阅读说明：本技术 光电传感器及其制备方法 (Photoelectric sensor and preparation method thereof ) 是由 孙塔 李碧洲 于 2021-08-31 设计创作，主要内容包括：本发明涉及一种光电传感器及其制备方法。所述光电传感器,包括：电路转接板、感光芯片、导电粘合剂与发光件；感光芯片位于电路转接板上；其中感光芯片形成有感光区与非感光区；感光芯片包括第一衬底、第一焊盘与导电凸点,第一衬底位于电路转接板上,第一焊盘位于第一衬底背向电路转接板的一侧,导电凸点位于第一焊盘背向第一衬底的一侧；第一焊盘与导电凸点位于非感光区；导电粘合剂位于第一焊盘背向第一衬底的一侧,且包覆导电凸点；发光件位于导电粘合剂上,且位于导电粘合剂背向第一焊盘的一侧,发光件通过导电粘合剂、导电凸点、第一焊盘与感光芯片电连接。根据本发明的实施例,减小光电传感器的尺寸。(The invention relates to a photoelectric sensor and a preparation method thereof. The photoelectric sensor includes: the circuit comprises a circuit adapter plate, a photosensitive chip, a conductive adhesive and a light-emitting piece; the photosensitive chip is positioned on the circuit adapter plate; wherein the photosensitive chip is formed with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are positioned in the non-photosensitive area; the conductive adhesive is positioned on one side of the first bonding pad, which is opposite to the first substrate, and covers the conductive bump; the light-emitting piece is positioned on the conductive adhesive and positioned on one side of the conductive adhesive back to the first bonding pad, and the light-emitting piece is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad. According to the embodiment of the present invention, the size of the photosensor is reduced.)

1. A photosensor, comprising:

a circuit adapter plate;

the photosensitive chip is positioned on the circuit adapter plate; the photosensitive chip is provided with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are positioned in the non-photosensitive area;

the conductive adhesive is positioned on one side, back to the first substrate, of the first bonding pad and covers the conductive bump;

and the light-emitting piece is positioned on the conductive adhesive and positioned on one side of the conductive adhesive, which is back to the first bonding pad, and the light-emitting piece is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad.

2. The photosensor of claim 1, wherein the conductive bump is a metal bump.

3. The photosensor of claim 2, wherein the conductive bump is gold.

4. The sensor of claim 2, wherein the conductive bump comprises a bump structure and a plating layer, the plating layer covers the bump structure, the bump structure is made of copper, and the plating layer is made of gold.

5. The photosensor of any of claims 1-4, wherein the conductive adhesive is a silver paste comprising a liquid adhesive and silver particles.

6. The photosensor of claim 1, wherein the material of the first pad is aluminum or gold or copper.

7. The photosensor of claim 1, wherein the light emitter comprises a second substrate and a first electrode, the first electrode being located between the conductive adhesive and the second substrate;

the material of the second substrate is gallium arsenide.

8. The photoelectric sensor of claim 1, further comprising a transparent encapsulation layer, wherein the transparent encapsulation layer is located on the circuit interposer and wraps the photosensitive chip, the conductive adhesive and the light emitting element.

9. A method for manufacturing a photoelectric sensor, comprising:

placing a photosensitive chip on the circuit adapter plate; the photosensitive chip is provided with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are positioned in the non-photosensitive area;

dripping semi-liquid conductive adhesive on the first bonding pad, wherein the semi-liquid conductive adhesive is positioned on one side, opposite to the first substrate, of the first bonding pad and submerges the conductive bump;

and placing the light-emitting piece on a semi-liquid conductive adhesive, curing the conductive adhesive, coating the conductive bump with the cured conductive adhesive, wherein the light-emitting piece is positioned on one side of the conductive adhesive, which is back to the first bonding pad, and is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad.

