CN110697648B

CN110697648B - Technological method for realizing microwave port of MEMS (micro-electromechanical system) laminated device

Info

Publication number: CN110697648B
Application number: CN201910984823.5A
Authority: CN
Inventors: 钱可强; 吴杰; 王冬蕊; 姜理利; 黄旼; 郁元卫
Original assignee: Clp Guoji Nanfang Group Co ltd
Current assignee: Clp Guoji Nanfang Group Co ltd
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2022-03-04
Anticipated expiration: 2039-10-16
Also published as: CN110697648A

Abstract

The invention discloses a process method for realizing a microwave port of an MEMS (micro-electromechanical system) laminated device, which realizes a bonding surface port leading-out mode by leading out a lower substrate port and graphically etching an upper substrate port window, and exposes a microwave test port while completing chip separation in a one-time cutting mode, thereby avoiding the complicated process steps of leading the test port to an upper substrate or a lower substrate through a through hole, shortening the length of a transmission line and reducing the microwave loss; the test port is arranged on the middle bonding layer, so that the height of the gold wire lead exposed out of the chip in the micro-assembly process is reduced, and the packaging or micro-assembly volume can be greatly reduced; the final exposure of the port is completed by using a cutting mode, the process steps are not increased, and the manufacturing cost of the chip can be greatly reduced. The invention can be applied to the exposure of ports of radio frequency microsystems, bulk acoustic wave devices, wafer level packaging and the like.

Description

Technological method for realizing microwave port of MEMS (micro-electromechanical system) laminated device

Technical Field

The invention belongs to the technical field of micro-electro-mechanical system packaging, and particularly relates to a process method for realizing a microwave port of an MEMS (micro-electromechanical system) laminated device.

Background

In a radio frequency micro-system, active chips, passive integrated devices (IPD), bulk acoustic wave devices (FBAR), Micro Electro Mechanical Systems (MEMS) sensors and other multi-field devices or chips are integrated in a three-dimensional stacking mode. The leading-out of the test port is generally led to a top layer or a bottom layer substrate through a silicon through hole (TSV) in a tapping mode, then the interconnection or packaging between chips/devices is completed in a surface mounting or gold wire leading mode, and the manufacturing process is complex and difficult. The MEMS sensor comprises a plurality of movable structures which can realize different functions, a large number of cavity structures are adopted in three-dimensional stacking, the ultrathin cavity structures, the movable structures and a chip which is provided with an air bridge device cannot adopt a surface-mounted mode, and a test port is led out through the surface and is not suitable for being applied to the device.

Disclosure of Invention

The invention aims to provide a process method for realizing a microwave port of an MEMS (micro electro mechanical system) stacked device, which is used for reducing the complicated process steps added for leading out a test port in the manufacturing of the MEMS stacked device.

The technical solution for realizing the purpose of the invention is as follows: a process method for realizing a microwave port of a MEMS laminated device comprises the following steps:

step 1, manufacturing an MEMS device, a circuit or a functional module on a lower substrate;

step 2, leading out a test port on the lower substrate;

step 3, manufacturing a bonding auxiliary layer on the lower substrate to form an auxiliary pattern;

step 4, manufacturing the MEMS device, the circuit or the functional module on the upper layer substrate;

step 5, manufacturing a bonding auxiliary layer on the upper layer substrate to form an auxiliary pattern;

step 6, forming a port window on the upper layer substrate through photoetching, etching the substrate through to form a penetrating window, and forming the window through dry etching, wet etching or laser cutting;

step 7, bonding the upper and lower layers of substrates;

step 8, scribing is adopted to complete chip segmentation, and meanwhile microwave test ports are separated;

and 9, cleaning, namely cutting off silicon on the test port.

Compared with the prior art, the invention has the beneficial effects that: (1) according to the invention, the leading-out of the test port is formed on the bonding surface, so that the complicated process step of leading-out through the TSV is avoided, and the manufacturing cost of the chip is greatly reduced; (2) by forming the leading-out of the test port on the bonding surface, the height of a layer of substrate is saved in the process of gold wire leading, the height of a packaging tube shell can be reduced, and the packaging volume is greatly reduced; (3) by forming the leading-out of the test port on the bonding surface, the size of a leading-out tap line is shorter, the microwave loss is smaller, and the microwave performance of the chip can be greatly improved; (4) the port window is formed by patterning and etching the upper-layer substrate, the process can be completed with the deep etching of the upper-layer substrate device at one time, and no process step is added; (5) the port exposure is formed when the chip separation is completed through the cutting, and because the port position has no upper-layer substrate, the edge breakage near the port metal is smaller and less contaminated after the cutting is completed, the cutting channel size can be reduced, and the effective use area of the wafer is increased.

