KR101505906B1 - Wafer level packaging method of electronic device and wafer level package - Google Patents

Abstract

A wafer level packaging method of an electronic device according to an embodiment of the present invention includes the steps of forming an adhesive layer on a front surface of a wafer including an electronic device layer having an electronic device formed therein and a pad for connecting the electronic device to the outside, Forming a through hole at a position corresponding to the pad of the glass substrate, aligning the wafer and the photosensitive glass substrate such that the through hole is positioned on the pad, and bonding the adhesive layer and the photosensitive glass substrate And removing the adhesive layer corresponding to the lower portion of the through hole and filling the through hole with a metal material to form a through electrode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a wafer level packaging method for an electronic device,

The present invention relates to a wafer level packaging method of an electronic device and a wafer level package.

As technology advances, various electronic devices are integrated on a chip of a wafer. BACKGROUND OF THE INVENTION [0002] A backside illumination (BSI) image sensor of an electronic device is an electronic device that increases the amount of received light per unit area of a pixel by receiving light to the back side of the wafer.

The chip alone can not receive electrical signals from the outside or transmit electrical signals to the outside. In addition, since the electronic components of the chip are made of fine electronic circuits, they can be easily damaged by an external impact. Therefore, it is necessary to establish a physical function and shape by electrically connecting the chip to the chip and sealing it to withstand the external impact, which is called a semiconductor packaging process.

Wire bonding may be used for electrical connection between electronic elements of a chip and an external device such as a PCB (Printed Circuit Board) substrate. However, in this case, the size of the package increases, There is a problem that the cost is increased due to the packaging process.

KR 1020110072517 A

SUMMARY OF THE INVENTION The present invention is directed to a wafer level packaging method for electronic devices and a wafer level package.

A wafer level packaging method of an electronic device according to an embodiment of the present invention includes the steps of forming an adhesive layer on a front surface of a wafer including an electronic device layer having an electronic device formed therein and a pad for connecting the electronic device to the outside, Forming a through hole at a position corresponding to the pad of the glass substrate, aligning the wafer and the photosensitive glass substrate such that the through hole is positioned on the pad, and bonding the adhesive layer and the photosensitive glass substrate And removing the adhesive layer corresponding to the lower portion of the through hole and filling the through hole with a metal material to form a through electrode.

The electronic device is a photoelectric conversion unit, and the wafer level packaging method of the electronic device may further include removing a rear portion of the wafer.

The wafer-level packaging method of the electronic device may further include forming a color filter and microlens on a rear surface of the wafer from which the rear portion is removed.

The photosensitive glass substrate may include a photosensitive glass in a glass state or in a crystalline state.

The adhesive layer may be an ultraviolet resin.

The adhesive layer may be a baked frit glass paste.

The adhesive layer may be a photoresist (PR) or an adhesive film.

The metallic material may be molten metal.

The melting temperature of the molten metal may be at least 250 degrees Celsius and not more than 400 degrees Celsius.

The step of forming the penetrating electrode may include an electroplating step.

The wafer level packaging method of the electronic device may further include forming an external connection terminal connected to the penetrating electrode.

The wafer and the photosensitive glass substrate each include an alignment key and the wafer and the photosensitive glass substrate are aligned so that the through hole is positioned on the pad, and the adhesive layer and the photosensitive glass substrate are combined May include aligning the wafer and the photosensitive glass substrate using the alignment key.

Wherein the adhesive layer is a posi-type photoresist, the photosensitive glass substrate is in a crystalline state, removing the adhesive layer corresponding to the lower portion of the through hole, and filling the through hole with a metal material to form the penetrating electrode, The step of irradiating light onto the photosensitive glass substrate, and the step of dissolving the adhesive layer corresponding to the lower portion of the through hole with a developer and removing the adhesive layer by washing.

A wafer level package according to another embodiment of the present invention includes a wafer including an electronic element layer having an electronic element formed therein and a pad for connecting the electronic element to the outside, an adhesive layer bonded to the front surface of the wafer, And a penetrating electrode which penetrates the adhesive layer and the photosensitive glass substrate and is in contact with the pad. The photosensitive glass substrate and the wafer may be aligned such that the penetrating electrode is positioned on top of the pad.

The wafer level package may further include an external connection terminal connected to the penetrating electrode.

The electronic device may be a photoelectric conversion unit.

The wafer level package may further include a color filter disposed on a rear surface of the wafer, and a microlens under the color filter.

