CN-121985767-A - Method and device for separating adhesive film of MEMS wafer

CN121985767ACN 121985767 ACN121985767 ACN 121985767ACN-121985767-A

Abstract

The invention provides a method and a device for separating an adhesive film of an MEMS wafer, which relate to the technical field of wafer packaging, the method firstly utilizes a lower heating disc to adsorb and fix the back surface of the wafer, and the front of the wafer is provided with a film layer, and then the film layer is heated to a foaming temperature which can be greater than or equal to the bonding failure temperature of the film layer, so that the bonding failure of the film layer is caused. And then the upper heating disc is used for adsorbing and fixing the adhesive film layer, the upper heating disc is driven to translate towards the direction far away from the lower heating disc, the adhesive film layer is separated from the wafer, and finally the wafer is taken down. Compared with the prior art, the embodiment of the invention realizes parallel stripping by adopting vertical vacuum adsorption after heating, can avoid the traditional tearing action, effectively reduces the mechanical stress generated during stripping, reduces the risk of damaging the thin film structure and the wafer, obviously improves the yield of the thinning process, realizes the horizontal adsorption stripping technology of non-mechanical pulling, and greatly reduces the damage rate of the thin film structure of the wafer.

Inventors

ZHANG WENYAN
QIAN YULI
KANG ZHILONG

Assignees

苏州共进微电子技术有限公司

Dates

Publication Date: 20260505
Application Date: 20260212

Claims (10)

1. The method for separating the adhesive film of the MEMS wafer is characterized by comprising the following steps of: the wafer is adsorbed and fixed by using a lower heating disc, wherein the wafer is a whole MEMS wafer after a thinning process, the back surface of the wafer is adsorbed and fixed on the lower heating disc, and the front surface of the wafer is provided with a glue film layer which is a single-layer high-purity polymer added with a thermal decomposition foaming agent; heating the adhesive film layer to a foaming temperature, wherein the foaming temperature is greater than or equal to the bonding failure temperature of the adhesive film layer; The upper heating disc is utilized to adsorb and fix the adhesive film layer; driving the upper heating plate to translate towards a direction away from the lower heating plate so as to separate the adhesive film layer from the wafer; And taking down the wafer.
2. The method of claim 1, wherein the step of attaching the wafer by using the lower heating plate comprises: placing a wafer on a lower heating plate, and vacuum-adsorbing the back surface of the wafer by utilizing the lower heating plate; setting the temperature of the lower heating plate to a preheating temperature; Moving the upper heating plate to the upper part of the adhesive film layer; the temperature of the upper heating plate is set to a preheating temperature.
3. The method of claim 2, wherein the step of heating the glue film layer to a foaming temperature comprises: the temperatures of the upper and lower heating plates were set to the foaming temperature.
4. A method of separating a film of a MEMS wafer according to claim 2 or 3, wherein the pre-heating temperature is between 130-150 ℃ and the foaming temperature is between 185-200 ℃.
5. The method of claim 1, wherein the step of attaching the adhesive film layer by using an upper heating plate comprises: Pressing the upper heating plate on the adhesive film layer, wherein the pressing pressure is less than 0.05Mpa; And vacuum adsorbing the adhesive film layer by using the upper heating plate.
6. The method of claim 1, wherein the step of removing the wafer comprises: Ejecting the wafer by using a lifting mechanism so as to separate the wafer from the lower heating plate; And removing the wafer from the jacking mechanism.
7. The film separation device for MEMS wafer, which is applicable to the film separation method for MEMS wafer according to claim 1, comprising: The lower heating disc is used for adsorbing and fixing the back surface of the wafer, and the front surface of the wafer is provided with a glue film layer; The upper heating plate is arranged above the lower heating plate and used for adsorbing and fixing the adhesive film layer, and the lower heating plate and the upper heating plate are also used for heating the adhesive film layer to a heating temperature; the driving mechanism is connected to the upper heating plate in a transmission manner and is used for driving the upper heating plate to translate towards a direction away from the lower heating plate under the condition that the upper heating plate adsorbs and fixes the adhesive film layer, so that the adhesive film layer is separated from the wafer.
8. The device for separating a film from a MEMS wafer according to claim 7, wherein a first ceramic vacuum chuck is provided on a side of the upper heating plate adjacent to the lower heating plate, the first ceramic vacuum chuck is provided with a plurality of first vacuum suction holes, and the plurality of first vacuum suction holes are used for vacuum suction of the film layer.
9. The device for separating a film from a MEMS wafer according to claim 7, wherein a second ceramic vacuum chuck is provided on a side of the lower heating plate adjacent to the upper heating plate, the second ceramic vacuum chuck being provided with a plurality of second vacuum suction holes for vacuum suction of a back surface of the wafer.
10. The apparatus according to claim 7, wherein a lifting mechanism is further provided on the lower heating plate, and the lifting mechanism is used for lifting the wafer so as to separate the wafer from the lower heating plate.

