Method for solder bumping, and solder-bumping structures produced thereby
AssigneeSTATS ChipPAC, Ltd.
InventorsByung Do, Romeo Alvarez, Yaojian Lin
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Abstract
A method for solder bumping provides a substrate and forms a film on the substrate. The film has openings therethrough. A stencil is aligned on the film. The stencil has openings therethrough over the openings through the film. Solder paste is printed onto the substrate and into the openings through the stencil and the openings through the film. The solder paste is reflowed to form solder balls therefrom. The stencil and the film are then removed.
Claims20
A method for solder bumping, comprising:
- providing a substrate;
- forming a film on the substrate, the film having openings therethrough;
- aligning a stencil on the film, the stencil having openings therethrough over the openings through the film;
- printing solder paste onto the substrate and into the openings through the stencil and the openings through the film;
- reflowing the solder paste to form solder balls therefrom;
- and
- removing the stencil and the film.
A method for solder bumping, comprising:
- providing a flip chip having under bump metallurgy layers exposed thereon;
- forming a laminated dry film on the flip chip having openings therethrough over respective under bump metallurgy layers, to provide access to the under bump metallurgy layers therebeneath;
- electroforming a metal stencil and aligning the metal stencil on the laminated dry film, the metal stencil having openings therethrough substantially centered over the openings through the laminated dry film to provide access to the under bump metallurgy layers therebeneath;
- screen printing solder paste onto the flip chip and the under bump metallurgy layers and filling the openings through the metal stencil and the openings through the laminated dry film;
- reflowing the solder paste to form solder balls therefrom upon and in electrical contact with the under bump metallurgy layers;
- and
- removing the metal stencil and the laminated dry film.
A solder-bumping structure, comprising:
- a substrate;
- a film on the substrate, the film having openings therethrough;
- a stencil on the film, the stencil having openings therethrough over the openings through the film;
- and
- solder paste printed onto the substrate and into the openings through the stencil and the openings through the film.
A solder-bumping structure, comprising:
- a flip chip having under bump metallurgy layers exposed thereon;
- a laminated dry film on the flip chip having openings therethrough over respective under bump metallurgy layers, to provide access to the under bump metallurgy layers therebeneath;
- an electroformed metal stencil on the laminated dry film, the metal stencil having openings therethrough substantially centered over the openings through the laminated dry film to provide access to the under bump metallurgy layers therebeneath;
- and
- solder paste screen-printed onto the flip chip and the under bump metallurgy layers and filling the openings through the metal stencil and the openings through the laminated dry film.
Dependencies are inferred from the claim text.