Ceramic copper-clad plate as well as preparation method and application thereof

Abstract

The invention discloses a ceramic copper-clad plate and a preparation method and application thereof, and belongs to the technical field of electronic packaging, and the ceramic copper-clad plate is prepared by sequentially carrying out electron beam bombardment, ion beam injection, primary high-power pulse magnetron sputtering, secondary high-power pulse magnetron sputtering and electroplating on a ceramic substrate. The ceramic copper-clad plate sequentially comprises a ceramic substrate, an ion beam injection layer, a high-power pulse magnetron sputtering layer and an electroplated layer from bottom to top. The ceramic copper-clad plate prepared by the preparation method disclosed by the invention has relatively good binding force and tensile modulus, and cracking between ceramic and a copper foil can be effectively reduced; in addition, the preparation method has the advantages of low energy consumption, high practicability, large-scale production and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic packaging, and particularly relates to a ceramic copper clad laminate and a preparation method and application thereof. Background Art

[0002] Most of the currently disclosed ceramic copper clad laminates are made by directly laminating or brazing ceramics and copper foils to combine ceramics and copper foils, and a small amount uses magnetron sputtering to prepare a transition layer to increase the bonding force between the copper foil and the ceramics. For example, Chinese Patent CN201710620249.6 uses a laminating technique to bond ceramics and copper foils; CN201410638370.8 uses a vacuum brazing technique to bond ceramics and copper foils. The master's thesis of Huazhong University of Science and Technology, "Research on the Preparation Technology of Dam-Containing Electroplated Ceramic Substrates", uses magnetron sputtering technology to prepare a transition layer.

[0003] The above laminating or magnetron sputtering methods have certain effects on small-area ceramic copper clad laminates, but when used in large-area ceramic copper clad laminates or fields with large temperature differences, problems such as cracking and failure of ceramics and copper foils may occur due to too long a conduction distance of the thermal expansion and contraction coefficient and too large stress accumulation.

[0004] Therefore, there is an urgent need to provide a large-area ceramic copper clad laminate with excellent bonding properties and a preparation method thereof. Summary of the Invention

[0005] In view of the above technical problems, the present invention provides a ceramic copper clad laminate and a preparation method and application thereof. The ceramic copper clad laminate prepared by this method has good bonding force and tensile modulus, and can effectively reduce cracking between ceramics and copper foils.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A ceramic copper clad laminate, which sequentially includes from bottom to top: a ceramic substrate, an ion beam implantation layer, a high-power pulsed magnetron sputtering layer, and an electroplating layer;

[0009] Among them, the high-power pulsed magnetron sputtering layer includes a high-power pulsed magnetron sputtering transition layer and a secondary high-power pulsed magnetron sputtering layer from bottom to top.

[0010] Preferably, the metal elements in the high-power pulsed magnetron sputtering transition layer and the metal elements in the ion beam implantation layer are homogeneous elements, that is, the same elements.

[0011] Furthermore, the elements in the ion beam implantation layer and the high-power pulsed magnetron sputtering transition layer are all one or more of Ti, Al, Ni, or Cr.

[0012] Preferably, the ion beam implantation layer is in a fence shape and is implanted into the ceramic substrate.

[0013] Preferably, the thickness of the ion beam implantation layer is 0.5 - 10 nm; and / or

[0014] the thickness of the high-power pulsed magnetron sputtering transition layer is 5 - 1000 nm; and / or

[0015] the thickness of the secondary high-power pulsed magnetron sputtering layer is 0.5 - 2 μm; and / or

[0016] the thickness of the electroplated layer is 0.2 - 0.5 mm.

[0017] The second technical solution of the present invention:

[0018] The preparation method of the ceramic copper clad laminate includes the following steps:

[0019] The ceramic copper clad laminate is prepared by sequentially performing electron beam bombardment, ion beam implantation, primary high-power pulsed magnetron sputtering, secondary high-power pulsed magnetron sputtering, and electroplating on the ceramic substrate.

[0020] Beneficial effects: The present invention uses electron beam treatment on the ceramic substrate to increase its roughness and uniformity, which is beneficial to the adhesion of the thin film; using ion beam implantation can make metal ions penetrate into the interior of the ceramic matrix and form a homologous metallurgical bond with the external coating; using high-power pulsed magnetron sputtering technology to prepare a smooth and dense transition layer; finally, electroplating to thicken to 0.2 - 0.5 mm.

