Abstract: An interposer structure permits a differential transverse displacement of contact pads on opposite sides of the interposer to reduce thermal stresses when the interposer is bonded to contact pads of a chip and a substrate with different thermal coefficients of expansion. The effective elasticity of the interposer between top and bottom contact pads of the interposer is facilitated by perforations which define flap-like regions. A flexible trace couples top contact pads to bottom contact pads through a via while permitting substantial transverse relative displacement of the top and bottom contact pads in flap-like regions.

Abstract: Methods of forming patterns in photo-sensitive resist layers with high aspect ratio features are described. The photosensitive layer is patterned exposed to actinic radiation and thereafter developed. For high aspect ratio patterns, the inventors have often observed a residue of resist material at the bottom of such features, and that this residue interferes with subsequent processing, such as filling the pattern with metal by a plating operation. To remove this residue, the patterned locations of the resist are exposed to a low dose of low-energy electron beam radiation, preferably having energy of less than 6 KeV and dosage of less than 200 .mu.C/cm.sup.2. After the electron beam exposure, the aperture is again exposed to a developer solution, which may be of the same composition as the developer initially used to develop the patterns.

Abstract: An interconnecting post for mounting a microelectronic device such as an integral circuit chip is fabricated with generally uniform cross-section, by forming a first layer of positive photoresist on a substrate, soft-baking that first layer and exposing it for a short time with a wide-apertured mask or simply a UV blank flood exposure. Without developing the first layer, a second layer of positive resist is then applied over the first layer, soft-baked, and then exposed with a narrow-apertured mask. During the soft-baking of the second layer, some of its activator in the photoresist compound diffuses into the exposed portion of the first layer and modifies its solubility in such a way that, when the layers are subsequently developed, the developer partially undercuts the unexposed portion of the first layer to form in the photoresist an opening of generally uniform cross-section. This opening can then be filled by plating to produce a strong, integral interconnect post.

Abstract: Methods of planarizing structures formed on the surfaces of substrates and wafers are disclosed. The methods form a planarizing layer over the surface and the structures, or the locations where the structures are to be formed, such that the top surface of the layer has low areas between the locations of the structures, and such that the low areas lie substantially within a plane which is below the tops of the structures. A polish-stop layer is then formed over the low areas of the planarizing layer, the polish-stop layer being more resistant to polishing than the planarizing layer and, preferably, the structures. The resulting surface is then polished. The polishing may be accomplished by, for example, standard mechanical polishing, and chemical-mechanical polishing.

Abstract: Methods of wet etching through a silicon substrate using composite etch-stop layers are disclosed. In one embodiment, the composite etch stop comprises a layer of silicon dioxide and a layer of polyimide.

Abstract: An interposer substrate for mounting an integrated circuit chip to a substrate, and method of making the same, are shown. The interposer substrate comprises power supply paths and controlled impedance signal paths that are substantially isolated from each other. Power supply is routed though rigid segments and signals are routed though a thin film flexible connector that runs from the upper surface of the interposer substrate to the lower surface. Bypass capacitance is incorporated into the interposer substrate and connected to the power supply so that it is positioned very close to the integrated circuit chip. The interposer may be fabricated by forming a multilayered thin film structure including the signal paths over a rigid substrate having vias formed therein, removing the central portion of the substrate leaving the two end segments, and folding and joining the end segments such that the vias are connected.

Abstract: Described are methods of manufacturing large substrate capacitors for multi-chip module applications and the like using procedures compatible with common semiconductor fabrication procedures. A capacitor is formed where the top electrode thereof is divided into a plurality of segmented pads which are initially electrically isolated from one another. Each segmented pad forms a capacitor with the underlying dielectric layer and bottom capacitor electrode. Each segmented capacitor is electrically tested, and defective ones are identified. A conductive layer is thereafter formed over the segmented pads such that the conductive layer is electrically isolated from the pads of defective capacitors. The conductive layer electrically couples the good capacitors in parallel to form a high-value bypass capacitor which has low parasitic inductance. Large embedded MCM bypass capacitors can thereby be fabricated with minimal impact to the overall manufacturing yield.

Abstract: Methods of forming patterns in photo-sensitive resist layers with high aspect ratio features are described. The photosensitive layer is patterned exposed to actinic radiation and thereafter developed. For high aspect ratio patterns, the inventors have often observed a residue of resist material at the bottom of such features, and that this residue interferes with subsequent processing, such as filling the pattern with metal by a plating operation. To remove this residue, the patterned locations of the resist are exposed to a low dose of low-energy electron beam radiation, preferably having energy of less than 6 KeV and dosage of less than 200 .mu.C/cm.sup.2. After the electron beam exposure, the aperture is again exposed to a developer solution, which may be of the same composition as the developer initially used to develop the patterns.

