Lead frame processing method, lead frame and chip packaging product

Abstract

The embodiment of the invention provides a lead frame processing method, a lead frame and a chip packaging product, and the lead frame processing method comprises the steps: providing a lead frame which comprises a base island, and the base island is used for placing a chip; a bonding enhancement layer is formed on the surface of the base island of the lead frame, the bonding enhancement layer covers an area used for placing a chip, and the bonding enhancement layer comprises a metal polycrystalline material. The processing method of the lead frame is used for processing the lead frame, the processed lead frame is used for chip packaging, good binding force exists between the lead frame and the packaging material, the layering risk is reduced, and the packaging reliability is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of chip packaging, and in particular to a lead frame processing method, a chip packaging method and a chip packaging product. Background Art

[0002] In the field of chip packaging, a lead frame is usually used as a carrier for mounting the chip, and the electrodes on the chip are connected to the lead frame through bonding wire welding, so as to connect the electrodes of the chip; at the same time, plastic packaging materials are needed to seal the chip and the bonding wires to protect the chip and the bonding wires from interference and influence of the external environment.

[0003] Usually, packaging materials are used to wrap the chip, bonding wires, and most of the lead frame to complete the packaging. Therefore, the bonding strength between the packaging material and the lead frame will affect the strength and stability of the package. Usually, the lead frame is made of copper alloy, and the bonding wire is made of gold. In order to enhance the welding firmness between the bonding wire and the lead frame, silver is usually electroplated on the lead frame first, and then the bonding wire is welded on the silver. Since the bonding force between the packaging material and the copper alloy is greater than its bonding force with silver, the formation of electroplated silver reduces the area of ​​the copper alloy bonded to the packaging material, resulting in a decrease in the strength of the package. In actual packaging, the packaging material and the lead frame are prone to delamination.

[0004] In order to enhance the package strength, the unsilver-plated area on the lead frame surface is usually treated. One of the treatment methods is oxidation treatment. The oxidized lead frame surface has a certain strengthening of the bonding strength with the packaging material. However, the bonding strength between the lead frame surface and the packaging material may decrease over time, and the packaging material and the lead frame may be delaminated, resulting in package failure; especially when the silver-plated area is large, delamination is more likely to occur.

[0005] Therefore, a new method for processing lead frames is needed. Summary of the invention

[0006] In order to solve the problem of delamination between packaging materials and lead frames during chip packaging and improve the reliability of packaging, an embodiment of the present disclosure provides a method for processing a lead frame, including: providing a lead frame, the lead frame including a base island, the base island being used to place the chip; forming a bonding enhancement layer on the surface of the base island of the lead frame, the bonding enhancement layer covering the area for placing the chip, the bonding enhancement layer including a metal polycrystalline material.

[0007] In some embodiments, before forming the bonding enhancement layer, a patterned mask layer is further formed on the surface of the base island of the lead frame to expose the area where the bonding enhancement layer is to be formed.

[0008] In some embodiments, forming the bonding enhancement layer includes: forming the bonding enhancement layer on the surface of the base island of the lead frame by electrochemical reaction.

[0009] In some embodiments, the electrochemical reaction comprises: using a copper salt solution with a concentration of 0.1 to 2 mol / L or a solution containing a copper cyanide complex ion with a concentration of 0.1 to 2 mol / L as a reaction solution, using the lead frame as a cathode, and reacting at 0.1 to 100 A / dm 2 The electrochemical reaction was carried out at a current density of .

[0010] In some embodiments, forming the bonding enhancement layer further comprises: after the electrochemical reaction, removing the patterned mask layer by using an alkaline solution with a concentration of 0.1-2 mol / L.

[0011] In some embodiments, forming the bonding enhancement layer includes: forming the bonding enhancement layer on the surface of the base island of the lead frame by 3D printing.

[0012] In some embodiments, the 3D printing includes: performing 3D printing on the surface of the base island with ink containing 20 wt % to 80 wt % of copper, and the viscosity of the ink is 1 to 1000 cp.

[0013] In some embodiments, the bonding enhancement layer includes polycrystalline copper.

[0014] In some embodiments, the bonding enhancement layer has a thickness of 0.1 μm to 5 μm.

[0015] In some embodiments, after forming the bonding enhancement layer, the lead frame processing method further includes: performing an oxidation process on at least a portion of the bonding enhancement layer to form an oxide layer.