10. The method of claim 9, wherein after the disposing the light emitting element on the semi-liquid conductive adhesive and curing the conductive adhesive, further comprising:

and forming a transparent packaging layer, wherein the transparent packaging layer is positioned on the circuit adapter plate and wraps the photosensitive chip, the conductive adhesive and the light-emitting piece.

Technical Field

The application relates to the technical field of sensors, in particular to a photoelectric sensor and a preparation method thereof.

Background

In the related art, the photoelectric sensor includes a circuit adapter plate, a light-emitting chip and a photosensitive chip, wherein the light-emitting chip and the photosensitive chip are respectively located on the circuit adapter plate, and a certain distance exists between the light-emitting chip and the photosensitive chip. The photoelectric sensor of this structure is limited in product size reduction and cannot meet the demand for miniaturization.

Disclosure of Invention

The invention provides a photoelectric sensor and a preparation method thereof, which aim to solve the defects in the related art.

According to a first aspect of embodiments of the present invention, there is provided a photosensor including:

a circuit adapter plate;

the photosensitive chip is positioned on the circuit adapter plate; the photosensitive chip is provided with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are positioned in the non-photosensitive area;

the conductive adhesive is positioned on one side, back to the first substrate, of the first bonding pad and covers the conductive bump;

and the light-emitting piece is positioned on the conductive adhesive and positioned on one side of the conductive adhesive, which is back to the first bonding pad, and the light-emitting piece is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad.

In one embodiment, the conductive bump is a metal bump.

In one embodiment, the material of the conductive bump is gold.

In one embodiment, the conductive bump includes a bump structure and a plating layer, the plating layer covers the bump structure, the bump structure is made of copper, and the plating layer is made of gold.

In one embodiment, the conductive adhesive is a silver paste including a liquid adhesive and silver particles.

In one embodiment, the material of the first bonding pad is aluminum or gold or copper.

In one embodiment, the light emitting member includes a second substrate and a first electrode between the conductive adhesive and the second substrate;

the material of the second substrate is gallium arsenide.

In one embodiment, the photoelectric sensor further comprises a transparent packaging layer, wherein the transparent packaging layer is located on the circuit adapter plate and wraps the photosensitive chip, the conductive adhesive and the light emitting piece.

According to a second aspect of the embodiments of the present invention, there is provided a method for manufacturing a photosensor, including:

placing a photosensitive chip on the circuit adapter plate; the photosensitive chip is provided with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are positioned in the non-photosensitive area;

dripping semi-liquid conductive adhesive on the first bonding pad, wherein the semi-liquid conductive adhesive is positioned on one side, opposite to the first substrate, of the first bonding pad and submerges the conductive bump;

and placing the light-emitting piece on a semi-liquid conductive adhesive, curing the conductive adhesive, coating the conductive bump with the cured conductive adhesive, wherein the light-emitting piece is positioned on one side of the conductive adhesive, which is back to the first bonding pad, and is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad.

In one embodiment, after the disposing the light emitting member on the semi-liquid conductive adhesive and curing the conductive adhesive, the method further includes:

and forming a transparent packaging layer, wherein the transparent packaging layer is positioned on the circuit adapter plate and wraps the photosensitive chip, the conductive adhesive and the light-emitting piece.

According to the above embodiments, the size of the photosensor can be reduced by stacking the light emitting member on the non-photosensitive region of the photosensitive chip. The photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate, the first bonding pad and the conductive bump are positioned in the non-photosensitive area, the conductive adhesive is positioned on one side of the first bonding pad, which is back to the first substrate, and wraps the conductive bump, the luminescent part is positioned on the conductive adhesive and is positioned on one side of the conductive adhesive, which is back to the first bonding pad, and the luminescent part is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad. The photoelectric sensor can be packaged by adopting an injection molding packaging process, and has high reliability and good conductivity. Moreover, the conductive bump is prepared without high-temperature equipment, and mass production can be realized by adopting equipment of a common bonding wire process.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic diagram of a photosensor according to an embodiment of the present invention;

FIG. 2 is a flow chart illustrating a method of fabricating a photosensor according to an embodiment of the present invention;

FIGS. 3-5 are schematic structural diagrams of intermediate transition structures generated during the fabrication of a photosensor according to embodiments of the present invention.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

Fig. 1 is a diagram illustrating a photosensor according to an embodiment of the present invention. As shown in fig. 1, the photosensor includes: the circuit board comprises a circuit adapter plate 11, a photosensitive chip 12, a conductive adhesive 13, a light emitting piece 14 and a transparent packaging layer 15.