Abstract: A multichip module substrate for use in a three-dimensional multichip module, and methods of making the same, are disclosed. The substrate comprises a thin film structure, for routing signals to and from integrated circuit chips, formed over a rigid support base. Apertures are formed in the support base exposing the underside of the thin film structure, thereby allowing high density connectors to be mounted on both surfaces of the thin film structure, greatly enhancing the ability to communicate signals between adjacent substrates in the chip module. This avoids the need to route the signals either through the rigid support base or to the edges of the thin film structure. Power and ground, which do not require a high connection density, are routed in low impedance paths through the support base. Preferably, the thin film structure is made of alternating layers of patterned metal, such as copper, and a low dielectric organic polymer, such as a polyimide.

Abstract: Methods of forming high-aspect ratio blind apertures and thereafter filling the apertures with a plating solution are disclosed. A layer of photosensitive material is pattern exposed to actinic radiation to define the apertures, and thereafter exposed to aqueous developer solution. The apertures are then rinsed with water and thereafter exposed to plating solution without drying the aperture of water or developer solution. This is contrary to conventional practice where photoresist layers are dried, and usually post-baked after the development step in order to improve dimensional integrity and reduce swelling of the photoresist material.

Abstract: An interconnecting post for mounting a microelectronic device such as an integral circuit chip is fabricated with generally uniform cross-section, by forming a first layer of positive photoresist on a substrate, soft-baking that first layer and exposing it for a short time with a wide-apertured mask or simply a UV blank flood exposure. Without developing the first layer, a second layer of positive resist is then applied over the first layer, soft-baked, and then exposed with a narrow-apertured mask. During the soft-baking of the second layer, some of its activator in the photoresist compound diffuses into the exposed portion of the first layer and modifies its solubility in such a way that, when the layers are subsequently developed, the developer partially undercuts the unexposed portion of the first layer to form in the photoresist an opening of generally uniform cross-section. This opening can then be filled by plating to produce a strong, integral interconnect post.

Abstract: Methods for pretreating patterned masks layers, such as photoresist masks, with electron-beam radiation for use in high temperature processes are disclosed. The electron-beam exposure deactivates compounds within the mask material which would ordinarily decompose and produce gasses within the photoresist layer. The gasses cause blistering in the untreated photoresist layer, which in turn degrades the dimensional integrity of the untreated layer.

Abstract: A three dimensional module for housing a plurality of integrated circuit chips is shown. The IC chips are mounted in rows on a plurality of substrates. Parallel to each row are communications bars which provide signal paths allowing chips on one substrate to communicate with those on another substrate. The communications bars also serve as spacers between substrates, thereby forming cooling channels. The IC chips are disposed in the cooling channels so that they come into direct contact with the cooling fluid. Signal lines to and from the IC chips are kept as separated as possible from the power lines so as to minimize noise. To this end, relatively thick power supply straps are mounted to each substrate below each row of IC chips. The power supply straps are, in turn, connected to power feed straps such that a very low impedance power supply path to the IC chips is maintained.

Abstract: Simple and cost-effective methods for forming tall, high-aspect ratio structures in a material layer comprising a first layer of a image-reversal-type photo-sensitive material and a second layer of a positive-type photo-sensitive material is disclosed. The layers are formed, exposed to actinic radiation, and developed such that the formation, exposure, and development of the second layer does not substantially modify or destroy the patterns formed in the first layer. In one embodiment, the first layer is exposed to actinic radiation through a first mask comprising the complimentary image, or negative, of a desired high-aspect ratio structure. The image in the first layer is then reversed by heating to an elevated temperature and subsequently blank flood exposure of actinic radiation. A second layer of a positive type photo-sensitive material chemically compatible with the IRP layer is then formed over the first layer.

Abstract: A thin-film bypass capacitor is fabricated by forming a plurality of through holes through the thickness of a nonconductive base substrate and filling the through holes with a conductive material to form ground vias and power vias. A sequence of back side metalization layers are applied to the back side surface of the base substrate. A sequence of bottom contact layers are applied to the front side surface of the base substrate. A bottom contact power terminal is formed in the bottom contact layer and is electrically isolated from remaining portions of the bottom contact layers by insulating plugs. A bottom contact metalization layer is applied to the surface of the bottom contact layers and the insulating plugs. A dielectric layer is formed on the surface of the bottom contact metalization layer. A ground metalization via and a power metalization via are formed at the surface of the dielectric layer.