CN113113321B - Semiconductor high-density lead frame and manufacturing process thereof - Google Patents
Semiconductor high-density lead frame and manufacturing process thereof Download PDFInfo
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- CN113113321B CN113113321B CN202110325931.9A CN202110325931A CN113113321B CN 113113321 B CN113113321 B CN 113113321B CN 202110325931 A CN202110325931 A CN 202110325931A CN 113113321 B CN113113321 B CN 113113321B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4821—Flat leads, e.g. lead frames with or without insulating supports
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0254—After-treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
- C23C22/52—Treatment of copper or alloys based thereon
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/82—After-treatment
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/02—Local etching
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/26—Electroplating: Baths therefor from solutions of cadmium
- C25D3/28—Electroplating: Baths therefor from solutions of cadmium from cyanide baths
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
- C25F1/02—Pickling; Descaling
- C25F1/04—Pickling; Descaling in solution
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4821—Flat leads, e.g. lead frames with or without insulating supports
- H01L21/4828—Etching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4821—Flat leads, e.g. lead frames with or without insulating supports
- H01L21/4835—Cleaning, e.g. removing of solder
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4821—Flat leads, e.g. lead frames with or without insulating supports
- H01L21/4842—Mechanical treatment, e.g. punching, cutting, deforming, cold welding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
- H01L23/495—Lead-frames or other flat leads
- H01L23/49579—Lead-frames or other flat leads characterised by the materials of the lead frames or layers thereon
- H01L23/49586—Insulating layers on lead frames
Abstract
The invention discloses a semiconductor high-density lead frame and a manufacturing process thereof, wherein the manufacturing process comprises the steps of pretreatment, electroplating, browning, rolling, photoetching and the like, and the semiconductor lead frame with high density and high precision is prepared; then placing the copper substrate in an acid solution, wherein the step is to completely remove the oxide film on the surface of the copper substrate; and then, carrying out surface activation on the copper substrate, and keeping the surface activity of the copper substrate, so that the copper substrate and a subsequent coating can be well combined, and the pretreated copper substrate is obtained. According to the method, the photoetching pattern is formed on the surface of the copper substrate after photoetching, processes such as subsequent metal layer electroplating and chip bonding can be carried out during actual operation, and the surface of the prepared lead frame is free from scratches, dents and stains, and can be widely applied to the directions of chip packaging and the like.
Description
Technical Field
The invention relates to the technical field of lead frames, in particular to a semiconductor high-density lead frame and a manufacturing process thereof.
Background
The lead frame is used as a chip carrier of an integrated circuit, is a key structural member for realizing the electrical connection between a leading-out end of an internal circuit of a chip and an external lead by means of bonding materials (gold wires, aluminum wires and copper wires) to form an electrical circuit, plays a role of a bridge connected with an external lead, needs to be used in most semiconductor integrated blocks and is an important basic material in the electronic information industry.
At present, the processing method of the lead frame comprises a die stamping method and a chemical etching method, wherein the die stamping method has high production efficiency, but the processing precision is difficult to ensure, and burrs are easy to appear in the appearance in the processing process and are gradually eliminated by people; the chemical etching method is a common processing method, but the existing etching method still has many disadvantages in the processing process, such as low precision of the photoetching pattern, lateral corrosion and the like, which brings inconvenience in the processing and manufacturing process of the lead frame.
Based on this situation, we disclose a semiconductor high-density lead frame and a manufacturing process thereof to solve the problem.
Disclosure of Invention
The present invention is directed to a semiconductor high-density lead frame and a manufacturing process thereof, which solves the above problems of the prior art.
In order to solve the technical problems, the invention provides the following technical scheme:
a manufacturing process of a semiconductor high-density lead frame comprises the following steps:
(1) taking a copper substrate, washing the copper substrate with deionized water for 3-5min, sequentially removing oil stains and oxidation films on the surface of the copper substrate, then placing the copper substrate in an activating solution for activation, and washing the copper substrate with deionized water to obtain a pretreated copper substrate;
(2) placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate to obtain a copper substrate with the pure copper layer plated on the surface;
(3) taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 55-60s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer;
(4) taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition;
(5) and (4) taking the rolled copper substrate in the step (4), spin-coating photoresist on the upper surface, placing the copper substrate in a baking oven for baking and curing, then exposing, placing the copper substrate in a baking oven for baking for 3-4min at the temperature of 80-85 ℃ after exposure, then placing the copper substrate in an ultrasonic condition for processing for 8-10min, placing the copper substrate in a developing solution for developing, cleaning the copper substrate with deionized water, drying the copper substrate, placing the copper substrate in an etching solution for pattern etching, and removing the photoresist to obtain a finished product.