Drawings

FIG. 1 is a schematic diagram of a conventional method of introducing test ports through vias to an upper or lower substrate.

FIG. 2 is a schematic diagram of the invention with the test port brought out through an intermediate layer.

FIG. 3 is a cross-sectional view of a lower substrate after completion of the device or circuit and test port fabrication process of the present invention.

Fig. 4 is a top view of a lower substrate after completion of the device or circuit, test port processing of the present invention.

Fig. 5 is a top view of the lower substrate with the auxiliary bonding layer completed in accordance with the present invention.

Fig. 6 is a schematic cross-sectional view of a device or circuit processed by an upper substrate according to the present invention. .

Fig. 7 is a schematic top view of an upper substrate with an auxiliary bonding layer thereon according to the present invention.

FIG. 8 is a schematic diagram of an upper substrate port window etch in accordance with the present invention.

Fig. 9 is a schematic view of the present invention after bonding of the upper and lower substrates.

Fig. 10 is a top view of a die after dicing is completed in the present invention.

In the figure: 101 is a lower substrate, 201 is an upper substrate, 301 is a package substrate, 102 and 105 are lower substrate MEMS devices, 103 is a lower substrate insulating layer, 104 and 106 are lower substrate metal test ports, 107 is a lower substrate microstrip test port, 108 and 109 are lower substrate bonding auxiliary layers, 202 and 205 are upper substrate MEMS devices, 203 are upper interconnect traces, 204 and 206 are upper substrate bonding auxiliary layers, 207 is an upper port window, and 208 and 209 are scribe mark lines.

Detailed Description

A process method for realizing a microwave port of a MEMS laminated device comprises the following steps:

manufacturing a designed MEMS device, circuit or functional module on a lower substrate, wherein the MEMS device comprises a movable structure device, a radio frequency device or a bulk acoustic wave device, the circuit is a microwave circuit, a digital circuit or an analog circuit, and the functional module is a radio frequency micro-system functional module, a heterogeneous functional module or a bionic chemical functional module;

secondly, leading out a test port on the lower layer substrate, wherein the test port is a microstrip line or a metal pad;

thirdly, manufacturing a bonding auxiliary layer on the lower substrate, and forming an auxiliary pattern by adopting photoetching, metal stripping or electroplating;

manufacturing a designed MEMS device, circuit or functional module on the upper layer substrate, wherein the MEMS device comprises a movable structure device, a radio frequency device or a bulk acoustic wave device, the circuit is a microwave circuit, a digital circuit or an analog circuit, and the functional module is a radio frequency micro-system functional module, a heterogeneous functional module or a bionic chemical functional module;

fifthly, manufacturing a bonding auxiliary layer on the upper layer substrate, and forming an auxiliary pattern by adopting photoetching, metal stripping or electroplating;

forming a port window on the upper layer substrate by photoetching, etching the substrate through to form a penetrating window, and forming the window by dry etching, wet etching or laser cutting and the like;

bonding the upper and lower layers of substrates, wherein the bonding is metal alloy bonding, silicon-silicon bonding or polymer bonding;

(eighth), chip segmentation is completed by scribing, and meanwhile, the microwave test port is separated, wherein the scribing can be completed by means of grinding wheel scribing, laser scribing or water laser scribing;

and (nine) cleaning, and removing silicon on the test port.

Further, the thickness of the upper and lower substrates is 50-1000 μm, and the materials are silicon, silicon compounds, ceramics, metals or polymers.

Further, the thickness of the metal layer of the test port is 1-50 μm, and the metal layer is made of one of metal or metal alloy materials.

The test port metal layer is patterned through one method of stripping, photoetching electroplating or sputtering photoetching corrosion, the metal line width is 5-500 mu m, and the line width error is smaller than 0.5 mu m.

Furthermore, the bonding auxiliary layer in the third step(s) and the fifth step(s) is made of a dielectric material, a high molecular polymer or a metal alloy material, the used material has good adhesion with the substrate, and a bonding pattern is formed by photoetching, metal stripping or electroplating.

The thickness of the bonding auxiliary layer is 1 mu m-50 mu m, and the graph has high flatness and consistency. The bonding auxiliary layer can be respectively completed simultaneously with the substrate functional device or circuit manufacturing process in the step (I) and the step (IV), and the process steps of the MEMS laminated device are further simplified.

Further, the upper port window is processed by dry etching, wet etching or laser cutting. The etching depth is the thickness of the upper substrate, the etching transverse length is smaller than 1/2 of the length of the chip, and the thickness of the side wall is smaller than 0.1 mu m.

Furthermore, the bonding is completed by melting, diffusing or forming molecular bonds of the bonding auxiliary layer materials of the upper substrate and the lower substrate, the shearing force of the bonding strength is more than 10Kg, and the bonding temperature is lower than 400 ℃.