In the present embodiment, the circuit interposer 11 is a PCB (printed circuit board).

In the present embodiment, as shown in fig. 1, the photosensitive chip 12 is located on the circuit interposer 11. The photosensitive chip 12 is formed with a photosensitive area a and a non-photosensitive area B. The photo sensor chip 12 includes a first substrate 121, a first circuit (not shown), a first bonding pad 122 and a conductive bump 123, wherein the first substrate 121 is disposed on the circuit board 11, and the first substrate 121 may be disposed in a photo-sensing area a and a non-photo-sensing area B. The first pads 122 are located on a side of the first substrate 121 opposite to the circuit interposer 11 and connected to the first circuit, and the conductive bumps 123 are located on a side of the first pads 122 opposite to the first substrate 121. The first pads 122 and the conductive bumps 123 are located in the non-photosensitive region B.

In the present embodiment, the material of the first pad 122 is aluminum. Of course, the material of the first pad 122 may also be an aluminum-copper alloy, in which aluminum accounts for 95%, copper accounts for 3%, and the rest is 2%. The material of the first pad 122 may also be gold or copper or other metals.

In the present embodiment, the conductive bump 123 is a metal bump. The metal bumps have good conductivity, which is beneficial to improving the conductivity of the light-emitting element 14 and the light-sensing chip 12.

In this embodiment, the material of the conductive bump is gold. Since gold has a relatively good conductivity, it is beneficial to improve the conductivity of the light emitting element 14 and the light sensing chip 12. In other embodiments, the conductive bump may include a bump structure and a plating layer, the plating layer covers the bump structure, the material of the bump structure is copper, and the material of the plating layer is gold.

In the present embodiment, the conductive adhesive 13 is located on a side of the first pad 122 opposite to the first substrate 121, and covers the conductive bump 123. The conductive adhesive 13 may be an epoxy conductive adhesive, but is not limited thereto.

In the present embodiment, the conductive adhesive 13 is a cured silver paste. The silver paste comprises a liquid adhesive and silver particles. Because the adhesive force between the silver paste and the conductive salient points made of gold is larger, the stress of the plastic package body caused by expansion with heat and contraction with cold can be resisted, and therefore the photoelectric sensor can be packaged by adopting an injection molding packaging process, and the photoelectric sensor is high in reliability and good in conductivity. Moreover, the conductive bumps can be produced in mass production by adopting equipment of a common bonding wire process without using high-temperature equipment, and the method is particularly simple to apply to the most ubiquitous bonding wire process production line and does not need a wafer-level ball-planting process.

It should be noted that, in the technical field, a technical solution for adhering two chips by using silver paste and conductive bumps has not yet appeared. Because the direct bonding force between the silver paste and the aluminum pad hardly meets the reliability requirement above MSL3, the technical scheme for bonding the two chips by matching the silver paste with the conductive bumps provided by the embodiment of the invention is the first technical scheme provided in the field.

In the present embodiment, the light emitting element 14 is located in the non-photosensitive region of the photosensitive chip 12, and the light emitting element 14 is located on the conductive adhesive 13 and located on a side of the conductive adhesive 13 opposite to the first pad 122. By stacking the light emitting member on the non-photosensitive region of the photosensitive chip, the size of the photosensor can be reduced.

