DE112019006179T5 - Ceramic package and method of plating ceramic substrate - Google Patents

Abstract

The present invention provides a ceramic package in a form in which a ceramic substrate, a plating layer, a first plating layer, a second plating layer and a third plating layer are sequentially stacked, the plating layer containing molybdenum and manganese, the first plating layer containing nickel and the second The plating layer and the third plating layer each contain silver, and the second plating layer has a thickness of 0.5 to 3 µm, and the second plating layer is formed using a plating solution having a silver concentration lower than that of the third plating layer and at a current higher than the third plating layer is produced.

Description

TECHNICAL AREA

The present invention relates to a ceramic package and a method of plating a ceramic substrate.

GENERAL STATE OF THE ART

In the automotive industry, refractory materials such as ceramics are applied to many parts, including wear pads that are bonded to metal parts. In addition, ceramics are used in various electrical and electronic components such as power pipes, vacuum interrupters, semiconductor packages, multilayer substrates, ball grid assemblies, power dissipation packages, and sensor packages. However, one disadvantage is that it is difficult to bond ceramics to metals. Therefore, the surface of a ceramic has typically been metallized to be bonded to a metal.

In particular, this reveals U.S. Patent No. 6,840,429 (Patent Document 1) a method of processing a non-metallic heat-resistant material, the method comprising coating the surface of the material with a coating composition including a binder with a group 4B transition metal, a hydrocarbon resin and a styrene block copolymer, and a fluid carrier, drying the coated surface, including applying a solder filler material to the dried coated surface and heating the solder filler material. As disclosed in Patent Document 1, however, when the surface of a ceramic material is coated with a coating composition and a nickel plating layer is formed using electroless plating or electrolytic plating, followed by application of a solder filler and then heat treatment, there is a problem that a process for joining a ceramic material and a metal material is tedious.

In addition, Korean Laid-Open No. 2015-0135155 (Patent Document 2) discloses a method of sealing, the method comprising the steps of arranging a metallization layer containing molybdenum on a portion of an alumina component, arranging a nickel-containing plating layer and a melting point inhibitor on the metallization layer by screen printing, sintering the plating layer at a temperature less than 1,000 ° C to form a metal barrier layer and joining the portion of the alumina component to a nickel-containing metal component by brazing through the metallization layer and the metal barrier layer. However, as disclosed in Patent Document 2, when a plating layer is arranged on a ceramic substrate and then a plating layer containing nickel is arranged on the plating layer, if there are foreign substances between the plating layer and the plating layer, there is a problem that a bubble phenomenon occurs. in which the plating layer is peeled off from the plating layer during brazing due to the foreign matter.

Therefore, there is a need for research and development of a method of plating a ceramic substrate in which bubbles less occur between a plating layer and a plating layer during brazing and the bonding strength between the plating layer and the plating layer is excellent.

DISCLOSURE OF THE INVENTION

TECHNICAL PROBLEM

One aspect of the present invention provides a method of plating a ceramic substrate and a ceramic package made thereby, wherein a bubble phenomenon in which a plating layer peeled off caused by strong bonding strength between a plating layer and the plating layer occurs less frequently and the plating layer occurs plated to a uniform thickness.

TECHNICAL SOLUTION

According to one aspect of the present invention, there is provided a ceramic package in a form in which a ceramic substrate, a plating layer, a first plating layer, a second plating layer and a third plating layer are sequentially stacked, the plating layer containing molybdenum and manganese, the first plating layer containing nickel and the second plating layer and the third plating layer each contain silver, and wherein the second plating layer has a thickness of 0.5 to 3 µm, and wherein the second plating layer is made using a plating solution having a lower silver concentration and a higher current than the third plating layer will be produced.

According to another aspect of the present invention, there is provided a method of plating a ceramic substrate, the method forming a plating layer containing molybdenum and manganese on a ceramic substrate, a first plating step of forming a first plating layer containing nickel on the plating layer, a second plating step of forming a second plating layer containing silver on the first plating layer and a third plating step of forming a third plating layer containing silver on the second plating layer, the second plating step being performed at a higher current than the third plating step and a plating solution in the second plating step has a lower silver concentration than a plating solution in the third plating step.