[0021] Compared with the single lamination or magnetron sputtering technology, through the preparation method of the present invention, a metallurgical bond that mutually penetrates can be formed between the ceramic substrate and the thin film, effectively improving the bonding force between the ceramic substrate and the copper cladding, and reducing the cracking phenomenon of the ceramic substrate and the copper cladding caused by different coefficients of thermal expansion. In addition, the preparation method of the present invention and the ceramic copper clad laminate prepared thereby also have the characteristics of simple structure, low energy consumption, strong practicability, and suitability for large-scale production.

[0022] Preferably, the conditions during the electron beam bombardment process are: the electron source beam current is 0.1 - 10 mA, and the electron energy is 1 - 100 eV; and / or

[0023] the conditions during the ion beam implantation process are: the ion beam implantation source is a metal source, the beam current size is 0.1 - 100 mA, and the electron energy is 5 - 50 keV; and / or

[0024] the conditions during the primary high-power pulsed magnetron sputtering process are: the sputtering current is 100 - 2000 A, and the bias voltage is (-50) - (-1200) V;

[0025] The conditions in the secondary high-power pulsed magnetron sputtering process are as follows: the sputtering current is 0.5 A - 30 A, and the bias voltage is (-50) - (-1200) V.

[0026] Preferably, the sputtering source used in the secondary high-power pulsed magnetron sputtering process is copper element.

[0027] Preferably, the electroplating used is direct current electroplating, and the output voltage is 5 - 30 V.

[0028] Preferably, the processes of electron beam bombardment, ion beam implantation, primary high-power pulsed magnetron sputtering, and secondary high-power pulsed magnetron sputtering are all sequentially completed in the same vacuum device, and the vacuum degree is 10 -3 -10 -5 Pa.

[0029] The third technical solution of the present invention:

[0030] The application of the ceramic copper clad laminate in large-area power semiconductor devices.

[0031] Preferably, the semiconductor device is a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT).

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] The present invention combines the technology of increasing the film adhesion by electron beam bombardment, the technology of ion beam implantation to form a metallurgical bond between the film and the ceramic substrate, the high-power pulsed magnetron sputtering technology to form a dense transition copper layer, and then uses electroplating to thicken it to prepare a ceramic copper clad laminate with high bonding strength, providing conditions for large-area power semiconductor packaging. At the same time, it effectively reduces energy consumption and can be applied to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0035] Figure 1 It is a structural diagram of the ceramic copper clad laminate prepared by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] The various exemplary embodiments of the present invention will be described in detail below. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0037] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0039] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0040] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0041] As Figure 1 shown, an embodiment of the present invention discloses a ceramic copper clad laminate, and the ceramic substrate copper cladding includes a ceramic substrate modified by electron beam bombardment, an ion beam implanted sparse transition layer (i.e., a fence-shaped ion beam implanted layer), a homogeneous element transition layer prepared by high power pulsed magnetron sputtering and ion beam implantation (a high power pulsed magnetron sputtering transition layer), a copper transition layer prepared by high power pulsed magnetron sputtering (a secondary high power pulsed magnetron sputtering layer), and an electroplated thick copper layer.

[0042] Among them, electron beam bombardment increases the surface roughness and uniformity of the ceramic copper clad substrate; the sparse transition layer implanted with ions is for forming a tight metallurgical combination between the ceramic substrate and the copper cladding, the purpose of high power pulsed magnetron sputtering of homogeneous elements is to better increase the bonding force, and high power pulsed magnetron sputtering of copper is for tightly bonding with the uppermost electroplated layer.

[0043] In some preferred embodiments, the main elements in the ion beam implanted layer (the ion beam implanted sparse transition layer) are one or more of Ti, Al, Ni, or Cr (a mixture).

[0044] The present invention also discloses a method for preparing a ceramic copper clad laminate, comprising the following steps:

[0045] Ultrasonically clean the ceramic substrate with acetone for 10 - 40 minutes to obtain a clean ceramic substrate; then perform the following steps:

[0046] First step: Place it in a vacuum chamber, evacuate to a vacuum degree of 10 -3 -10 -5 Pa, turn on the electron source, turn on the bias voltage, adjust the parameters of the power supply and the bias power supply, bombard the ceramic substrate for 2 - 30 minutes; turn off the electron source;

[0047] Second step: Turn on the ion beam implantation source, turn on the extraction power supply, the suppression power supply, and the arc power supply, adjust the parameters of the ion beam implantation source, work for 2 - 30 minutes to form an ion implantation film with a thickness of 0.5 - 10 nm, and turn off the ion implantation source;