In the present embodiment, the light emitting member 14 may be a light emitting chip. The light emitting element 14 includes a second substrate, a second circuit, a first electrode and a second electrode, the first electrode is located between the conductive adhesive 13 and the second substrate, the second circuit is located on the second substrate, the second electrode is located on a side of the second substrate facing away from the conductive adhesive 13, and the first electrode and the second electrode are respectively connected to the second circuit. Wherein the material of the second substrate is gallium arsenide. The material of the second electrode may be gold, but is not limited thereto. The first electrode is positioned on the conductive adhesive 13 and is in contact with the conductive adhesive 13 to achieve electrical connection.

In the present embodiment, the light emitting member 14 is electrically connected to the photosensitive chip 12 through the conductive adhesive 13, the conductive bump 123, and the first pad 122.

In the present embodiment, the transparent encapsulation layer 15 is located on the circuit interposer 11 and wraps the photo sensor chip 12, the conductive adhesive 13 and the light emitting element 14.

In this embodiment, the transparent encapsulating layer 15 may be obtained by an injection molding encapsulating process, and the material of the transparent encapsulating layer 15 may be, for example, epoxy resin, which may allow light to transmit therethrough. The material of the transparent encapsulating layer 15 may be doped with a specific element so that the optical signal for device operation can be transmitted through the transparent encapsulating layer 15 and other optical signals cannot be transmitted.

Moreover, since the material of the first pad 122 is aluminum and aluminum is not well adhered to the silver paste, the aluminum is better adhered to the conductive bump 123 by ultrasonic welding, and the adhesion force of the silver paste to the conductive bump is higher. Therefore, the silver paste is used to electrically connect the first pad 122, the conductive bump 123 and the light emitting element 14, so as to improve the reliability of the electrical connection between the light emitting element 14 and the light sensing chip 12.

In the embodiment of the invention, the light-emitting part is stacked on the non-photosensitive area on the photosensitive chip, so that the size of the photoelectric sensor can be reduced. The photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate, the first bonding pad and the conductive bump are positioned in the non-photosensitive area, the conductive adhesive is positioned on one side of the first bonding pad, which is back to the first substrate, and wraps the conductive bump, the luminescent part is positioned on the conductive adhesive and is positioned on one side of the conductive adhesive, which is back to the first bonding pad, and the luminescent part is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad. The photoelectric sensor can be packaged by adopting an injection molding packaging process, and has high reliability and good conductivity. Moreover, the conductive bump is prepared without high-temperature equipment, and mass production can be realized by adopting equipment of a common bonding wire process.

The technical scheme provided by the embodiment of the invention can realize good electrical conduction, the injection molding packaging reliability can reach the international industrial standard, and stable mass injection molding production and application can be realized. Moreover, mass production can be realized on a common bonding wire packaging production line.

In addition, the technical scheme of bonding the two chips by using the silver paste provided by the embodiment of the invention is not only suitable for minimizing the packaging size of the photoelectric sensor by adopting an injection molding packaging process, and meets the requirement of market miniaturization application development, but also suitable for an injection molding packaging process and a non-injection molding packaging process of non-photoelectric sensor products. For example, of the two stacked chips, the chip located above may also be a Vertical Cavity Surface Emitting Laser (VCSEL) die having a back electrode or a MOSFET die having a back electrode.

The embodiment of the invention also provides a preparation method of the photoelectric sensor, which is used for preparing the photoelectric sensor of any one of the embodiments. As shown in fig. 2, the method for manufacturing the photoelectric sensor may include the following steps 201 to 204:

in step 201, a photosensitive chip is placed on a circuit adapter plate; wherein, the photosensitive chip is provided with a photosensitive area and a non-photosensitive area; the photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, wherein the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, and the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate; the first bonding pad and the conductive bump are located in the non-photosensitive area.

In this embodiment, before the photosensitive chip is placed on the circuit interposer, the conductive bumps are first prepared on the first pads of the photosensitive chip. Wherein, the conductive bump is a metal bump. When the conductive bump is made of gold, a gold bonding wire can be used, and when the conductive bump is made of alloy, an alloy bonding wire can be used.