BENEFICIAL EFFECTS

A method of plating a ceramic substrate according to the present invention can suppress the occurrence of bubbles generated between a plating layer and a plating layer, and can form the plating layer with a uniform thickness.

In addition, a ceramic package according to the present invention includes a plating layer having a uniform thickness and has strong bonding strength between a plating layer and the plating layer, so that there is an advantage that a phenomenon in which the plating layer is peeled off occurs less frequently.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, the present invention will be described in detail.

Ceramic case

A ceramic package according to the present invention is in a form in which a ceramic substrate, a plating layer, a first plating layer, a second plating layer, and a third plating layer are sequentially stacked.

Ceramic substrate

The ceramic substrate is not particularly limited as long as it is typically used as a material for a case. In particular, the ceramic substrate can contain an electrically insulating ceramic. More specifically, the ceramic substrate may include alumina, yttria, zirconia, yttria stabilized zirconia, yttria-aluminum garnet, magnesia-alumina spinel, or yttria-aluminate perovskite.

Metallization layer

The metallization layer is formed on the ceramic substrate to serve as an intermediate crosslinking agent between a ceramic and a metal, and has conductive properties and thus has the effect of enabling plating.

The metallization layer contains molybdenum and manganese. In addition, the metallization layer can further contain one or more metals selected from the group consisting of tungsten, niobium and tantalum.

The thickness of the metallization layer can be 10 to 50 μm and can be, for example, 15 to 40 μm. When the thickness of the metallization layer is in the above range, the metallization layer assists the bonding between the ceramic substrate and a heterogeneous material, and a suitable bonding strength, vacuum degree and conductivity are achieved.

First layer of cladding

The first clad layer is formed on the metallization layer and serves to improve the bonding strength between the metallization layer and the second clad layer and to reduce the occurrence of a problem in which the coefficient of thermal expansion (CTE) of the metallization layer and the second clad layer does not occur are the same.

The first plating layer contains nickel. In addition, the first plating layer can further contain one or more metals selected from the group consisting of cobalt, chromium, boron, phosphorus, zinc, tin, and iron.

The thickness of the first clad layer can be 1 to 20 µm and can be, for example, 2 to 10 µm. When the thickness of the first plating layer is in the above range, a good nickel plating layer (first plating layer) excellent in bonding strength and free from optical defects is formed, and prevention of corrosion of the plating layer is effected.

Second plating layer

The second clad layer is formed on the first clad layer and serves to increase the bonding strength between the first clad layer and the third clad layer.

The second plating layer contains silver. Additionally, the second plating layer can further include one or more metals selected from the group consisting of gold, platinum, bismuth, cobalt, nickel, indium, and tin.

The thickness of the second clad layer can be 0.5 to 3 µm and can be, for example, 1 to 3 µm. When the thickness of the second plating layer is in the above range, a plating layer having a uniform thickness is formed so that a good third plating layer without bubbles can be formed on the first plating layer.

In addition, the second plating layer is formed using a plating solution having a lower silver concentration than that in the third plating layer and a higher current than that in the third plating layer. Accordingly, the second clad layer may have an average thickness smaller than that of the third clad layer. As described above, when the second plating layer is made using a plating solution having a lower silver concentration and a higher current than the third plating layer and thus the second plating layer has an average thickness smaller than that of the third plating layer, the second plating layer can have an average thickness to increase the bonding strength between the third clad layer and the first clad layer.

Third plating layer

The third clad layer is formed on the second clad layer and is used to enable connection to a metal housing portion without a soldering material in the following process.

The third plating layer contains silver. In addition, the third plating layer can further include one or more metals selected from the group consisting of gold, platinum, bismuth, cobalt, nickel, indium, and tin.

The thickness of the third plating layer can be appropriately adjusted in accordance with application objects, sizes, and the like of a ceramic package. For example, the thickness of the third clad layer can be 20 to 50 µm and can be, for example, 25 to 50 µm. When the thickness of the third plating layer is in the above range, the formation of fillets between one Ceramic case and a metal during brazing, so that excellent bonding strength is effected.