The optimized scheme comprises the following steps:
(1) washing a copper substrate with deionized water for 3-5min, then placing the copper substrate in electrolyte for cathodic electrolysis for degreasing, washing with deionized water, then placing the copper substrate in a nitric acid solution for soaking for 20-30s to remove a surface oxide film, placing the copper substrate in an activating solution for activating for 3-5min after washing with deionized water, and washing with deionized water to obtain a pretreated copper substrate;
(2) placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate at the electroplating temperature of 60-65 ℃ for 50-60s to obtain the copper substrate with the pure copper layer plated on the surface;
(3) taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 55-60s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer;
(4) taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; the ultrasonic frequency is 28-30kHz during rolling, the rolling pressure is 0.2-0.3MPa, the rolling linear speed is 2m/min, and the vibration amplitude is 10-12 μm;
(5) and (4) taking the rolled copper substrate in the step (4), spin-coating photoresist on the upper surface, placing the copper substrate in a baking oven for baking and curing, then exposing, placing the copper substrate in a baking oven for baking at 80-85 ℃ for 3-4min after exposure, then placing the copper substrate in an ultrasonic condition for processing for 8-10min, placing the copper substrate in a developing solution for developing, cleaning the copper substrate by deionized water, performing microwave drying, placing the copper substrate in an etching solution after drying, performing pattern etching, and removing the photoresist to obtain a finished product.
According to the optimized scheme, in the step (5), the etching solution is a ferric chloride solution, step-by-step etching is adopted during etching, the etching is carried out for 5min, then deionized water is taken out for cleaning, microwave drying is carried out for 1-2min, etching is carried out after drying, and the step is repeated for 2-3 times to complete etching.
In an optimized scheme, in the step (5), the microwave drying frequency is 2-3 GHz.
According to an optimized scheme, in the step (3), the browning liquid comprises the following components: 20-25ml/L of sulfuric acid, 50-54ml/L of hydrogen peroxide, 4-5g/L of zinc sulfate, 1-1.2g/L of tetraethyl ammonium oxalate, 2-3g/L of methionine, 10-15g/L of benzotriazole and 4-5g/L of 2-mercaptobenzimidazole-5-sodium sulfonate dihydrate.
In the optimized scheme, in the step (5), during baking in an oven, the temperature is kept at 65 ℃ for 30-35min, 70 ℃ for 5-10min, 75 ℃ for 5-10min, 80 ℃ for 5-10min and 85 ℃ for 30-35min in sequence, and after baking, the temperature is naturally cooled to room temperature.
In the step (5), the ultrasonic frequency is 20kHz, the ultrasonic power is 180- & lt 300 & gt W, and the excitation current is 0.4-0.8A.
According to a more optimized scheme, in the step (2), the components of the electroplating solution comprise copper cyanide, potassium cyanide and sodium cyanide; the current density during electroplating is 3-4A/dm2。
The optimized scheme is that in the step (1), the electrolyte is mixed solution of trisodium phosphate, sodium hydroxide, sodium silicate and sodium carbonate, the temperature is 50-55 ℃ during electrolytic degreasing, and the current density is 10-12A/dm2The electrolytic degreasing time is 20-25 s.
A semiconductor high-density lead frame prepared according to the above manufacturing process.
