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US-12623305-B2 - Method for machining a metal-ceramic substrate, system for such a method and metal-ceramic substrates produced using such a method

US12623305B2US 12623305 B2US12623305 B2US 12623305B2US-12623305-B2

Abstract

A method of processing a metal-ceramic substrate ( 1 ), including providing a metal-ceramic substrate ( 1 ), wherein the metal-ceramic substrate ( 1 ) comprises at least one metal layer ( 21 ) and one ceramic element ( 11 ), which extend along a main extension plane (HSE) and are arranged one above the other along a stacking direction (S) extending perpendicularly to the main extension plane (HSE), and forming a recess ( 15 ), in particular a through recess ( 15 ), in the metal-ceramic substrate ( 1 ) by processing by means of laser light ( 10 ), in particular of an ultrashort pulse (UKP) laser.

Inventors

  • Thomas Kohl
  • Bernhard Rettinger

Assignees

  • ROGERS GERMANY GMBH

Dates

Publication Date
20260512
Application Date
20201203
Priority Date
20191211

Claims (14)

  1. 1 . A method of processing and fastening a metal-ceramic substrate ( 1 ), comprising providing a metal-ceramic substrate ( 1 ), wherein the metal-ceramic substrate ( 1 ) comprises at least one metal layer ( 21 ) and one ceramic element ( 11 ), which extend along a main extension plane (HSE) and are arranged one above the other along a stacking direction(S) extending perpendicularly to the main extension plane (HSE), and forming a recess ( 15 ), in the metal-ceramic substrate ( 1 ) by processing by means of laser light ( 10 ), characterized in that the recess ( 15 ) is used as an area through which a fastening element engages in order to fasten the metal-ceramic substrate ( 1 ) to a housing or another component and wherein as laser light ultrashort laser pulses are used to avoid the formation of burrs, wherein the laser light is directed onto the metal-ceramic substrate via at least one pivotable mirror element or reflective element and is moved over the metal-ceramic substrate by means of the at least one pivotable mirror element or reflective element, wherein the laser light is guided in section along a curved contour to form the recess.
  2. 2 . The method according to claim 1 , wherein a cross-section of the recess ( 15 ) extending parallel to the main extension plane (HSE) is larger than a cross-section of the laser light ( 10 ) measured along the same plane.
  3. 3 . The method according to claim 2 , wherein the cross-section of the recess ( 15 ) has a first diameter and the cross-section of the laser light has a second diameter, wherein a ratio of the second diameter to the first diameter assumes a value below 0.2.
  4. 4 . The method according to claim 1 , wherein the laser light ( 10 ) is directed to a processing region of the metal-ceramic substrate ( 1 ) via a lens ( 20 ), and wherein a distance (A) between a lens ( 20 ) and an upper surface (OS) of the metal-ceramic substrate ( 1 ) is changed during processing.
  5. 5 . The method according to claim 1 , wherein a focal length of a lens (L) is greater than 300 mm.
  6. 6 . The method according to claim 5 , wherein a change of the distance (A) is made continuously or in discrete steps.
  7. 7 . The method according to claim 1 , wherein the metal-ceramic substrate ( 1 ) comprises at least one backside metallization ( 30 ).
  8. 8 . The method of claim 7 , wherein the at least one backside metallization ( 30 ) and the at least one metallization ( 21 ) are arranged on opposite sides of the ceramic element ( 11 ).
  9. 9 . The method according to claim 1 , wherein a separated component of the metal-ceramic substrate ( 1 ) is removed.
  10. 10 . The method according to claim 1 , wherein the recess ( 15 ) is created by repeatedly traversing the metal-ceramic substrate ( 1 ) with the laser light ( 10 ) along the same contour.
  11. 11 . The method according to claim 1 , wherein the laser light ( 10 ) is incident perpendicularly on the upper surface of the metal-ceramic substrate ( 1 ) during processing.
  12. 12 . The method according to claim 1 , wherein a further laser light is provided, wherein by means of the laser light ( 10 ) and the further laser light the recess ( 15 ) is formed.
  13. 13 . The method according to claim 1 , wherein a ceramic element of the metal-ceramic substrate ( 1 ) is glass-free.