Furthermore, the upper scribing is completed by one or more of grinding wheel scribing, laser scribing or water laser scribing, the edge of the test port has no broken angle, and the front broken edge of the test port is smaller than 10 mu m.

Furthermore, the upper cleaning is a method of soaking in an organic solution, washing with deionized water or cleaning with other scribing cleaning solutions, and the cleaning is completed to ensure that the metal of the port is free from contamination and scratches.

Further, the size of the port window in the step (six) is set according to the port position and the microwave test position in the actual design, but the total length cannot exceed 1/2 of the chip size, so that the upper substrate has enough strength to complete the manufacturing process.

Furthermore, the etching of the port window can be completed simultaneously with the step (IV) of the manufacturing process of the lower-layer substrate functional device or the circuit, so that the processing steps of the MEMS laminated device are further simplified.

Furthermore, in the step (seven), the bonding layer is made of metal, metal alloy, silicon compound or polymer, bonding is completed through melting, diffusion or formation of molecular bonds, the bonding strength shearing force is more than 10Kg, and the bonding temperature is lower than 400 ℃.

The bonding process can adopt vacuum or fill inert gas to meet the requirements of different devices on vacuum degree and gas pressure.

In the step (eight), the microwave test port is exposed by adopting a scribing mode, and the scribing mode comprises the following steps: the grinding wheel is used for cutting, and is suitable for a totally-enclosed type bonding device; laser cutting is suitable for semi-closed bonding devices, and silicon chips can be prevented from being embedded into the devices; the water laser cutting is suitable for the MEMS laminated device with the thickness exceeding 1.5mm, the cutting surface is ensured to be completely vertical, and the cut is less than 100 mu m.

Because the MEMS laminated device is provided with a thicker metal layer and a glass-like material, scribing can adopt the combination of a plurality of scribing modes, for example, grooving of a metal surface can be finished by adopting water laser cutting, and then chip separation is finished by adopting grinding wheel scribing.

Further, in the step (nine), a method of soaking with an organic solution, washing with deionized water or cleaning with other scribing cleaning solutions is adopted to clean silicon chips or metal chips remained on the port, so that the microwave performance is ensured not to have deviation.

Fig. 1 is a schematic diagram of a conventional method for guiding a test port to an upper substrate or a lower substrate through a through hole, where 301 is a package substrate, 101 is the lower substrate, and 201 is the upper substrate, where the test port is guided to a top substrate or a bottom substrate through a Through Silicon Via (TSV) by tapping, and then interconnection or packaging between chips/devices is completed by surface mounting or gold wire lead. FIG. 2 is a schematic diagram of leading out a test port through an intermediate layer in the present invention, which avoids a complicated process step of leading out through TSV by forming the leading out of the test port on a bonding surface, thereby greatly reducing the manufacturing cost of a chip; the height of a layer of substrate is saved in the process of the gold wire lead, the height of the packaging tube shell can be reduced, and the packaging volume is greatly reduced; the size of the lead-out tap line is shorter, the microwave loss is smaller, and the microwave performance of the chip can be greatly improved; the leading-out of the test port is completed through the bonding surface, so that the damage to the front structure of the chip is avoided, and the electrical performance of the microwave test port is not influenced.

The present invention will be further described with reference to the following examples.

Examples

as shown in fig. 3, a completed device or circuit 102 is fabricated on an underlying substrate 101, an insulating layer 103 is grown as an electrically isolating layer of metal lines and substrate material, which may be an oxide of silicon, an electrically insulating polymer, etc., having a thickness of 100 a-5000 a, at locations where it is desired to bring out test ports. Forming a metal layer 104 on the substrate 103 through a metallization process, wherein the metal layer 104 is used as a microwave test port, the thickness of the metal layer is 5000A-10 [ mu ] m, and the manufacturing method comprises the following steps: forming 104 according to a photoetching pattern, metal sputtering or evaporation and stripping process sequence; forming 104 according to the process sequence of sputtering a metal seed layer, photoetching a pattern, electroplating and photoresist removing; the process sequence of sputtering a metal seed layer, electroplating, patterning by photolithography, etching, and photoresist stripping 104. A planar pattern of the lower substrate 101 and microwave port 104 of the completed device or circuit 105 is fabricated, as shown in fig. 4, 106 being a metal test port and 107 being a microstrip line test port.

Then, bonding

auxiliary layers

108 and 109 are formed on the lower substrate 101, as shown in fig. 5, the bonding auxiliary layer is made of a metal, a metal alloy, a silicon compound or a polymer, and the forming method includes: the metal material is formed in the same manner as the port fabrication process; the polymer is formed by spin coating, photoetching and etching.