Compared with the prior art, the invention has the following beneficial effects:
the invention discloses a semiconductor high-density lead frame and a manufacturing process thereof, wherein the manufacturing process comprises the steps of pretreatment, electroplating, browning, rolling, photoetching and the like, and the semiconductor lead frame with high density and high precision is prepared; then placing the copper substrate in an acid solution, wherein the acid solution is not limited to a nitric acid solution, but also comprises other acid solutions capable of removing the oxide film, and the step is to completely remove the oxide film on the surface of the copper substrate; and then, carrying out surface activation on the copper substrate, keeping the surface activity of the copper substrate, enabling the copper substrate to be well combined with a subsequent coating, and washing with deionized water after activation to obtain the pretreated copper substrate.
The raw material is C7025 copper alloy, in the practical application process, because the copper alloy is easy to oxidize, an oxide film is formed on the surface of the copper alloy, and meanwhile, the copper alloy is subjected to heat treatment for many times in the packaging process of the lead frame, the oxidation degree of the lead frame wire is greatly improved in the heat treatment process, so that the packaging failure caused by the stripping of the oxide film is easy to occur; one of the purposes is that the content of copper oxide in the oxide film is high, and the stripping resistance of the oxide film is poor; however, the content of the copper oxide in the oxide film greatly depends on the material selection of the copper substrate, so in order to avoid the limitation on the material of the copper substrate and solve the problem of oxide film stripping, the application selects to electroplate a pure copper layer on the surface of the copper substrate, because the oxide on the surface of the pure copper layer is mainly cuprous oxide, the content of the copper oxide is very low, and the cuprous oxide has excellent stripping resistance.
On the basis, the pure copper film formed by electroplating is pre-oxidized, the surface treatment is carried out by using a browning liquid, at the moment, an oxidizing agent hydrogen peroxide oxidizes an electroplated copper layer to generate cuprous oxide, components such as methionine, benzotriazole, 2-mercaptobenzimidazole-5-sodium sulfonate dihydrate and the like are introduced into the browning liquid to serve as corrosion inhibitors, the components contain heteroatoms such as N, O, S and the like, the interaction with the electroplated copper layer is strong, the components can be coordinated with the cuprous oxide to form an organic metal oxide film on the surface of the electroplated copper layer, the problem of poor stripping performance of the cupric oxide is avoided due to the formation of the metal oxide film, and the introduced organic matter can improve the adhesive force between the photoresist and the electroplated copper layer and improve the operation effect of the photoetching process.
In the browning process, a sulfuric acid solution is added, the sulfuric acid solution can carry out micro-acid etching on the surface of the electroplated copper layer so as to improve the surface roughness of the electroplated copper layer, but after the whole browning process is carried out, the rough structure of the surface of the electroplated copper layer is not uniform, because an ultrasonic rolling process is added in the subsequent process, the dense uniformity of the structure is ensured while the surface roughness of a lead frame is improved, so that in the browning process, the content of sulfuric acid is greatly reduced, the sulfuric acid content in the conventional browning solution is as high as 50-60ml/L, some operation processes are even more, only 20-25ml/L is added, the formation of an organic metal oxide film is promoted by using the sulfuric acid solution, and the influence on the rough structure of the surface of a copper substrate is far smaller than that in the conventional technology.
This application only carries out the brown ization to the upper surface of copper base plate and handles at brown ization in-process, consequently pastes one deck protection film at the lower surface, and this protection film can set up to tear the membrane during actual operation for protect the lower surface.
Therefore, after the process operation, the ultrasonic rolling is carried out, the rolling pressure is controlled to be 0.2-0.3MPa, the rolling linear speed is 2m/min, the vibration amplitude is 10-12 mu m, the ultrasonic frequency is 28-30kHz and other parameters, the roughness of the surface of the copper substrate after rolling is greatly increased, the surface rough structure is uniform, and the bonding strength is increased during subsequent coating with photoresist.
