Metal-ceramic substrate having a contact area

Abstract

To provide a metal-ceramic substrate which has an increased resistance to thermal shock.SOLUTION: A metal-ceramic substrate 1 comprises: a) a ceramic body 10 having a primary boundary surface 15; b) a metal layer 20 having a primary boundary surface, the metal layer being connected over its surface to the ceramic body, the metal layer comprising a structuring region 4 including (i) partially solid material 50 and (ii) partially non-solid material; and c) a contact area 8 containing silver 60, and disposed on the metal layer. In a cross-section through the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body, the structuring region has a geometry satisfying the following requirement: S(BCsolid) / S(BCtotal)>60%, where S(BCtotal) stands for the total length of the line between points B and C, and S(BCsolid) stands for the length of the line between the points B and C that intersects the solid material. The solid material has an increased silver content in the region adjacent to the upper half of the contour line.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a metal-ceramic substrate, an electronic component comprising a metal-ceramic substrate, and a method for manufacturing a metal-ceramic substrate.

[0002] Metal-ceramic substrates play a crucial role in the field of power electronics. They are essential elements in constructing electronic components, ensuring the rapid dissipation of large amounts of heat during the operation of these components. Metal-ceramic substrates typically consist of a ceramic layer and a metal layer bonded to the ceramic layer.

[0003] Several methods for bonding a metal layer to a ceramic layer are known from the prior art. In the so-called DCB ("direct copper bonding") method, copper is reacted with a reactive gas (usually oxygen) to form a copper compound (usually copper oxide) with a lower melting point than copper on the surface of the copper foil. When the copper foil thus treated is applied to a ceramic body and the composite is heated, the copper compound melts, wetting the surface of the ceramic body and achieving a stable cohesive bond between the copper foil and the ceramic body. This method is described, for example, in U.S. Patent No. 3,744,120(A) or German Patent No. 2,319,854(C2).

[0004] Alternatively, metal foil can be bonded to a ceramic body at a temperature of approximately 650–1000°C, using a specific solder containing a metal (usually silver) with a melting point of at least 700°C and an active metal. The active metal's role is to react with the ceramic material, thus facilitating the bonding of the ceramic material to the rest of the solder and forming a reaction layer, while the metal with a melting point of at least 700°C helps to bond this reaction layer to the metal foil. For example, Japanese Patent No. 4812985(B2) proposes bonding copper foil to a ceramic body using a solder containing 50–89 weight percent silver, as well as copper, bismuth, and an active metal. This method ensures a reliable bond between the copper foil and the ceramic body. Alternatively, metal foil can be bonded to a ceramic body using silver-free solder. These solders are based, for example, on a high-melting-point metal (especially copper), a low-melting-point metal (such as bismuth, indium, or tin), and an active metal (such as titanium). Such techniques are proposed, for example, in German Patent Application Publication No. 102017114893(A1). This technique essentially results in a new, independent class of compounds because the base of the solder used is formed by a different metal (copper instead of silver), leading to changes in material properties and adaptation to other solder components and modified bonding conditions.

[0005] In the construction of electronic components, chips are typically mounted on metal-ceramic substrates. To mount a chip on a metal-ceramic substrate, it is usually necessary to create a silver-containing contact area in the region of the substrate where the chip will be mounted. By creating a silver-containing contact area, the chip can be more easily connected to the metal-ceramic substrate using common processes such as sintering or soldering. To create the contact area, the metal-ceramic substrate is typically first treated with an etching solution in specific areas to form the desired structure. Then, the contact area is created by partially applying a silver-containing coating to the surface of the structured metal-ceramic substrate.

[0006] Metal-ceramic substrates manufactured in this manner are typically subjected to large temperature fluctuations during operation as part of electronic components. During periods of interruption, depending on the environment, temperatures can drop to, for example, below -20°C, while the temperature of the metal-ceramic substrate can easily rise to over 150°C during operation. The metal-ceramic substrate is regularly exposed to these temperature differences. Due to the different coefficients of thermal expansion of metals and ceramics, repeated temperature changes can cause the metal layer to delaminate (exfoliate) from the ceramic body, potentially degrading performance. Therefore, high thermal shock resistance is a crucial criterion for the suitability of metal-ceramic substrates in electronics, particularly power electronics applications.

[0007] Therefore, it is desirable to further improve the thermal shock resistance of metal-ceramic substrates.

[0008] Therefore, the object of the present invention is to provide a metal-ceramic substrate with improved resistance to thermal shock.

[0009] This objective is achieved by the metal-ceramic substrate of claim 1. Therefore, the present invention relates to a metal-ceramic substrate, a) A ceramic body having a primary interface, b) A metal layer having a primary interface, wherein the metal layer is connected to a ceramic body at its surface, and the metal layer (i) Partially containing solid material, (ii) A metal layer having a structured region that partially contains a non-solid material, c) A metal-ceramic substrate comprising a contact region containing silver and disposed on a metal layer, In a cross-section passing through the metal-ceramic substrate perpendicular to the primary interface of the ceramic body, the structured region has a geometric shape that satisfies the following requirements: S(BC solid ) / S(BC total )>60%, During the ceremony, S(BC total ) represents the total length of the line between point B and point C. S(BC solid) means the length of the line between point B and point C that intersects the solid material, Points B and C are determined as follows: 1. The best-fit line between the ceramic body and the metal layer is determined, 2. The contour line that separates the solid material from the non-solid material is determined, 3. Point A where the perpendicular line to the best-fit line intersects the contour line is determined at a distance of 150 μm from the best-fit line on the perpendicular line to the best-fit line, 4. Point B where the perpendicular line to the best-fit line intersects the contour line is determined at a distance of 80 μm from the best-fit line on the perpendicular line to the best-fit line, 5. Point C where the line passing through points A and B intersects the best-fit line is determined on the line passing through points A and B, The contour line extends from the primary interface of the metal layer to the primary interface of the ceramic body. The contour line has an upper half and a lower half. The upper half of the contour line extends from the primary interface of the metal layer towards the primary interface of the ceramic body, and the lower half of the contour line extends from the primary interface of the ceramic body towards the primary interface of the metal layer. The solid material in the region adjacent to the upper half of the contour line has a higher silver content than the region adjacent to the lower half of the contour line, providing a metal-ceramic substrate.

[0010] Furthermore, the present invention relates to an electronic component comprising such a metal-ceramic substrate.

[0011] In addition, the present invention relates to a method for manufacturing a metal-ceramic substrate.

[0012] The metal-ceramic substrate according to the present invention comprises a ceramic body having a primary interface.

[0013] The ceramic body is preferably a body formed from ceramic. The body can have any geometric shape, but is preferably designed as a rectangular parallelepiped. The ceramic body has interfaces, and in the case of a rectangular parallelepiped, it has six interfaces. In this specification, the primary interfaces preferably refer to interfaces that connect to a metal layer at their surface (particularly very preferably, the interfaces having the largest surface area). The primary interfaces are particularly preferably interfaces that connect to a metal layer having a structured region at their surface (particularly very preferably, the interfaces having the largest surface area), and particularly very preferably interfaces that connect to a metal layer having a contact region containing silver at their surface (particularly the interfaces having the largest surface area). The primary interfaces are preferably located in or extending parallel to the primary extension plane of the ceramic body. Thus, the primary extension plane of the ceramic body is preferably understood to be a plane that extends parallel to or surrounds the primary interfaces of the ceramic body.

