Atomically thin highly resistive barrier layer in a copper via
First Claim
1. A process of filling copper into a vertical interconnection hole extending through an inter-level dielectric layer formed in a substrate and having sides and a bottom, comprising the steps of:
- coating sides and a bottom of said hole with a barrier layer of a metal oxide or nitride having an electrical resistivity greater than 500 microohm-cm;
sputtering a copper target opposed to said substrate under conditions such that a copper layer is deposited on said sides of said hole while simultaneously said barrier layer is removed from said bottom of said hole; and
then electroplating copper into said hole.
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Accused Products
Abstract
A method of forming a copper via and the resultant structure. A thin layer of an insulating barrier material, such as aluminum oxide or tantalum nitride, is conformally coated onto the sides and bottom of the via hole, for example, by atomic layer deposition (ALD) to a thickness of less than 5 nm, preferably less than 2 nm and having an electrical resistivity of more than 500 microohm-cm. A copper seed layer is then deposited under conditions such that copper is deposited on the via sidewalls but not deposited over most of the bottom of via hole. Instead energetic copper ions sputter the barrier material from the via bottom. Copper is electroplated into the via hole lined only on its sidewalls with the barrier. The invention preferably extends also to dual-damascene structures in which the copper seed sputter process sputters the barrier layer from the via bottom but not the trench floor.
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Citations
33 Claims
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1. A process of filling copper into a vertical interconnection hole extending through an inter-level dielectric layer formed in a substrate and having sides and a bottom, comprising the steps of:
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coating sides and a bottom of said hole with a barrier layer of a metal oxide or nitride having an electrical resistivity greater than 500 microohm-cm;
sputtering a copper target opposed to said substrate under conditions such that a copper layer is deposited on said sides of said hole while simultaneously said barrier layer is removed from said bottom of said hole; and
then electroplating copper into said hole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31)
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12. A process of filling copper into a vertical interconnection hole extending through an inter-level dielectric layer formed in a substrate and having sides and a bottom, comprising the steps of:
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coating sides and a bottom of said hole with a barrier layer of a metal oxide or nitride having an electrical resistivity greater than 500 microohm-cm and a thickness on said sides of less than 5 nm;
removing said barrier layer from said bottom;
sputtering a copper target opposed to said substrate to deposit a copper layer on at least said sides; and
then electroplating copper into said hole.
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19. A copper via structure, comprising:
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a lower dielectric layer having a copper feature formed in its surface;
an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said copper feature;
a barrier layer comprising a metal oxide formed on sides of said hole but not on a bottom of said hole facing said copper feature; and
copper filled into said hole and contacting said copper feature.
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25. A copper via structure, comprising:
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a lower dielectric layer having a copper feature formed in its surface;
an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said copper feature;
a barrier layer comprising a metal oxide or nitride formed on sides of said hole to a thickness of no more than 5 nm but not on a bottom of said hole facing said copper feature; and
copper filled into said hole and contacting said copper feature.
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32. A copper via structure, comprising:
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a lower dielectric layer having a conductive feature formed in its surface;
an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said conductive feature;
a barrier layer comprising tantalum nitride formed on sides of said hole to a thickness of greater than 0.5 nm and no more than 5 nm but not on a bottom of said hole facing said conductive feature; and
copper filled into said hole. - View Dependent Claims (33)
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Specification