A completed device or circuit 205 is fabricated on the upper substrate 201, and then bonding

auxiliary layers

204 and 206 are fabricated on the upper substrate 201, as shown in fig. 6 and 7, the bonding auxiliary layer is made of a metal, a metal alloy, a silicon compound or a polymer, and the fabrication method includes: the metal material is formed in the same manner as the port fabrication process; the polymer is formed by spin coating, photoetching and etching.

The upper substrate 201 is patterned by photolithography and etching to form a port window pattern, and etching is performed by one or more of dry etching, wet etching, laser cutting, and the like to form a through port window 207, as shown in fig. 8, which may be performed together with the MEMS deep etching device.

The upper substrate 201 and the lower substrate 101 are bonded by the auxiliary bonding layers 108, 109, 204 and 206 to complete the stacked device, as shown in fig. 9, which is a front plan view. The bonding mode can be determined by the material of the bonding auxiliary layer, and the general bonding mode is metal alloy bonding, silicon-silicon bonding or polymer bonding. The bonding temperature can not exceed 400 ℃ so as to ensure the performance and reliability of the MEMS device structure and special circuits.

The bonded stacked device 101/201 is diced, as shown in fig. 9, in dicing paths 208 and 209 by means of grinding wheel cutting, laser cutting, and water laser cutting. After the dicing is completed, the chips are completely separated and the microwave test ports are simultaneously exposed, as shown in fig. 10.

In summary, the invention provides a process method for realizing a microwave port of an MEMS stacked device, which includes the steps of patterning an upper substrate to etch a port window, and completing separation of the stacked device by cutting while exposing a microwave test port, thereby avoiding a complicated process step in which the test port is led to the upper substrate or a lower substrate through a through hole, shortening the length of a transmission line, and reducing microwave loss; the height of the gold wire lead exposed out of the chip in the micro-assembly process is reduced, so that the packaging volume can be greatly reduced.

Claims

1. A process method for realizing a microwave port of an MEMS laminated device is characterized by comprising the following steps:

step 2, leading out a test port on the lower substrate;

step 7, bonding the upper layer substrate and the lower layer substrate through the bonding auxiliary layer to complete the stacked device;

and 9, cleaning, namely cutting off silicon on the test port.

2. The process method for realizing the microwave port of the MEMS laminated device as claimed in claim 1, wherein the MEMS device is a movable structure device, a radio frequency device or a bulk acoustic wave device, the circuit is a microwave circuit, a digital circuit or an analog circuit, and the functional module is a radio frequency microsystem functional module, a heterogeneous functional module or a bionic chemical functional module.

3. The process method for realizing the microwave port of the MEMS laminated device as recited in claim 1, wherein the test port on the lower substrate is a microstrip line or a metal pad;

the thickness of the metal layer of the test port is 1-50 mu m, and the material is one of metal or metal alloy material; the test port metal layer is patterned through stripping, photoetching electroplating or sputtering photoetching corrosion, the metal line width is 5-500 mu m, and the line width error is smaller than 0.5 mu m.

4. The process method for realizing the microwave port of the MEMS laminated device according to claim 1, wherein the bonding auxiliary layer is made of one of a dielectric material, a high molecular polymer or a metal alloy material, and the thickness of the bonding auxiliary layer is 1 μm-50 μm.

5. The process of claim 1, wherein the bonding is metal alloy bonding, silicon-silicon bonding or polymer bonding, the bonding between the upper and lower substrates is performed by melting, diffusing or forming molecular bonds of the bonding auxiliary layer materials of the upper and lower substrates, the shear force of the bonding strength is greater than 10Kg, and the bonding temperature is lower than 400 ℃.

6. The process method for realizing the microwave port of the MEMS laminated device as recited in claim 1, wherein the auxiliary pattern is formed by photolithography etching, metal stripping or electroplating.

7. The process method for realizing the microwave port of the MEMS laminated device according to claim 1, wherein the scribing is finished by means of grinding wheel scribing, laser scribing or water laser scribing, the edge of the test port has no broken corner, and the front broken edge of the test port is smaller than 10 μm.

8. The process method for realizing the microwave port of the MEMS laminated device according to claim 1, wherein the thickness of the upper substrate and the lower substrate is 50-1000 μm, and the material is silicon, a silicon compound, a ceramic, a metal or a polymer.

9. The process method for realizing the microwave port of the MEMS laminated device as recited in claim 1, wherein the upper port window is processed by dry etching, wet etching or laser cutting; the etching depth is the thickness of the upper substrate, the etching transverse length is smaller than 1/2 of the length of the chip, and the thickness of the side wall is smaller than 0.1 mu m.

10. The process method for realizing the microwave port of the MEMS laminated device as recited in claim 1, wherein the cleaning in the step 9 is performed by soaking in an organic solution and rinsing with deionized water.