[0014] The ceramic material of the ceramic body is preferably an insulating ceramic. According to a preferred embodiment, the ceramic is selected from the group consisting of oxide ceramics, nitride ceramics, and carbide ceramics. According to a further preferred embodiment, the ceramic is selected from the group consisting of metal oxide ceramics, silicon oxide ceramics, metal nitride ceramics, silicon nitride ceramics, boron nitride ceramics, and boron carbide ceramics. According to a particularly preferred embodiment, the ceramic is selected from the group consisting of aluminum nitride ceramics, silver nitride ceramics, and aluminum oxide ceramics (such as ZTA ("zirconia toughened alumina") ceramics). In yet another very preferred embodiment, the ceramic body comprises (1) at least one element selected from the group consisting of silicon and aluminum, (2) at least one element selected from the group consisting of oxygen and nitrogen, optionally (3) at least one element selected from the group consisting of (3a) rare earth metals, (3b) metals of group 2 elements of the periodic table, (3c) zirconium, (3d) copper, (3e) molybdenum, and (3f) silicon, and optionally (4) unavoidable impurities. In yet another very preferred embodiment, the ceramic body does not contain bismuth, gallium, and zinc.

[0015] The ceramic body preferably has a thickness in the range of 0.05 to 10 mm, more preferably in the range of 0.1 to 5 mm, and particularly preferably in the range of 0.15 to 3 mm.

[0016] The metal-ceramic substrate according to the present invention comprises a metal layer having a primary interface, the metal layer being connected to a ceramic body at its surface, and the metal layer comprising structured regions that (i) partially contain a solid material and (ii) partially contain a non-solid material.

[0017] The metal layer has an interface. The metal layer has a primary interface. The primary interface is preferably referred herein to as the interface on the opposite side from the ceramic body (particularly very preferably the interface having the maximum surface area). Thus, the primary interface is preferably referred to as the interface where the contact region containing silver is located (particularly very preferably the interface having the maximum surface area). The primary interface is preferably located in or extending parallel to the primary extension plane of the metal layer. Thus, the primary extension plane of the metal layer is preferably understood to be a plane that extends parallel to or surrounds the primary interface of the metal layer. The primary interface of the metal layer is preferably extending parallel to the primary interface of the ceramic body, and particularly preferably spaced apart from it.

[0018] The metal layer is preferably integrally bonded to the ceramic body. In a preferred embodiment, the metal layer is bonded to the ceramic body by a DCB (direct copper bonding) process. In a more preferred embodiment, the metal layer is connected to the ceramic body by a brazing process. The brazing process can be, for example, an AMB (active metal brazing) process, and preferably a silver-free brazing alloy (silver content is, for example, less than 1.0 weight percent based on the solid content of the brazing alloy) or a silver-containing brazing alloy (silver content is, for example, at least 50 weight percent based on the solid content of the brazing alloy) is used. Thus, the metal layer may have a bonding layer in contact with the ceramic body. The bonding layer can be, for example, a solder layer (particularly a brazing layer) or a diffusion layer.

[0019] The metal layer is connected to the ceramic body at its surface. Therefore, the metal layer is preferably connected to the primary interface of the ceramic body at its surface. The metal layer is preferably not connected to the entire primary interface of the ceramic body. In particular, the primary interface of the ceramic body can be larger than the surface of the metal layer connected to the ceramic body. In these cases, the primary interface of the ceramic body protrudes. In addition, the metal layer is preferably structured. Structured portions are understood to mean recesses in the metal layer that preferably separate individual parts of the metal layer from each other and thus electrically insulate them. Such structured portions are usually created using etching techniques.

[0020] Therefore, the metal layer comprises a structured region. The structured region is a part of the metal layer that includes a structured portion. The structured portion is preferably a recess in the metal layer. Thus, the primary interface of the metal layer contains the metal of the metal layer interrupted by the recess of the structured region.

[0021] The structured region comprises a region containing solid materials and a region containing non-solid materials.

[0022] The region containing the solid material preferably contains (i) the metal of the metal layer (optionally including the bonding layer, if present) and (ii) the metal of the contact region (particularly silver).

[0023] The region containing the non-solid material preferably includes a gaseous material. Therefore, the non-solid material preferably includes a gaseous material. The non-solid material is preferably a gaseous material filling the recesses of the metal layer. This gaseous material usually originates from the ambient atmosphere. Therefore, preferably, the gaseous material contains at least one element selected from the group consisting of nitrogen, oxygen, and noble gases. Most preferably, the gaseous material is a mixed gas, particularly air.

[0024] In a preferred embodiment, the recess extends from the primary interface of the ceramic body to the primary interface of the metal layer in a direction perpendicular to the primary interface of the ceramic body. The recess forms a channel that is preferably filled with a non-solid material to at least 50 volume percent, more preferably at least 80 volume percent, even more preferably at least 90 volume percent, particularly preferably at least 95 volume percent, particularly very preferably at least 99 volume percent, and especially completely.

[0025] The metal layer preferably comprises at least one metal selected from the group consisting of copper, aluminum, and molybdenum. In a more preferred embodiment, the metal layer comprises at least one metal selected from the group consisting of copper and molybdenum. In a particularly very preferred embodiment, the metal layer comprises copper. In a further preferred embodiment, the metal layer comprises copper and unavoidable impurities. In a further preferred embodiment, the proportion of copper is at least 60 weight percent, more preferably at least 65 weight percent, even more preferably at least 70 weight percent, and particularly preferably at least 75 weight percent, based on the total weight of the metal layer (preferably including any bonding layers that may be present).

[0026] In a preferred embodiment, the metal layer is produced by bonding copper foil (preferably high-purity copper foil) to a ceramic body. In a preferred embodiment, the connection can be made by a DCB (direct copper bonding) process or a brazing process. The brazing process can be, for example, an AMB (active metal brazing) process, and preferably a silver-free brazing alloy (silver content is, for example, less than 1.0 weight percent based on the solid content of the brazing alloy) or a silver-containing brazing alloy (silver content is, for example, at least 50 weight percent based on the solid content of the brazing alloy) is used. In this case, the metal layer may include, in addition to copper derived from the copper foil, metals from the bonding layer, particularly the solder layer (e.g., the brazing layer) or the diffusion layer.

[0027] The metal layer preferably has a thickness in the range of 0.01 to 10 mm, particularly preferably in the range of 0.03 to 5 mm, and most preferably in the range of 0.05 to 3 mm.