[0048] Third step: Turn on the high - power pulsed magnetron sputtering source, turn on the bias power supply, sputter the same - element as in the second step for 2 - 30 minutes to form a film with a thickness of 5 - 1000 nm, and stop working; during this period, adjust the sputtering parameters to gradually transition the coefficient of thermal expansion and contraction of the film layer from that of the ceramic substrate to that of pure copper;

[0049] Fourth step: Turn on the high - power pulsed magnetron sputtering source, turn on the bias power supply, sputter copper element, the sputtering current is between 0.5 A and 30 A, the bias voltage is between - 50 - (- 1200 V), the sputtering time is between 2 and 300 minutes to form a film with a thickness of 0.5 - 2 μm, and stop working; during this period, adjust the sputtering parameters to gradually transition the coefficient of thermal expansion and contraction of the film layer from that of the third step to that of pure copper;

[0050] Fifth step: Take out the semi - finished product of the fourth step from the vacuum chamber, place it in an electroplating bath, the electroplating voltage is between 2 - 24 V, the working time is between 10 - 120 minutes to form a plating layer with a thickness of 0.2 - 0.5 mm; stop working and take out the manufactured ceramic copper clad laminate.

[0051] The above is achieved through five steps in sequence, that is, the first step is the electron beam bombardment work and stop; the second step is the high - energy ion beam bombardment work and stop; the third step is the high - power pulsed magnetron sputtering to prepare the homologous gradient film layer work and stop; the fourth step is the high - power pulsed magnetron sputtering to prepare the copper gradient film layer work and stop; finally, the fifth step is the electroplating copper work and stop; among them, the first four steps are completed in sequence in the same vacuum device.

[0052] In some preferred embodiments, in the first step, the electron beam current of the electron source is between 0.1 - 10 mA, and the electron energy is between 1 - 100 eV.

[0053] In some preferred embodiments, in the second step, the ion implantation source is a metal source, the beam current is between 0.1 and 100 mA, and the electron energy is between 5 and 50 keV.

[0054] In some preferred embodiments, in the third step, the sputtering current of the high-power pulsed magnetron sputtering is between 100 and 2000 A, and the bias voltage is between -50 and -1200 V.

[0055] All raw materials used in the present invention are obtained by purchasing on the market. The ceramic substrate used in the following examples is an aluminum nitride ceramic substrate.

[0056] The technical solution of the present invention will be further described below through examples.

[0057] Example 1

[0058] First step: Immerse all the ceramic substrates in acetone, with an ultrasonic power of 300 w, and clean the ceramic substrates at room temperature (acetone cleaning) for 30 minutes.

[0059] Second step: Place the ceramic substrates in a vacuum chamber, evacuate to 10 -4 Pa, adjust the glow cleaning power supply to 0.5 A, the electron source beam current is 6 mA, the electron energy is 50 ev, the bias power supply is 30 V, bombard the ceramic substrates for 15 minutes, and the device substrates rotate automatically at 30 r / min.

[0060] Third step: Use a high-purity nickel target (7N) for the metal ion beam implantation source, the ion beam current is 10 mA, the electron energy is 25 keV, adjust the extraction voltage to 30 KV, the ignition voltage is 6 KV, the average arc current is 1 A, the frequency is 50 Hz, the suppression power supply is -1.5 KV, work for 10 minutes, and form a 0.5 nm ion implantation film.

[0061] Fourth step: Use a high-purity nickel target (6N) for the high-power pulsed magnetron sputtering source, the sputtering current is 200 A, the voltage is -800 V, the frequency is 400 Hz, the duty cycle is 0.2, the bias power supply is -700 V, and the sputtering time is 30 minutes to form a 70 nm thin film.

[0062] Fifth step: Use a high-purity copper target (5N) for the high-power pulsed magnetron sputtering source, the sputtering current is 10 A, the sputtering voltage is -1000 V, the bias voltage is -800 V, and the sputtering time is 250 minutes to form a 0.5 um thin film.

[0063] Sixth step: Take out the semi-finished product from the fifth step from the vacuum chamber, put it into an electroplating bath, with an electroplating voltage of 18 V and a working time of 60 minutes, to form a coating with a thickness of 0.4 mm. Stop working and take out the manufactured ceramic copper clad laminate.

