# US 11,309,251 B2 · Selective metallization of integrated circuit packages

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- Number: US 11,309,251 B2
- Document ID: US11309251B2
- Status: Granted
- Kind: B2
- Application number: 16/051,093
- Filed: 2018-07-31
- Published: 2019-01-31
- Granted: 2022-04-19
- Earliest claimed: 2017-07-31
- Assignees: AdTech Ceramics Company
- Applicants: AdTech Ceramics Company
- Inventors: Aaron Fitzsimmons; William Minehan
- Web page: https://patentgrep.com/patent/US11309251B2

## CPC

- H10W 70/611: {for connecting multiple chips together}
- H10P 14/3406: {Carbon, e.g. diamond-like carbon}
- H10P 14/3408: {Silicon carbide}
- H10P 14/3416: {Nitrides}
- H10P 14/3426: {Oxides}
- H10W 40/228: {the projecting parts being wire-shaped or pin-shaped}
- H10W 40/255: {having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates}
- H10W 70/635: {Through-vias}
- H10W 70/685: comprising multiple insulating layers
- H10W 72/90: Bond pads, in general
- H10W 70/682: {comprising holes having chips therein}
- H10W 70/692: Ceramics or glasses
- H10W 72/884: {Die-attach connectors and bond wires}
- H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W 90/754: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The disclosed technology generally relates to metallization of substrates, and more particularly to selective metallization of ceramic substrates. A method of selectively metallizing a substrate includes forming a base metal layer comprising a refractory metal on a substrate, forming a base nickel (Ni) layer over the base metal layer by a vapor phase process, forming a palladium (Pd) layer on the base Ni layer by electroless plating, and forming a gold (Au) layer on the Pd layer.

## Claims

### Claim 1

A method of metallizing a ceramic package configured to house an electronic component, the method comprising:
providing a ceramic substrate having a via formed therethrough;
forming a base metal layer comprising a refractory metal on the ceramic substrate, the base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition;
forming a base nickel (Ni) layer formed on the base metal layer, wherein the base Ni layer is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
selectively forming a nickel (Ni) layer over the base metal layer by electroless plating;
forming a palladium (Pd) layer on the Ni layer by electroless plating; and
forming a gold (Au) layer on the Pd layer,
wherein one or more of the base Ni layer, the Pd layer and the Au layer formed on the via portion of the base metal layer extend through the via.

### Claim 2 (depends on 1)

The method of claim 1, wherein the refractory metal comprises one or both of tungsten (W), molybdenum (Mo).

### Claim 3 (depends on 2)

The method of claim 2, wherein forming the base Ni layer activates the base metal layer prior to forming the Ni layer, wherein activating increases the rate of electroless plating of Ni relative to a rate of electroless plating of Ni without activating.

### Claim 4 (depends on 3)

The method of claim 3, wherein the base Ni layer is formed on the base metal layer by a vapor phase deposition process.

### Claim 5 (depends on 4)

The method of claim 4, wherein the Ni layer is formed without performing a cleaning process that removes organic material immediately prior to selectively forming the base Ni layer.

### Claim 6 (depends on 4)

The method of claim 4, further comprising forming an interfacial layer between the base Ni layer and the base metal layer, wherein the interfacial layer comprises Ni and the refractory metal.

### Claim 7 (depends on 6)

The method of claim 6, wherein forming the interfacial layer comprises thermally annealing the base metal layer and the base Ni layer at a temperature of 700° C. to 1200° C.

### Claim 8 (depends on 7)

The method of claim 7, wherein thermally annealing causes sintering of the base Ni layer such that an average grain size of the base Ni layer is about 1 μm to 5 μm in a direction parallel to major surface of the base Ni layer.

### Claim 9 (depends on 4)

The method of claim 4, wherein the base Ni layer is substantially free of P and B.

### Claim 10 (depends on 4)

The method of claim 4, wherein forming the base Ni layer comprises selectively depositing on the base metal layer using a first reactant comprising Ni and a second reactant comprising an iodide.

