A method for nickel plating on diamond copper heat sink for microwave high-power device packaging shell

Abstract

The present invention discloses a method for nickel plating on diamond copper heat sink for microwave high-power device packaging shell, including alkaline ultrasonic degreasing, tap water ultrasonic, acidic degreasing, tap water ultrasonic, hydrochloric acid activation, pure water washing, rapid drying, magnetron sputtering, hydrochloric acid activation, tap water washing, pure water washing, electroplating nickel, pure water washing, and rapid drying. The invention provides a formula and use method of an alkaline degreasing agent and an acidic degreasing agent respectively. The two degreasing agents can play a complementary role, respectively targeting the machining oil, animal fats and oxide layers on the surface of diamond copper materials for targeted removal, which can improve the pre-treatment effect and help improve the bonding strength between the substrate and the subsequent nickel plating layer. The nickel plating obtained by plating on the surface of diamond copper in the invention has a good appearance, and the plating does not peel or bubble after high-temperature brazing at 800°C, and has good bonding strength.

Description

Technical Field

[0001] The invention relates to a diamond copper heat sink nickel plating method, in particular to a diamond copper heat sink nickel plating method for a microwave high-power device packaging shell, belonging to the technical field of semiconductor packaging shell plating. Background Art

[0002] The package ceramic shell and metal glass shell have the characteristics of high structural strength, excellent electrothermal performance and microwave performance, and can be used for the preparation of microwave power devices, high-power module GaN devices, hybrid integrated circuits, optical communication devices and other components, and are widely used in the fields of communications, aviation, aerospace, navigation and electronic consumer products. With the continuous increase in the output power of the device, the package shell is required to have a better heat dissipation capacity, so the shell heat sink material needs to have better thermal conductivity.

[0003] At present, conventional oxygen-free copper and CPC heat sink materials can no longer meet the use conditions of packaging shells with higher heat dissipation requirements. Diamond copper composite materials have the advantages of high thermal conductivity and low thermal expansion coefficient of diamond particles while having the good electrical and thermal conductivity of copper. It is an ideal high thermal conductivity and low expansion electronic packaging material. It can be used as an upgraded alternative product for traditional thermal conductive and heat dissipation materials. During use, the temperature rise of the device can be greatly reduced.

[0004] When diamond copper is used as a shell heat sink, the introduction of diamond particles causes the wettability of this type of material to deteriorate, resulting in poor solderability. Therefore, when used, a metal film layer needs to be plated on the surface of the diamond copper to improve its solderability. Since it is difficult to deposit a coating with good bonding strength on the diamond surface through conventional plating processes, defects such as coating peeling, blistering, and bottom exposure are prone to occur. In addition, conventional plating processes often require the use of multiple methods such as roughening, palladium activation, and chemical nickel plating. Plating efficiency, yield rate, and cost are difficult to meet the needs of mass production.

[0005] In view of the above situation, the present invention provides a method for nickel plating of diamond copper heat sink for microwave high-power device packaging shell to solve the problems existing in diamond copper plating. The process of the method is simple and efficient, the obtained coating has a good appearance, and the coating does not peel or bubble after high-temperature brazing at 800°C, and has good bonding strength. Summary of the invention

[0006] The purpose of the present invention is to provide a method for nickel plating of diamond copper heat sink for packaging shell of microwave high-power device in order to solve at least one of the above technical problems.

[0007] The present invention achieves the above-mentioned purpose through the following technical scheme: A method for nickel plating of diamond copper heat sink for microwave high-power device packaging shell, comprising the following steps:

[0008] S1 Alkaline Ultrasonic Degreasing: Effectively removes mineral oil stains caused by mechanical processing on the surface of diamond copper;

[0009] S2 tap water ultrasound: tap water ultrasound for 8-10 minutes to clean the degreasing liquid remaining on the surface of the shell;

[0010] S3 acid degreasing: complementary to the degreasing process in step S1, used to remove animal oils and metal oxide layers on the surface of the material;

[0011] S4 tap water ultrasound: the conditions are the same as step S2;

[0012] S5 hydrochloric acid activation: 35-45℃, use 10% hydrochloric acid by volume for 1-2min to completely remove the oxide layer on the surface of the substrate to be plated, expose the fresh substrate to be plated, and improve the bonding strength of the subsequent metal layer;

[0013] S6 pure water washing: room temperature, 2-5min, to remove the residual activation solution;

[0014] S7 rapid drying: 110℃, 2--5min, rapid drying under blast conditions;

[0015] S8 magnetron sputtering: sputtering Cu / TiW bottom metal to provide a magnetron sputtering seed layer with good bonding strength for the subsequent nickel plating layer;

[0016] S9 hydrochloric acid activation: 20-25℃, use 10% volume fraction hydrochloric acid to activate for 5-10s, remove a small amount of oxide layer on the material surface, activate the metal surface of the seed layer, and improve the bonding strength of subsequent coatings;

[0017] S10 tap water washing: room temperature, 1-2 minutes, to remove the residual activation solution;

[0018] S11 pure water washing: room temperature, 1-2min, to remove the residual activation solution;

[0019] S12 Electroplating Pre-nickel Plating: Improve the bonding strength between the base material and the subsequent plating layer;

[0020] S13 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0021] S14 nickel electroplating: plating to obtain the required nickel layer, using the aminosulfonic acid nickel system;

[0022] S15 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0023] S16 rapid drying: 110℃, 2-5min, rapid drying under blast conditions.

