# US 12,470,190 B2 · Blackened wafers and method for manufacturing the same, and wave filter device having the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,470,190 B2
- Document ID: US12470190B2
- Status: Granted
- Kind: B2
- Application number: 17/874,905
- Filed: 2022-07-27
- Published: 2022-11-17
- Granted: 2025-11-11
- Earliest claimed: 2020-09-28
- Assignees: Fujian Jing'an Optoelectronics Co., Ltd.
- Applicants: Fujian Jing'an Optoelectronics Co., Ltd.
- Inventors: Yilin Liu; Zhonghe Lin; Yenfu Lin; Shihwei Huang; Minghui Fang; Shengyu Yang
- Web page: https://patentgrep.com/patent/US12470190B2

## CPC

- H03H 3/08: for the manufacture of resonators or networks using surface acoustic waves
- H03H 9/02559: {of lithium niobate or lithium-tantalate substrates}
- H03H 9/02921: {Measures for preventing electric discharge due to pyroelectricity}
- H03H 9/145: for networks using surface acoustic waves
- H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)}
- H03H 9/64: using surface acoustic waves
- Y10T 29/42: Piezoelectric device making
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for blackening at least one wafer includes: (a) performing a reduction treatment on the at least one wafer; and (b) illuminating the at least one wafer with an ultraviolet light. The at least one wafer after the illumination of the UV light has a blackening uniformity value (DE value) smaller than 0.6, and a chromatic value (L value) smaller than 54. In addition, a blackened wafer made from the method is also provided.

## Claims

### Claim 1

A method for blackening at least one wafer, comprising the steps of:
(a) performing a reduction treatment on the at least one wafer; and
(b) illuminating the at least one wafer with an ultraviolet (UV) light,
wherein the at least one wafer after the illumination of the UV light has a blackening uniformity value (DE value) smaller than 0.6, and a chromatic value (L value) ranging from 46 to 54.

### Claim 2 (depends on 1)

The method of claim 1, wherein the DE value ranges from 0.3 to 0.6 and the L value ranges from 48 to 54.

### Claim 3 (depends on 1)

The method of claim 1, wherein the reduction treatment is performed before the illumination of the UV light.

### Claim 4 (depends on 1)

The method of claim 1, wherein the reduction treatment is performed after the illumination of the UV light.

### Claim 5 (depends on 1)

The method of claim 1, wherein the at least one wafer has a size of 6 inch, 8 inch or 10 inch.

### Claim 6 (depends on 1)

The method of claim 1, wherein in step (b), the at least one wafer is illuminated with the UV light for an illumination time period ranging from 0.1 hr to 2.5 hr, and the UV light has a wavelength ranging from 200 nm to 450 nm.

### Claim 7 (depends on 6)

The method of claim 6, wherein the at least one wafer is illuminated with the UV light for 1 hr.

### Claim 8 (depends on 1)

The method of claim 1, wherein the at least one wafer includes a plurality of the wafers, and
wherein in step (a), the reduction treatment is performed on the wafers and includes the following steps:
providing a reduction medium mixture including a plurality of reduction medium layers;
alternately stacking the wafers and the reduction medium layers; and
reductively treating the wafers with the reduction medium mixture under a reduction temperature ranging from 360° C. to 550° C. for a reduction time period ranging from 2 hr to 5 hr.

### Claim 9 (depends on 1)

A blackened wafer made from the method of claim 1, wherein said blackened wafer has a transmittance larger than 0% and smaller than 5% at a light wavelength ranging from 300 nm to 900 nm, the DE value ranging from 0.3 to 0.6, and the L value ranging from 48 to 54.

### Claim 10 (depends on 9)

The blackened wafer of claim 9, wherein the DE value of said blackened wafer ranges from 0.3 to 0.5.

### Claim 11 (depends on 9)

The blackened wafer of claim 9, wherein the L value of said blackened wafer ranges from 48 to 52.

### Claim 12 (depends on 9)

The blackened wafer of claim 9, wherein said blackened wafer has a size of 6 inch, 8 inch or 10 inch.

### Claim 13 (depends on 12)

The blackened wafer of claim 12, wherein said blackened wafer is a piezoelectric wafer which is made of lithium tantalate (LiTaO3) or lithium niobate (LiNbO3).

### Claim 14 (depends on 9)

A wave filter device, comprising:
said blackened wafer of claim 9; and
a transducer unit disposed on said blackened wafer,
wherein said transducer unit includes a first transducer as an input device and a second transducer as an output device.

### Claim 15 (depends on 14)

The wave filter device of claim 14, wherein the wave filter device is a surface acoustic wave filter.

### Claim 16 (depends on 14)

The wave filter device of claim 14, wherein said first transducer and said second transducer are interdigital transducers.