[0028] The metal-ceramic substrate according to the present invention contains silver and comprises contact areas disposed on a metal layer. The contact areas preferably serve to facilitate the connection of a chip to the metal layer. The chip is preferably connected to the metal layer by sintering, soldering, or bonding. In particular, since the attachment of a chip to the metal layer of the metal-ceramic substrate is not easy, the metal layer is preferably provided with contact areas. The contact areas are preferably made of silver or a silver-containing alloy. In the case of a silver-containing alloy, it contains at least 50% by weight of silver based on the weight of the silver alloy. Preferably, contact areas are provided on the metal layer of the metal-ceramic substrate at all locations where a chip will later be mounted on the metal-ceramic substrate. The contact areas can be formed on the metal layer of the metal-ceramic substrate using various techniques. For example, contact areas can be provided by depositing a silver-containing layer. The deposition of the silver-containing layer is preferably carried out chemically (e.g., electrochemically) or physically. The chemical deposition of the silver-containing layer can be carried out, for example, galvanically or electrolessly. Preferably, the chemical deposition of the silver-containing layer is carried out electrolessly by applying a silver-containing solution, where charge exchange occurs between the metals, the metal in the metal layer partially dissolves, and the silver in the solution is deposited. According to a preferred embodiment, the silver-containing solution contains a silver salt, particularly preferably silver nitrate. According to a particularly preferred embodiment, the silver-containing solution is an acidic solution of silver nitrate, particularly preferably a nitric acid solution of silver nitrate. The physical deposition of the silver-containing layer can be carried out, for example, by vapor deposition. Preferred methods of vapor deposition are, in particular, electron beam deposition, laser beam deposition, arc discharge deposition, or cathode sputtering.

[0029] The structured region of the metal layer in a metal-ceramic substrate has the geometric shape described herein. The geometric shape of the structured region is determined in a cross-section passing through the metal-ceramic substrate perpendicular to the primary interface of the ceramic body.

[0030] In a cross-section passing through the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body, the structured region of the metal layer has a geometric shape that satisfies the following requirements: S(BC solid ) / S(BC total ) > 60%, where: S(BC total ) means the total length of the line between point B and point C, S(BC solid ) means the length of the line between point B and point C that intersects with the solid material.

[0031] According to a preferred embodiment, in a cross-section passing through the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body, the structured region of the metal layer has a geometric shape such that the ratio S(BC solid ) / S(BC total ) is > 70%, more preferably > 80%, still more preferably > 85%, particularly preferably > 90%, and particularly very preferably > 95%.

[0032] According to a further preferred embodiment, in a cross-section passing through the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body, the structured region of the metal layer has a geometric shape such that the ratio S(BC solid ) / S(BC total ) is in the range of 70 - 100%, particularly preferably in the range of 80 - 100%, and particularly very preferably in the range of 80 - 99%.

[0033] To determine points B and C, the cross-section of the structured region of the metal layer of the metal-ceramic substrate is observed. The cross-section extends perpendicular to the primary boundary surface of the ceramic body. Preferably, the observation of the cross-section can be performed by cutting the metal-ceramic substrate perpendicular to the primary boundary surface of the ceramic body and capturing an image of the thus obtained cross-section with an optical microscope.

[0034] Points B and C of the line BC can be determined in the cross-section as described below.

Brief Description of the Drawings

[0035] For illustrative purposes, please refer to Figures 1 and 2 as examples. [Figure 1] Figure 1 shows a schematic diagram of this type of metal-ceramic substrate. [Figure 2] Figure 2 schematically shows a metal-ceramic substrate according to the present invention, which has a structured region in which the solid material in the region adjacent to the upper half of the contour line has a higher silver content than the region adjacent to the lower half of the contour line. [Figure 3] Figure 3 shows a portion of the cross-section through the metal-ceramic substrate according to the present invention. [Figure 4] Figure 4 shows an example of an optical microscope image of a cross-section of the structured region of the copper layer of a copper-ceramic substrate according to Example 1. [Figure 5] Figure 5 shows an example of an optical microscope image of a cross-section of the structured region of the copper layer in a copper-ceramic substrate according to Comparative Example 1. [Modes for carrying out the invention]

[0036] The metal-ceramic substrate 1 shown in Figure 1 comprises a ceramic body 10. The ceramic body 10 has a primary interface 15. The metal-ceramic substrate 1 comprises a metal layer 20. The metal layer 20 has a primary interface 24 on its upper surface opposite to the primary interface 15 of the ceramic body 10, which is parallel to the primary interface 15 of the ceramic body 10. The metal layer 20 is connected to the primary interface 15 of the ceramic body 10 at its surface. In the embodiment shown in Figure 1, the metal-ceramic substrate 1 further comprises a further metal layer 200 connected to the ceramic body 10 at its surface. The metal layer 20 has a contact region 8 containing silver. The metal layer 20 comprises a structured region, which is formed by a recess 22 in the metal layer 20. The recess 22 contains a non-solid material. The structured region 4 partially comprises the metal of the metal layer 20 and the recess 22. Thus, the structured region 4 partially comprises a solid material 50 formed by the metal of the metal layer 20 and a non-solid material (e.g., a gas phase material) filling the recess 22. The gas phase material is typically ambient air. The solid material 50 is separated from the non-solid material of the recess 22 by the contour line 40. The primary interface 24 of the metal layer 20 contains the metal of the metal layer 20, which is interrupted by the recess 22 in the structured region. The recess 22 extends from the primary interface 24 of the metal layer 20 to the primary interface 15 of the ceramic body 10, in a direction perpendicular to the primary interface 15 of the ceramic body 10, and preferably forms a channel that is completely or largely filled with the non-solid material.

[0037] The metal-ceramic substrate shown in Figure 2 has the same basic structure as the metal-ceramic substrate shown in Figure 1. The contour line 40 has an upper half and a lower half. The upper half of the contour line 40 extends from the primary interface 24 of the metal layer 20 toward the primary interface 15 of the ceramic body 10. The lower half of the contour line 40 extends from the primary interface 15 of the ceramic body 10 toward the primary interface 24 of the metal layer 20. The solid material 50 contains silver 60 in the region adjacent to the upper half of the contour line 40. In the region adjacent to the lower half of the contour line 40, the solid material contains little to no silver 60.

[0038] In a portion of the cross-section passing through the metal-ceramic substrate according to the present invention shown in Figure 3, a portion of the structured region can be seen. The region of the ceramic body 10 connected to the region of the metal layer 20 on its surface is shown. The contour line 40 separates the non-solid material and the solid material 50 of the recess 22 of the metal layer 20.

[0039] The determination of points B and C on line BC in the cross-section is preferably carried out in several steps. In the first step, the best fit line 30 between the ceramic body 10 and the metal layer 20 is determined. For this purpose, the regions of the ceramic body 10 and the metal layer 20 are optically determined, and the best fit line 30 is defined as the boundary between the ceramic body 10 and the metal layer 20 that can be observed in cross-section.

[0040] In the second step, a contour line 40 is determined that separates the solid material 50 from the non-solid material of the recess 22. The solid material 50 is determined optically, and this is typically the material of the metal layer 20. The non-solid material is also determined optically. The non-solid material is typically the gas phase material that fills the structured portion as the recess 22 of the metal layer 20.

[0041] In the third step, point A, where the perpendicular to the best-fit line 30 intersects the contour line 40, is determined on the perpendicular to the best-fit line 30 at a distance of 150 μm from the best-fit line 30.