The wafer level packaging method and the wafer level package of an electronic device according to the embodiment of the present invention have an effect of reducing the manufacturing cost and the size of the package by forming the through electrode by joining the substrate having the through holes to the wafer.

On the other hand, by using the photosensitive glass substrate, the through holes can be formed small, and the time and cost required for packaging can be reduced.

1 shows a wafer level package according to an embodiment of the present invention.
Fig. 2 shows a wafer level package when the electronic device of Fig. 1 is a photoelectric conversion portion. Fig.
FIGS. 3 to 11 are cross-sectional views sequentially illustrating a process of manufacturing the wafer-level package of FIG.
12 is a flowchart showing a wafer level packaging method of an electronic device according to embodiments of the present invention.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are only for the purpose of illustrating embodiments of the inventive concept, But may be embodied in many different forms and is not limited to the embodiments set forth herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. It should be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms disclosed, but includes all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are intended to distinguish one element from another, for example, without departing from the scope of the invention in accordance with the concepts of the present invention, the first element may be termed the second element, The second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity. When a layer is referred to as being "on" another layer or substrate, or when it is mentioned that a layer is bonded or bonded to another layer or substrate, it may be formed directly on another layer or substrate, May be intervening. Like numbers refer to like elements throughout the specification.

Terms such as top, bottom, top, bottom, front, rear, or top, bottom, etc. are used to distinguish relative positions in the components. For example, in the case of naming the upper part of the drawing as upper part and the lower part as lower part in the drawings for convenience, the upper part may be named lower part and the lower part may be named upper part without departing from the scope of right of the present invention .

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings.

1 shows a wafer level package according to an embodiment of the present invention.

Referring to FIG. 1, a wafer level package 100 may include a wafer 110, an adhesive layer 120, a photosensitive glass substrate 130, a penetrating electrode 140, and an external connection terminal 150. have.

The wafer 110 may be a semiconductor wafer before it is separated into dies. The wafer 110 may include an electronic device layer (not shown) having an electronic device formed therein, and may include a pad 111 for connecting the electronic device (not shown) to the outside. The electronic device (not shown) may be a photoelectric conversion unit, a memory, a central processing unit (CPU), a micro processing unit (MPU), a surface acoustic wave (SAW) In the following description, the face on which the pads 111 of the wafer 110 are arranged is defined as the front face, and the opposite face is defined as the rear face.

The adhesive layer 120 may be adhered to the entire surface of the wafer 110 and the photosensitive glass substrate 130 may be adhered to the entire surface of the adhesive layer 120. [ The wafer 110 and the photosensitive glass substrate 130 may be aligned and bonded so that the penetrating electrode 140 is positioned on the pad 111 of the wafer 110. [

The penetrating electrode 140 contacts the pad 111 through the adhesive layer 120 and the photosensitive glass substrate 130 so that a signal of an electronic element (not shown) in the wafer 110 is transferred from the pad 111 to the external connection terminal (150).

The external connection terminal 150 is connected to the penetrating electrode 140 to transmit a signal of an electronic device (not shown) to an external device such as a PCB (Printed Circuit Board) substrate. The external connection terminal 150 may be formed in various forms and may be formed of a conductive bump, a solder ball, an anisotropic conductive paste (ACP), an anisotropic conductive film (ACF) Non Conductive Paste (NCP), Non Conductive Film (NCF), or a combination thereof.

Fig. 2 shows a wafer level package when the electronic device of Fig. 1 is a photoelectric conversion portion. Fig.

2, the wafer level package 200 includes a wafer 210, an adhesive layer 220, a photosensitive glass substrate 230, a penetrating electrode 240 and an external connection terminal 250, and the color filter 260 And a microlens 270. The microlenses 270 may be formed of a transparent material such as glass or plastic. The structure of the adhesive layer 220, the photosensitive glass substrate 230, the penetrating electrode 240, and the external connection terminal 250 is the same as that shown in FIG. 1, and a detailed description thereof will be omitted.

The wafer 210 includes a pad 211, an interlayer insulating layer 213, and a photoelectric conversion portion 215. The interlayer insulating layer 213 may include a plurality of wiring layers (not shown) and an interlayer insulating film (not shown). The photoelectric conversion unit 215 may include a pixel array including a plurality of photodiodes.