The surface roughness of the ceramic housing can be 2.0 to 6.5 µm. In particular, the surface roughness of the ceramic housing can be 2.0 to 5.0 or 3.0 to 4.5 μm. If the surface roughness of the ceramic package is in the above range, it is possible to prevent the joint from failing during brazing.

In addition, the bond strength of the ceramic package with a metal can be 2,000 kgf / cm ² (about 196.1 MPa) to 3,000 kgf / cm ² (about 294.2 MPa). Specifically, the bond strength of the ceramic package with a metal can range from 2,200 kgf / cm ² (about 215.0 MPa) to 2,900 kgf / cm ² (about 284.4 MPa) or 2,500 kgf / cm ² (about 245.1 MPa) to 2,800 kgf / cm ² (about 274.6 MPa).

As described above, the ceramic package according to the present invention includes a plating layer having a uniform thickness and has strong bonding strength between a plating layer and the plating layer, so that there is an advantage that a phenomenon in which the plating layer is peeled off is less frequent occurs. In addition, the ceramic package may not have a solder layer containing silver and copper, which are typically used to join a ceramic and a metal.

Method of plating a ceramic substrate

A method of plating a ceramic substrate according to the present invention includes forming a plating layer containing molybdenum and manganese on a ceramic substrate, a first plating step of forming a first plating layer containing nickel on the plating layer, a second plating step of forming a second plating layer containing silver on the first plating layer and a third plating step of forming a third plating layer containing silver on the second plating layer.

Forming the metallization layer

In the step of forming a metallization layer, a metallization layer containing molybdenum and manganese is formed on a ceramic substrate.

The materials of the ceramic substrate and the metallization layer and the thickness of the metallization layer are the same as defined in the above description with respect to the ceramic package.

A plating layer can be formed by a typical method of stacking a plating layer on the surface of a ceramic substrate. For example, the formation of a metallization layer can be carried out by depositing or applying a metal paste containing molybdenum and manganese to a ceramic substrate. The deposition can be, for example, physical vapor deposition techniques, screen printing, sputtering, and the like. In addition, the application can be, for example, by dipping, spraying, ink printing, syringe or nozzle brushing, or tape transfer and the like.

The surface of the ceramic substrate can be polished before the formation of the metallization layer in order to remove surface damage caused during manufacture and to improve the surface flatness. In addition, the surface of the ceramic substrate can be chemically cleaned prior to the formation of the metallization layer in order to remove impurities that can impair the bonding of the metallization layer. In addition, the ceramic substrate can be annealed before the formation of the metallization layer in order to reduce contamination and internal stresses. That is, the ceramic substrate can be subjected to the steps of polishing, chemical cleaning, annealing and the like prior to the formation of the metallization layer.

In addition, the ceramic substrate with the metallization layer can be subjected to steps such as hot water washing, degreasing, ultrasonic cleaning, pickling, and water washing. For example, degreasing and pickling can be carried out using an acidic solution, and hot water washing, ultrasonic cleaning and water washing can be carried out using water. As described above, the ceramic substrate with the Metallization layer can be subjected to cleaning prior to the first plating step, and as a result, the subsequent formation of a first plating layer can be facilitated.

First plating step

In the first plating step, a first plating layer containing nickel is formed on the plating layer. At this time, the materials and the thickness of the first plating layer are the same as defined in the description of the ceramic case.

The first plating can be performed by immersing the ceramic substrate with the plating layer in a first plating solution containing nickel and then applying a current thereto. At this time, the first plating solution may contain nickel and boric acid. In particular, the first plating solution may contain 50 to 75 g / l or 55 to 70 g / l nickel and 10 to 40 g / l or 10 to 35 g / l boric acid. When the nickel concentration of the first plating solution is in the above range, a nickel plating layer can be formed uniformly. And when the boric acid concentration is in the above range, it causes it to serve as a buffer for reducing pH fluctuations of the plating solution and relieving the internal stress of the plating solution.