In this embodiment, after the conductive bumps are prepared on the first pads of the photo-sensing chip, the photo-sensing chip is placed on the circuit interposer. The first bonding pad is positioned on one side of the first substrate, which faces away from the circuit adapter plate.

In this embodiment, after step 201, an intermediate transition structure as shown in fig. 3 can be obtained.

In step 202, a semi-liquid conductive adhesive is dripped on the first bonding pad, wherein the semi-liquid conductive adhesive is positioned on the side, opposite to the first substrate, of the first bonding pad, and the conductive bump is immersed.

In this embodiment, a semi-liquid conductive adhesive may be dropped on the first pad by a dropping process, and the semi-liquid conductive adhesive may immerse the conductive bump. Of course, other processes may be used to drop a semi-liquid conductive adhesive on the first pad.

In this embodiment, the semi-liquid conductive adhesive may be silver paste.

In this embodiment, after step 202, an intermediate transition structure as shown in fig. 4 may be obtained. In fig. 4, the semi-liquid conductive adhesive 13' submerges the conductive bump 123.

In step 203, the light emitting element is placed on the semi-liquid conductive adhesive, the conductive adhesive is cured, the cured conductive adhesive covers the conductive bump, the light emitting element is located on the side of the conductive adhesive opposite to the first pad, and the light emitting element is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first pad.

In this embodiment, after the light emitting element is placed on the semi-liquid conductive adhesive, the light emitting element is pressed to be flat and compact to force out the air bubbles, so as to improve the conductive connection performance between the conductive adhesive and the conductive bumps, and then the conductive adhesive is cured to coat the conductive bumps with the cured conductive adhesive, so that the light emitting element is effectively and firmly connected with the photosensitive chip through the conductive adhesive, the conductive bumps and the first bonding pad.

In this embodiment, after step 203, an intermediate transition structure as shown in fig. 5 can be obtained.

In step 204, a transparent encapsulation layer is formed, and the transparent encapsulation layer is located on the circuit interposer and wraps the light-sensing chip, the conductive adhesive and the light-emitting element.

In this embodiment, an injection molding packaging process is used to form a transparent packaging layer on the circuit interposer, so that the transparent packaging layer encapsulates the photosensitive chip, the conductive adhesive and the light emitting element.

In this embodiment, after step 204, a photosensor as shown in fig. 1 can be obtained.

In this embodiment, the size of the photosensor can be reduced by stacking the light emitting member on the non-photosensitive region of the photosensitive chip. The photosensitive chip comprises a first substrate, a first bonding pad and a conductive bump, the first substrate is positioned on the circuit adapter plate, the first bonding pad is positioned on one side of the first substrate, which is back to the circuit adapter plate, the conductive bump is positioned on one side of the first bonding pad, which is back to the first substrate, the first bonding pad and the conductive bump are positioned in the non-photosensitive area, the conductive adhesive is positioned on one side of the first bonding pad, which is back to the first substrate, and wraps the conductive bump, the luminescent part is positioned on the conductive adhesive and is positioned on one side of the conductive adhesive, which is back to the first bonding pad, and the luminescent part is electrically connected with the photosensitive chip through the conductive adhesive, the conductive bump and the first bonding pad. The photoelectric sensor can be packaged by adopting an injection molding packaging process, and has high reliability and good conductivity. Moreover, the conductive bump is prepared without high-temperature equipment, and mass production can be realized by adopting equipment of a common bonding wire process.

It is noted that in the drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. Also, it will be understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element or layer or intervening layers may also be present. In addition, it will be understood that when an element or layer is referred to as being "under" another element or layer, it can be directly under the other element or intervening layers or elements may also be present. In addition, it will also be understood that when a layer or element is referred to as being "between" two layers or elements, it can be the only layer between the two layers or elements, or more than one intermediate layer or element may also be present. Like reference numerals refer to like elements throughout.

In the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" means two or more unless expressly limited otherwise.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.