[0064] Example 2

[0065] Step 1: Immerse all the substrates in acetone, with an ultrasonic power of 500 W, and clean the ceramic substrates at a temperature of 20 minutes.

[0066] Step 2: Place it in a vacuum chamber, evacuate to 10 -5 Pa, adjust the glow cleaning power supply to 1 A, the electron source beam current to 6 mA, the electron energy to 50 eV, the bias power supply to 40 V, bombard the ceramic substrate for 10 minutes, and the device substrate rotates automatically at 50 r / min.

[0067] Step 3: Use a high-purity chromium target (5N) for the metal ion beam injection source, the ion beam current is 10 mA, the electron energy is 25 keV, the extraction voltage is adjusted to 50 KV, the ignition voltage is 12 KV, the average arc current is 2 A, the frequency is 70 Hz, the suppression power supply is -1.5 KV, work for 10 minutes to form a 0.2 nm ion implantation film.

[0068] Step 4: Use a high-purity chromium target (5N) for the high-power pulsed magnetron sputtering source, the sputtering current is 200 A at peak value, the voltage is -1200 V, the frequency is 300 Hz, the duty cycle is 0.1, the bias power supply is -500 V, and the sputtering time is 20 minutes to form a 70 nm thin film.

[0069] Step 5: Use a high-purity copper target (5N) for the high-power pulsed magnetron sputtering source, the sputtering current is 10 A, the sputtering voltage is -900 V, the bias voltage is -500 V, and the sputtering time is 200 minutes to form a 0.4 µm thin film.

[0070] Step 6: Take out the semi-finished product from the fifth step from the vacuum chamber, place it in an electroplating tank, with an electroplating voltage of 24 V and a working time of 80 minutes to form a coating with a thickness of 0.8 mm. Stop working and take out the manufactured ceramic copper clad laminate.

[0071] Comparative Example 1

[0072] Step 1: Immerse all the ceramic substrates in acetone, with an ultrasonic power of 300 W, and clean the ceramic substrates at room temperature (acetone cleaning) for 30 minutes.

[0073] Step 2: Place the ceramic substrates in a vacuum chamber, evacuate to 10 -4 Pa, adjust the glow cleaning power supply to 0.5 A, the electron source beam current to 6 mA, the electron energy to 50 eV, the bias power supply to 30 V, bombard the ceramic substrate for 15 minutes, and the device substrate rotates automatically at 30 r / min.

[0074] Step 3: Use a high-purity nickel target (6N) for the high-power pulsed magnetron sputtering source, the sputtering current is 200 A at peak value, the voltage is -800 V, the frequency is 400 Hz, the duty cycle is 0.2, the bias power supply is -700 V, and the sputtering time is 30 minutes to form a 70 nm thin film.

[0075] Step 4: The high-power pulsed magnetron sputtering source uses a high-purity copper target (5N), the sputtering current is 10 A, the sputtering voltage is -1000 V, the bias voltage is -800 V, and the sputtering time is 250 minutes to form a 0.5-μm thin film.

[0076] Step 5: Take out the semi-finished product of Step 5 from the vacuum chamber and put it into the electroplating bath. The electroplating voltage is 18 V and the working time is 60 minutes to form a coating with a thickness of 0.4 mm. Stop working and take out the manufactured ceramic copper clad laminate.

[0077] Comparative Example 2

[0078] Step 1: Immerse all the ceramic substrates in acetone, with an ultrasonic power of 300 W, and clean the ceramic substrates at room temperature (acetone cleaning) for 30 minutes.

[0079] Step 2: Put the ceramic substrates into the vacuum chamber, evacuate to 10 -4 Pa, adjust the glow cleaning power supply to 0.5 A, the electron beam current is 6 mA, the electron energy is 50 eV, the bias power supply is 30 V, bombard the ceramic substrates for 15 minutes, and the device substrates rotate automatically at 30 r / min.

[0080] Step 3: The metal ion beam injection source uses a high-purity nickel target (7N), the beam current is 10 mA, the electron energy is 25 keV, the extraction voltage is adjusted to 30 kV, the ignition voltage is 6 kV, the average arc current is 1 A, the frequency is 50 Hz, the suppression power supply is -1.5 kV, and it works for 10 minutes to form a 0.5-nm ion implantation film.

[0081] Step 4: The high-power pulsed magnetron sputtering source uses a high-purity copper target (5N), the sputtering current is 10 A, the sputtering voltage is -1000 V, the bias voltage is -800 V, and the sputtering time is 250 minutes to form a 0.5-μm thin film.

