阅读说明：本技术 降低mems芯片应力的方法 (Method for reducing stress of MEMS chip ) 是由 任子龙 韩金龙 于 2020-06-09 设计创作，主要内容包括：本发明公开了一种降低MEMS芯片应力的方法,涉及一种微机电技术领域,包括如下步骤：步骤一：定制硅片,在硅片的表面镀铝得到镀铝硅片；步骤二：将得到的镀铝硅片上的铝层与MEMS芯片底部的接地通过银胶粘贴在一起得到MEMS芯片和镀铝硅片结合体；步骤三：将得到的MEMS芯片和镀铝硅片结合体进行烘烤得到烘烤后的MEMS芯片和镀铝硅片结合体；步骤四：将得到的烘烤后的MEMS芯片和镀铝硅片结合体进行固化,得到的固化后的MEMS芯片和镀铝硅片结合体；步骤五：将得到的固化后的MEMS芯片和镀铝硅片结合体通过硅胶粘贴在载体表面得到总结合体；步骤六：将得到的总结合体进行固化,得到固化后的总结合体；步骤七：将得到的固化后的总结合体上的铝层与载体通过打线方式连接。(The invention discloses a method for reducing the stress of an MEMS chip, which relates to the technical field of micro electro mechanical systems and comprises the following steps: the method comprises the following steps: customizing a silicon wafer, and aluminizing the surface of the silicon wafer to obtain an aluminized silicon wafer; step two: the aluminum layer on the obtained aluminum-plated silicon wafer is attached to the ground at the bottom of the MEMS chip through silver paste to obtain a combination of the MEMS chip and the aluminum-plated silicon wafer; step three: baking the obtained MEMS chip and aluminized silicon wafer combination to obtain a baked MEMS chip and aluminized silicon wafer combination; step four: curing the obtained baked MEMS chip and aluminum-plated silicon wafer combination to obtain a cured MEMS chip and aluminum-plated silicon wafer combination; step five: adhering the obtained solidified MEMS chip and aluminized silicon wafer combination on the surface of a carrier through silica gel to obtain a total combination; step six: curing the obtained total composite body to obtain a cured total composite body; step seven: and connecting the aluminum layer on the solidified final assembly body with the carrier in a routing mode.)

1. The method for reducing the stress of the MEMS chip is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: customizing a silicon wafer, and aluminizing the surface of the silicon wafer to obtain an aluminized silicon wafer;

step two: pasting the aluminum layer on the aluminum-plated silicon wafer obtained in the step one and the grounding of the bottom of the MEMS chip together through silver paste to obtain a combination of the MEMS chip and the aluminum-plated silicon wafer;

step three: baking the MEMS chip and aluminum-plated silicon wafer combination obtained in the step two to obtain a baked MEMS chip and aluminum-plated silicon wafer combination;

step four: curing the baked MEMS chip and aluminum-plated silicon wafer combination obtained in the third step to obtain a cured MEMS chip and aluminum-plated silicon wafer combination, wherein the grounding of the bottom of the MEMS chip is conducted with an aluminum layer on the aluminum-plated silicon wafer;

step five: adhering the solidified MEMS chip and the aluminized silicon wafer combination obtained in the fourth step to the surface of a carrier through silica gel to obtain a total combination;

step six: curing the total composite body obtained in the fifth step to obtain a cured total composite body;

step seven: and connecting the aluminum layer on the solidified general assembly obtained in the sixth step with the carrier in a routing mode.

2. The method of reducing the stress of the MEMS chip of claim 1, wherein: the length of the silicon chip is 2 +/-0.2 mm greater than that of the MEMS chip, and the width of the silicon chip is 1 +/-0.2 mm greater than that of the MEMS chip.

3. The method of reducing the stress of the MEMS chip of claim 1, wherein: and bonding four corners of the aluminized silicon wafer with the carrier through silica gel.

4. The method of reducing the stress of the MEMS chip of claim 1, wherein: and the thickness of the silica gel in the fifth step is more than 100 um.

Technical Field

The invention relates to the technical field of micro electro mechanical systems, in particular to a method for reducing stress of an MEMS chip.

Background

The bottom of the MEMS chip needs to be grounded, and is usually adhered to the surface of a carrier (such as a substrate and a tube shell) by silver paste, and then is baked and cured;

2. the bottom of the chip is connected with the carrier through the silver colloid, so that the grounding of the bottom of the chip is conducted to the carrier, and the chip is led out;

3. after baking and curing, the MEMS chip is stressed to cause the deformation of the comb teeth, so that the performance of the product is influenced;

4. the material through the analysis chip is the composition of silicon, and the carrier is mainly pottery and PCB base plate, and thermal expansion coefficient is different when toasting, waits that the silver colloid cooling solidification back, and the stress of carrier can be passed through the silver colloid and is conveyed on the MEMS chip to lead to the broach to warp.