[0042] In the fourth step, point B, where the perpendicular to the best-fit line 30 intersects the contour line 40, is determined on the perpendicular to the best-fit line 30 at a distance of 80 μm from the best-fit line 30.

[0043] In the fifth step, point C is determined on the line passing through points A and B, where the line intersects the best-fitting line 30.

[0044] Preferably, the cross-section of the metal-ceramic substrate perpendicular to the primary interface of the ceramic body, and the image of the cross-section thus obtained, are captured using an optical microscope (incident light / bright field), as described later. In the first step, first, from the metal-ceramic substrate to be inspected, 100 mm 2 ~Max 400mm 2 A rectangular sample blank with a rectangular base is cut out by sawing perpendicular to the plane formed by the primary interface of the ceramic body of the metal-ceramic substrate using a low-speed diamond saw blade and lubricant (Exakt). Thus, the sample blank has a sample surface to be inspected. Therefore, this sample surface extends perpendicular to the plane formed by the primary interface of the ceramic body of the metal-ceramic substrate before sawing. Thus, it comprises a portion of the ceramic body and a portion of the metal layer (including optionally present bonding layers). The sample blank is first embedded in a mold containing low-shrinkage epoxy resin (Caldo-Fix, Struers), with the sample surface oriented perpendicular to the mold wall. The epoxy resin is then cured in a drying oven at 75°C. After curing, the sample surface of the sample blank is mechanically polished in an automated polishing machine (Tegrapole, Struers) to achieve a roughness of 1 μm or less.

[0045] In the second step, structured regions containing both solid and non-solid materials are identified in the metal layer using an optical microscope (Leica, DM6000M, incident light / brightfield) at 200x magnification in the analysis zone. The solid and non-solid materials can be clearly distinguished in the structured regions by their different colors.

[0046] Line S(BC) total ) and S(BC solid The length of the ) is preferably determined by a standard method, for example, using image analysis software (e.g., IMS Client, Imagic).

[0047] Preferably, as used herein, the term “in cross-section” refers to a total of (preferably representative) cross-sections, particularly preferably at least 10 cross-sections, very preferably 20 or fewer cross-sections, particularly 10 cross-sections. The cross-sections are preferably parallel to one another and evenly spaced apart from one another.

[0048] The ratio S(BC) for the observed metal-ceramic substrate solid ) / S(BC total To obtain ), the following procedure is preferably used. 1. At least 10, and more preferably 10, different cross-sections of the structured region are inspected. 2. The ratio S(BC) for each of these cross-sections. solid ) / S(BC total ) is required. 3. The ratio S(BC) for each of these cross-sections. solid ) / S(BC total ) is averaged to obtain the observed ratio S(BC) for metal-ceramic substrates. solid ) / S(BC total ) obtain.

[0049] According to a preferred embodiment, the ratio S(BC) over at least 10 different cross-sections of the structuring region of the metal layer, more preferably over 20 or fewer different cross-sections of the structuring region of the metal layer, and particularly very preferably over 10 different cross-sections of the structuring region of the metal layer. solid ) / S(BC total The sample standard deviation SSD is 10% or less, more preferably 7% or less, particularly preferably 5% or less, and most preferably 3% or less. The sample standard deviation SSD is calculated using the following formula.

[0050]

number

[0051]

number

[0052] According to the present invention, in a cross-section passing through a metal-ceramic substrate perpendicular to the primary interface of the ceramic body, the structured region has a geometric shape in which the contour line extends from the primary interface of the metal layer to the primary interface of the ceramic body, and the contour line has an upper half and a lower half, the upper half of the contour line extends from the primary interface of the metal layer toward the primary interface of the ceramic body, and the lower half of the contour line extends from the primary interface of the ceramic body toward the primary interface of the metal layer, and the solid material in the region adjacent to the upper half of the contour line has a higher silver content than the region adjacent to the lower half of the contour line.

[0053] Therefore, according to the present invention, the contour line extends from the primary interface of the metal layer to the primary interface of the ceramic body. Preferably, the contour line does not extend along the primary interface of the ceramic and does not extend along the primary interface of the metal layer. Therefore, preferably, the contour line extends over a region that does not include the primary interface of the ceramic and the primary interface of the metal layer.

[0054] The contour line has an upper half and a lower half. The upper half of the contour line extends from the primary interface of the metal layer toward the primary interface of the ceramic body. The lower half of the contour line extends from the primary interface of the ceramic toward the primary interface of the metal layer.

[0055] According to the present invention, the solid material in the region adjacent to the upper half of the contour line has a higher silver content than the region adjacent to the lower half of the contour line. In a preferred embodiment, the ratio of the silver content of the solid material in the region adjacent to the lower half of the contour line to the silver content of the solid material in the region adjacent to the upper half of the contour line is less than 0.8, more preferably less than 0.5, even more preferably less than 0.3, particularly preferably less than 0.1, and particularly very preferably less than 0.05.

[0056] The region of solid material adjacent to the contour line preferably has a width in the range of 0.3 to 1.0 μm, particularly preferably in the range of 0.5 to 0.6 μm, and most preferably 0.5 μm. Thus, the contour line preferably represents the outer shape of the solid material, and the composition of the solid material (including the silver content) is preferably determined using the method described above in a region limited by (i) the primary interface of the metal layer, (ii) the primary interface of the ceramic body, (iii) the contour line, and (iv) a parallel shift of the contour line in the direction of the solid material of 0.3 to 1.0 μm, particularly preferably 0.5 to 0.6 μm, and most preferably 0.5 μm. The contour line is preferably divided into an upper half and a lower half midway between the primary interface of the metal layer and the primary interface of the ceramic body, with the upper half of the contour line extending from the primary interface of the metal layer toward the primary interface of the ceramic body, and the lower half of the contour line extending from the primary interface of the ceramic body toward the primary interface of the metal layer. Therefore, the region of the solid material being measured consists of an upper half adjacent to the upper half of the contour line and a lower half adjacent to the lower half of the contour line.

[0057] The silver content of the solid material in the region adjacent to the upper half of the contour line, and the silver content of the solid material in the region adjacent to the lower half of the contour line, are preferably determined by energy-dispersive X-ray spectroscopy (EDX) combined with a scanning electron microscope (SEM) (SEM-EDX).

[0058] In SEM-EDX, a focused primary electron beam is guided (scanned) point by point across the sample surface. Scattered electrons are detected using a detector, and the number of electrons per pixel yields a grayscale microscopic image of the sample surface. Furthermore, the primary electron beam excites the sample to emit characteristic X-ray radiation, and the elements in the sample and their weight percentages can be determined by analyzing the energy spectrum using the EDX detector.

[0059] For the inspection, a scanning electron microscope (JSM-6060 SEM, JEOL Ltd) equipped with a silicon drift EDX detector (NORAN, Thermo Scientific Inc.) and analysis software (Pathfinder Mountaineer EDS System, e.g., version 2.8, Thermo Scientific Inc.) are used. For the scanning electron microscope, the following settings can be used: magnification: 200x, acceleration voltage = 10kV, working distance = 10mm, spot size (50-60) (set to reach 25%+ / -5% of the EDX detector's dead time). The EDX spectrum can be captured using the following settings for the EDX detector: live time = 30 seconds, speed = automatic, low energy cutoff = 100keV, high energy cutoff = automatic (per SEM acceleration voltage). Depending on the selected magnification and the thickness of the metal layer, several SEM-EDX measurements may be required to image the entire structured region.