In addition, the pH of the first plating solution can be 3.0 to 5.5 or 3.0 to 5.0. If the pH of the first plating layer is in the above range, it has the effect of preventing optical defects on the surface of the first plating layer.

The first plating can be carried out at 40 to 60 ° C at a current of 1 to 5 A / dm ² . In particular, the first plating can be carried out at 40 to 55 ° C. at a current of 1.5 to 4 A / dm ² . When the temperature during the first plating is in the above range, a uniform plating rate is maintained, and when the current is in the above range, the first plating layer can be formed with a uniform thickness and a nickel plating layer can be formed with a good surface.

Second plating step

In the second plating step, a second plating layer containing silver is formed on the first plating layer. The present step is performed in order to improve the bonding strength between a third plating layer and the first plating layer during a third plating, which is the following step, by forming a thin silver plating layer as a second plating layer on the first plating layer.

The materials and the thickness of the second clad layer are the same as defined in the description of the ceramic case.

The second plating can be performed by immersing the ceramic substrate having the first plating layer and the metallizing layer in a second plating solution containing silver and then applying a current thereto. At this time, the second plating solution may contain silver and cyan (CN). In particular, the second plating solution may contain 1 to 15 g / L or 1.5 to 10 g / L silver and 45 to 160 g / L or 50 to 100 g / L cyan. If the silver concentration of the second plating solution is in the above range, it causes an increase in a plating rate during silver plating and an increase in current density. When the cyan concentration is in the above range, it is possible to effectively form metal deposit ions during silver plating and to dissolve a positive electrode to improve silver plating efficiency.

The second plating can be carried out at 15 to 30 ° C for 10 to 60 seconds at a current of 3 to 6 A / dm ² . In particular, the second plating can be carried out at 18 to 28 ° C. for 10 to 50 seconds at a current of 3 to 5.5 A / dm ² . When the temperature during the second plating is in the above range, a uniform plating rate can be maintained, and when the current is in the above range, the second plating layer can be formed with a uniform thickness.

The second plating step is carried out at a higher current than the third plating step. In particular, a current used in the second plating step is 1.1 to 3 times or 1.3 to 2.5 times higher than a current used in the third plating step. When the amperage of the second plating step is higher than the amperage of the third plating step, a thin one becomes thin The second plating layer is formed on the entire surface of the first plating layer to improve the bonding strength between the first plating layer and the third plating layer during the third plating, which is the following step, so that a ceramic package with less bubbles can be manufactured.

A plating solution (second plating solution) in the second plating step has a lower silver concentration than a plating solution (third plating solution) in the third plating step. In particular, the silver concentration of the plating solution in the third plating step may be 5 to 25 times or 8 to 20 times higher than the silver concentration of the plating solution in the second plating step. As described above, when the silver concentration of the second plating solution is lower than the silver concentration of the third plating solution, a thin second plating layer is formed on the entire surface of the first plating layer in order to improve the bonding strength between the first plating layer and the third plating layer during the third plating, which is the The next step is to improve so that a ceramic package with fewer bubbles can be made.

Third plating step

In the third plating step, a third plating layer containing silver is formed on the second plating layer. In particular, in the present step, a silver plating layer can be formed up to a target thickness.

The materials and the thickness of the third plating layer are the same as defined in the description relating to the silver plating layer of the ceramic case.

The third plating can be performed by immersing the ceramic substrate having the second plating layer, the first plating layer, and the metallizing layer in a third plating solution containing silver, and then applying a current thereto. At this time, the third plating solution may contain silver and cyan (CN). In particular, the third plating solution may contain 20 to 150 g / L or 20 to 100 g / L silver and 30 to 150 g / L or 25 to 145 g / L cyan. If the silver concentration of the third plating solution is in the above range, it has the effect of improving a plating rate and increasing current density. If the cyan concentration is in the above range, it causes metal deposition ions to be formed during plating and a positive electrode to dissolve to improve plating efficiency.