5. The stress can be reduced by replacing the silver colloid with the silica gel, but the grounding at the bottom of the chip cannot be led out.

Disclosure of Invention

The invention solves the technical problem of providing a method for reducing the stress of an MEMS chip, which has strong conduction performance, reduces the stress and does not deform.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method for reducing the stress of the MEMS chip comprises the following steps:

the method comprises the following steps: customizing a silicon wafer, and aluminizing the surface of the silicon wafer to obtain an aluminized silicon wafer, wherein an aluminum layer on the aluminized silicon wafer can be conducted;

step two: pasting the aluminum layer on the aluminum-plated silicon wafer obtained in the step one and the grounding of the bottom of the MEMS chip together through silver glue to obtain a combination of the MEMS chip and the aluminum-plated silicon wafer, wherein the silver glue has a conductive characteristic, so that the grounding of the bottom of the MEMS chip can be conducted with the aluminum layer through the silver glue;

step three: baking the MEMS chip and aluminum-plated silicon wafer combination obtained in the step two to obtain the baked MEMS chip and aluminum-plated silicon wafer combination, wherein the main component of the MEMS chip is silicon, the main component of the silicon wafer is also silicon, the silicon is bonded with the silicon, the expansion and contraction coefficients are the same, and meanwhile, the aluminum-plated silicon wafer cannot deform due to the change of temperature, so that the MEMS chip is not influenced by the stress of an aluminum layer;

step four: curing the baked MEMS chip and aluminum-plated silicon wafer combination obtained in the third step to obtain a cured MEMS chip and aluminum-plated silicon wafer combination, wherein the grounding of the bottom of the MEMS chip is conducted with an aluminum layer on the aluminum-plated silicon wafer;

step five: adhering the solidified MEMS chip and the aluminized silicon wafer combination obtained in the fourth step to the surface of a carrier through silica gel to obtain a total combination;

step six: curing the total composite body obtained in the fifth step to obtain a cured total composite body;

step seven: and C, connecting the aluminum layer on the solidified general assembly obtained in the step six with the carrier in a routing mode, and conducting the aluminum layer with the carrier in the routing mode.

Further, the method comprises the following steps: the length of the silicon chip is 2 +/-0.2 mm greater than that of the MEMS chip, the width of the silicon chip is 1 +/-0.2 mm greater than that of the MEMS chip, a certain space is reserved for facilitating welding, and the grounding on the aluminum layer is conducted to the carrier through welding, so that the outside of a product is led out.

Further, the method comprises the following steps: and bonding four corners of the aluminized silicon wafer with the carrier through the silica gel, so that the stress of the carrier is not transmitted to the silicon wafer, and the MEMS chip is not affected by the stress basically.

Further, the method comprises the following steps: and the thickness of the silica gel in the fifth step is more than 100 um.

The invention has the beneficial effects that: the surface of the silicon chip is plated with an aluminum layer, the conductive property of the silver adhesive ensures that the bottom of the MEMS chip is communicated with the aluminum layer through the silver adhesive, the main component of the MEMS chip is silicon, the main component of the silicon chip is also silicon, the silicon is bonded with the silicon, the expansion and contraction coefficients are the same, meanwhile, the silicon chip can not deform due to the change of temperature, the MEMS chip can not be influenced by the stress of the aluminum layer, simultaneously, the conductive property of the aluminum layer is utilized, the grounding at the bottom of the MEMS chip can be communicated to the aluminum layer on the surface of the silicon chip, the carrier and the silicon chip are bonded by using the silica gel, the thickness of the glue is controlled to be 100 mu m, only four corners are bonded by using the silica gel, the stress of the carrier can not be transmitted to the silicon chip, so that the MEMS chip can not be influenced by the stress basically, the long sides of the silicon chip are more than 2 +/-mm, thereby leading out of the product.

