrate based on the obtained position of the substrate, and attaching the conductive balls onto the substrate.

5. The method according to claim 4, wherein the first and second cameras are moved integrally in association with movement of the suction head.

6. The method according to claim 5, wherein the first camera is positionally related to the suction head such that the first camera is located above the first mark when the suction head is located at the flux supply section, and the second camera is mounted to the suction head.

7. A method of attaching conductive balls onto a substrate, comprising:

vacuum-attaching a plurality of conductive balls onto a lower surface of a suction head;

moving the suction head to a flux supply section;

depositing flux from the flux supply section onto the conductive balls that are vacuum-attached to the suction head;

during said flux-depositing step, observing a first mark formed on the substrate with a first camera and observing a second mark formed on the substrate with a second camera, thereby recognizing a position of said first mark and a position of said second mark; and

obtaining a position of the substrate based on the recognized positions of said first and second marks, positioning the suction head with respect to the substrate based on the obtained position of the substrate, and attaching the conductive balls onto the substrate.

8. The method according to claim 7, wherein the first and second cameras are moved integrally in association with movement of the suction head.

9. The method according to claim 8, wherein the first and second cameras are positionally related to the suction head such that the first and second cameras are located above the first and second marks, respectively, when the suction head is located at the flux supply section.

10. A method of attaching conductive balls onto a substrate, comprising:

vacuum-attaching a plurality of conductive balls onto a lower surface of a suction head;

moving the suction head above the substrate;

observing a first mark formed on the substrate with a first camera and observing a second mark formed on the substrate with a second camera, thereby recognizing a position of said first and second marks, said first and second marks being spaced a distance from one another, said first camera being secured to the suction head at a first location and said second camera being secured to the suction head at a second location, said first location being spaced from said second location; and

obtaining a position of the substrate based on the recognized positions of said first and second marks, positioning the suction head with respect to the substrate based on the obtained position of the substrate, and attaching the conductive balls onto the substrate.