The third plating can be carried out at 29 to 45 ° C for 10 to 60 minutes at a current of 0.5 to 3.5 A / dm ² . More specifically, the third plating can be carried out at 29 to 40 ° C for 20 to 55 minutes at a current of 1 to 3.3 A / dm ² . If the temperature during the third plating is in the above range, it is effective to maintain a constant plating rate, and if the current is in the above range, it is possible to form a plating layer with a uniform thickness and to adjust the surface roughness of the plating layer appropriately.

The ceramic substrate with the third plating layer can then be washed with water, washed with hot water, and dried. The water washing can be carried out using water, and the hot water washing can be carried out using water at 70 to 90 ° C.

As described above, the method of plating a ceramic substrate according to the present invention can suppress the occurrence of bubbles generated between a plating layer and a plating layer on the plating layer, and can form the plating layer with a uniform thickness. In addition, the plating process may not form a solder layer containing silver and copper that are typically used to join a ceramic and a metal.

EMBODIMENT OF THE INVENTION

In the following, the present invention will be described in more detail with reference to examples. However, the following examples are only illustrative of the present invention and are not intended to limit the scope of the present invention.

[Examples]

Example 1. Plating a ceramic substrate

A sample of a ceramic substrate with a metallization layer of molybdenum, manganese and alpha-alumina was washed with hot water at 75 ° C. Thereafter, the sample was degreased with 10% by weight of an acidic aqueous solution and then ultrasonically cleaned using an ultrasonic cleaner and washed with water. Thereafter, using a first plating solution (pH 4.0) containing 70 g / l nickel and 35 g / l boric acid, the first plating was carried out at 45 ° C. for 10 minutes at a current of 2.5 A / dm ² to form a first clad layer.

Thereafter, the sample having the first plating layer was washed with water, and then using a second plating solution containing 2 g / l silver and 80 g / l cyan (CN), the second plating was carried out for 55 seconds at 25 ° C at a Current of 4 A / dm ^{2 was} carried out to form a second clad layer.

Thereafter, the sample having the second plating layer was washed with water, and then using a third plating solution containing 40 g / l silver and 100 g / l cyan (CN), the third plating was carried out for 40 minutes at 30 ° C at a Current of 2.0 A / dm ^{2 was} carried out to form a third clad layer. Thereafter, the sample was washed with water, followed by washing with hot water at 75 ° C, and then dried to prepare a ceramic case.

Examples 2 to 4 and Comparative Examples 1 to 4.

A ceramic package was manufactured by plating a ceramic substrate in the same manner as in Example 1 except that the concentration of silver and cyan of the second plating solution, the plating conditions at the time of the second plating, the concentration of silver and cyan of the third The plating solution and plating conditions at the time of the third plating were set as shown in Table 1 below. [Table 1] example 1 Example 2 Example 3 Example 4 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Second plating solution Silver concentration (g / l) 2 7th 10 12th - 20th 0.5 10 Cyan concentration (g / l) 80 130 95 110 - 60 80 130 Second plating Current (A / dm ² ) 4th 3.5 4.5 4.0 - 4th 3 7th duration 50 sec. 40 sec. 30 sec. 15 sec. - 50 sec. 20 sec. 70 sec. temperature 25 ° C 20 ° C 25 ° C 23 ° C - 25 ° C 25 ° C 25 ° C Third plating solution Silver concentration (g / l) 40 60 50 60 40 40 40 50 Cyan concentration (g / l) 100 80 125 130 100 100 100 100 Third plating Current (A / dm ² ) 2.0 3.0 2.0 2.0 2.0 2.0 2.0 2.0 duration 40 min. 25 min. 40 min. 40 min. 40 min. 40 min. 40 min. 40 min. temperature 30 ° C 40 ° C 32 ° C 30 ° C 30 ° C 30 ° C 30 ° C 40 ° C

Test example 1. Measurement of bubble generation

The bubble generation amounts for 200 ceramic packages manufactured in Example 1 and Comparative Example 1, respectively, were measured, and the generation rates were calculated therefrom. The results are shown in Table 2.

