# US 10,483,147 B2 · Dual-purpose vias for use in ceramic pedestals

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- Number: US 10,483,147 B2
- Document ID: US10483147B2
- Status: Granted
- Kind: B2
- Application number: 16/196,571
- Filed: 2018-11-20
- Published: 2019-05-23
- Granted: 2019-11-19
- Earliest claimed: 2017-11-21
- Assignees: Wallow Electric Manufacturing Company
- Applicants: Watlow Electric Manufacturing Company
- Inventors: Mohammad Nosrati; Kevin Ptasienski
- Web page: https://patentgrep.com/patent/US10483147B2

## CPC

- H10P 72/722: {Details of electrostatic chucks}
- H05K 1/0212: {Printed circuits or mounted components having integral heating means}
- H05K 1/0224: {Patterned shielding planes, ground planes or power planes (H05K1/0253 takes precedence)}
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 1/09: Use of materials for the {conductive, e.g. } metallic pattern
- H05K 1/115: {Via connections; Lands around holes or via connections (H05K1/112 takes precedence)}
- H05K 3/4038: {Through-connections; Vertical interconnect access [VIA] connections (H05K3/403, H05K3/42 take precedence)}
- H10P 72/0432: {mainly by conduction}
- H10P 72/0434: {mainly by convection}
- H10P 72/72: using electrostatic chucks
- H10P 72/7614: {characterised by a plurality of individual support members, e.g. support posts or protrusions}
- H10P 72/7624: {characterised by the mechanical construction of the susceptor, stage or support}
- H01Q 1/38: formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142)}
- H05K 2201/09827: Tapered, e.g. tapered hole, via or groove
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A ceramic pedestal assembly and a method of forming a ceramic pedestal assembly is provided. The ceramic pedestal assembly includes a ceramic substrate defining an upper surface and a lower surface, at least one via extending through the ceramic substrate, an upper conductive foil layer extending across the upper surface of the ceramic substrate and a lower conductive foil layer extending across the lower surface of the ceramic substrate. Each via includes an upper via defining a cavity and a lower via defining a corresponding tapered insert. In one form, the upper via, the lower via, and the conductive foil layers define a material having a melting temperature greater than 2,000° C. and a CTE less than or equal to the ceramic substrate.

## Claims

### Claim 1

A ceramic pedestal assembly comprising:
a substrate having a first functional layer and a second functional layer, the first and second functional layers disposed at opposite sides of the substrate; and
at least one via extending through the substrate comprising:
an upper via defining a cavity; and
a lower via defining a corresponding insert,
wherein the first functional layer, the second functional layer, and the at least one via define a material having a melting temperature greater than 2,000° C. and a CTE (coefficient of thermal expansion) lower than the substrate.

### Claim 2 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein the substrate is made of an aluminum nitride material, and the at least one via, the first functional layer, and the second functional layer are made of a molybdenum material.

### Claim 3 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein the lower via is received by the cavity of the upper via such that an interference fit is formed between the upper and lower via when the ceramic substrate is heated.

### Claim 4 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein a top portion of the upper via and a bottom portion of the lower via is tapered.

### Claim 5 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein the first functional layer is a resistive heater layer having at least one resistive heating element and the second functional layer is a routing layer, wherein each resistive heating element defines at least one resistive heating zone.

### Claim 6 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein the cavity of the upper via and the corresponding insert of the lower cavity have a cross-sectional shape selected from the group consisting of polygonal, planar, circular, oval, triangular, and elliptical.

### Claim 7 (depends on 1)

The ceramic pedestal assembly according to claim 1 further comprising at least one sacrificial layer across at least one of the first functional layer and the second functional layer.

### Claim 8 (depends on 7)

The ceramic pedestal assembly according to claim 7, wherein the sacrificial layer is selected from the group consisting of Tungsten, Tungsten Carbide, and Boron Nitride.

### Claim 9 (depends on 1)

The ceramic pedestal assembly according to claim 1 further comprises an RF grid layer.

### Claim 10 (depends on 1)

The ceramic pedestal assembly according to claim 1,
wherein the first functional layer is an upper conductive foil layer extending across an upper surface of the substrate
and the second functional layer is a lower conductive foil layer extending across a lower surface of the substrate.

### Claim 11 (depends on 1)

The ceramic pedestal assembly according to claim 1, wherein the cavity of the upper via is tapered and the lower via defines a corresponding taper.

### Claim 12

A method of forming a ceramic pedestal assembly comprising:
forming a ceramic substrate in a green state with at least one aperture;
placing an upper via defining a cavity through an upper surface of the ceramic substrate;
placing a lower via defining a corresponding insert through a lower surface of the ceramic substrate;
placing an upper functional layer across the upper surface of the ceramic substrate;
placing a lower functional layer extending across the lower surface of the ceramic substrate; and
hot pressing the assembly in a uniaxial direction,
wherein the upper via, the lower via, and the functional layers define a material having a melting temperature greater than 2,000° C. and a CTE (coefficient of thermal expansion) less than or equal to the ceramic substrate.

### Claim 13 (depends on 12)

The method of claim 12 further comprising sintering the ceramic pedestal assembly at a temperature ranging from about 1700° C. to about 2,000° C.

### Claim 14 (depends on 12)

The method of claim 12 further comprising placing the assembly into a graphite mold.

### Claim 15 (depends on 12)

The method of claim 12 further comprising placing at least one sacrificial layer across at least one of the upper functional layer and the lower functional layer.

### Claim 16 (depends on 12)

The method of claim 12 further comprising forming a Radio Frequency (RF) grid layer on the substrate.