Description

Method and device for separating adhesive film of MEMS wafer Technical Field The invention relates to the technical field of wafer packaging, in particular to a method and a device for separating an adhesive film of an MEMS wafer. Background The conventional wafer thinning process of the MEMS film cavity structure is extremely fragile and sensitive to pressure, and the wafer thinning process cannot generally adopt a standard process of hard fitting and mechanical grinding. The front surface of the wafer needs to be protected during thinning, and the front surface of the wafer can be protected by using a UV adhesive film, and the adhesive film layer is removed in a subsequent process after the thinning is completed. In the conventional process for removing the UV film, the UV film is stripped by mechanical means after being irradiated by UV light. However, when mechanically tearing the membrane, extremely high transient stresses are generated at the peel line, and as the MEMS electrode is empty below it, the membrane collapses because it is not able to resist the stresses. The thinned wafer (with the thickness of generally less than 200 μm) is extremely fragile, cannot bear the conventional mechanical stripping force, and easily causes the problems of fragments and cracks. In addition, the tear film may instantaneously create a local instantaneous vacuum or air pressure fluctuation over the cavity that directly "pulls" the film. Disclosure of Invention The invention aims to provide a method and a device for separating an adhesive film of an MEMS wafer, which can avoid the traditional tearing action, effectively reduce the mechanical stress generated during peeling, reduce the risk of damaging a film structure and the wafer, and remarkably improve the yield of a thinning process. In a first aspect, the present invention provides a method for separating a film from a MEMS wafer, including: the wafer is adsorbed and fixed by using a lower heating disc, wherein the wafer is a whole MEMS wafer after a thinning process, the back surface of the wafer is adsorbed and fixed on the lower heating disc, and the front surface of the wafer is provided with a glue film layer which is a single-layer high-purity polymer added with a thermal decomposition foaming agent; heating the adhesive film layer to a foaming temperature, wherein the foaming temperature is greater than or equal to the bonding failure temperature of the adhesive film layer; The upper heating disc is utilized to adsorb and fix the adhesive film layer; driving the upper heating plate to translate towards a direction away from the lower heating plate so as to separate the adhesive film layer from the wafer; And taking down the wafer. In an alternative embodiment, the step of adsorbing and fixing the wafer by using the lower heating plate includes: placing a wafer on a lower heating plate, and vacuum-adsorbing the back surface of the wafer by utilizing the lower heating plate; setting the temperature of the lower heating plate to a preheating temperature; Moving the upper heating plate to the upper part of the adhesive film layer; the temperature of the upper heating plate is set to a preheating temperature. In an alternative embodiment, the step of heating the adhesive film layer to a foaming temperature includes: the temperatures of the upper and lower heating plates were set to the foaming temperature. In an alternative embodiment, the pre-heat temperature is between 130-150 ℃ and the foaming temperature is between 185-200 ℃. In an alternative embodiment, the step of using the upper heating plate to adsorb and fix the adhesive film layer includes: Pressing the upper heating plate on the adhesive film layer, wherein the pressing pressure is less than 0.05Mpa; And vacuum adsorbing the adhesive film layer by using the upper heating plate. In an alternative embodiment, the step of removing the wafer includes: Ejecting the wafer by using a lifting mechanism so as to separate the wafer from the lower heating plate; And removing the wafer from the jacking mechanism. In a second aspect, the present invention provides a film separation device for a MEMS wafer, which is applicable to the film separation method for a MEMS wafer according to the foregoing embodiment, and includes: The lower heating disc is used for adsorbing and fixing the back surface of the wafer, and the front surface of the wafer is provided with a glue film layer; The upper heating plate is arranged above the lower heating plate and used for adsorbing and fixing the adhesive film layer, and the lower heating plate and the upper heating plate are also used for heating the adhesive film layer to a heating temperature; the driving mechanism is connected to the upper heating plate in a transmission manner and is used for driving the upper heating plate to translate towards a direction away from the lower heating plate under the condition that the upper heating plate adsorbs and fixes the adhesive fil