The microlens 270 condenses the light irradiated to the rear surface of the wafer 210 and transmits the light to the color filter 260. The color filter 260 filters the received light and transmits it to the photoelectric conversion unit 215. The photoelectric conversion unit 215 converts the filtered light into an electric signal and transmits the converted electric signal through the wiring layer (not shown), the penetrating electrode 240 and the external connection terminal 250 in the interlayer insulating layer 213 Lt; / RTI >

According to another embodiment, the wafer level package 200 may be implemented without including the microlens 270 and the color filter 260, and the photoelectric conversion portion 215 may receive light directly from the outside.

FIGS. 3 to 11 are cross-sectional views sequentially illustrating a process of manufacturing the wafer-level package of FIG.

Referring to FIG. 3, the wafer 210 'before packaging includes a pad 211, an interlayer insulating layer 213, a photoelectric conversion portion 215, and a rear portion 217.

Referring to FIGS. 3 and 4, an adhesive layer 220 is formed on the entire surface of the wafer 210 '. The adhesive layer 220 may have a thickness greater than the height of the pad 211.

The adhesive layer 220 may be an ultraviolet curable adhesive, for example, an ultraviolet resin. According to the embodiment, only the bonding surface of the UV resin with the pad is cured and the other non-bonding surface is not cured. However, the scope of the present invention is not limited thereto, and other UV resin may be used.

If the adhesive layer 220 is formed on the entire surface of the wafer 210 'through high-temperature processing, the thermal expansion coefficients of the constituent materials of the wafer 210' and the adhesive layer 220 are different, Can be bent. The UV resin can be adhered to the wafer 210 'through ultraviolet irradiation at room temperature, so that there is no problem caused by thermal expansion.

According to another embodiment, the adhesive layer 220 may be formed by firing a frit glass paste (also referred to as a "glass frit paste"). According to another embodiment, the adhesive layer 220 may be an adhesive tape including a photoresist (PR), an epoxy resin adhesive, or the like, and the other interlayer insulating layer 13 may be an adhesive tape, The material to be bonded to the wafer 210 at a temperature not affecting the wafer 210. According to another embodiment, the adhesive layer 220 may be composed of a mixture of the above materials, and a separate layer may be formed in the middle of the adhesive layer 220.

Referring to FIG. 5, a through hole 231 is formed at a position corresponding to the pad 211 of the photosensitive glass substrate 230. A photosensitive glass is generally in a transparent glassy state, but it may become opaque due to a crystalline state formed therein by an exposure and a heat treatment process. The photosensitive glass substrate 230 may include a photosensitive glass in a glass state or in a crystalline state.

According to the embodiment, the region for forming the through-hole 231 in the glass-based photosensitive glass substrate 230 may be exposed and heat-treated to be crystallized, and then the crystal region may be removed to form the through-hole. An aqueous solution containing hydrogen fluoride (HF) can be used to remove the crystal region.

Referring to FIG. 6, the wafer 210 and the photosensitive glass substrate 230 are aligned such that the through-holes 231 of the photosensitive glass substrate 230 are positioned above the pads 211 of the wafer 210. For example, the wafer 210 and the photosensitive glass substrate 230 may each include an alignment key (not shown) at the rim portion, and the alignment can be performed using the alignment key.

Thereafter, the adhesive layer 220 and the photosensitive glass substrate 230 are bonded. The adhesive layer 220 and the photosensitive glass substrate 230 may be bonded to each other through ultraviolet irradiation, high temperature treatment, high pressure treatment, or the like. For example, when the adhesive layer 220 is a UV resin, ultraviolet light is irradiated at room temperature, and when the adhesive layer 220 is a frit glass paste, heat treatment is performed at a temperature of 400 ° C to 500 ° C to bond the adhesive layer 220 and the photosensitive glass substrate 230 ) Can be bonded.

Referring to FIGS. 3, 6 and 7A, the adhesive layer 221 corresponding to the lower portion of the through hole 231 is removed to expose the pad 211.

The method of exposing the pad 211 may vary. For example, when the adhesive layer 220 is a posi-type photoresist and the photosensitive glass substrate 230 is in a crystalline state, the photosensitive glass substrate 230 is irradiated with light. The positive type photoresist is a photosensitive resin in which a polymer is solubilized and the resist disappears only in a portion irradiated with light, and examples thereof include polymethyl methacrylate, naphthoquinone diazide, and polybutene-1-sulfone . At this time, the photosensitive glass substrate 230 functions as a photomask. That is, the photosensitive glass substrate 230 does not pass light but passes through the through hole 231 only. Therefore, only the adhesive layer 221 corresponding to the lower portion of the through hole 231 is exposed to light and becomes soluble, dissolved by the developer, and then removed through cleaning.