After ultrasonic rolling, the upper surface of the lead frame is in a uniform and compact rough structure so as to ensure that the photoresist can be tightly combined with the copper substrate in the photoetching process, and the precision of the photoresist mask is accurate; in the process of carrying out pattern photoetching on the upper surface of a copper substrate, after a photoresist is coated in a spinning mode, the copper substrate is placed in an oven for baking and curing, and the baking and curing process is set to be in a step-type temperature rise during operation, so that the temperature change gradient is reduced, and the photoresist is prevented from shrinking, cracking and the like;
carrying out exposure, baking and curing after exposure, introducing ultrasound for assistance, treating for 8-10min under an ultrasonic condition, damaging winding and crosslinking of the photoresist to a certain extent under ultrasonic vibration, and carrying out stress release and stress dispersion on the photoresist so as to avoid the influence of internal stress on the pattern progress of a subsequent developing step; this application develops the sculpture after the supersound, shows the sculpture pattern, and drying method adopts microwave drying this moment, and the condition such as shrink, bonding can take place for the photoresist in the conventional drying process, leads to the photoetching pattern precision to descend, and carries out microwave drying under 2-3GHz microwave frequency, the precision of assurance photoresist pattern that can the very big degree, and the photoetching glue can not take place the bending yet simultaneously, the condition of collapsing, the improvement of very big degree photoetching effect.
And then carrying out wet etching, wherein ferric trichloride is selected as an etching liquid, step-by-step etching is selected in the process, deionized water is taken out for cleaning after 5min of etching, microwave drying is carried out for 1-2min, the etching step is repeated after drying, and the whole etching process is realized by repeating the steps for 2-3 times.
The photoetching pattern is formed on the surface of the copper substrate after photoetching, processes such as subsequent metal layer electroplating, chip bonding and the like can be carried out during actual operation, the method is simple to operate, the prepared lead frame has no scratch, dent and stain on the surface, can be widely applied to directions such as chip packaging and the like, and has higher practicability.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a flow chart of a process for manufacturing a semiconductor high-density lead frame.
Detailed Description
The drawings and technical solutions in the embodiments of the present invention will be clearly and completely described below, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
a manufacturing process of a semiconductor high-density lead frame comprises the following steps:
(1) washing a copper substrate with deionized water for 3min, then placing the copper substrate in an electrolyte for cathodic electrolysis for degreasing, washing with deionized water, then placing the copper substrate in a nitric acid solution for soaking for 20s, removing a surface oxide film, washing with deionized water, then placing the copper substrate in an activating solution for activating for 3min, and washing with deionized water to obtain a pretreated copper substrate; the electrolyte is a mixed solution of trisodium phosphate, sodium hydroxide, sodium silicate and sodium carbonate, the temperature is 50 ℃ during electrolytic degreasing, and the current density is 10A/dm2And the electrolytic degreasing time is 20 s.
(2) Placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate at the electroplating temperature of 60 ℃ for 50s to obtain the copper substrate with the pure copper layer plated on the surface; the components of the electroplating solution comprise copper cyanide, potassium cyanide and sodium cyanide; the current density during electroplating is 3A/dm2。
(3) Taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 55s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer; wherein the browning liquid comprises the following components: 20ml/L of sulfuric acid, 50ml/L of hydrogen peroxide, 4g/L of zinc sulfate, 1g/L of tetraethylammonium oxalate, 2g/L of methionine, 10g/L of benzotriazole and 4g/L of 2-mercaptobenzimidazole-5-sodium sulfonate dihydrate.
(4) Taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; the ultrasonic frequency is 28kHz during rolling, the rolling pressure is 0.2MPa, the rolling linear speed is 2m/min, and the vibration amplitude is 10 μm;
(5) taking the copper substrate rolled in the step (4), spin-coating photoresist on the upper surface of the copper substrate, placing the copper substrate in an oven for baking and curing, and when baking in the oven, sequentially preserving heat at 65 ℃ for 30min, 70 ℃ for 5min, 75 ℃ for 5min, 80 ℃ for 5min and 85 ℃ for 30min, and naturally cooling to room temperature after baking;
exposing, baking at 80 deg.C for 3min, and treating under ultrasonic condition for 8min with ultrasonic frequency of 20kHz, ultrasonic power of 180W, and excitation current of 0.4A; and then placing the substrate in a developing solution for developing, washing the substrate by deionized water, carrying out microwave drying, placing the substrate in an etching solution after drying, carrying out pattern etching, and removing the photoresist to obtain a finished product.
Wherein the etching solution is ferric chloride solution, step-by-step etching is adopted during etching, the deionized water is taken out for cleaning after etching for 5min, microwave drying is carried out for 1min, etching is carried out after drying, and the step is repeated for 2 times to complete etching; in the step (5), the microwave drying frequency is 2 GHz.