[0024] As a further solution of the present invention: in step S1, the alkaline degreasing solution is composed of: 25% sodium carbonate, 20% sodium hydroxide, 20% corrosion inhibitor, 20% emulsifier, 15% pure water, the temperature range is 65-80°C, and the time is 8-15 minutes.

[0025] As a further solution of the present invention: in step S3, the acidic degreasing solution is composed of: 150-200 ml / L sulfuric acid, 0.2-0.3 g / L butynediol, 20-50 ml / L emulsifier, 0.3-0.5 g / L sodium dodecyl sulfate, temperature range 65-80°C, time 5-10 min.

[0026] As a further solution of the present invention: in step S8, the composition and thickness of the magnetron sputtering seed layer are:

[0027]

[0028] As a further solution of the present invention: in step S12, the pre-nickel electroplating temperature is 30-40°C, the time is 1-2 minutes, and the current density is 3-4A / dm 2 .

[0029] As a further solution of the present invention: in step S14, the nickel electroplating temperature is 50-65°C, the time is 10-20 minutes, and the current density is 1-1.5A / dm 2 , the thickness of the nickel plating layer is 1.5-3μm.

[0030] As a further solution of the present invention: in step S14, the nickel electroplating uses an aminosulfonate nickel system.

[0031] The beneficial effects of the present invention are:

[0032] (1) Compared with conventional processes, the process flow of the invention is simple, no activation agent containing precious metal palladium is required for activation treatment, and the cost is low;

[0033] (2) Compared with conventional processes, the pre-treatment process of the present invention does not include a roughening process, which can prevent the surface roughness of the material from becoming larger after plating, thereby affecting the use effect;

[0034] (3) The invention provides a formula and method of use of an alkaline degreasing agent and an acidic degreasing agent, respectively. The two degreasing agents can play a complementary role and specifically remove machining oil stains, animal fats and oxide layers on the surface of diamond copper materials, respectively, which can improve the pre-treatment effect and help improve the bonding strength between the substrate and the subsequent nickel plating layer;

[0035] (4) The nickel coating obtained by plating on the surface of diamond copper in the present invention has a good appearance. After high-temperature brazing at 800°C, the coating does not peel or bubble, and has good bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Embodiment 1

[0039] A method for nickel plating a diamond copper heat sink for a microwave high-power device packaging shell, taking a diamond volume fraction of 60% and a particle size of 100 μm as an example, comprises the following steps:

[0040] S1 alkaline ultrasonic degreasing: the alkaline degreasing agent ratio is: sodium carbonate 25%, sodium hydroxide 20%, corrosion inhibitor 20%, emulsifier 20%, pure water 15%. The degreasing temperature range is 65-70℃, and the degreasing time is 8-10min. It is used to remove mineral oil stains caused by mechanical processing of diamond copper surface;

[0041] S2 tap water ultrasound: tap water ultrasound for 8-10 minutes to clean the degreasing liquid remaining on the surface of the shell;

[0042] S3 acid degreasing: The acid degreasing agent ratio is: sulfuric acid 150-200ml / L, butynediol 0.2-0.3g / L, emulsifier 20-50ml / L, sodium dodecyl sulfate 0.3-0.5g / L. The degreasing temperature range is 75-80℃, and the degreasing time is 8-10min. This process is complementary to the degreasing process in step 1 and is used to remove animal oils and metal oxide layers on the surface of the material;

[0043] S4 tap water ultrasound: conditions are the same as step 2;

[0044] S5 hydrochloric acid activation: 35-45℃, use 10% hydrochloric acid by volume for 1-2min to completely remove the oxide layer on the surface of the substrate to be plated, expose the fresh substrate to be plated, and improve the bonding strength of the subsequent metal layer;

[0045] S6 pure water washing: room temperature, 2-5min, to remove the residual activation solution;

[0046] S7 rapid drying: 110℃, 2--5min, rapid drying under blast conditions;

[0047] S8 magnetron sputtering: sputtering Cu / TiW bottom metal to provide a seed layer with good bonding strength for the subsequent nickel plating layer; the composition and thickness of the magnetron sputtering seed layer are:

