CN101850942B - Micro-Electro-Mechanical System Package Structure - Google Patents

Abstract

The invention discloses a micro electro mechanical system packaging structure which comprises a chip, a cover body, a substrate, a plurality of wires, a sealing colloid and a moisture-resistant material layer. The chip is provided with an active area, and the chip is provided with at least one micro-electromechanical element in the active area. The cover body covers the chip, and the substrate is used for bearing the chip and the cover body. The plurality of wires are electrically connected between the substrate and the chip, and the sealing colloid is sealed around the cover body and exposes the upper surface of the cover body. The moisture-resistant material layer covers the sealing colloid to improve the sealing property and the moisture resistance of the sealing colloid.

Description

Micro-Electro-Mechanical System Package Structure

【Technical field】

The present invention relates to a chip packaging structure, and in particular to a micro-electromechanical system packaging structure.

【Background technique】

Micro-Electro-Mechanical Systems (MEMS) are tiny electro-mechanical components manufactured in miniaturized packages. The manufacturing technology is very similar to the technology of manufacturing integrated circuits, but MEMS devices interact with their surroundings in more ways than traditional Integrated circuits, such as mechanical, optical or magnetic interactions.

MEMS devices can include extremely small electromechanical components (such as switches, mirrors, capacitors, accelerometers, inductors, capacitive sensors or actuators, etc.), and MEMS devices can be integrated with integrated circuits in a monolithic manner, while greatly improving Insertion loss and electrical isolation of the entire solid-state device. However, MEMS devices are extremely fragile in the macroscopic world of the entire packaging structure, and may be affected by tiny static electricity or surface tension at any time to cause failure. Therefore, in order to prevent the MEMS device from being polluted or damaged, its MEMS components are usually sealed in a cavity between the wafer and the cover plate.

FIG. 1 is a schematic diagram of a conventional MEMS packaging structure. Referring to FIG. 1 , the cover plate 110 is fixed on the wafer 100 by the glue frame 112 , so that the MEMS element 104 is sealed in a cavity 106 between the wafer 100 and the cover plate 110 . Next, the wafer 100 and the cover plate 110 are cut into individual units, so that the MEMS elements 104 are sealed in each independent MEMS structure. Since the MEMS element 104 is protected in the cavity 106 , it is ensured that the MEMS element 104 can operate normally. Next, each MEMS structure is sealed with an encapsulant (not shown in the figure) to complete the micro-electro-mechanical system packaging structure.

However, conventionally, when an organic polymer compound is used as the plastic frame 112 or the sealing body, the moisture cannot be completely isolated. Over a long period of time, the sealability of the plastic frame 112 or the sealing body becomes poor, thereby affecting the normal operation of the MEMS element 104 .

Therefore, it is necessary to provide a MEMS packaging structure to solve the problems existing in the prior art.

【Content of invention】

The main purpose of the present invention is to provide a micro-electro-mechanical system packaging structure, which improves the sealing performance and moisture resistance of the encapsulant through the anti-moisture material.

To achieve the above purpose, the present invention provides a micro-electro-mechanical system packaging structure, which includes a chip, a cover, a substrate, a plurality of wires, encapsulant, and a moisture resistant layer. The chip has an active area, and the chip is provided with at least one micro-electromechanical element in the active area. The cover covers the chip, and the substrate is used for carrying the chip and the cover. A plurality of wires are electrically connected between the substrate and the chip. The sealant is sealed around the cover and exposes the upper surface of the cover. The anti-moisture material layer covers the sealing body to improve the sealing performance and moisture resistance of the sealing body.

Compared with the prior art, the MEMS packaging structure of the present invention can indeed improve the sealing performance and moisture resistance of the encapsulant through the anti-moisture material.

【Description of drawings】

Figure 1: A schematic diagram of an existing MEMS packaging structure.

Fig. 2: A schematic diagram of a MEMS packaging structure according to an embodiment of the present invention.

Fig. 3: A schematic diagram of a MEMS package structure according to another embodiment of the present invention.

【Detailed ways】

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the preferred embodiments of the present invention will be specifically cited below, together with the accompanying drawings, for a detailed description as follows:

Please refer to FIG. 2 , which is a schematic diagram of a MEMS packaging structure according to an embodiment of the present invention, and FIG. 3 is a schematic diagram of a MEMS packaging structure according to another embodiment of the present invention.

The MEMS packaging structure includes a chip 200 , a cover 210 , a substrate 220 , a plurality of wires 230 , encapsulant 240 and a moisture resistant layer 250 . The chip 200 has an active area 202 , and the chip 200 is provided with at least one MEMS device 204 in the active area 202 . The cover 210 covers the chip 200 , and the cover 210 has an upper surface 212 . The substrate 220 is used to carry the chip 200 and the cover 210 . A plurality of wires 230 are electrically connected between the substrate 220 and the chip 200 . The encapsulant 240 is sealed around the cover 210 and exposes the upper surface 212 of the cover 210 . The anti-moisture material layer 250 covers the encapsulant 240 . The chip 200 is, for example, a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) photo-sensing chip, and the active area 202 is, for example, a photo-sensing area.