According to another embodiment, the adhesive layer 221 may be removed using plasma, solvent cleaning, acid etching, ultraviolet irradiation, or a laser.

For example, if the bonding layer 221 is cured only on the bonding surface with the pad, and the non-bonding surface on the opposite side is a UV resin that is not cured, it can be removed by cleaning. When the adhesive layer 221 is other UV resin or adhesive film, it may be dissolved in a solvent and removed by washing, or may be burned by applying a plasma. In the case where the adhesive layer 221 is a frit glass paste, since the glass is corroded by the acid, the acid can be added and etched.

A protective layer such as a SiO ₂ thin film may be formed on the entire surface of the wafer 210 'during the last element process before packaging. In this case, the SiO ₂ thin film is exposed to the top of the pad 211 by removing the adhesive layer 221, and the thin film is also removed with an aqueous solution containing hydrofluoric acid. Accordingly, when the through electrode is formed later, the pad 211 and the through electrode can be made conductive.

7A to 8, a penetrating electrode 240 is formed in a portion of the through hole 231. The penetrating electrode 240 may be formed, for example, according to the following procedure.

Referring to FIG. 7B, a metal seed layer 241 is formed on the entire surface of the through hole 231 and the photosensitive glass substrate 230 of FIG. 7A. It is difficult to directly attach a metal material to the photosensitive glass. Therefore, the metal seed layer 241 is used to fill the metal material in the through hole 231 without voids. The metal seed layer 241 may be, for example, nickel.

The metal seed layer 241 may be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD).

The physical vapor deposition method is a method of coating a gasified substance in a vacuum on a basic surface, and is divided into a vacuum deposition method and a sputtering method. Vacuum deposition is a method of heating a metal under high vacuum and attaching evaporated metal particles to a substrate to form a thin film. Sputtering refers to a process in which a thin film is formed on an object surface by using a phenomenon that an atom or molecule constituting the material protrudes and adheres to an object surface around the material when an ion impact is applied to the material.

The chemical vapor deposition method is a method in which a raw material gas is flowed on a substrate to be coated in the manufacturing process, external energy is applied to form a thin film by chemical coupling, decomposition of a raw material gas, or the like.

7B and 7C, the metal material 243 is filled in the through hole 231 in which the metal seed layer 241 is formed.

According to one embodiment, the metal material 243 may be a molten metal. The penetrating electrode 240 can be formed by filling the molten metal in the through hole 231 and solidifying it. The melting temperature of the molten metal may be 250 degrees Celsius or more, so that the penetrating electrode 240 is not affected by other processes. When the wiring layer (not shown) in the interlayer insulating layer 213 and the external device (e.g., the PCB substrate) are made of aluminum, the melting temperature of the molten metal may be 400 DEG C or less because the molten metal does not affect aluminum . For example, by using an eutectic alloy as the metal material 243, a low melting temperature can be obtained.

According to another embodiment, the metal material 243 may be filled in the through hole 231 by electroplating.

According to another embodiment, the metal material 243 may be silver electrical conductive pastes or solder paste. The metal material 243 may be filled in the through holes 231 and heat- Can be formed.

According to another embodiment, the through hole 231 can be filled by sputtering without separately filling the metal material 243.

7C and 8, after the metal material 243 is filled in the through hole 231, the entire surface of the photosensitive glass substrate 230 may be polished and planarized. Accordingly, the penetrating electrode 240 can be formed by removing the metal seed layer and the metal material portion 245 formed outside the through hole 231. At this time, the penetrating electrode 240 may be composed of the metal seed layer 241 and the metal material 243. For convenience of explanation, the metal seed layer 241 and the metal material 243 are not shown in the following drawings, but are simply represented by the penetrating electrode 240. [

Although the method for forming the penetrating electrode 240 has been described above, the scope of the present invention is not limited thereto, and the penetrating electrode 240 may be formed by various methods.

Referring to FIGS. 8 and 9, the rear portion 217 of the wafer 210 'is removed. The back surface 217 may be removed by polishing, for example, a chemical mechanical polishing (CMP) process.

Referring to FIG. 10, a color filter 260 is formed on the rear surface of the wafer 210 from which the rear portion 217 is removed. The color filter 260 may be disposed corresponding to each of red, blue, and green pixels (not shown) of a pixel array (not shown) in the photoelectric conversion unit 215.

Referring to FIG. 11, a microlens 270 is formed under the color filter 260.

Then, the penetrating electrode 240 and an external connection terminal 250 connected between an external device such as a PCB substrate may be formed.