### Claim 11 (depends on 3)

The method of claim 3, wherein the Ni layer is formed without forming a catalyzing Pd layer prior to selectively forming the Ni layer.

### Claim 12 (depends on 3)

The method of claim 3, wherein activating comprises forming a catalyzing Pd layer prior to selectively forming the Ni layer.

### Claim 13 (depends on 1)

The method of claim 1, further comprising:
forming on the ceramic substrate a second base metal layer comprising the refractory metal at a different location than the base metal layer, and
forming a metal layer different from the Ni layer over the second base metal layer.

### Claim 14 (depends on 13)

The method of claim 13, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper, niobium, platinum or silver.

### Claim 15 (depends on 14)

The method of claim 14, wherein forming the metal layer comprises brazing the metal layer and the second base metal using a filler metal.

### Claim 16 (depends on 14)

The method of claim 14, further comprising, forming on the metal:
selectively forming a second Ni layer on the second base metal layer by electroless plating;
forming a second palladium Pd layer on the second Ni layer by electroless plating; and
forming a second Au layer on the second Pd layer by an immersion process.

### Claim 17 (depends on 16)

The method of claim 16, further comprising forming a base Ni layer between the base metal layer and the Ni layer, and forming a second base Ni layer between the second base metal layer and the second Ni layer, wherein the base Ni layer and the second base Ni layer are formed by a vapor phase deposition process.

### Claim 18 (depends on 17)

The method of claim 17, wherein the base Ni layer and the second base Ni layer are formed simultaneously.

### Claim 19

A method of metallizing a ceramic package configured to house an electronic component, the method comprising:
providing a ceramic substrate having a via formed therethrough;
forming a base metal layer comprising a refractory metal on the ceramic substrate, the base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition;
forming a base nickel (Ni) layer on the base metal layer by a vapor phase process, wherein the base Ni layer is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
forming a (Pd) layer over the base nickel layer by electroless plating; and
forming a gold (Au) layer on the Pd layer,
wherein one or more of the base Ni layer, the Pd layer and the Au layer formed on the via portion of the base metal layer extend through the via.

### Claim 20 (depends on 19)

The method of claim 19, wherein the base Ni layer is substantially free of P and B.

### Claim 21 (depends on 20)

The method of claim 20, wherein forming the base Ni layer comprises selectively depositing on the base metal layer using a first gas phase reactant comprising Ni and a second gas phase reactant comprising an iodide.

### Claim 22 (depends on 21)

The method of claim 21, further comprising thermally annealing the base Ni layer prior to forming the Ni layer.

### Claim 23 (depends on 20)

The method of claim 20, further comprising forming a Ni layer on the base Ni layer by electroless plating.

### Claim 24 (depends on 23)

The method of claim 23, further comprising:
forming on the ceramic substrate a second base metal layer comprising the refractory metal at a different location than the base metal layer,
forming a second base Ni layer on the second base metal layer, and
forming a metal layer different from the Ni layer over the second base metal layer.

### Claim 25 (depends on 24)

The method of claim 24, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper, niobium, platinum or silver.

### Claim 26 (depends on 25)

The method of claim 25, further comprising, forming, over the metal layer:
a second Pd layer over the second base Ni layer by electroless plating; and
second Au layer on the second Pd layer by an immersion process.

### Claim 27 (depends on 26)

The method of claim 26, further comprising simultaneously electroplating a Ni layer on the base Ni layer and a second Ni layer on the second base Ni layer, wherein the first and second base Ni layers.

### Claim 28 (depends on 27)

The method of claim 27, wherein the Ni layer and the second Ni layer comprise P or B at a concentration exceeding 5%.

### Claim 29 (depends on 24)

The method of claim 24, wherein the base Ni layer and the second base Ni layer are formed by a vapor phase deposition process.

