Power Semiconductor Chip with a Formed Patterned Thick Metallization Atop
First Claim
1. A power semiconductor chip comprising:
- an active area having a plurality of trenches filed with an insulated gate material extending into an epitaxial layer overlaying a substrate layer functioning as a drain;
body regions extending between trenches;
source regions disposed in body regions next to the trenches;
a dielectric layer overlaying the semiconductor surface with contact openings thereon; and
a metal layer overlaying the dielectric layer contacting the source regions through the contact openings, wherein said metal layer comprising a thin metallization layer in the bottom and a thick metallization layer on the top with the composition of said thin metallization layer comprises a Si content higher than the Si content of said thick metallization layer.
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Abstract
A method is disclosed for forming a patterned thick metallization atop a semiconductor chip wafer. The method includes fabricating a nearly complete semiconductor chip wafer ready for metallization; depositing a bottom metal layer of sub-thickness TK1 together with its built-in alignment mark using a hot metal process; depositing a top metal layer of sub-thickness TK2 using a cold metal process thus forming a stacked thick metallization of total thickness TK=TK1+TK2; then, use the built-in alignment mark as reference, patterning the stacked thick metallization. A patterned thick metallization is thus formed with the advantages of better metal step coverage owing to the superior step coverage nature of the hot metal process as compared to the cold metal process; and lower alignment error rate owing to the lower alignment signal noise nature of the cold metal process as compared to the hot metal process.
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Citations
15 Claims
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1. A power semiconductor chip comprising:
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an active area having a plurality of trenches filed with an insulated gate material extending into an epitaxial layer overlaying a substrate layer functioning as a drain; body regions extending between trenches; source regions disposed in body regions next to the trenches; a dielectric layer overlaying the semiconductor surface with contact openings thereon; and a metal layer overlaying the dielectric layer contacting the source regions through the contact openings, wherein said metal layer comprising a thin metallization layer in the bottom and a thick metallization layer on the top with the composition of said thin metallization layer comprises a Si content higher than the Si content of said thick metallization layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A power semiconductor chip comprising:
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a power semiconductor chip with a plurality of contact zones; a dielectric layer overlaying the semiconductor surface extending over said plurality of contact zones and having a plurality of contact openings thereon; a metal layer overlaying the dielectric layer contacting the source regions through the contact openings, wherein said metal layer comprising a thin metallization layer in the bottom and a thick metallization layer on the top with a composition of said thin metallization layer different from a composition of said thick metallization layer, wherein the ratio of thick metallization thickness to thin metallization thickness ranges from about 3;
1 to about 7;
1. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification