CN101712449A

CN101712449A - Double-corrosion groove capable of realizing MEMS wafer-level airtight encapsulation of glass slurry and method

Info

Publication number: CN101712449A
Application number: CN200910198655A
Authority: CN
Inventors: 陈骁; 罗乐
Original assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Current assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Priority date: 2009-11-11
Filing date: 2009-11-11
Publication date: 2010-05-26
Anticipated expiration: 2029-11-11
Also published as: CN101712449B

Abstract

The invention relates to a double-corrosion groove structure of MEMS wafer-level airtight encapsulation and a method. The double-corrosion groove structure is characterized in that both sides of an area in which a seal ring of glass slurry drops on a silicon cover plate are provided with two annular corrosion grooves. The distance of the edges in the two annular corrosion grooves is 1.0-1.2 times of the width of the seal ring of the glass slurry. The depths of the corrosion grooves are 30-40 microns. In the encapsulating method, before a wire screen is printed, two annular corrosion groove arrays are engraved at both sides of the area in which the seal ring of the glass slurry of the silicon cover plate drops by an etching process; and then the glass slurry is positioned and printed to the position between the two corrosion grooves of the silicon cover plate by a wire screen printing machine to realize bonding with a silicon wafer with an MEMS device array. Because the structure of the double-corrosion groove strictly limits the bonding size of the glass slurry, the yield of airtight encapsulation is greatly improved.

Description

Can realize two etching tanks and the method for glass paste in MEMS wafer level level Hermetic Package

Technical field

The present invention relates to a kind of two etching tanks and method that realizes MEMS (MEMS) device level Hermetic Package, belong to MEMS device encapsulation field.

Background technology

MEMS (microelectromechanical system) is meant the Micrometer-Nanometer Processing Technology system that make, that integrate microsensor, micro parts, miniature actuator, signal processing, control circuit etc. that adopts.The MEMS device all has very wide application prospect in a lot of fields.Yet; in the MEMS device; contain movable member; these movable members are very fragile; very easily be subjected to the influence of the factor such as dust, air-flow, humidity, machinery in scribing and the assembling process, thereby cause the decline of the overall performance of the breaking-up of device or device, therefore; must adopt the level Hermetic Package measure, protect these key positions.

In order to realize the level Hermetic Package of MEMS device, people have proposed multiple MEMS device level Hermetic Package method, and its basic thought is that the cover plate with an attached cavity is bonded to another and contains on the MEMS device wafer, thus the movable member of protection MEMS device.At present, the bonding method of MEMS device level Hermetic Package mainly contains: silex glass anode linkage, silicon silicon fusion bonding, glass Direct Bonding, organic binder bond bonding and low temperature glass slurry bonding etc.Silex glass anode linkage, silicon silicon fusion bonding and glass Direct Bonding technology often need can realize under higher temperature, as the anode linkage temperature is 450 ℃, silicon silicon fusion bonding temperature is up to 1000 ℃, high like this temperature is unfavorable to the MEMS device that requires the low stress level Hermetic Package, silex glass anode linkage, silicon silicon fusion bonding require the surfacing of bonding and smooth, any small mechanical mark will produce gas leakage on the surface, and influences hermetic properties.Organic binder bond can be implemented in level Hermetic Package MEMS device under the lower temperature, but will discharge some solvents and micro-molecular gas in the process of bonding, is difficult to obtain good air-tightness.

Low temperature glass slurry bonding is implemented in level Hermetic Package MEMS device under the lower temperature, generally glass paste is printed on and forms the glass paste sealing ring on the cover plate that has cavity with method of printing, aim at the silicon chip that has the MEMS device, make glass paste be in the periphery of MEMS device.In bonding process, the glass paste fusing, under the effect of bonding pressure, extend to both sides, be difficult to control the glass paste width behind the bonding, the groove that glass paste flows to the MEMS device very easily takes place, the cooling disposed slurry will be firmly fixing MEMS device movable member, cause the MEMS device function to lose efficacy.

So the present inventor considers to propose a kind of structure, realize having the wafer level level Hermetic Package of MEMS device array to utilize the low temperature glass slurry easily, thereby be guided out design of the present invention.

Summary of the invention

In order to guarantee the bonding quality of wafer level packaging, the width of the glass paste behind the necessary strict control bonding, avoid the glass paste behind the bonding to touch the MEMS device, the present invention proposes two etching tank structures and the method for glass paste that realize in MEMS wafer level level Hermetic Package.This structure can be realized MEMS device disc grade level Hermetic Package at a lower temperature, not only can control the glass paste width behind the bonding effectively, and improves the yield rate of MEMS device disc grade encapsulation.

The invention provides a kind of glass paste of realizing is characterised in that at two etching tanks of MEMS wafer level level Hermetic Package:

(1) on the silicon cover plate, there is the etching tank of two sealing rings the regional both sides that the glass paste sealing ring falls into, and glass paste forms sealing ring through dropping into two positions between the etching tank after the serigraphy;

(2) the glass paste sealing ring on the silicon cover plate is corresponding with the MEMS device, and through contraposition and bonding, the MEMS device passes the glass paste bonded layer by the Al metal lead wire, can realize being electrically connected of outside and MEMS device;

(3) glass paste flow in the etching tank of both sides during bonding, limits it and extends to both sides, has effectively controlled the width behind the glass paste bonding.

The width of two etching tanks of described silicon cover plate is that the degree of depth of 50～70 μ m, sealing ring etching tank is 30～40 μ m.

Distance between two etching tank inward flanges of described silicon cover plate is 1～1.2 times of printed glass paste sealing ring width.

The processing step of the MEMS wafer level level Hermetic Package that the present invention proposes is: before 1. carrying out serigraphy, and two the ring-type etching tanks of both sides etching in the zone that silicon cover-plate glass slurry sealing ring falls into; 2. the printing of the location by screen process press accurately is printed onto on the silicon cover plate zone between two etching tanks with glass paste, thus with the wafer bonding that has the MEMS device array, form the encapsulation cavity; When carrying out bonding with the silicon chip that has the MEMS device, the effect that glass paste is subjected to bonding pressure is extended to both sides, owing to being in molten condition, slurry has flowability, in the process that slurry extends, can vertically flow in the etching tank, the extension of its width groove that just is corroded stops, and can control the bonding width of glass paste effectively.

Beneficial effect of the present invention: can realize MEMS device disc grade level Hermetic Package at a lower temperature, not only can control the glass paste width behind the bonding effectively, and improve the yield rate of MEMS device disc grade encapsulation.

Description of drawings

Fig. 1 is the silicon chip vertical view that has the MEMS device array.

Fig. 2 is the silicon cover plate vertical view that does not have the glass paste sealing ring array of two etching tanks.

Fig. 3 is the cover plate vertical view that has two etching tank arrays.

Fig. 4 has on the cover plate of two etching tanks the cross section structure figure of glass paste sealing ring after serigraphy.

Fig. 5 has the silicon chip of MEMS array and the cross section structure figure of the encapsulation unit behind the silicon cover plate usefulness glass paste sealing ring bonding.

Among the figure: 101 silicon chips; The 102MEMS device array; 103 metal lead wires; 201 silicon cover plates; 202 glass paste sealing rings; Two etching tanks of 301 sealing rings.

The specific embodiment

For advantage of the present utility model and good effect are found full expression, the utility model is further specified below in conjunction with drawings and Examples.

On silicon chip 101, MEMS device array 102 usefulness semiconductor technologies are made, and Al metal lead wire 103 forms with the MEMS device and is electrically connected.(Fig. 1)

On silicon cover plate 201, glass paste sealing ring 202 is to obtain by the silk-screen printing technique printing, and it is corresponding mutually with MEMS device array 102 among Fig. 1.

In Fig. 3, on silicon cover plate 201, the glass paste printing is fallen into regional both sides in advance, adopt lithographic technique to make the etching tank 103 of two width 50～70 μ m, the degree of depth 30～40 μ m sealing rings.Distance between the two groove inward flanges is 1～1.2 times of printing back glass paste sealing ring width.

In Fig. 4, screen process press prints glass paste sealing ring 202 to the assigned address of silicon cover plate, and two etching tanks 301 are positioned at the both sides of glass paste.

In Fig. 5, the silicon chip 101 that has a MEMS array and silicon cover plate 201 are through aiming at bonding, glass paste 202 is in the process that extends to both sides under the effect of bonding pressure, owing to being in molten condition, slurry has flowability, thereby flow in the etching tank 301 of both sides, the width behind the glass paste bonding is controlled in just be corroded groove restriction of the extension of its slurry width effectively.In addition, Al metal lead wire 103 passes the glass paste bonded layer, has realized the MEMS device and outside being electrically connected of encapsulation inside cavity.

Claims

1.MEMS two etching tank structures of wafer level level Hermetic Package is characterized in that having in the regional both sides that silicon cover-plate glass slurry sealing ring falls into the etching tank of two ring-types.

2. by two etching tank structures of the described MEMS wafer level of claim 1 level Hermetic Package, the width that it is characterized in that described every ring-type etching tank is 50-70 μ m.

3. by two etching tank structures of the described MEMS wafer level of claim 1 level Hermetic Package, the degree of depth that it is characterized in that described etching tank is 30-40 μ m.

4. by two etching tank structures of claim 1,2 or 3 described MEMS wafer level level Hermetic Package, the spacing that it is characterized in that described two etching tank inward flanges is 1-1.2 times of width of glass paste sealing ring.

5. the method that is used to encapsulate by two etching tank structures of each described MEMS wafer level level Hermetic Package among the claim 1-3 is characterized in that the processing step that encapsulates is:

A) before carrying out serigraphy, the both sides in the zone that silicon cover-plate glass slurry sealing ring falls into are with the etching tank array of two ring-types of etching technics etching;

B) printing of the location by screen process press is printed onto the glass paste sealing ring between two etching tanks of silicon cover plate and the silicon cover plate bonding that has the MEMS device array, encapsulates cavity thereby form.

6. by the described method for packing of claim 5, the MEMS device array that it is characterized in that encapsulating in the cavity is to be realized by the Al metal lead wire that passes the glass paste bonded layer with outside being electrically connected.