### Claim 30 (depends on 29)

The method of claim 29, wherein the base Ni layer and the second base Ni layer are formed simultaneously.

### Claim 31 (depends on 24)

The method of claim 24, wherein the refractory metal comprises one or both of tungsten (W), and molybdenum (Mo).

### Claim 32

A ceramic package configured to house an electronic component, the ceramic package comprising:
a ceramic substrate having a via formed therethrough;
a base metal layer comprising a refractory metal, the base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition;
a base nickel (Ni) layer formed on the base metal layer, wherein the base Ni layer is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
a palladium (Pd) layer formed over the base Ni layer; and
a gold (Au) layer formed on the palladium layer,
wherein one or more of the base Ni layer, the Pd layer and the Au layer formed on the via portion of the base metal layer extend through the via.

### Claim 33 (depends on 32)

The ceramic package of claim 32, further comprising a Ni layer comprising P or B at a concentration exceeding 5% interposed between the base Ni layer and the Pd layer.

### Claim 34 (depends on 33)

The ceramic package of claim 33, wherein the ceramic package is substantially free of Pd between the ceramic substrate and the Ni layer.

### Claim 35 (depends on 33)

The ceramic package of claim 33, wherein an interfacial layer is formed between the Ni layer and the base metal layer, wherein the interfacial layer comprises Ni and the refractory metal.

### Claim 36 (depends on 32)

The ceramic package of claim 32, further comprising:
a second base metal layer comprising the refractory metal formed at a different location than the base metal layer on the ceramic substrate;
a second base Ni layer on the second base metal layer; and
a metal layer different from the Ni layer over the second base metal layer.

### Claim 37 (depends on 36)

The ceramic package of claim 36, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper or silver.

### Claim 38 (depends on 36)

The ceramic package of claim 36, further comprising:
a second Ni layer formed on the second base metal layer, wherein the second Ni layer comprises P or B at a concentration exceeding 5%;
a second Pd layer formed on the second Ni layer; and
a second Au layer formed on the second Pd layer.

### Claim 39 (depends on 32)

The ceramic package of claim 32, wherein the refractory metal comprises one or both of tungsten (W), and molybdenum (Mo).

### Claim 40 (depends on 32)

The ceramic package of claim 32, wherein the base metal layer fills the via.

### Claim 41 (depends on 32)

The ceramic package of claim 32, wherein the base Ni layer, the Pd layer and the Au layer are formed on both ends of the via formed through the ceramic substrate.

### Claim 42

A ceramic package configured to house an electronic component, the ceramic package comprising:
a ceramic substrate having a via formed therethrough;
a first base metal layer and a second base metal layer formed at different locations on the ceramic substrate and comprising a refractory metal, the first base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition,
wherein the first and second base metal layers have formed thereon different metal layer stacks each comprising:
a base nickel (Ni) layer that is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
a Ni layer over the base Ni layer;
a palladium (Pd) layer formed on the Ni layer; and
a gold (Au) layer formed on the Pd layer,
wherein one or more of the base Ni layer, the Pd layer and the Au layer formed on the via portion of the first base metal layer extend through the via.

### Claim 43 (depends on 42)

The ceramic package of claim 42, wherein the refractory metal comprises one or both of tungsten (W) and molybdenum (Mo).

### Claim 44 (depends on 42)

The ceramic package of claim 42, wherein the Ni layer is formed directly on the base Ni layer over the first base metal layer.

### Claim 45 (depends on 44)

The ceramic package of claim 44, wherein a metal layer is interposed between the Ni layer and the base Ni layer over the second base metal layer.

### Claim 46 (depends on 45)

The ceramic package of claim 45, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper, niobium, platinum or silver.

### Claim 47 (depends on 42)

The ceramic package of claim 42, wherein the Ni layer comprises P or B at a concentration exceeding 5%.