[0082] Step 5: Take out the semi-finished product of Step 5 from the vacuum chamber and put it into the electroplating bath. The electroplating voltage is 18 V and the working time is 60 minutes to form a coating with a thickness of 0.4 mm. Stop working and take out the manufactured ceramic copper clad laminate.

[0083] Effect Verification

[0084] 1. Peel strength: Test according to the test standard of "IPC-TM-650";

[0085] 2. Tensile modulus: Test according to 2.4.18.3 in the standard "IPC-TM-650".

[0086] Test the ceramic copper clad laminates prepared in Examples 1-2 and Comparative Examples 1-2 according to the above test methods, and the effect data are shown in Table 1:

[0087] Table 1

[0088] Peeling strength / (N / mm) Tensile modulus / MPa Example 1 1.72 1521 Example 2 1.80 1576 Comparative Example 1 1.04 833 Comparative Example 2 1.06 794

[0089] As can be seen from Table 1, through the synergistic coupling effect of multiple methods of "electron beam bombardment + ion beam implantation + high-power pulsed magnetron sputtering + electroplating" defined by the present invention, the ceramic copper clad laminates prepared in Examples 1-2 have high bonding strength and also have a relatively high tensile modulus, indicating that the material has small deformation when subjected to tensile force and has higher rigidity and anti-deformation ability.

[0090] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A ceramic copper clad laminate, characterized in that, From bottom to top, it successively includes: A ceramic substrate, an ion beam implantation layer, a high-power pulsed magnetron sputtering layer, and a plating layer; Wherein, the high-power pulsed magnetron sputtering layer includes a high-power pulsed magnetron sputtering transition layer and a secondary high-power pulsed magnetron sputtering layer from bottom to top.

2. A ceramic copper clad laminate according to claim 1, wherein, The metal elements in the high-power pulsed magnetron sputtering transition layer and the metal elements in the ion beam implantation layer are the same elements.

3. A ceramic copper clad laminate according to claim 2, wherein, The elements in the ion beam implantation layer and the high-power pulsed magnetron sputtering transition layer are one or more of Ti, Al, Ni, or Cr.

4. A ceramic clad copper laminate according to claim 1, characterized in that, The ion beam implantation layer is in a fence shape and is implanted into the ceramic substrate.

5. A ceramic copper clad laminate according to claim 1, characterized in that, The thickness of the ion beam implantation layer is 0.5 - 10 nm; and / or The thickness of the high-power pulsed magnetron sputtering transition layer is 5 - 1000 nm; and / or The thickness of the secondary high-power pulsed magnetron sputtering layer is 0.5 - 2 μm; and / or The thickness of the plating layer is 0.2 - 0.5 mm.

6. A preparation method of a ceramic copper clad laminate, characterized in that, It includes the following steps: The ceramic substrate is successively subjected to electron beam bombardment, ion beam implantation, primary high-power pulsed magnetron sputtering, secondary high-power pulsed magnetron sputtering, and plating to prepare the ceramic copper clad laminate according to any one of claims 1 - 5.

7. A method for preparing a ceramic copper clad laminate according to claim 6, wherein The conditions during the electron beam bombardment process are: the electron source beam current is 0.1 - 10 mA, and the electron energy is 1 - 100 eV; and / or The conditions during the ion beam implantation process are: the ion beam implantation source is a metal source, the beam current magnitude is 0.1 - 100 mA, and the electron energy is 5 - 50 keV; and / or The conditions during the primary high-power pulsed magnetron sputtering process are: the sputtering current is 100 - 2000 A, and the bias voltage is (-50) - (-1200) V; The conditions during the secondary high-power pulsed magnetron sputtering process are: the sputtering current is 0.5 A - 30 A, and the bias voltage is (-50) - (-1200) V.

8. The preparation method of a ceramic clad copper laminate according to claim 7, characterized in that, The sputtering source used during the secondary high-power pulsed magnetron sputtering process is copper element.

9. The preparation method of a ceramic clad copper laminate according to claim 6, characterized in that The processes of electron beam bombardment, ion beam implantation, primary high-power pulsed magnetron sputtering, and secondary high-power pulsed magnetron sputtering are all sequentially completed within the same vacuum device, and the vacuum degree is 10 -3 -10 -5 Pa.

10. The application of the ceramic copper clad laminate according to any one of claims 1 - 5 in a large-area power semiconductor device.

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