Example 2:
a manufacturing process of a semiconductor high-density lead frame comprises the following steps:
(1) washing a copper substrate with deionized water for 4min, then placing the copper substrate in an electrolyte for cathodic electrolysis for degreasing, washing with deionized water, then placing the copper substrate in a nitric acid solution for soaking for 25s, removing a surface oxide film, washing with deionized water, then placing the copper substrate in an activating solution for activating for 4min, and washing with deionized water to obtain a pretreated copper substrate; the electrolyte is a mixed solution of trisodium phosphate, sodium hydroxide, sodium silicate and sodium carbonate, the temperature is 52 ℃ during electrolytic degreasing, and the current density is 11A/dm2The electrolytic degreasing time is 23 s.
(2) Placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate at the electroplating temperature of 62 ℃ for 55s to obtain the copper substrate with the pure copper layer plated on the surface; the components of the electroplating solution comprise copper cyanide, potassium cyanide and sodium cyanide; the current density during electroplating is 3A/dm2。
(3) Taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 58s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer; wherein the browning liquid comprises the following components: 23ml/L of sulfuric acid, 52ml/L of hydrogen peroxide, 4g/L of zinc sulfate, 1.1g/L of tetraethylammonium oxalate, 2.5g/L of methionine, 12g/L of benzotriazole and 4g/L of 2-mercaptobenzimidazole-5-sodium sulfonate dihydrate.
(4) Taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; when rolling, the ultrasonic frequency is 29kHz, the rolling pressure is 0.2MPa, the rolling linear speed is 2m/min, and the vibration amplitude is 12 μm;
(5) taking the copper substrate rolled in the step (4), spin-coating photoresist on the upper surface of the copper substrate, placing the copper substrate in an oven for baking and curing, and when baking in the oven, sequentially preserving heat at 65 ℃ for 33min, 70 ℃ for 8min, 75 ℃ for 8min, 80 ℃ for 8min and 85 ℃ for 32min, and naturally cooling to room temperature after baking;
exposing, baking at 82 deg.C for 3.5min, and treating under ultrasonic condition for 9min with ultrasonic frequency of 20kHz, ultrasonic power of 240W, and exciting current of 0.6; and then placing the substrate in a developing solution for developing, washing the substrate by deionized water, carrying out microwave drying, placing the substrate in an etching solution after drying, carrying out pattern etching, and removing the photoresist to obtain a finished product.
Wherein the etching solution is ferric chloride solution, step-by-step etching is adopted during etching, the deionized water is taken out for cleaning after etching for 5min, microwave drying is carried out for 1.5min, etching is carried out after drying, and the step is repeated for 3 times to complete etching; in the step (5), the microwave drying frequency is 2 GHz.
Example 3:
a manufacturing process of a semiconductor high-density lead frame comprises the following steps:
(1) washing a copper substrate with deionized water for 5min, then placing the copper substrate in an electrolyte for cathodic electrolysis for degreasing, washing with deionized water, then placing the copper substrate in a nitric acid solution for soaking for 30s, removing a surface oxide film, washing with deionized water, then placing the copper substrate in an activating solution for activating for 5min, and washing with deionized water to obtain a pretreated copper substrate; the electrolyte is a mixed solution of trisodium phosphate, sodium hydroxide, sodium silicate and sodium carbonate, the temperature is 55 ℃ during electrolytic degreasing, and the current density is 12A/dm2And the electrolytic degreasing time is 25 s.
(2) Placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate at the electroplating temperature of 65 ℃ for 60s to obtain the copper substrate with the pure copper layer plated on the surface; the components of the electroplating solution comprise copper cyanide and cyanogenPotassium cyanide and sodium cyanide; the current density during electroplating is 4A/dm2。
(3) Taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 60s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer; wherein the browning liquid comprises the following components: 25ml/L of sulfuric acid, 54ml/L of hydrogen peroxide, 5g/L of zinc sulfate, 1.2g/L of tetraethylammonium oxalate, 3g/L of methionine, 15g/L of benzotriazole and 5g/L of sodium 2-mercaptobenzimidazole-5-sulfonate dihydrate.
