# US 11,114,483 B2 · Cavityless chip-scale image-sensor package

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

- Number: US 11,114,483 B2
- Document ID: US11114483B2
- Status: Granted
- Kind: B2
- Application number: 16/100,835
- Filed: 2018-08-10
- Published: 2020-02-13
- Granted: 2021-09-07
- Earliest claimed: 2018-08-10
- Assignees: OmniVision Technologies, Inc.
- Applicants: OmniVision Technologies, Inc.
- Inventors: Chien-Chan Yeh; Ying-Chih Kuo; Wei-Feng Lin; Chun-Sheng Fan
- Web page: https://patentgrep.com/patent/US11114483B2

## CPC

- H10F 39/804: {Containers or encapsulations}
- H10F 39/806: {Optical elements or arrangements associated with the image sensors}
- H10F 39/014: {of CMOS image sensors}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/805: {Coatings}
- H10F 39/8063: {Microlenses}
- H10F 39/8067: {Reflectors}
- G02F 1/133526: {Lenses, e.g. microlenses or Fresnel lenses}
- H10W 72/012: {of bump connectors, dummy bumps or thermal bumps}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A cavityless chip-scale image-sensor package includes a substrate, a microlens array, and a low-index layer. The substrate includes a plurality of pixels forming a pixel array. The microlens array includes a plurality of microlenses each (i) having a lens refractive index, (ii) being aligned to a respective one of the plurality of pixels and (iii) having a non-planar microlens surfaces facing away from the respective one of the plurality of pixels. The low-index layer has a first refractive index less than the lens refractive index. The low-index layer also includes a bottom surface, at least part of which is conformal to each non-planar microlens surface. The microlens array is between the pixel array and the low-index layer.

## Claims

### Claim 1

A cavityless chip-scale image-sensor package comprising:
a substrate that includes a plurality of pixels forming a pixel array;
a microlens array that includes a plurality of microlenses each (i) having a lens refractive index, (ii) being aligned to a respective one of the plurality of pixels, and (iii) having a non-planar microlens surface facing away from the respective one of the plurality of pixels;
a low-index layer formed of either nanoporous silicon dioxide or nanoporous aluminum oxyhydroxide, and having (i) a first refractive index less than the lens refractive index, (ii) a bottom surface, at least part of which is conformal to each non-planar microlens surface, and (iii) a non-planar top surface that is conformal to the bottom surface and opposite the bottom surface, the microlens array being between the pixel array and the low-index layer; and
a bonding layer adjoining the low-index layer such that the low-index layer is between the microlens array and the bonding layer; and
a cover glass disposed on the bonding layer opposite the low-index layer,
the bonding layer and the cover glass having a second refractive index and a third refractive index respectively, each exceeding the first refractive index.

### Claim 2 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the first refractive index being between 1.20 and 1.25.

### Claim 3 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, thickness of the low-index layer above an apex of one of the plurality of microlenses being between 95 nanometers and 115 nanometers.

### Claim 4 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the low-index layer having, at a visible electromagnetic wavelength, a quarter-wave optical thickness above an apex of one of the plurality of microlenses.

### Claim 5 (depends on 4)

The cavityless chip-scale image-sensor package of claim 4, the visible electromagnetic wavelength being between 480 nanometers and 515 nanometers.

### Claim 6 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the lens refractive index exceeding the first refractive index by at least Δn=0.20 for a range of visible electromagnetic wavelengths.

### Claim 7 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the bottom surface of the low-index layer adjoining each non-planar microlens surface.

### Claim 8 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the pixel array being configured to detect light incident on a top die-surface of the substrate, the top die-surface including a bond pad adjacent to the pixel array and beneath the low-index layer.

### Claim 9 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the low-index layer completely covering the microlens array.

### Claim 10 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the pixel array being configured to detect light incident on a top die-surface of the substrate, the top die-surface including a bond pad adjacent to the pixel array and beneath each of the low-index layer, the bonding layer, and the cover glass.

### Claim 11 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the lens refractive index, the second refractive index, and the third refractive index being equal to within Δn=0.08 for a range of visible electromagnetic wavelengths.

### Claim 12 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the lens refractive index, the second refractive index, and the third refractive index being in the range from 1.46 to 1.54 for a range of visible electromagnetic wavelengths.

### Claim 13 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the bonding layer having a coefficient of thermal expansion less than 200 ppm/K for a temperature range below a glass transition temperature of the plurality of microlenses.

### Claim 14 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1, the bonding layer being between five micrometers and ten micrometers thick.

### Claim 15 (depends on 1)

The cavityless chip-scale image-sensor package of claim 1,
a diameter of each of the plurality of microlenses being between eight micrometers and nine micrometers;
a peak-to-valley height of the non-planar microlens surface being between thirteen percent and twenty-three percent of the diameter.

### Claim 16

A cavityless chip-scale image-sensor package comprising:
a substrate that includes a plurality of pixels forming a pixel array configured to detect light incident on a top die-surface of the substrate;
a microlens array that includes a plurality of microlenses each (i) having a lens refractive index, (ii) being aligned to a respective one of the plurality of pixels, and (iii) having a non-planar microlens surface facing away from the respective one of the plurality of pixels;
a low-index layer having (i) a first refractive index less than the lens refractive index, (ii) a bottom surface, at least part of which is conformal to each non-planar microlens surface, and (iii) a non-planar top surface that is conformal to the bottom surface and opposite the bottom surface, the microlens array being between the pixel array and the low-index layer; and
a bonding layer adjoining the low-index layer such that the low-index layer is between the microlens array and the bonding layer;
a cover glass disposed on the bonding layer opposite the low-index layer; and
a bond pad adjacent to the pixel array and beneath the low-index layer,
the bonding layer and the cover glass having a second refractive index and a third refractive index respectively, each exceeding the first refractive index.