Method for producing damper structures on a micromechanical wafer

Abstract

A method for producing damper structures on a micromechanical wafer. The method includes: providing an at least partially UV-transparent master mold for molding damper structures; inserting and pressing a micromechanical wafer into the master mold so that micromechanical structures in the wafer are aligned in relation to the damper structures; filling the master mold with UV-curing LSR and subsequent UV irradiation; and mold release and removal of the connected structure of the micromechanical wafer with attached dampers. A method for producing a singulated MEMS chip comprising a UV-cured damper is also described.

Claims

1. A method for producing damper structures on a micromechanical wafer, comprising the following steps: A. providing an at least partially UV-transparent master mold for molding damper structures; B. inserting and pressing a micromechanical wafer into the master mold so that micromechanical structures in the wafer are aligned in relation to the damper structures; C. filling the master mold with UV-curing LSR, and subsequent to the filling, UV irradiating the UV-curing LSR; and D. releasing the mold and removing a connected structure of the micromechanical wafer with attached dampers.

2. The method for producing damper structures on a micromechanical wafer as recited in claim 1, wherein in step C, the LSR is processed at a temperature of 20-60° C.

3. A method for producing a singulated MEMS chip having a UV-cured damper, comprising the following steps: A. providing an at least partially UV-transparent master mold for molding damper structures; B. inserting and pressing a micromechanical wafer into the master mold so that micromechanical structures in the wafer are aligned in relation to the damper structures; C. filling the master mold with UV-curing LSR, and subsequent to the filling, UV irradiating the UV-curing LSR; D. releasing the mold and removing a connected structure of the micromechanical wafer with attached dampers; and E. after step D, singulating the micromechanical wafer including attached dampers into chips by sawing the wafer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a and 1b show schematically a method according to an example embodiment of the present invention for producing damping structures on a micromechanical wafer.

(2) FIG. 2 shows a singulated MEMS chip comprising a UV-cured damper, in accordance with an example embodiment of the present invention.

(3) FIG. 3 schematically shows a packaged component including a MEMS chip having a UV-cured damper, in accordance with an example embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(4) FIGS. 1a and 1b show schematically a method according to an example embodiment of the present invention for producing damper structures on a micromechanical wafer.

(5) FIG. 1a shows in stages A, B, C, D tools and the device to be produced in various stages of the production method. FIG. 1b shows schematically the production method itself.

(6) In the example shown, the production method features the following steps:

(7) A—providing a UV-transparent master mold 10 for molding damper structures. It is at least partially UV-transparent and part of a molding form.

(8) B—inserting and pressing the capped sensor wafer 20 into mold 10 so that the sensor structures in the wafer are precisely aligned with the damper structures.

(9) There are several possibilities for this alignment: In the most simple case, the alignment may occur via mechanical stops when inserting the wafer. It is also possible, however, to align optically. For this purpose, for example, a microscopic camera image of the alignment structure is recorded and stored. Subsequently, the wafer is inserted, which has corresponding alignment markings, and is shifted with the help of micro-manipulating aids in such a way that the current image of the wafer comes to coincide with the recorded image. If necessary, it is also possible to use an IR-recording for this purpose, which makes it possible to detect structures within the wafer.

(10) C—filling the mold (cavities) with UV-curing LSR 30 and subsequent UV irradiation 40.

(11) D—mold release and removal of the connected structure of sensor wafer 20 with attached dampers 35, in particular with the help of mold release aids.

(12) The micromechanical wafer composite 20 is thus equipped with damper structures 35.

(13) Subsequently, individual MEMS chips having UV-cured dampers may be produced from the wafer composite with damper structures.

(14) For this purpose, in method step E, the composite of wafer and damper structures is separated into individual sensors having their respective dampers, for example by sawing or laser cutting through the wafer composite.

(15) For this purpose, the micromechanical wafer may be a wafer having micromechanical function elements, a wafer piece or a composite wafer, for example made up of a MEMS substrate wafer and a cap wafer.

(16) FIG. 2 schematically shows a micromechanical module having a UV-cured damper. The figure shows a singulated MEMS chip 25 having damper 35 formed on it.

(17) FIG. 3 schematically shows a packaged component including a MEMS chip having a UV-cured damper. The figure shows MEMS chip 25 having a damper 35 formed on it, which is fastened with this damper on an upper side of substrate 70. The MEMS chip is electrically connected to an ASIC 50 via bonding wires 60. For electrical contacting, soldering globules 80 (in a BGA, ball grid array) or contact surfaces (in an LGA, land grid array) may be situated on a lower side of the substrate. The ASIC and the MEMS chip are packaged by a housing 90.

LIST OF REFERENCE NUMERALS

(18) 10 UV-transparent master mold 20 capped sensor wafer 25 MEMS chip 30 UV-cured LSR 35 damper 40 UV radiation 50 ASIC 60 bonding wire 70 circuit board 80 soldering globule 90 housing