# US 10,375,826 B2 · High temperature drilling electronics

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- Number: US 10,375,826 B2
- Document ID: US10375826B2
- Status: Granted
- Kind: B2
- Application number: 15/859,068
- Filed: 2017-12-29
- Published: 2019-07-04
- Granted: 2019-08-06
- Earliest claimed: 2017-12-29
- Assignees: China Petroleum & Chemical Corporation
- Applicants: China Petroleum & Chemical Corporation; Sinopec Tech Houston, LLC.
- Inventors: Sheng Zhan; Jinhai Zhao; Fengtao Hu; Herong Zheng
- Web page: https://patentgrep.com/patent/US10375826B2

## CPC

- H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion}
- H05K 1/0201: {Thermal arrangements, e.g. for cooling, heating or preventing overheating}
- H05K 1/0353: {consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement}
- H05K 1/111: {Pads for surface mounting, e.g. lay-out}
- H05K 1/115: {Via connections; Lands around holes or via connections (H05K1/112 takes precedence)}
- H05K 1/181: associated with surface mounted components
- H05K 3/244: {Finish plating of conductors, especially of copper conductors, e.g. for pads or lands (selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3465)}
- H05K 3/282: {for inhibiting the corrosion of the circuit, e.g. for preserving the solderability}
- H05K 1/0346: {containing N}
- H05K 2201/0154: Polyimide
- H05K 2201/09227: Layout details of a plurality of traces, e.g. escape layout for Ball Grid Array [BGA] mounting
- H05K 2201/09509: Blind vias, i.e. vias having one side closed
- H05K 2201/098: Special shape of the cross-section of conductors, e.g. very thick plated conductors
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A printed circuit board assembly (PCBA) for downhole applications has a printed circuit board (PCB) and a plurality of electronic components installed on the PCB. The PCB comprises a polyimide substrate, a lead-free surface finish, a plurality of traces, a plurality of surface mount pads, and a plurality of VIAs. The ratio between the width of one of the plurality of surface mount pads to the width of the trace connected thereto is 2 or less.

## Claims

### Claim 1

A printed circuit board assembly (PCBA) for downhole applications, comprising:
a printed circuit board (PCB) and a plurality of electronic components installed on the PCB;
wherein the PCB comprises a polyimide substrate, a lead-free surface finish, a plurality of traces, a plurality of surface mount pads, and a plurality of VIAs, and
wherein a ratio between a width of one of the plurality of surface mount pads to a width of the trace connected thereto is 2 or less,
wherein X/Y ranges from 0.8 to about 0.86, wherein X is a minimum trace width of the plurality of traces and Y is the minimum spacing between the two adjacent traces amongst the plurality of traces.

### Claim 2 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the polyimide substrate is polyimide 35N or polyimide 85N.

### Claim 3 (depends on 2)

The printed circuit board assembly (PCBA) of claim 2, wherein the polyimide substrate is polyimide 85N.

### Claim 4 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the lead-free surface finish is electroless nickel immersion gold (ENIG), electroless gold, electroless palladium, immersion silver, immersion tin (ENEPIG), organic solder-ability preservatives (OSP), or direct gold on copper (DIG).

### Claim 5 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the lead-free surface finish is electroless nickel immersion gold (ENIG).

### Claim 6 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the plurality of traces have a width of 0.5 mm or higher.

### Claim 7 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the plurality of VIAs comprises one or more microVlAs, one or more blind VIAs, and one or more buried VIAs.

### Claim 8 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the plurality of VIAs each has a diameter of 0.30 mm or larger.

### Claim 9 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the PCB further comprises one or more plated thru-holes for mounting the plurality of electronic components.

### Claim 10 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the plurality of electronic components has a distance to an edge of the PCB that follows the following relation, when a height of the electronic component is less than 3 mm, the distance is at least 2.0 mm; and when a height of the electronic component is 3 mm or higher, the distance is at least 2.5 mm.

### Claim 11 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the PCBA is operable at up to 200° C. for more than 500 hrs.

### Claim 12 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the PCB has a copper thickness of 2 oz or less.

### Claim 13 (depends on 1)

The printed circuit board assembly (PCBA) of claim 1, wherein the width of the trace is 0.5 mm or higher.