Specifically, the amount of bubble generation was measured by heat treating a ceramic case at 600 ° C. for 3 hours and then observing the surface of the ceramic case with the naked eye. [Table 2] Whether a second plating was performed Production quantity Bubble generation amount Bubble generation rate example 1 Yes 200 pcs 10 pcs 5% Comparative example 1 no 200 pcs 186 pcs 93%

As shown in Table 2, Example 1 in which the second plating was performed had a small bubble generation amount and a low bubble generation rate. On the other hand, Comparative Example 1 in which the second plating was not performed had a large amount of bubble generation and a high bubble generation rate. From the above, it can be seen that a second plating layer improves the bonding strength between a first plating layer (nickel plating layer) and a third plating layer

Test example 2. Measurement of physical properties of ceramic packages

The average thickness of a silver plating layer (second plating layer + third plating layer), surface roughness and bonding strength were measured and calculated for 100 ceramic packages of Examples 1 to 4 and Comparative Examples 1 to 4, and the results are shown in Table 3 below.

Specifically, the thickness of the silver plating layer was measured using X-ray fluorescence (XRF), and the surface roughness was measured by contact using a simple surface roughness meter. In addition, the bonding strength was measured by bonding a copper pin to each ceramic case of Examples and Comparative Examples, and then removing the copper pin using a universal testing machine. [Table 3] Average thickness of the silver plating layer (µm) Surface roughness (µm) Bond Strength (kgf / cm ² ) Second plating layer Third plating layer example 1 1.0 35.7 3.2 2,780 Example 2 1.5 35.9 3.5 2,510 Example 3 2.1 37.2 3.8 2,600 Example 4 2.8 45.8 4.0 2,250 Comparative example 1 0.0 35.5 3.8 560 Comparative example 2 4.3 36.0 7.6 1.110 Comparative example 3 0.3 34.1 5.2 730 Comparative example 4 3.5 36.3 8.2 1,420

As shown in Table 3, the ceramic packages of Examples 1 to 4 have suitable surface roughness and excellent bonding strength, and therefore may not have a solder layer containing silver and copper, which is typically used for joining a ceramic to a metal.

On the other hand, it was confirmed that Comparative Example 1 in which no second clad layer was formed had significantly lower bonding strength than Examples 1 to 4. In addition, it was confirmed that Comparative Examples 2 and 4 had poor surface roughness and poor bonding strength because the average thickness of the second plating layer thereof exceeded 3 µm. In addition, Comparative Example 3, in which the second clad layer was too thin, had significantly poor bonding strength.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 6840429 [0003]

Claims (7)

A ceramic package in a form in which a ceramic substrate, a plating layer, a first plating layer, a second plating layer and a third plating layer are stacked one after the other, wherein: the metallization layer contains molybdenum and manganese; the first plating layer contains nickel; and the second plating layer and the third plating layer each contain silver, and the second plating layer has a thickness of 0.5 to 3 µm and the second plating layer is formed using a plating solution having a lower silver concentration and a higher current than the third plating layer. Ceramic housing according to Claim 1 wherein: the metallization layer has a thickness of 10 to 50 µm; the first plating layer has a thickness of 1 to 20 µm; and the third plating layer has a thickness of 20 to 50 µm. A method of plating a ceramic substrate, the method comprising: Forming a metallization layer containing molybdenum and manganese on a ceramic substrate; a first plating step of forming a first plating layer, containing nickel on the metallization layer; a second plating step of forming a second plating layer, containing silver on the first plating layer; and a third plating step in which a third plating layer containing silver is formed on the second plating layer, the second plating step being carried out at a higher current than the third plating step and a plating solution in the second plating step having a lower silver concentration than a plating solution in the third plating step having. Procedure according to Claim 3 wherein the silver concentration of the plating solution in the third plating step is 5 to 25 times higher than the silver concentration of the plating solution in the second plating step. Procedure according to Claim 3 wherein the silver concentration of the plating solution in the second plating step is 1 to 15 g / L, and the second plating step is carried out for 10 to 60 seconds. Procedure according to Claim 3 wherein the silver concentration of the plating solution in the third plating step is 20 to 150 g / L, and the third plating step is carried out for 10 to 60 minutes. Procedure according to Claim 3 wherein a current used in the second plating step is 1.1 to 3 times higher than a current used in the third plating step.