[0048]

[0049] S9 hydrochloric acid activation: 20-25℃, use 10% volume fraction hydrochloric acid to activate for 5-10s, remove a small amount of oxide layer on the material surface, activate the metal surface of the seed layer, and improve the bonding strength of subsequent coatings;

[0050] S10 tap water washing: room temperature, 1-2 minutes, to remove the residual activation solution;

[0051] S11 pure water washing: room temperature, 1-2min, to remove the residual activation solution;

[0052] S12 electroplating pre-nickel plating: temperature is 30-40℃, time is 1-2min, current density is 3-4A / dm 2 . Improve the bonding strength between the base material and the subsequent coating;

[0053] S13 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0054] S14 nickel electroplating: temperature is 50-65℃, time is 10-20min, current density is 1-1.5A / dm 2 , the thickness of the nickel plating layer is 1.5-3μm, and the aminosulfonic acid nickel system is selected;

[0055] S15 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution;

[0056] S16 rapid drying: 110℃, 2--5min, rapid drying under blast conditions.

[0057] Embodiment 2

[0058] A method for nickel plating a diamond copper heat sink for a microwave high-power device packaging shell, taking a diamond volume fraction of 60% and a particle size of 150 μm as an example, comprises the following steps:

[0059] S1 Alkaline ultrasonic degreasing: The alkaline degreasing agent ratio is: 25% sodium carbonate, 20% sodium hydroxide, 20% corrosion inhibitor, 20% emulsifier, and 15% pure water. The degreasing temperature range is 70-75℃, and the degreasing time is 10-12min. It is used to remove mineral oil stains caused by mechanical processing of diamond copper surface;

[0060] S2 tap water ultrasound: tap water ultrasound for 8-10 minutes to clean the degreasing liquid remaining on the surface of the shell;

[0061] S3 acid degreasing: The acid degreasing agent ratio is: sulfuric acid 150-200ml / L, butynediol 0.2-0.3g / L, emulsifier 20-50ml / L, sodium dodecyl sulfate 0.3-0.5g / L. The degreasing temperature range is 70-75℃, and the degreasing time is 6-8min. This process is complementary to the degreasing process in step 1 and is used to remove animal oils and metal oxide layers on the surface of the material;

[0062] S4 tap water ultrasound: conditions are the same as step 2;

[0063] S5 hydrochloric acid activation: 35-45℃, use 10% hydrochloric acid by volume for 1-2min to completely remove the oxide layer on the surface of the substrate to be plated, expose the fresh substrate to be plated, and improve the bonding strength of the subsequent metal layer;

[0064] S6 pure water washing: room temperature, 2-5min, to remove the residual activation solution;

[0065] S7 rapid drying: 110℃, 2--5min, rapid drying under blast conditions;

[0066] S8 magnetron sputtering: sputtering Cu / TiW bottom metal to provide a seed layer with good bonding strength for the subsequent nickel plating layer; the composition and thickness of the magnetron sputtering seed layer are:

[0067]

[0068] S9 hydrochloric acid activation: 20-25℃, use 10% volume fraction hydrochloric acid to activate for 5-10s, remove a small amount of oxide layer on the material surface, activate the metal surface of the seed layer, and improve the bonding strength of subsequent coatings;

[0069] S10 tap water washing: room temperature, 1-2 minutes, to remove the residual activation solution;

[0070] S11 pure water washing: room temperature, 1-2min, to remove the residual activation solution;

[0071] S12 electroplating pre-nickel plating: temperature is 30-40℃, time is 1-2min, current density is 3-4A / dm 2 . Improve the bonding strength between the base material and the subsequent coating;

[0072] S13 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0073] S14 nickel electroplating: temperature is 50-65℃, time is 10-20min, current density is 1-1.5A / dm 2 , the thickness of the nickel plating layer is 1.5-3μm, and the aminosulfonic acid nickel system is selected;

[0074] S15 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0075] S16 rapid drying: 110℃, 2--5min, rapid drying under blast conditions.

[0076] Embodiment 3

[0077] A method for nickel plating a diamond copper heat sink for a package shell for a high-power device, taking a diamond volume fraction of 60% and a particle size of 200 μm as an example, the method comprises:

[0078] S1 alkaline ultrasonic degreasing: the alkaline degreasing agent ratio is: sodium carbonate 25%, sodium hydroxide 20%, corrosion inhibitor 20%, emulsifier 20%, pure water 15%. The degreasing temperature range is 75-80℃, and the degreasing time is 12-15min. It is used to remove mineral oil stains caused by mechanical processing of diamond copper surface;

[0079] S2 tap water ultrasound: tap water ultrasound for 8-10 minutes to clean the degreasing liquid remaining on the surface of the shell;