Drawings

FIG. 1 is a schematic diagram of a first embodiment of a method for reducing the stress of a silica gel of a MEMS chip;

labeled as: 1. an MEMS chip; 2. a silicon wafer; 3. a carrier; 4. silver glue; 5. silica gel; 6. gold or aluminum wires; 7. an aluminum layer.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

The method for reducing the stress of the MEMS chip comprises the following steps:

the method comprises the following steps: customizing a silicon wafer, and aluminizing the surface of the silicon wafer to obtain an aluminized silicon wafer, wherein an aluminum layer on the aluminized silicon wafer can be conducted;

step two: pasting the aluminum layer on the aluminum-plated silicon wafer obtained in the step one and the grounding of the bottom of the MEMS chip together through silver glue to obtain a combination of the MEMS chip and the aluminum-plated silicon wafer, wherein the silver glue has a conductive characteristic, so that the grounding of the bottom of the MEMS chip can be conducted with the aluminum layer through the silver glue;

step three: baking the MEMS chip and aluminum-plated silicon wafer combination obtained in the step two to obtain the baked MEMS chip and aluminum-plated silicon wafer combination, wherein the main component of the MEMS chip is silicon, the main component of the silicon wafer is also silicon, the silicon is bonded with the silicon, the expansion and contraction coefficients are the same, and meanwhile, the aluminum-plated silicon wafer cannot deform due to the change of temperature, so that the MEMS chip is not influenced by the stress of an aluminum layer;

step four: curing the baked MEMS chip and aluminum-plated silicon wafer combination obtained in the third step to obtain a cured MEMS chip and aluminum-plated silicon wafer combination, wherein the grounding of the bottom of the MEMS chip is conducted with an aluminum layer on the aluminum-plated silicon wafer;

step five: and adhering the cured MEMS chip and the aluminized silicon wafer combination obtained in the fourth step to the surface of a carrier through silica gel to obtain a total combination, wherein the carrier can be ceramic or PCB, and the PCB is selected in the embodiment.

Step six: curing the total composite body obtained in the fifth step to obtain a cured total composite body;

step seven: and C, connecting the aluminum layer on the cured total assembly obtained in the step six with the carrier in a routing mode, conducting the aluminum layer with the carrier in the routing mode, and connecting the aluminum layer with the carrier through an aluminum wire or a gold wire, wherein the aluminum wire is selected in the embodiment.

On the basis, the length of the silicon wafer is 2 +/-0.2 mm greater than that of the MEMS chip, the width of the silicon wafer is 1 +/-0.2 mm greater than that of the MEMS chip, a certain space is reserved for facilitating welding, the grounding on the aluminum layer is conducted to the carrier through welding, and then the outside of a product is led out, the length of the silicon wafer can be 1.8mm, 2.0mm or 2.2mm greater than that of the MEMS chip, 2.0mm greater than that in the embodiment, 0.8mm, 1.0mm or 1.2mm greater than that in the embodiment, and 1.0mm greater than that in the embodiment.

On the basis, in the fifth step, the four corners of the aluminized silicon wafer are bonded with the carrier through the silica gel, so that the stress of the carrier is not transmitted to the silicon wafer, and the MEMS chip is not affected by the stress basically.

On the basis, the thickness of the silica gel in the fifth step is larger than 100 um.

In addition, as shown in fig. 1, the first embodiment:

the method comprises the following steps: customizing a silicon wafer 2, and aluminizing the surface of the silicon wafer 2 to obtain an aluminized silicon wafer 2, wherein the length of the silicon wafer 2 is 2.0mm greater than that of the MEMS chip 1, and the width of the silicon wafer 2 is 1.0mm greater than that of the MEMS chip 1;

step two: pasting the aluminum layer 7 on the aluminum-plated silicon wafer 2 obtained in the step one and the grounding of the bottom of the MEMS chip 1 together through the silver adhesive 4 to obtain a combination of the MEMS chip and the aluminum-plated silicon wafer;

step three: baking the MEMS chip and aluminum-plated silicon wafer combination obtained in the step two to obtain a baked MEMS chip and aluminum-plated silicon wafer combination;

step four: curing the baked MEMS chip and aluminum-plated silicon wafer combination obtained in the third step to obtain a cured MEMS chip and aluminum-plated silicon wafer combination, wherein the grounding of the bottom of the MEMS chip 1 is conducted with an aluminum layer 7 on the aluminum-plated silicon wafer 2;

step five: adhering the solidified MEMS chip and the aluminized silicon wafer combination obtained in the fourth step to the surface of the PCB through silica gel 5 to obtain a total combination;

step six: curing the total composite body obtained in the fifth step to obtain a cured total composite body;

step seven: and connecting the aluminum layer 7 on the solidified total assembly obtained in the step six with the PCB in a routing mode by using an aluminum wire 6.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.