[0016] In some embodiments, the oxidation treatment includes: immersing the lead frame in an oxidation treatment solution to form an oxide layer on a portion of the surface of the lead frame, the oxidation treatment solution includes an oxidant, a first modifier and a first additive, and the mass fraction of the oxidant is 1% to 10%; cleaning the lead frame.

[0017] In some embodiments, the first modifier includes one or more of triazole, tetrazole, and imidazole, the first additive includes amine or quaternary ammonium salt, and the oxidant includes one or more of hydrogen peroxide, sodium persulfate, and sodium chlorite.

[0018] In some embodiments, before performing the oxidation treatment, the processing method of the lead frame also includes: performing oxidation pretreatment on the lead frame; the oxidation pretreatment includes: placing the lead frame in an oxidation pretreatment liquid, the oxidation pretreatment liquid includes: a second modifier and a second additive, the mass fraction of the second modifier is 1% to 10%, and the mass fraction of the second additive is 1% to 10%.

[0019] In some embodiments, the second modifier includes one or more of triazole, tetrazole, and imidazole, and the second additive includes amine or quaternary ammonium salt.

[0020] In some embodiments, after the oxidation treatment, the processing method of the lead frame further includes: performing post-oxidation treatment on the lead frame; the post-oxidation treatment includes: placing the lead frame in a post-oxidation treatment liquid, the post-oxidation treatment liquid includes a complexing agent or a chelating agent, and the mass fraction of the complexing agent or the chelating agent is 1% to 10%.

[0021] In some embodiments, the complexing agent or chelating agent includes one or more of a nitrogen-containing compound, an oxygen-containing compound, or a sulfur-containing compound.

[0022] In some embodiments, after the post-oxidation treatment, the ratio of the actual surface area of ​​the oxide layer to the area occupied by the oxide layer on the surface of the lead frame is 1-5.

[0023] In some embodiments, after the post-oxidation treatment, the thickness of the oxide layer is

[0024] An embodiment of the present disclosure also provides a lead frame, which includes: a base island suitable for placing a chip; a bonding enhancement layer located on the surface of the base island, the bonding enhancement layer covers the area for placing the chip, and the bonding enhancement layer includes a polycrystalline material of a metal; and an oxide layer located on the surface of the bonding enhancement layer.

[0025] In some embodiments, the bonding enhancement layer includes polycrystalline copper.

[0026] In some embodiments, the lead frame is made of copper alloy or copper.

[0027] In some embodiments, the thickness of the oxide layer is

[0028] In some embodiments, a ratio of an actual area of ​​the surface of the oxide layer to an area occupied by the oxide layer on the surface of the lead frame is 1-5.

[0029] An embodiment of the present disclosure also provides a chip packaging product, which includes: any of the above lead frames; a chip mounted on a base island of the lead frame; bonding wires electrically connecting the chip to the lead frame; and packaging material, which encapsulates the chip, the bonding wires, and at least part of the lead frame.

[0030] In some embodiments, the encapsulation material includes epoxy resin.

[0031] Compared with the prior art, the technical solution of the embodiment of the present disclosure has the following beneficial effects:

[0032] The lead frame processing method of the embodiment of the present disclosure forms a bonding enhancement layer on the surface of the base island of the lead frame, the bonding enhancement layer includes a metal polycrystalline material, and the bonding enhancement layer is oxidized to form an oxide layer with a certain roughness. The processed lead frame is used for chip packaging. The oxide layer has good bonding strength with the packaging material, which reduces the risk of delamination and improves the reliability of packaging.

[0033] The lead frame of the embodiment of the present disclosure includes a bonding enhancement layer and an oxide layer. When the lead frame is used for chip packaging, the packaging material enters the gaps or recesses on the oxide layer on the base island of the lead frame during the packaging process. After the packaging material is solidified, the oxide layer and the packaging material have good bonding force, thereby improving the strength and reliability of the package. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features and advantages of the present disclosure will be better understood through the following detailed description of the optional embodiments in conjunction with the accompanying drawings, in which the same reference numerals represent the same or similar components, wherein:

[0035] Figure 1 A schematic flow chart showing a method for processing a lead frame according to an embodiment of the present disclosure is shown;

[0036] Figure 2 A side structural schematic diagram of a lead frame according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0037] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as limiting the present disclosure.