(4) Taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; when rolling, the ultrasonic frequency is 30kHz, the rolling pressure is 0.3MPa, the rolling linear speed is 2m/min, and the vibration amplitude is 12 mu m;
(5) taking the copper substrate rolled in the step (4), spin-coating photoresist on the upper surface of the copper substrate, placing the copper substrate in an oven for baking and curing, and when baking in the oven, sequentially preserving heat at 65 ℃ for 35min, 70 ℃ for 10min, 75 ℃ for 10min, 80 ℃ for 10min and 85 ℃ for 35min, and naturally cooling to room temperature after baking;
exposing, baking at 85 deg.C for 4min, and treating under ultrasonic condition for 10min with ultrasonic frequency of 20kHz, ultrasonic power of 300W, and excitation current of 0.8A; and then placing the substrate in a developing solution for developing, washing the substrate by deionized water, carrying out microwave drying, placing the substrate in an etching solution after drying, carrying out pattern etching, and removing the photoresist to obtain a finished product.
Wherein the etching solution is ferric chloride solution, step-by-step etching is adopted during etching, the deionized water is taken out for cleaning after etching for 5min, microwave drying is carried out for 2min, etching is carried out after drying, and the step is repeated for 3 times to complete etching; in the step (5), the microwave drying frequency is 3 GHz.
Comparative example 1: comparative example 1a control experiment was set up on the basis of example 2, and comparative example 1 was processed up to step (4) without plating, to obtain a sample of comparative example 1.
Comparative example 2: comparative example 2a control experiment was set up on the basis of example 2, and comparative example 2 was not browned and was processed to step (4) to give a sample of comparative example 2.
And (3) detection test:
1. the copper substrates selected in examples 1 to 3 were all C7025 copper alloy, and the copper substrate processed in step (4) in examples 1 to 3 was used as a sample, and bonding strength between the oxide film and the copper substrate was measured, square grids with a side length of 2 mm were scribed on the surface of the sample substrate at room temperature, and the copper plating layer was cut at one time by the pressure used during scribing to reach the copper substrate, and then the tape was bonded to the surface of the sample, and pressed with a finger, and after 10 seconds, the tape was quickly pulled up in the direction perpendicular to the surface of the sample, and whether the oxide film was peeled off was observed.
Before the test, heat treatment is carried out for 8min at 250 ℃, 280 ℃, 300 ℃ and 330 ℃ in sequence, the detection method is carried out again, and the stripping condition is observed.
2. The copper substrates processed in the step (4) of examples 1 to 3 were sampled, and the samples were placed in 5 wt% NaCl aqueous solution at room temperature to observe corrosion.
3. The samples of comparative example 1 and comparative example 2 were taken, the above test was performed, and the test results were recorded.
4. The photoetching pattern is formed on the surface of the copper substrate after photoetching, processes such as subsequent metal layer electroplating, chip bonding and the like can be carried out in practical operation, and the observation of the lead frame samples prepared in the embodiments 1-3 shows that the surface of the lead frame prepared by the method has no scratch, dent and stain, the side corrosion phenomenon does not occur during processing, no burr is arranged at the edge, the size precision of the pattern is high, and the prepared lead frame can be widely applied to the directions such as chip packaging and the like and has higher practicability.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A manufacturing process of a semiconductor high-density lead frame is characterized in that: the method comprises the following steps: (1) taking a copper substrate, washing the copper substrate with deionized water for 3-5min, sequentially removing oil stains and oxidation films on the surface of the copper substrate, then placing the copper substrate in an activating solution for activation, and washing the copper substrate with deionized water to obtain a pretreated copper substrate; (2) placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate to obtain a copper substrate with the pure copper layer plated on the surface; (3) taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 55-60s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer; (4) taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; (5) and (4) taking the rolled copper substrate in the step (4), spin-coating photoresist on the upper surface, placing the copper substrate in a baking oven for baking and curing, then exposing, placing the copper substrate in a baking oven for baking for 3-4min at the temperature of 80-85 ℃ after exposure, then placing the copper substrate in an ultrasonic condition for processing for 8-10min, placing the copper substrate in a developing solution for developing, cleaning the copper substrate with deionized water, drying the copper substrate, placing the copper substrate in an etching solution for pattern etching, and removing the photoresist to obtain a finished product.