[0080] S3 acid degreasing: The acid degreasing agent ratio is: sulfuric acid 150-200ml / L, butynediol 0.2-0.3g / L, emulsifier 20-50ml / L, sodium dodecyl sulfate 0.3-0.5g / L. The degreasing temperature range is 65-70℃, and the degreasing time is 5-6min. This process is complementary to the degreasing process in step 1 and is used to remove animal oils and metal oxide layers on the surface of the material;

[0081] S4 tap water ultrasound: conditions are the same as step 2;

[0082] S5 hydrochloric acid activation: 35-45℃, use 10% hydrochloric acid by volume for 1-2min to completely remove the oxide layer on the surface of the substrate to be plated, expose the fresh substrate to be plated, and improve the bonding strength of the subsequent metal layer;

[0083] S6 pure water washing: room temperature, 2-5min, to remove the residual activation solution;

[0084] S7 rapid drying: 110℃, 2--5min, rapid drying under blast conditions;

[0085] S8 magnetron sputtering: sputtering Cu / TiW bottom metal to provide a seed layer with good bonding strength for the subsequent nickel plating layer; the composition and thickness of the magnetron sputtering seed layer are:

[0086]

[0087] S9 hydrochloric acid activation: 20-25℃, use 10% volume fraction hydrochloric acid to activate for 5-10s, remove a small amount of oxide layer on the material surface, activate the metal surface of the seed layer, and improve the bonding strength of subsequent coatings;

[0088] S10 tap water washing: room temperature, 1-2 minutes, to remove the residual activation solution;

[0089] S11 pure water washing: room temperature, 1-2min, to remove the residual activation solution;

[0090] S12 electroplating pre-nickel plating: temperature is 30-40℃, time is 1-2min, current density is 3-4A / dm 2 . Improve the bonding strength between the base material and the subsequent coating;

[0091] S13 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0092] S14 nickel electroplating: temperature is 50-65℃, time is 10-20min, current density is 1-1.5A / dm 2 , the thickness of the nickel plating layer is 1.5-3μm, and the aminosulfonic acid nickel system is selected;

[0093] S15 pure water washing: room temperature, 2-5min, to remove residual nickel plating solution.

[0094] S16 rapid drying: 110℃, 2--5min, rapid drying under blast conditions.

[0095] Working principle: The formula and use method of an alkaline degreasing agent and an acidic degreasing agent are provided respectively. The two degreasing agents can complement each other and respectively remove machining oil, animal grease and oxide layer on the surface of diamond copper materials, which can improve the pre-treatment effect and help improve the bonding strength between the substrate and the subsequent nickel plating layer.

[0096] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0097] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for nickel plating of diamond copper heat sink for microwave high-power device packaging shell, characterized in that: The method consists of the following steps: S1 alkaline ultrasonic degreasing; In step S1, the alkaline degreasing solution is composed of: 25% sodium carbonate, 20% sodium hydroxide, 20% corrosion inhibitor, 20% emulsifier, 15% pure water, the temperature range is 65-80°C, and the time is 8-15min; S2 tap water ultrasound: tap water ultrasound for 8-10 minutes; S3 acid degreasing: complementary to the degreasing process in step S1; In step S3, the acidic degreasing solution is composed of: 150-200 ml / L sulfuric acid, 0.2-0.3 g / L butynediol, 20-50 ml / L emulsifier, 0.3-0.5 g / L sodium dodecyl sulfate, the temperature range is 65-80°C, and the time is 5-10 min; S4 tap water ultrasound: the conditions are the same as step S2; S5 hydrochloric acid activation: 35-45℃, use 10% volume fraction hydrochloric acid for activation for 1-2min; S6 pure water washing: room temperature, 2-5min; S7 fast drying: 110℃, 2-5min; S8 magnetron sputtering: sputtering Cu / TiW base metal; In step S8, the composition and thickness of the magnetron sputtering seed layer are: TiW: 1500±500Å Cu: 3-5 μm S9 hydrochloric acid activation: 20-25℃, use 10% volume fraction hydrochloric acid for activation for 5-10s; S10 tap water washing: room temperature, 1-2min; S11 pure water washing: room temperature, 1-2min; S12 electroplating pre-nickel; In S12, the pre-nickel electroplating temperature is 30-40°C, the time is 1-2min, and the current density is 3-4A / dm 2 ; S13 pure water washing: room temperature, 2-5min; S14 nickel electroplating: plating to obtain the required nickel layer, using the aminosulfonic acid nickel system; In S14, the nickel electroplating temperature is 50-65°C, the time is 10-20 minutes, and the current density is 1-1.5 A / dm 2 , the thickness of nickel plating is 1.5-3μm; S15 pure water washing: room temperature, 2-5min; S16 quick drying: 110℃, 2-5min.

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