Process for self-alignment and planarization of semiconductor chips attached by solder die adhesive to multi-chip modules
First Claim
1. A method for attaching at least one semiconductor chip, with an electrical conductor disposed on an underside of each of said at least one chip, to a substrate having a surface, to cause self-alignment and PLANARIZATION of said at least one chip, comprising:
- providing on said substrate surface an inner layer of electrical conductor having solder wettability;
providing on said inner layer an outer layer of electrical conductor having solder nonwettability and having at least one window therein exposing said inner layer, said at least one window having a length and width substantially equal to an associated length and width of said at least one chip;
placing a solder preform on each respective one of said at least one window;
placing a chip on each respective one of said solder preforms;
placing said substrate into a structure capable of applying isostatic pressure;
overlaying said substrate and said at least one chip with a dielectric film layer;
applying pressure over said dielectric film layer; and
subsequentlyheating said substrate above the melting point of said solder preforms to align each of said at least one chip within said at least one window, and substantially simultaneously to planarize said at least one chip with respect to said surface.
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Accused Products
Abstract
A method for attaching a chip to a substrate includes providing the substrate with an outer layer of an electrical conductor which is not wettable by solder and which has a window exposing an inner layer of electrical conductor that is wettable by solder. A solder preform is placed on the window exposing the inner layer, and the chip is placed on the solder preform. The substrate is then heated so as to melt the solder preform. To achieve planarity, the substrate is be positioned in a pressurizing chamber with a film overlay having higher pressure above the film overlay than underneath the overlay, and heated above the melting point of the solder.
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Citations
12 Claims
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1. A method for attaching at least one semiconductor chip, with an electrical conductor disposed on an underside of each of said at least one chip, to a substrate having a surface, to cause self-alignment and PLANARIZATION of said at least one chip, comprising:
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providing on said substrate surface an inner layer of electrical conductor having solder wettability; providing on said inner layer an outer layer of electrical conductor having solder nonwettability and having at least one window therein exposing said inner layer, said at least one window having a length and width substantially equal to an associated length and width of said at least one chip; placing a solder preform on each respective one of said at least one window; placing a chip on each respective one of said solder preforms; placing said substrate into a structure capable of applying isostatic pressure; overlaying said substrate and said at least one chip with a dielectric film layer; applying pressure over said dielectric film layer; and
subsequentlyheating said substrate above the melting point of said solder preforms to align each of said at least one chip within said at least one window, and substantially simultaneously to planarize said at least one chip with respect to said surface. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for attaching at least one semiconductor chip, each with an electrical conductor disposed on an underside thereof, to a substrate having a surface, and having chip wells therein, causing chip attachment, chip alignment, and chip planarization substantially simultaneously, comprising:
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providing on said substrate surface an inner layer of electrical conductor having solder wettability; providing on said inner layer an outer layer of an electrical conductor having solder nonwettability and having at least one window therein exposing said inner layer, said at least one window having a length and width substantially equal to an associated length and width of said at least one chip; placing a solder preform on each respective one of said at least one window; placing a chip on each respective one of said solder preforms; placing said substrate into a structure capable of applying isostatic pressure; overlaying said substrate and said at least one chip with a dielectric film layer; applying pressure over said dielectric film layer; and
subsequentlyheating said substrate above the melting point of said solder preforms to cause each of said at least one chip to be substantially simultaneously self-aligned within said at least one window and planarized with respect to said surface. - View Dependent Claims (9, 10, 11, 12)
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Specification