# US 2020/0286802 A1 · Assembly of stacked elements and method of producing the same

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- Number: US 2020/0286802 A1
- Document ID: US20200286802A1
- Status: Published application
- Kind: A1
- Application number: 16/685,141
- Filed: 2019-11-15
- Published: 2020-09-10
- Earliest claimed: 2019-03-08
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Yongfu CAI; Shuhei MIYAZAKI
- Web page: https://patentgrep.com/patent/US20200286802A1

## CPC

- H10W 74/01: Manufacture or treatment
- H10W 70/09: extending onto an encapsulation that laterally surrounds the chip or wafer, e.g. fan-out wafer level package [FOWLP] RDLs
- H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40)
- H10W 74/014: {using batch processing}
- H10W 74/129: {forming a chip-scale package [CSP]}
- H10W 74/473: {containing a filler}
- H10W 70/099: {Connecting interconnections to insulating or insulated package substrates, interposers or redistribution layers}
- H10W 70/6528: {of the portions that connect to chips, wafers or package parts}
- H10W 72/0198: {batch processes}
- H10W 72/073: {of die-attach connectors}
- H10W 72/874: {On different surfaces}
- H10W 72/9413: {on encapsulations}
- H10W 74/142: {the encapsulations exposing the passive side of the semiconductor body}
- H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W 99/00: Subject matter not provided for in other groups of this subclass
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

In an assembly in which a space between two elements is filled with a filler containing resin, a configuration that can limit both the size of the assembly and the cost of the fillers is provided. Assembly 10 of stacked elements has: first element 2 having first surface 21; resin layer 61 that is arranged on first surface 21 and that contains a plurality of fillers F; and second element 4 that is arranged on resin layer 61 and that has second surface 41 that is in contact with resin layer 61. In a section that is perpendicular to second surface 41, the average flattening ratio of fillers F2 that are in contact with second surface 41 is larger than the average flattening ratio of fillers F1, F3 that are not in contact with second surface 41. Here, the flattening ratio is a ratio of the maximum length of the filler in a direction parallel to second surface 41 to the maximum thickness of the filler in a direction perpendicular to second surface 41.

## Claims

### Claim 1

An assembly of stacked elements comprising:
a first element having a first surface;
a resin layer that is arranged on the first surface and that contains a plurality of fillers; and
a second element that is arranged on the resin layer and that has a second surface that is in contact with the resin layer,
wherein, in a section that is perpendicular to the second surface, an average flattening ratio of the fillers that are in contact with the second surface is larger than an average flattening ratio of the fillers that are not in contact with the second surface, wherein the flattening ratio is a ratio of a maximum length of the filler in a direction parallel to the second surface to a maximum thickness of the filler in a direction perpendicular to the second surface.

### Claim 2 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface is in surface contact with the second surface.

### Claim 3 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface has the maximum length on the second surface.

### Claim 4 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface extends flatly along the second surface.

### Claim 5 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface has a whisker that extends on the second surface at an end of the filler.

### Claim 6 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface has a notch at an end of the filler.

### Claim 7 (depends on 1)

The assembly of stacked elements according to claim 1, wherein at least one of the fillers that are in contact with the second surface forms a cavity between the second surface and the filler.

### Claim 8 (depends on 1)

The assembly of stacked elements according to claim 1, wherein a surface of the resin layer that is in contact with the second surface is ground.

### Claim 9 (depends on 1)

A sensor package comprising the assembly of stacked elements according to claim 1, wherein the first element is a sensor unit, the second element is a conductive layer,
further comprising an extraction electrode that connects the sensor unit to the conductive layer, wherein the extraction electrode and the resin layer are provided between the sensor unit and the conductive layer.

### Claim 10 (depends on 9)

The sensor package according to claim 9, wherein more than one of the extraction electrodes are connected to the sensor unit, and more than one of the conductive layers are connected to the extraction electrodes, respectively,
further comprising external connection terminals that are connected to the conductive layers, respectively, and a minimum rectangle that envelops the external connection terminals envelops the sensor unit, as seen in a direction perpendicular to the second surface.

### Claim 11

A method of manufacturing an assembly of stacked elements comprising:
a first element forming step to form a first element having a first surface;
a resin layer forming step to form a resin layer on the first surface, wherein the resin layer contains a plurality of fillers;
a grinding step to grind an upper surface of the resin layer; and
a second element forming step to form a second element on the upper surface of the resin layer that has been ground, wherein the second element has a second surface that is in contact with the upper surface,
wherein, before the grinding step and after the resin layer forming step, a diameter of at least one of the fillers that are contained in the resin layer is larger than a gap between the first surface and the second surface.

### Claim 12 (depends on 11)

The method according to claim 11, wherein some of the fillers that are contained between the upper surface of the resin layer that is present before the grinding step and the upper surface of the resin layer that is present after the grinding step are entirely or partially removed in the grinding step.

### Claim 13 (depends on 11)

The method according to claim 11, wherein the filler that is exposed on the upper surface of the resin layer after the grinding step is made flat on the upper surface.

### Claim 14 (depends on 11)

The method according to claim 11, wherein the grinding step is carried out by mechanical grinding.

### Claim 15 (depends on 11)

The method according to claim 11, wherein a maximum diameter of the fillers is equal to or more than 50 μm.

### Claim 16 (depends on 11)

A method of manufacturing a sensor package comprising the method according to claim 11, wherein
in the first element forming step, a sensor unit is formed as the first element, wherein the sensor unit has an extraction electrode formed on an upper surface thereof;
in the resin layer forming step, the sensor unit and the extraction electrode are sealed with the resin layer;
in the grinding step, the resin layer and the extraction electrode are ground until a thickness of the extraction electrode is reduced to less than a maximum thickness of the fillers;
in the second element forming step, a conductive layer is formed as the second element, wherein the conductive layer is connected to the extraction electrode; and
after the second element forming step, an external connection terminal is formed on the conductive layer.