Please refer to FIG. 2, in this embodiment, the cover body 210 (such as a glass substrate) is fixed to the wafer (not shown) by a plastic frame 214 and a metal ring (such as a copper ring, such as the hatched part) above it. , so that the MEMS components 204 are sealed in each cavity 206 between the wafer and the cover 210 . Next, the wafer and the cover body 210 are cut into individual units, so that the MEMS element 204 is sealed in each independent MEMS structure. Then, the MEMS structure is disposed on the substrate 220 , and electrically connected between the substrate 220 and the chip 200 by a plurality of wires 240 bonded by wires. Next, seal the encapsulant 240 around the cover 210 by dispensing glue, and expose the upper surface 212 of the cover 210, so that the light sensing area of the light sensing chip can receive the light penetrating the cover 210, for subsequent image processing.

It is worth noting that the encapsulant 240 is an organic polymer compound, such as epoxy resin. Since the molecular structure of the organic compound has many hydrophilic groups, it can only block external pollution and some moisture, but cannot completely block Hydrophilic groups interact with moisture. Therefore, the present invention uses chemical vapor deposition or physical vapor deposition to form a moisture-resistant material layer 250 covering the encapsulant 240 to effectively block the interaction between the hydrophilic groups of the encapsulant 240 and moisture. In this way, the MEMS device 204 can normally operate in the MEMS package structure 260a.

In this embodiment, the material of the anti-moisture material layer 250 is an inorganic insulating material with high density, such as silicon oxide, silicon nitride, silicon oxynitride or other nitrides without hydrophilic groups, Oxide and nitrogen oxide have a moisture resistance greater than that of the sealing body 240 . That is, since the inorganic insulating material does not contain a hydrophilic group, it does not interact with moisture, so it can effectively block moisture. Over a long period of time, the sealability of the plastic frame 214 or the sealing body 240 will not change.

In the next embodiment, the anti-moisture material layer 250 is also used to cover the encapsulant 240 , with only some changes in the structure. The cover 210 is, for example, a transparent substrate or an opaque silicon substrate. Please refer to the following description.

Please refer to FIG. 3 , in this embodiment, the back surface of the chip 200 is first attached to the substrate 220 , and a plurality of wires 230 electrically connected between the substrate 220 and the chip 200 by wire bonding. Next, the cover 210 is fixed on the substrate 220 with the plastic frame 214 and the metal ring (hatched part) above it, so that the chip 200 configured with the micro-electromechanical element 204 and the plurality of wires 230 are sealed between the substrate 220 and the cover 210 In the cavity 206 between. Next, the encapsulant 240 is sealed around the cover 210 by dispensing glue, and the upper surface 212 of the cover 210 is exposed. In this way, the MEMS device 204 can normally operate on the MEMS package structure 260b.

In the above two embodiments, the micro-electromechanical packaging structure of the present invention first uses the encapsulant (organic polymer material) to perform the sealing step of the first layer, and then uses another layer of high-density moisture-resistant material (inorganic insulating material) material) to carry out the moisture-proof step of the second layer to cover the organic polymer material. Therefore, MEMS components such as switches, mirrors, capacitors, accelerometers, inductors, capacitive sensors or actuators can be sealed in the cavity to avoid external pollution and moisture, so it can effectively improve the reliability of operation Spend.

Claims (5)

1. micro electromechanical system packaging structure, it is characterized in that: said micro electromechanical system packaging structure comprises:

One chip have an active region, and said chip is provided with at least one microcomputer electric component in said active region;

One lid is covered on the said chip, and said lid has a upper surface;

One substrate is in order to carry said chip and said lid;

Many leads electrically connect between said substrate and the said chip;

An one glue frame and a becket, said becket are above said glue frame, and said glue frame and said becket are connected between said chip and the said lid to form a cavity, and said microcomputer electric component is sealed in the said cavity;

One adhesive body is high-molecular organic material, be sealed in said lid around, and appear said upper surface; And

One moisture-resistant gas material layer for the inorganic insulating material of moisture-resistant gas ability greater than said adhesive body, is covered on the said adhesive body.

2. micro electromechanical system packaging structure as claimed in claim 1 is characterized in that: the material of said adhesive body is an epoxy resin.

3. micro electromechanical system packaging structure as claimed in claim 1 is characterized in that: the material of said moisture-resistant gas material layer is silica, silicon nitride or silicon oxynitride.

4. micro electromechanical system packaging structure as claimed in claim 1 is characterized in that: said chip is an optical sensing chip, and said active region is an optical sensing area.

5. micro electromechanical system packaging structure as claimed in claim 1 is characterized in that: said lid comprises transparent substrates or non-transparent substrates.

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