[0060] The silver content is measured at at least five, and more preferably ten, representative locations within the region adjacent to the upper half of the contour line and the region adjacent to the lower half of the contour line. The silver content is preferably understood to be the arithmetic mean of each individual measurement.

[0061] Surprisingly, metal-ceramic substrates having the geometric shape according to the present invention were found to have improved thermal shock resistance compared to metal-ceramic substrates of the prior art. These metal-ceramic substrates have a high proportion of solid material within the metal layer at the boundary with the surface of the ceramic body. In contrast, the proportion of solid material within the metal layer at the boundary with the surface of the ceramic body was found to be significantly lower in metal-ceramic substrates of the prior art when they have a contact area containing silver arranged in the metal layer.

[0062] While not bound by explanation, this may be due to the fact that, in the prior art, manufactured metal-ceramic substrates are typically first structured and then silver-plated on the surface to create contact areas; however, the already structured areas of the metal-ceramic substrate surface are not adequately masked during silver plating. For this purpose, areas of the structured metal-ceramic substrate surface that are not coated with silver are typically masked first before silver plating. A film (e.g., a dry film) is usually used for masking. This film spans the structured areas of the metal-ceramic substrate, so the structured areas are covered by the film but not completely lined, especially in areas close to the ceramic body. The subsequent silver plating is usually carried out by immersing the structured and masked metal-ceramic substrate in a bath containing a solution containing silver ions. The silver ion-containing solution can clean beneath the masking film, resulting in direct contact with the underlying structured areas. During the silver plating process, metal ions electrochemically elute from the metal layer of the metal-ceramic substrate in the structured region and are replaced by silver ions. It has been shown that the elution of metal ions from the metal layer and the deposition of silver ions occur in spatially separated regions near the ceramic body. Therefore, while silver deposition often occurs directly on the surface of the structured region, metal ions are preferably released from regions close to the ceramic body (a distance of approximately 50 μm from the ceramic body surface). As a result, the surface of the structured region close to the ceramic body is gradually removed as contact time with the silver ion-containing solution increases. This leads to the removal of solid material, particularly the metal from the metal foil, from the region close to the ceramic body, thus creating a weak point for delamination of the metal layer from the ceramic body, which adversely affects thermal shock resistance. Therefore, the removal of solid material in the structured region may be due to the lack of lining of the structured region by a masking film. However, according to the present invention, a structured region containing a sufficient amount of solid material is created in the region close to the ceramic body, thereby preventing delamination of the metal layer from the ceramic body and achieving improved thermal shock resistance.

[0063] The solid material contains silver in the region adjacent to the upper half of the contour line. This is because, according to one embodiment, the mask is applied by a printing process before silver plating. Since the structured portion of the metal-ceramic substrate typically has a curved geometric shape, the structured portion is (almost) completely covered by the mask in the region close to the ceramic body, improving thermal shock resistance. In contrast, the region of the structured portion further away from the ceramic body is typically not completely masked and, as a result, is at least partially coated with silver in the subsequent silver plating step.

[0064] In a preferred embodiment, the metal-ceramic substrate comprises a further (second) metal layer connected to the ceramic body at its surface. The further metal layer is preferably connected at its surface to an interface opposite to the primary interface of the ceramic (preferably extending parallel to the primary interface). The further (second) metal layer may have the same properties as the (first) metal layer, or its properties may differ from those of the (first) metal layer. The properties of the further (second) metal layer are described above with reference to the description of the (first) metal layer.

[0065] The metal-ceramic substrate according to the present invention can be used in particular in applications in electronics, especially in the field of power electronics.

[0066] Therefore, the present invention also provides electronic components comprising a metal-ceramic substrate according to the present invention.

[0067] According to a preferred embodiment, the electronic component comprises a metal-ceramic substrate and at least one chip according to the present invention. The at least one chip is preferably connected on its surface to a contact area containing silver disposed in the (first) metal layer. Thus, the electronic component preferably comprises a chip in contact with the (first) metal layer of the metal-ceramic substrate via a contact area containing silver.

[0068] In a more preferred embodiment, the metal-ceramic substrate of the electronic component comprises a further (second) metal layer. The further (second) metal layer is preferably connected to the ceramic body at its surface. In this case, the further metal layer is preferably connected at its surface to the interface of the ceramic body opposite to (preferably extending parallel to) the primary interface of the ceramic body.

[0069] In a more preferred embodiment, the electronic component comprises a base plate, which is preferably connected at its surface to a further (second) metal layer of the metal-ceramic substrate. Alternatively, the further (second) metal layer of the metal-ceramic substrate can be designed as a heat sink.

[0070] In a more preferred embodiment, the electronic component comprises a metal-ceramic substrate having a (first) metal layer and a further (second) metal layer (the further metal layer is preferably connected on its surface to an interface opposite to the primary interface of the ceramic body), a base plate, and at least one chip, the at least one chip being connected on its surface to the first metal layer of the metal-ceramic substrate via a contact area disposed in the metal layer, which includes silver, and the base plate being connected across its surface to the further (second) metal layer of the metal-ceramic substrate.

[0071] The metal-ceramic substrate according to the present invention can be obtained by various manufacturing processes.

[0072] The present invention also provides a method for manufacturing a metal-ceramic substrate having a structured portion and a contact area containing silver.

[0073] A method for manufacturing a metal-ceramic substrate having a structured portion and a contact area containing silver is, a) A step of providing a metal-ceramic substrate, wherein the metal-ceramic substrate is a1) Ceramic body and, a2) A step comprising a metal layer connected to the ceramic body on its surface, b) A step of structuring the metal layer, c) The step of applying a mask to a structured metal layer by applying a liquid medium containing a masking agent to a specific area of ​​the structured metal layer and allowing the masking agent to solidify, d) A step of depositing a silver-containing layer in an unmasked region of a structured metal layer to obtain a silver-containing contact region, e) a step of removing the mask, and

[0074] In step a), the metal-ceramic substrate is first provided.

[0075] This metal-ceramic substrate comprises a ceramic body and a metal layer connected to the ceramic body on its surface. The metal-ceramic substrate can be a standard metal-ceramic substrate. The ceramic body and the metal layer may have the compositions described above with respect to the metal-ceramic substrate. The metal layer can preferably be integrally bonded to the ceramic body as described above with respect to the metal-ceramic substrate.

[0076] In step b), the metal layer is structured.

