Method and resulting structure for manufacturing semiconductor substrates

Abstract

A semiconductor wafer composite is used as a basis for fabricating semiconductor chips, especially compound semiconductor devices. The semiconductor wafer composite advantageously comprises a metallic substrate 210 and multiple semiconductor tiles 220 bonded to the surface of the metallic substrate 210. The semiconductor wafer composite is effectively used as a single large semiconductor wafer for volume fabrication, and can be used to fabricate semiconductor devices in a similar manner.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application claims priority to Australian Provisional Patent Application No. PS1122 filed Mar. 14, 2002, commonly assigned, and hereby incorporated by references for all purposes. STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT BACKGROUND OF THE INVENTION [0002] The present invention relates generally to manufacturing substrates. More particularly, the invention provides a method and device for improved semiconductor substrates to form advanced semiconductor devices. Merely by way of example, the invention has been applied to a metallic substrate that includes a plurality of panels and / or tiles, which are bonded on the substrate, for the manufacture of the advanced semiconductor devices. But it would be recognized that the invention has a much broader range of applicability. [0003] As technology progresses, semiconductor manufacturers have continually strived to use ever larger wafers to...

AI Technical Summary

Benefits of technology

[0021] According to the present invention, techniques for manufacturing substrates are provided. More particularly, the invention provides a method and device for improved semiconductor substrates to form advanced semiconductor devices. Merely by way of example, the invention has been applied to a metallic substrate that includes a plurality of panels and / or tiles, which are bonded on the substrate, for the manufacture of the advanced semiconductor devices. But, it would be recognized that the invention has a much broader range of applicability.

[0023] Multiple wafer tiles are advantageously bonded to the metallic substrate before any front-side processing. The metallic substrate desirably remains attached to the semiconductor material when the composite is divided into individual chips. The semiconductor wafer composite is effectively used as a single large semiconductor wafer, and can be used to fabricate semiconductor devices in a similar manner. By way of the metal substrate, the composite is more durable and efficient.

[0024] The semiconductor tiles are advantageously square or rectangular, or one or more other shapes able to be conveniently tessellated on the metallic substrate to efficiently cover the surface of the metallic substrate. These shapes are conventionally cut from the standard “clipped-circular” wafer shape.

[0026] In a further alternative embodiment, the invention provides a bonded semiconductor wafer composite for fabricating semiconductor devices. The bonded semiconductor wafer has a metal support substrate. The metal substrate has a first diameter and an upper surface, which is substantially planar. The metal support structure is characterized by a first coefficient of thermal expansion parameter. The wafer also has a plurality of trapezoidal shaped tiles comprising a compound semiconductor material. The plurality of trapezoidal shaped tiles are bonded onto the upper surface of the metal support substrate. Each of the trapezoidal shaped tiles includes at least one edge, which is aligned with an edge of a different trapezoidal shaped tile. Each of the plurality of trapezoidal shaped tiles is characterized by a second coefficient of thermal expansion parameter. A eutectic bonding material is coupled between each of the trapezoidal shaped tiles and a portion of the upper surface of the metal support substrate. The eutectic bonding material provides a continuous mechanical and electrical contact between the portion of the upper surface and the trapezoidal shaped tile. The first coefficient of thermal expansion parameter is within a predetermined amount of the second coefficient of thermal expansion parameter. The predetermined amount is selected to reduce a possibility of breakage of any portion of any trapezoidal shaped tile bonded to the portion of the upper surface of the metal substrate from a thermal influence, e.g., contraction, expansion. Each of the trapezoidal shaped tiles is derived from a compound semiconductor substrate of a second diameter, which is less than the first diameter associated with the metal substrate. Each of the trapezoidal shaped tiles comprises a predetermined thickness.

[0027] Various advantages can be achieved through use of a semiconductor tile bonded to a metallic substrate. The semiconductor wafer composite is less fragile than the semiconductor tile, and can thus be handled in larger areas. As a result, cost savings can be achieved through larger volume fabrication.

Problems solved by technology

Unfortunately, integrated circuits made from these semiconducting compounds are still relatively expensive compared to circuits made from silicon semiconductors.

This cost difference is largely attributable to the respective material costs, and wafer processing costs.

Other limitations also exist with compound semiconductor materials.

Compound semiconductor wafers are more prone to damage.

For example, they are more brittle than conventional single crystal silicon wafers.

Growing large crystal boules of compound semiconductor material is extremely difficult compared with growing large single crystal silicon boules.

Unfortunately, larger diameter wafers are difficult to make efficiently.

Even if larger boules of compound semiconductor material could be produced, handling the resulting large-diameter compound semiconductor wafers would generally be problematic.

Compound semiconductor wafers of the desired thickness and diameter would be extremely fragile and prone to breakage.

Here, the larger wafers would generally break due to the brittle nature of these semiconductor compounds.

Handling thinned compound semiconductor wafers is often difficult, and compound semiconductor wafers are commonly broken from step (iv) onwards.

Breakage is costly, since most of the processing (steps (i) to (iii)) is already complete.

The fragility of compound semiconductor materials also causes breakages of resulting chip devices, and restricts the larger size of practical chip designs that use compound semiconductor materials.

Here, larger sized compound semiconductor materials are not practical to make efficiently.

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