According to the above-described embodiments, the present invention can reduce the manufacturing cost and the size of the package by connecting the substrate on which the through-holes are formed and the through electrodes, without connecting the pads on the wafer and the external device by wire bonding It is effective.

On the other hand, assuming that a through hole is formed in a silicon substrate, since silicon is a semiconductor, silicon should be insulated. Since the through holes must be formed individually using a laser, it takes a lot of time and expensive process equipment should be used.

The present invention can form a small through-hole by using a photosensitive glass substrate and removing an aqueous solution containing hydrogen fluoride (HF) after crystallizing the region where the through hole is to be formed. In addition, since the through holes can be formed at one time and no separate insulating treatment is required, the time and cost required for packaging can be reduced.

12 is a flowchart showing a wafer level packaging method of an electronic device according to embodiments of the present invention.

1 and 12, an adhesive layer 120 is formed on a front surface of a wafer 110 including an electronic device (not shown) and a pad 111 (S301).

A through hole is formed at a position corresponding to the pad 111 of the photosensitive glass substrate 130 (S303).

The wafer 110 and the photosensitive glass substrate 130 are aligned so that the through holes are positioned above the pads 111 and the adhesive layer 120 and the photosensitive glass substrate 130 are bonded to each other at step S305.

The adhesive layer corresponding to the lower portion of the through hole is removed, and the penetrating electrode 140 is formed by filling the through hole with a metal material (S307).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

100, 200: wafer level package 110, 210, 210 ': wafer
111, 211: pads 120, 220: adhesive layer
130, 230: photosensitive glass substrate 140, 240: penetrating electrode
150, 250: external connection terminal 213: interlayer insulating layer
215: photoelectric conversion unit 217: rear side
260: Color filter 270: Micro lens

Claims (17)

Forming an adhesive layer on a front surface of a semiconductor wafer including an electronic element layer in which an electronic element is formed and a pad for connecting the electronic element to the outside;
Forming a through hole at a position corresponding to the pad of the photosensitive glass substrate;
Aligning the wafer and the photosensitive glass substrate such that the through hole is positioned on the pad, and bonding the adhesive layer and the photosensitive glass substrate;
Removing the adhesive layer corresponding to the lower portion of the through hole and exposing the pad; And
And filling the through hole with a metal material to form a penetrating electrode. The electronic device according to claim 1, wherein the electronic device
And a photoelectric conversion unit,
The wafer-level packaging method of the electronic device
And removing the backside portion of the wafer after forming the penetrating electrode. The method of claim 2, wherein the wafer level packaging method of the electronic device
Further comprising forming color filters and microlens on the backside of the wafer from which the backside has been removed. The method of claim 1, wherein the photosensitive glass substrate
A method of packaging wafer level packaging of an electronic device comprising a glassy or crystalline state photosensitive glass. The method according to claim 1, wherein the adhesive layer
Method for wafer level packaging of electronic devices, which is an ultra violet resin. The method according to claim 1, wherein the adhesive layer
A method for wafer level packaging of electronic devices that is a fritted glass paste. The method according to claim 1, wherein the adhesive layer
A method of wafer level packaging of an electronic device that is a photoresist (PR) or an adhesive film. The method of claim 1, wherein the metal material
A method for wafer level packaging of electronic devices that are molten metals. The method according to claim 8, wherein the melting temperature of the molten metal is
A method of packaging a wafer level of an electronic device having a temperature of at least 250 degrees Celsius and not more than 400 degrees Celsius. The method of claim 1, wherein forming the penetrating electrode comprises:
A method of packaging a wafer level of an electronic device comprising an electroplating step. The method of claim 1, wherein the wafer level packaging method of the electronic device
And forming an external connection terminal connected to the penetrating electrode. The method of claim 1, wherein each of the wafer and the photosensitive glass substrate
Includes an alignment key,
Aligning the wafer and the photosensitive glass substrate such that the through hole is located on the pad, and bonding the adhesive layer and the photosensitive glass substrate
And aligning the wafer and the photosensitive glass substrate using the alignment key. The method according to claim 1, wherein the adhesive layer
A posi-type photoresist,
The photosensitive glass substrate
Crystalline state,
The step of removing the adhesive layer corresponding to the lower portion of the through hole and filling the through hole with the metal material to form the penetrating electrode
Irradiating the photosensitive glass substrate with light; And
Further comprising the step of dissolving the adhesive layer corresponding to the lower portion of the through hole with a developing solution and then removing the adhesive layer through cleaning. delete delete delete delete

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