[0077] The structured portion is understood to preferably mean a recess in the metal layer that separates individual parts of the metal layer from each other and thus electrically insulates them. Thus, the structured portion preferably exposes a region of the ceramic body. Such a structured portion is usually made using etching techniques. For example, an etching mask can be applied to the metal layer first. The etching mask serves to protect the masked region of the metal layer from etching in the etching step. This ensures that only the unmasked and intended-to-structure region of the metal-ceramic substrate of the metal layer is accessible for etching. Thus, the etching mask is designed so that etching of the masked region of the metal layer does not occur during the etching step. The type of etching mask is not further limited. The etching mask can be, for example, a standard negative mask or a positive mask. A standard etching resist can be used to produce the etching mask. These etching resists preferably contain a curable polymer (e.g., a photocurable polymer) and can be applied to the metal layer, for example, as a film (e.g., as a dry film) or as a liquid (e.g., by printing or spraying). After application, the etching resist can be processed in an appropriate manner (e.g., cured by light irradiation) to obtain an etching mask. According to one possible embodiment, a photosensitive film is applied to a metal layer of a metal-ceramic substrate and then exposed to the area to be masked in order to obtain an etching mask. The unexposed areas of the photosensitive film can then be removed by conventional methods (e.g., using a sodium carbonate solution).

[0078] It is preferable to apply an etching mask to the metal layer and then etch the unmasked areas of the metal layer to obtain the structured areas. Etching is preferably carried out by standard conventional methods. Therefore, etching is preferably carried out using a standard etching solution. According to a preferred embodiment, the etching solution is selected from the group consisting of FeCl3 etching solutions and CuCl2 etching solutions. If necessary, further etching solutions can be used, for example, to structure the unmasked areas of the optionally included bonding layer. According to a preferred embodiment, further etching solutions can be selected from the group consisting of etching solutions containing hydrogen peroxide and etching solutions containing ammonium persulfate. For example, further etching solutions may be etching solutions containing ammonium fluoride and fluoroboric acid (e.g., HBF4) and hydrogen peroxide and / or ammonium persulfate.

[0079] Preferably, the etching mask is removed after etching the unmasked areas of the metal layer to obtain the structured portion. The etching mask can be removed by standard methods. For this purpose, for example, the etching mask can be removed by treating the metal-ceramic substrate with an alkaline solution (e.g., a 2.5% sodium hydroxide solution).

[0080] In step c), a mask is applied to the structured metal layer by applying a liquid medium containing a masking agent to a specific area of ​​the structured metal layer and allowing the masking agent to solidify.

[0081] The mask serves to protect the masked areas of the metal layer from the deposition of the silver-containing layer in step d). This ensures that the silver-containing layer is deposited only in the unmasked areas of the metal layer of the metal-ceramic substrate. Therefore, the mask is designed to prevent the deposition of the silver-containing layer in the masked areas of the metal layer of the metal-ceramic substrate.

[0082] According to a preferred embodiment, the structured metal layer to which the mask is applied also includes structured regions, particularly preferably between the primary interface of the metal layer and the primary interface of the ceramic. Thus, regions of the metal layer, particularly in the vicinity of the ceramic body, are also provided with a mask to protect those regions from dissolution during the deposition of the silver-containing layer, especially when in contact with the silver ion-containing solution in step d).

[0083] To apply the mask, a liquid medium containing a masking agent is applied to a specific area of ​​the structured metal layer, and the masking agent is allowed to solidify.

[0084] The liquid medium is preferably a medium that is liquid at room temperature and atmospheric pressure. The liquid medium is preferably a medium containing a polar solvent, particularly preferably water. According to a preferred embodiment, the liquid medium is selected from the group consisting of solutions and suspensions.

[0085] The liquid medium contains a masking agent. The masking agent is preferably designed to be solidifiable. The masking agent is not limited. According to a preferred embodiment, the masking agent is curable, particularly UV curable. The UV curable masking agent preferably contains at least one compound selected from the group consisting of monomers and oligomers. According to a particularly preferred embodiment, the UV curable masking agent contains at least one compound selected from the group consisting of acrylates, epoxy and unsaturated polyester resins. The liquid medium preferably further contains a photoinitiator. The photoinitiator may be, for example, a compound that decomposes upon absorbing UV light to form a reactive species that can initiate polymerization and curing of the UV curable masking agent. In addition, the liquid medium may have other components such as colorants and additives.

[0086] A liquid medium containing a masking agent is applied to a specific area of ​​the structured metal layer. For this purpose, the liquid medium is preferably applied to the area of ​​the structured metal layer that is masked and protected from the deposition of the silver-containing layer in step d).

[0087] The liquid medium is preferably applied to the structured metal layer by printing, spraying, or painting. In a particularly preferred embodiment, the liquid medium is applied by printing using an inkjet process.

[0088] After application of the liquid medium, the contained masking agent is preferably solidified. For this purpose, the masking agent is preferably cured. Curing can be achieved, for example, by irradiating the liquid medium with UV light so that the masking agent (particularly monomers or oligomers) contained in the liquid medium polymerizes.

[0089] In a preferred embodiment, the application of a mask to a structured metal layer includes an additive masking step. The additive masking step means the application of a masking agent. In a more preferred embodiment, the application of a mask to a structured metal layer does not include a subtractive masking step. The subtractive masking step is understood to mean partially removing a masking agent that has been applied and solidified, for example, in an additive masking step, before, in particular, step d) depositing a silver-containing layer on an unmasked area of ​​the structured metal layer to obtain a silver-containing contact area. In this preferred embodiment, the liquid medium containing the masking agent is applied only to areas of the structured metal layer where the silver-containing layer is not deposited in step d), and, where appropriate, to areas of the ceramic body exposed by recesses in the metal layer that form the structured portion. In conventional masking methods, a masking agent is applied to the structured metal layer, preferably as a layer, particularly over the entire surface, in an additive masking step, and in a subsequent subtractive masking step, the solidified masking agent is removed in areas of the structured metal layer where the silver-containing layer is deposited in the subsequent step. By omitting the subtractive masking step, this preferred embodiment advantageously provides a particularly simple method for manufacturing a metal-ceramic substrate having a structured portion and a contact area containing silver.

[0090] In a preferred embodiment, in step c), a liquid medium containing a masking agent is applied to the region of the ceramic body exposed by the recess of the metal layer forming the structured portion, and the masking agent is allowed to solidify, thereby applying a mask to the region of the ceramic body exposed by the recess of the metal layer forming the structured portion. Applying a mask to the exposed region of the ceramic body may be advantageous in protecting the exposed region of the ceramic body from the deposition of the silver-containing layer in step d).

[0091] The application of a mask to a structured metal layer and the application of a mask to the region of the ceramic body exposed by the recesses in the metal layer forming the structure can be performed simultaneously or sequentially.

[0092] To apply a mask to the region of the ceramic body exposed by the recess of the metal layer forming the structured portion, the liquid medium and the application described above for the application of the mask to the structured metal layer can be used.

[0093] In step d), a silver-containing layer is deposited in the unmasked region of the structured metal layer to obtain a silver-containing contact region.