  14. 14 . The method according to claim 1 , wherein the recess is a through recess ( 15 ).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National Stage filing of PCT/EP2020/084469, filed Dec. 3, 2020, which claims priority to DE 10 2019 134 004.7, filed Dec. 11, 2019, both of which are incorporated by reference in their entirety herein. BACKGROUND The present invention relates to a method of processing metal-ceramic substrates, an apparatus for such a method, and metal-ceramic substrates produced by such a method. Electronic modules are well known from the prior art, for example as power electronic modules. Such electronic modules typically use switchable or controllable electronic components that are interconnected on a common metal-ceramic substrate via conductor tracks. Essential components of the metal-ceramic substrate are an insulation layer, which in the case of the metal-ceramic substrate is made of a material comprising a ceramic, and a metallization layer, which is preferably structured and formed on one component side of the metal-ceramic substrate to form conductor tracks. Typically, a metal-ceramic substrate is realized as a large card which is separated into smaller metal-ceramic substrates after or before structuring. Such large cards are processed by laser light to produce predetermined breaking lines and/or separation points. The respective metal-ceramic substrates can then be provided separately from the large card, e.g., by breaking them out. The use of ultrashort pulse lasers has proven advantageous here, as described for example in WO 2017/108 950 A1. From US 2016 0 207 143 A1 a method for processing a workpiece with laser light is known, wherein the workpiece is placed on a stage. EP 0 826 457 A1 also concerns the production of drill holes by means of laser light. SUMMARY Based on this prior art, the present invention has the object to improve the processing of metal-ceramic substrates. This object is achieved by a method for processing a metal-ceramic substrate as described herein, by an apparatus suitable therefor, and by a metal-ceramic substrate produced by such a method. Further embodiments are to be taken from the subclaims and the description. In accordance with a first aspect of the present invention, there is provided a method of processing a metal-ceramic substrate, comprising providing a metal-ceramic substrate, wherein the metal-ceramic substrate comprises at least one metal layer and one ceramic element, which in particular both extend along a main extension plane and are arranged one above the other along a stacking direction extending perpendicularly to the main extension plane, andforming a recess, in particular a through recess, in the metal-ceramic substrate by processing by means of laser light, in particular of an ultrashort pulse (UKP) laser. BRIEF DESCRIPTION OF THE FIGURES Further advantages and features result from the following description of embodiments with reference to the attached figures. Individual features of the individual embodiment can thereby be combined with each other within the scope of the invention, which show, in: FIG. 1: a schematic representation of a method for processing a metal-ceramic substrate according to a first exemplary embodiment of the present invention, FIG. 2: a schematic representation of a method for processing a metal-ceramic substrate according to a second exemplary embodiment of the present invention, FIG. 3 a schematic representation of a method for processing a metal-ceramic substrate according to a third exemplary embodiment of the present invention, and FIG. 4 a schematic representation of a method for processing a metal-ceramic substrate according to a fourth exemplary embodiment of the present invention. DETAILED DESCRIPTION In contrast to the methods known from the prior art, laser light is to be used to form the recess, in particular a UKP laser. In this context, the skilled person understands a recess to be an area which is surrounded or enclosed by the metal-ceramic substrate, preferably in one plane to an extent of more than 50%, preferably more than 75%, and particularly preferably completely, and which is free of metal and/or ceramic. For example, the recess is surrounded by a curved or polygonal contour produced by means of a laser light. In this context, it is conceivable that the recess, for example after an appropriate film and/or solder paste and/or other conductive material has been introduced, is used as a through-hole plating and/or preferably as an area through which a fastening element, such as a screw and/or bolt, engages in order to fasten the metal-ceramic substrate to a housing and/or another component. Fabrication using laser light has been shown to be advantageous, particularly in terms of quality and fabrication time in forming the recesses. For example, using ultra-short pulse laser light allows the number of post-processing steps for the metal-ceramic substrate to be reduced. In addition, it is advantageously possible, for example via a corresponding mirror element,