### Claim 48

A ceramic package configured to house an electronic component, the ceramic package comprising:
a ceramic substrate having a via formed therethrough;
a base metal layer comprising a refractory metal, the base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition;
a base nickel (Ni) layer formed on the base metal layer, wherein the base Ni layer is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
a palladium (Pd) layer formed over the base Ni layer; and
a gold (Au) layer formed on the palladium layer,
wherein the base Ni layer, the Pd layer and the Au layer are formed on both ends of the via formed through the ceramic substrate.

### Claim 49 (depends on 48)

The ceramic package of claim 48, further comprising a Ni layer comprising P or B at a concentration exceeding 5% interposed between the base Ni layer and the Pd layer.

### Claim 50 (depends on 49)

The ceramic package of claim 49, wherein the ceramic package is substantially free of Pd between the ceramic substrate and the Ni layer.

### Claim 51 (depends on 49)

The ceramic package of claim 49, wherein an interfacial layer is formed between the Ni layer and the base metal layer, wherein the interfacial layer comprises Ni and the refractory metal.

### Claim 52 (depends on 48)

The ceramic package of claim 48, further comprising:
a second base metal layer comprising the refractory metal formed at a different location than the base metal layer on the ceramic substrate;
a second base Ni layer on the second base metal layer; and
a metal layer different from the Ni layer over the second base metal layer.

### Claim 53 (depends on 52)

The ceramic package of claim 52, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper or silver.

### Claim 54 (depends on 52)

The ceramic package of claim 52, further comprising:
a second Ni layer formed on the second base metal layer, wherein the second Ni layer comprises P or B at a concentration exceeding 5%;
a second Pd layer formed on the second Ni layer; and
a second Au layer formed on the second Pd layer.

### Claim 55 (depends on 48)

The ceramic package of claim 48, wherein the refractory metal comprises one or both of tungsten (W), and molybdenum (Mo).

### Claim 56 (depends on 48)

The ceramic package of claim 48, wherein one or more of the base Ni layer, the Pd layer and the Au layer formed on the via portion of the base metal layer extend through the via.

### Claim 57 (depends on 48)

The ceramic package of claim 48, wherein the base metal layer fills the via.

### Claim 58

A ceramic package configured to house an electronic component, the ceramic package comprising:
a ceramic substrate having a via formed therethrough;
a first base metal layer and a second base metal layer formed at different locations on the ceramic substrate and comprising a refractory metal, the first base metal layer having upper and lower portions formed on opposing major surfaces of the ceramic substrate and further having a via portion extending through the via and connecting the upper and lower portions, wherein the upper, lower and via portions form a continuous base metal layer having the same composition,
wherein the first and second base metal layers have formed thereon different metal layer stacks each comprising:
a base nickel (Ni) layer that is free of phosphorus (P) and boron (B) or has concentrations of P and B each less than 0.01% on the basis of a weight of the base Ni layer;
a Ni layer over the base Ni layer;
a palladium (Pd) layer formed on the Ni layer; and
a gold (Au) layer formed on the Pd layer,
wherein the base Ni layer, the Pd layer and the Au layer are formed on both ends of the via formed through the ceramic substrate.

### Claim 59 (depends on 58)

The ceramic package of claim 58, wherein the refractory metal comprises one or both of tungsten (W) and molybdenum (Mo).

### Claim 60 (depends on 58)

The ceramic package of claim 58, wherein the Ni layer is formed directly on the base Ni layer over the first base metal layer.

### Claim 61 (depends on 60)

The ceramic package of claim 60, wherein a metal layer is interposed between the Ni layer and the base Ni layer over the second base metal layer.

### Claim 62 (depends on 61)

The ceramic package of claim 61, wherein the metal layer comprises a metal or an alloy, the metal or the alloy comprising one or more of titanium, tungsten, silicon, carbon, aluminum, nickel, iron, cobalt, molybdenum, copper, niobium, platinum or silver.

### Claim 63 (depends on 58)

The ceramic package of claim 58, wherein the Ni layer comprises P or B at a concentration exceeding 5%.