Metal fusion bonding – Process – Preplacing solid filler
Patent
1997-11-12
2000-01-11
Ryan, Patrick
Metal fusion bonding
Process
Preplacing solid filler
2281805, 228 45, 29843, B23K 100, B23K 3102
Patent
active
060126256
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a process and a device in accordance with the preamble of claims 1 and 4.
BACKGROUND OF THE INVENTION
In the known processes for forming raised contact metallizations, which are also technically described as so-called "bumps", a fundamental differentiation is to be made between mask-oriented processes and processes which are rather to be described as mechanical.
Processes are described as mask-oriented processes where the arrangement and geometric state of the raised contact metallizations are defined by surface masks which only leave free the regions of connection surfaces of a substrate surface which is otherwise covered by the mask. Only then in a second procedural step is the contact material applied to the connection surfaces, which are technically also described as so-called "pads", for example by means of galvanic or chemical separation processes.
In all of the aforementioned, mask oriented processes the selective application of the contact material intended for forming the raised contact metallizations is achieved by masking the substrate surface. To assemble the mask, usually photolithographic processes for structuring a photosensitive lacquer or similar processes are required. In addition, after the formation of the raised contact metallizations the mask must again be removed from the substrate surface. In particular the process expenditure associated with the formation of such a mask is only worthwhile with mass production of substrates with standardized connection-surface distribution.
In contrast, the aforementioned mechanical processes for forming raised contact metallizations have the advantage that a selective formation of raised contact metallizations on the pads is possible without the previous formation of an appropriate surface mask. With such processes the wire connection technology is used which has been developed in itself to make wire connections between connection surfaces of the same substrate or different substrates. In wire connection technology a process technically described as "ball-wedge-process" has become generally accepted, where first of all a ball is formed on a wire end section, drawn from the nose-piece of a bonding capillary, by means of thermal loading of the wire end. This ball is connected to the first connection surface with deformation by means of the nose-piece of the bonding capillary. Subsequently, a wire loop is formed to overcome the distance between the first connection surface and a second connection surface, and finally to make the connection between the wire end section and the second connection surface the wire end section is pressed with deformation against the second connection surface with a connection region of a pressure surface of the capillary nose piece, and with simultaneous separation of the partial wire section is connected to the connection surface. This second making of a connection is technically described as "wedge".
The use of this method known in itself from wire connection technology for the formation of a raised contact metallizations on a substrate connection surface is disclosed in DE- 32 09 242.
In the known process a wire ball formed with thermal loading at the free end of a wire end section drawn from the capillary nose piece is pressed against a substrate connection surface and is connected thereto. The separation of the wire end section drawn from the capillary nose piece to form the raised contact metallizations takes place by forming a weak point at the wire end section drawn from the capillary nose piece and by subsequently pulling at the weak point.
The raised contact metallizations formed with the known process has a substantially circular base because of the basic spherical shape of the wire end section drawn from the capillary nose-piece. This results in a relatively small overlap between the raised contact metallizations and the usually rectangular surface of the connection surface. In addition, the volume of the raised contact metallizations which can be atta
REFERENCES:
patent: 4415115 (1983-11-01), James
patent: 4645118 (1987-02-01), Biggs et al.
patent: 5090119 (1992-02-01), Tsuda et al.
patent: 5172851 (1992-12-01), Matsushita et al.
patent: 5299729 (1994-04-01), Matsushita et al.
patent: 5485949 (1996-01-01), Tomura et al.
patent: 5550083 (1996-08-01), Koide et al.
patent: 5740956 (1998-04-01), Seo et al.
Patent Abstracts of Japan; vol. 17, No. 640 (E-1465); A 5206223.
Search Report of PCT corresponding application (PCT/DE 96/00425).
Eldring Joachim
Nave Jens
Zakel Elke
Fraunhofer-Gesellschaft zur Forderungder angewandten Forschung e
Knapp Jeffrey T.
Ryan Patrick
LandOfFree
Process and device for forming raised metallised contacts does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and device for forming raised metallised contacts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and device for forming raised metallised contacts will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1455800