2. The process for manufacturing a semiconductor high-density lead frame according to claim 1, wherein: the method comprises the following steps: (1) washing a copper substrate with deionized water for 3-5min, then placing the copper substrate in electrolyte for cathodic electrolysis for degreasing, washing with deionized water, then placing the copper substrate in a nitric acid solution for soaking for 20-30s to remove a surface oxide film, placing the copper substrate in an activating solution for activating for 3-5min after washing with deionized water, and washing with deionized water to obtain a pretreated copper substrate; (2) placing the pretreated copper substrate in electroplating solution, and electroplating a pure copper layer on the surface of the pretreated copper substrate at the electroplating temperature of 60-65 ℃ for 50-60s to obtain the copper substrate with the pure copper layer plated on the surface; (3) taking the copper substrate electroplated in the step (2), pasting a protective film on the lower surface of the copper substrate, placing the copper substrate with the protective film in a browning liquid for browning treatment, wherein the browning temperature is 35 ℃, the browning time is 55-60s, forming a browning layer, removing the protective film, and washing with deionized water to obtain the copper substrate with the browning layer; (4) taking the copper substrate subjected to browning in the step (3), applying pressure on the browning layer, and rolling the browning layer under an ultrasonic condition; the ultrasonic frequency is 28-30kHz during rolling, the rolling pressure is 0.2-0.3MPa, the rolling linear speed is 2m/min, and the vibration amplitude is 10-12 μm; (5) and (4) taking the rolled copper substrate in the step (4), spin-coating photoresist on the upper surface, placing the copper substrate in a baking oven for baking and curing, then exposing, placing the copper substrate in a baking oven for baking at 80-85 ℃ for 3-4min after exposure, then placing the copper substrate in an ultrasonic condition for processing for 8-10min, placing the copper substrate in a developing solution for developing, cleaning the copper substrate by deionized water, performing microwave drying, placing the copper substrate in an etching solution after drying, performing pattern etching, and removing the photoresist to obtain a finished product.
3. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: in the step (5), the etching solution is ferric trichloride solution, step-by-step etching is adopted during etching, the etching is carried out for 5min, then deionized water is taken out for cleaning, microwave drying is carried out for 1-2min, etching is carried out after drying, and the step 2-3 times is repeated to complete etching.
4. The manufacturing process of a semiconductor high-density lead frame according to claim 3, characterized in that: in the step (5), the microwave drying frequency is 2-3 GHz.
5. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: in the step (3), the browning liquid comprises the following components: 20-25ml/L of sulfuric acid, 50-54ml/L of hydrogen peroxide, 4-5g/L of zinc sulfate, 1-1.2g/L of tetraethyl ammonium oxalate, 2-3g/L of methionine, 10-15g/L of benzotriazole and 4-5g/L of 2-mercaptobenzimidazole-5-sodium sulfonate dihydrate.
6. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: is characterized in that: in the step (5), when baking in the oven, the temperature is kept at 65 ℃ for 30-35min, 70 ℃ for 5-10min, 75 ℃ for 5-10min, 80 ℃ for 5-10min and 85 ℃ for 30-35min in sequence, and after baking, the product is naturally cooled to room temperature.
7. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: in the step (5), the ultrasonic frequency is 20kHz, the ultrasonic power is 180- & lt 300 & gt W, and the excitation current is 0.4-0.8A during ultrasonic treatment.
8. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: in the step (2), the components of the electroplating solution comprise copper cyanide, potassium cyanide and sodium cyanide; the current density during electroplating is 3-4A/dm 2.
9. The manufacturing process of a semiconductor high-density lead frame according to claim 2, characterized in that: in the step (1), the electrolyte is a mixed solution of trisodium phosphate, sodium hydroxide, sodium silicate and sodium carbonate, the temperature is 50-55 ℃, the current density is 10-12A/dm2, and the electrolytic degreasing time is 20-25 s.
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