[0094] The silver-containing layer is preferably a layer made of silver or a silver alloy, and is particularly preferably a layer made of silver. The silver-containing layer is preferably deposited chemically (e.g., electrochemically) or physically. The chemical deposition of the silver-containing layer can be carried out, for example, galvanically or electrolessly. Preferably, the chemical deposition of the silver-containing layer is carried out electrolessly by applying a silver-containing solution, where charge is exchanged between the metals, the metal in the metal layer partially dissolves, and the silver in the solution is deposited. According to a preferred embodiment, the silver-containing solution contains a silver salt, particularly preferably silver nitrate. According to a particularly preferred embodiment, the silver-containing solution is an acidic solution of silver nitrate, and particularly preferably a nitric acid solution of silver nitrate. The concentration of silver in the nitric acid solution can be, for example, in the range of 0.5 to 1.5 g / l, particularly preferably in the range of 0.6 to 1.4 g / l, and particularly very preferably in the range of 0.8 to 1.2 g / l. The physical deposition of the silver-containing layer can be carried out, for example, by vapor phase growth. Preferred methods for vapor phase growth include electron beam deposition, laser beam deposition, arc discharge deposition, or cathode sputtering.

[0095] In step e), remove the mask.

[0096] The mask can be removed by standard methods. For this purpose, the mask can be exposed to an alkaline solution (e.g., a 2.5% sodium hydroxide solution). After the removal of the mask, the metal-ceramic substrate has at least one contact area containing silver, and the surface of the metal layer without a silver-containing contact area is freely accessible.

[0097] The method described herein makes it possible to obtain a metal-ceramic substrate having a structured portion and a silver-containing contact area. By creating a silver-containing contact area, chips can be more easily bonded to the metal-ceramic substrate using common processes such as sintering or soldering. The metal-ceramic substrate thus obtained is characterized by particularly high resistance to thermal shock.

[0098] Exemplary Embodiments The present invention will be described in more detail below using exemplary embodiments, but should not be understood as limiting.

[0099] Example 1: Example 1a - Preparation of structured metal-ceramic substrates: In Example 1, a metal-ceramic substrate was used, in which a copper layer measuring 170 × 132 × 0.3 mm was bonded to both sides of a silicon nitride ceramic body measuring 177.8 × 139 × 0.32 mm using the AMB (Active Metal Brazing) process. This copper-ceramic substrate was first cleaned after manufacturing.

[0100] Next, a photosensitive film was applied to both copper layers of the copper-ceramic substrate using a hot roll laminator. To cure the polymer contained in the photosensitive film and obtain an etching mask, the photosensitive film was treated with 30 mJ / cm² of curing agent in each area to be masked. 2 The substrate was exposed to light. Subsequently, the unexposed areas of the photosensitive film were wet chemically removed using a sodium carbonate solution (concentration = 10 g / l). After applying an etching mask, the copper-ceramic substrate was rinsed and cleaned. Then, the unmasked areas of the copper layer of the copper-ceramic substrate were wet chemically etched. For this purpose, a copper hydrochloride solution containing hydrogen peroxide (copper ion content = 160 g / l) was sprayed onto the copper-ceramic substrate in an etching system. Etching was performed at a temperature of 50°C and a spray pressure of 2.8 bar. Etching removed material from the unmasked areas of the copper layer of the copper-ceramic substrate. The copper-ceramic substrate was then rinsed. Next, the unmasked areas of the bonding layer contained in the copper-ceramic substrate were also wet chemically etched. For this purpose, an etching solution containing ammonium fluoride, fluoroboric acid, and hydrogen peroxide was sprayed onto the copper-ceramic substrate again in an etching system. The copper-ceramic substrate was then rinsed and dried. Next, in the stripping system, the etching mask was removed using a 2.5% sodium hydroxide solution.

[0101] Example 1b - Preparation of a structured metal-ceramic substrate having a contact area containing silver: A silver-containing contact area was provided on the structured copper-ceramic substrate prepared in Example 1a. For this purpose, a mask was first applied to the structured copper layer of the copper-ceramic substrate (including the structured area) and the area of ​​the ceramic body exposed by the recesses in the copper layer forming the structured part (the exposed area of ​​the ceramic body). For this purpose, the structured copper-ceramic substrate was placed in an inkjet printer (MicroCraft C4K7861T, Sense Advanced Technology GmbH) and a mask was applied to the structured copper layer (including the structured area) and the exposed area of ​​the ceramic body. A liquid medium containing a masking agent (DiPaMAT Etch Resist ER02) was printed on the silver-free area of ​​the structured copper layer and the exposed area of ​​the ceramic body. Then, UV light (LED 390nm, 500mJ / cm) was applied. 2 The masking agent was cured using ). Thus, the silver-free regions of the structured copper layer and the exposed regions of the ceramic body were covered with a 30 μm thick mask.

[0102] Subsequently, a silver-containing contact area was deposited on the unmasked area of ​​the copper layer of the copper-ceramic substrate. For this purpose, the masked copper-ceramic substrate was first pre-treated with a first solution containing hydrogen peroxide and sulfuric acid, and then contacted with a nitric acid / silver nitrate solution (silver content = 1.0 g / l). After the deposition of the silver-containing contact area, the copper-ceramic substrate was carefully rinsed with water to remove any residue. The mask was then removed using a 2.5% sodium hydroxide solution in a stripping system.

[0103] The obtained copper-ceramic substrate could be laser-cut into individual parts with dimensions (20.5 × 17.0 mm), which could then be used for further investigation and the manufacture of electronic components.

[0104] Comparative Example 1: Comparative Example 1a - Preparation of Structured Metal-Ceramic Substrates: In Comparative Example 1a, a structured copper-ceramic substrate was manufactured in the same manner as in Example 1a.

[0105] Comparative Example 1b - Preparation of a structured metal-ceramic substrate having a contact area containing silver: A contact region containing silver was provided in the structured copper-ceramic substrate prepared in Comparative Example 1a. For this purpose, a mask was first applied to the structured copper layer (including the structured region) of the copper-ceramic substrate and to the region of the ceramic body exposed by the recesses in the copper layer forming the structured portion (the exposed region of the ceramic body). For this purpose, a photosensitive film was applied to the two etched surfaces of the structured copper-ceramic substrate using a hot roll laminator. To obtain a mask by curing the polymer contained in the photosensitive film, the photosensitive film was treated at 30 mJ / cm² in each of the regions to be masked. 2 The substrate was exposed to light. Then, the unexposed areas of the photosensitive film were wet chemically removed using a sodium carbonate solution (concentration = 10 g / l). After applying the mask, the copper-ceramic substrate was rinsed and washed again. Subsequently, a silver-containing contact area was deposited on the unmasked areas of the copper layer of the copper-ceramic substrate. For this purpose, the masked copper-ceramic substrate was first pre-treated with a first solution containing hydrogen peroxide and sulfuric acid, and then contacted with a nitric acid / silver nitrate solution (silver content = 1.0 g / l). After the deposition of the silver-containing contact area, the copper-ceramic substrate was carefully rinsed with water to remove any residue. Then, the mask was removed using a 2.5% sodium hydroxide solution in a peeling system.

[0106] The obtained copper-ceramic substrate could be laser-cut into individual parts with dimensions (20.5 × 17.0 mm), which could then be used for further investigation and the manufacture of electronic components.

