# US 2019/0170885 A1 · Method of Making Semiconductor X-ray Detectors

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- Number: US 2019/0170885 A1
- Document ID: US20190170885A1
- Status: Published application
- Kind: A1
- Application number: 16/253,614
- Filed: 2019-01-22
- Published: 2019-06-06
- Earliest claimed: 2016-08-30
- Assignees: Shenzhen Xpectvision Technology Co., Ltd.
- Applicants: Shenzhen Xpectvision Technology Co., Ltd.
- Inventors: Peiyan CAO; Yurun LIU
- Web page: https://patentgrep.com/patent/US20190170885A1

## CPC

- G01T 1/2928: {using solid state detectors}
- H10F 30/29: the devices being sensitive to radiation having very short wavelengths, e.g. X-rays, gamma-rays or corpuscular radiation
- H10F 39/1892: {Direct radiation image sensors}
- H10F 39/195: {X-ray, gamma-ray or corpuscular radiation imagers}
- H10F 77/933: {for devices having potential barriers}
- H10F 77/953: {for devices having potential barriers}
- H10W 90/00: Package configurations
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Disclosed herein is a method comprising: obtaining a substrate comprising an electronic system in or on the substrate, and a plurality of electric contacts on a first surface of the substrate, the electronic system being electrically connected to the electric contacts; obtaining a chip comprising an X-ray absorption layer, the X-ray absorption layer comprising an electrode; electrically connecting the electrode to at least one of the electric contacts by bonding the chip to the substrate; and thinning the substrate at a surface opposite the first surface.

## Claims

### Claim 1

A method comprising:
obtaining a substrate comprising an electronic system in or on the substrate, and a plurality of electric contacts on a first surface of the substrate, the electronic system being electrically connected to the electric contacts;
obtaining a chip comprising an X-ray absorption layer, the X-ray absorption layer comprising an electrode;
electrically connecting the electrode to at least one of the electric contacts by bonding the chip to the substrate; and
thinning the substrate at a surface opposite the first surface.

### Claim 2 (depends on 1)

The method of claim 1, wherein the electronic system is configured to process or interpret signals generated by X-ray photons incident on the X-ray absorption layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the X-ray absorption layer comprises a diode.

### Claim 4 (depends on 1)

The method of claim 1, wherein the electrode is in direct physical contact with the at least one of the electric contacts, or wherein the electrode is in contact with the at least one of the electric contacts through a solder bump.

### Claim 5 (depends on 1)

The method of claim 1, wherein thinning the substrate exposes a second surface of the substrate; and
wherein the method further comprises forming a redistribution layer (RDL) on the second surface.

### Claim 6 (depends on 5)

The method of claim 5, wherein the substrate comprises a via extending from the first surface to the second surface;
wherein the RDL comprises a transmission line; and
wherein the transmission line is connected to the via.

### Claim 7 (depends on 6)

The method of claim 6, wherein the electronic system is connected to the via.

### Claim 8 (depends on 6)

The method of claim 6, wherein the at least one of the electric contacts is connected to the via.

### Claim 9 (depends on 1)

The method of claim 1, further comprising mounting a backing substrate to the chip such that the chip is sandwiched between the backing substrate and the substrate.

### Claim 10 (depends on 1)

The method of claim 1, wherein the chip is smaller in area than the substrate.

### Claim 11 (depends on 1)

The method of claim 1, wherein a ratio between a thermal expansion coefficient of the chip and a thermal expansion coefficient of the substrate is two or more.

### Claim 12 (depends on 1)

The method of claim 1, wherein the X-ray absorption layer comprises silicon, germanium, GaAs, CdTe, CdZnTe, or a combination thereof.

### Claim 13 (depends on 1)

The method of claim 1, wherein the X-ray absorption layer is doped with chromium.

### Claim 14 (depends on 1)

The method of claim 1, wherein the electronics system comprises:
a first voltage comparator configured to compare a voltage of the electrode to a first threshold;
a second voltage comparator configured to compare the voltage to a second threshold;
a counter configured to register a number of X-ray photons reaching the X-ray absorption layer;
a controller;
wherein the controller is configured to start a time delay from a time at which the first voltage comparator determines that an absolute value of the voltage equals or exceeds an absolute value of the first threshold;
wherein the controller is configured to activate the second voltage comparator during the time delay; and
wherein the controller is configured to cause the number registered by the counter to increase by one, if the second voltage comparator determines that an absolute value of the voltage equals or exceeds an absolute value of the second threshold.

### Claim 15 (depends on 14)

The method of claim 14, wherein the electronics system further comprises a capacitor module electrically connected to the electrode of the X-ray absorption layer, wherein the capacitor module is configured to collect charge carriers from the electrode of the X-ray absorption layer.

### Claim 16 (depends on 14)

The method of claim 14, wherein the controller is configured to activate the second voltage comparator at a beginning or expiration of the time delay.

### Claim 17 (depends on 14)

The method of claim 14, wherein the electronics system further comprises a voltmeter, wherein the controller is configured to cause the voltmeter to measure the voltage upon expiration of the time delay.

### Claim 18 (depends on 17)

The method of claim 17, wherein the controller is configured to determine an X-ray photon energy based on a value of the voltage measured upon expiration of the time delay.

### Claim 19 (depends on 14)

The method of claim 14, wherein the controller is configured to connect the electrode of the X-ray absorption layer to an electrical ground.

### Claim 20 (depends on 14)

The method of claim 14, wherein a rate of change of the voltage is substantially zero at expiration of the time delay.

### Claim 21 (depends on 14)

The method of claim 14, wherein a rate of change of the voltage is substantially non-zero at expiration of the time delay.