[0107] evaluation: The ratio S(BC) of the copper-ceramic substrates obtained in Example 1 and Comparative Example 1 solid ) / S(BC totalThe ratio S(BC) was determined. For this purpose, as described herein, the copper-ceramic substrates were cut perpendicular to the primary interface of each ceramic body, and images of the resulting cross-sections were captured using an optical microscope. Points A, B, and C were determined in the cross-sections. Then, the ratio S(BC) for each of the copper-ceramic substrates was determined. solid ) / S(BC total To this end, we examined 10 different cross-sections of the structured region in the copper layer of the corresponding copper-ceramic substrate and determined the ratio S(BC) for the corresponding copper-ceramic substrate. solid ) / S(BC total To obtain the ratio S(BC) for each of these cross-sections, solid ) / S(BC total ) and determine the ratio S(BC) for each of these cross-sections. solid ) / S(BC total The average value was calculated. Furthermore, the standard deviation SSD was determined.

[0108] Similarly, for the copper-ceramic substrates obtained in Example 1 and Comparative Example 1, the silver content in the region adjacent to the upper half of the contour line and the region adjacent to the lower half of the contour line was determined as described above by energy-dispersive X-ray spectroscopy (EDX) combined with scanning electron microscopy (SEM) (SEM-EDX).

[0109] Figure 4 shows an example of an optical microscope image of a cross-section of the structured region of the copper layer of a copper-ceramic substrate according to Example 1, and Figure 5 shows an example of an optical microscope image of a cross-section of the structured region of the copper layer of a copper-ceramic substrate according to Comparative Example 1.

[0110] The results are shown in Table 1.

[0111] [Table 1]

[0112] The thermal shock resistance of copper-ceramic substrates was tested. For this purpose, thermal shock resistance tests were conducted.

[0113] Thermal shock resistance test: In preparation for the thermal shock resistance test, the copper-ceramic substrate was first checked for its integrity using an ultrasonic microscope (PVA Tepla SAM300). For the test, only copper-ceramic substrates that did not show delamination between the ceramic body and the copper layer, or other deformations (e.g., cracks) that could lead to delamination of the copper layer from the ceramic body, were used. To test thermal shock resistance, the copper-ceramic substrate was repeatedly exposed to a cold liquid (temperature -65°C, Galden Do2TS) and a hot liquid (temperature +150°C, Galden Do2TS) for 5 minutes each in a cycle chamber (ESPEC TSB-2151). Delamination and other deformations of the copper-ceramic substrate were re-examined every 1000 cycles using an ultrasonic microscope (PVA Tepla SAM300). The test was terminated after 3000 cycles. Subsequently, delamination and other deformations of the copper-ceramic substrate were re-examined using an ultrasonic microscope (PVA Tepla SAM300). The condition of each copper-ceramic substrate after the thermal shock resistance test was compared with the condition of the copper-ceramic substrate before the thermal shock resistance test to assess delamination and other deformations. Delamination and other deformations (e.g., cracks) appeared as white discoloration in the ultrasound images.

[0114] The results are shown in Table 2.

[0115] [Table 2]

[0116] The results show that, in terms of thermal shock resistance, the metal-ceramic substrate according to the present invention is clearly superior to the metal-ceramic substrate of Comparative Example 1. [Explanation of Symbols]

[0117] 1. Metal-ceramic substrate 4 Structured area 8 Contact area 10 Ceramic body 15 Primary interface of ceramic body 20 metal layer 22 recess 24 Primary interface of metal layers 40 Outline 50 solid materials 60 Silver 200 Further metal layer

Claims

1. A metal-ceramic substrate, a) A ceramic body having a primary interface, b) A metal layer having a primary interface, wherein the metal layer is connected to the ceramic body at its surface, and the metal layer is (i) Partially containing solid material, (ii) A metal layer having a structured region that partially contains a non-solid material, c) A metal-ceramic substrate comprising a contact region containing silver and disposed on the metal layer, In a cross-section of the ceramic body perpendicular to the primary interface and passing through the metal-ceramic substrate, the structured region has a geometric shape that satisfies the following requirements: S(BC ｓｏｌｉｄ ) / S(BC ｔｏｔａｌ )>60% During the ceremony, S (BC ｔｏｔａｌ ) represents the total length of the line between point B and point C. S (BC ｓｏｌｉｄ ) represents the length of the line between point B and point C that intersects with the solid material, Points B and C are determined as follows, that is, 1. The best fit line between the ceramic body and the metal layer is determined.

2. The contour line separating the solid material from the non-solid material is determined.

3. Point A, where the perpendicular to the best-fit line intersects the contour line, is determined on the perpendicular to the best-fit line at a distance of 150 μm from the best-fit line.

4. Point B where the perpendicular to the best-fit line intersects the contour line is determined on the perpendicular to the best-fit line at a distance of 80 μm from the best-fit line.

5. A point C is determined on the straight line passing through points A and B, where the straight line intersects the best-fit line. A metal-ceramic substrate characterized in that the contour line extends from the primary interface of the metal layer to the primary interface of the ceramic body, the contour line has an upper half and a lower half, the upper half of the contour line extends from the primary interface of the metal layer toward the primary interface of the ceramic body, the lower half of the contour line extends from the primary interface of the ceramic body toward the primary interface of the metal layer, and the solid material in the region adjacent to the upper half of the contour line has a higher silver content than the region adjacent to the lower half of the contour line.

2. The metal-ceramic substrate according to claim 1, characterized in that the ceramic of the ceramic body is selected from the group consisting of aluminum nitride ceramic, silicon nitride ceramic, and aluminum oxide ceramic.

3. The metal-ceramic substrate according to claim 1, characterized in that the metal layer contains copper.

4. The metal-ceramic substrate according to claim 1, characterized in that the solid material contains the metal of the metal layer.

5. The metal-ceramic substrate according to claim 1, characterized in that the non-solid material contains a gas-phase material.

6. The following requirements must be met, i.e., S(BC ｓｏｌｉｄ ) / S(BC ｔｏｔａｌ )>95% The metal-ceramic substrate according to claim 1, characterized in that it is such.

7. The ratio S(BC) across at least 10 different cross-sections of the structured region of the metal layer ｓｏｌｉｄ ) / S(BC ｔｏｔａｌ The metal-ceramic substrate according to claim 1, characterized in that the sample standard deviation SSD of the material is 10% or less.

8. The metal-ceramic substrate according to claim 1, characterized in that the ratio of the silver content of the solid material in the region adjacent to the lower half of the contour line to the silver content of the solid material in the region adjacent to the upper half of the contour line is less than 0.

8.

9. An electronic component comprising a metal-ceramic substrate as described in claim 1.

10. A method for manufacturing a metal-ceramic substrate according to claim 1, wherein a structured portion and a contact region containing silver are provided, a) A step of providing a metal-ceramic substrate, wherein the metal-ceramic substrate is a1) Ceramic body and a2) A step comprising a metal layer connected to the ceramic body on its surface, b) A step of structuring the metal layer, c) The step of applying a mask to the structured metal layer by applying a liquid medium containing a masking agent to a region of the structured metal layer close to the ceramic body and allowing the masking agent to solidify, d) A step of depositing a silver-containing layer in an unmasked area of ​​the structured metal layer to obtain a silver-containing contact area, e) The step of removing the mask, A method that includes this.

Images