[0038] In order to solve the problem of delamination between packaging materials and lead frames due to insufficient bonding force or other reasons during chip packaging and to improve the reliability of packaging, an embodiment of the present disclosure provides a method for processing a lead frame, including: providing a lead frame, the lead frame including a base island, the base island being used to place the chip; forming a bonding enhancement layer on the surface of the base island of the lead frame, the bonding enhancement layer covering the area for placing the chip, the bonding enhancement layer including a metal polycrystalline material.

[0039] Figure 1 A schematic diagram of a process flow of a lead frame processing method according to an embodiment of the present disclosure is shown below. Figure 1 The lead frame processing method of the embodiment of the present disclosure is described in detail.

[0040] refer to Figure 1 In S11, a lead frame is provided, wherein the lead frame includes a base island, and the base island is used to place a chip. In some specific embodiments, the lead frame is made of copper or copper alloy.

[0041] In S12, the lead frame is pre-treated, and the pre-treatment includes pre-cleaning and activation. The pre-cleaning includes: cleaning the lead frame with a cleaning solution, and then cleaning with deionized water to remove pollutants or contamination marks such as oil, dust, stains, fingerprints, etc. on the surface of the lead frame. In some specific embodiments, the cleaning solution includes an alkaline solution or an organic solvent, such as a sodium hydroxide aqueous solution with a concentration of 10 to 50 g / L or a triethylamine solution with a mass fraction of 5% to 10%. In some specific embodiments, cleaning is to immerse the lead frame in a cleaning solution to remove pollutants.

[0042] After cleaning, activation is performed to remove the residual cleaning solution on the lead frame and make the surface of the lead frame free and clean. In some specific embodiments, the activation includes: using an inorganic acid to remove any residual alkali film and / or oxide film on the lead frame, and the inorganic acid includes one or more of hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid. In some specific embodiments, the activation is to immerse the lead frame in an inorganic acid to fully remove the residue on the surface of the lead frame.

[0043] In S13, a bonding enhancement layer is formed on the surface of the base island of the lead frame, and then a subsequent processing process is performed based on the bonding enhancement layer, so as to increase the bonding force between the lead frame and the packaging material.

[0044] In some specific embodiments, forming the bonding enhancement layer on the surface of the base island of the lead frame includes: forming the bonding enhancement layer on the surface of the base island of the lead frame by an electrochemical reaction.

[0045] In order to better control the area where the bonding enhancement layer is formed in the electrochemical reaction, in some specific embodiments, before the electrochemical reaction is carried out, a patterned mask layer is also formed on the surface of the base island of the lead frame to expose the area where the bonding enhancement layer is subsequently formed. The shape of the mask layer is determined according to factors such as the size of the lead frame, the size of the chip, and the size and position of the pad on the lead frame. In some specific embodiments, a patterned mechanical mask is used to cover the base island of the lead frame as a patterned mask layer to expose the area where the bonding enhancement layer is subsequently formed. In some specific embodiments, a patterned dry film is formed on the base island of the lead frame by laser direct imaging technology as a patterned mask layer to expose the area where the bonding enhancement layer is subsequently formed.

[0046] In some specific embodiments, the electrochemical reaction comprises: using a copper salt solution with a concentration of 0.1 to 2 mol / L or a solution containing a copper cyanide complex ion with a concentration of 0.1 to 2 mol / L as a reaction solution, using the base island of the lead frame as a cathode, and using stainless steel, titanium or copper as an anode at a current of 0.1 to 100 A / dm 2 An electrochemical reaction is carried out at a current density of to form a bonding enhancement layer on the surface of the base island.

[0047] In some specific embodiments, in the copper salt solution, copper exists in the form of copper ions. In the electrochemical reaction, the base island of the lead frame serves as a cathode, and the copper ions obtain electrons at the base island and are converted into zero-valent copper and deposited on the base island to form a bonding enhancement layer. In some specific embodiments, the copper salt solution includes: copper sulfate solution, copper chloride solution, or copper nitrate solution, etc.

[0048] In some specific embodiments, in a solution containing copper cyanide complex ions, copper exists in the form of copper cyanide complex ions. In an electrochemical reaction, the base island of the lead frame serves as a cathode, and the copper cyanide complex ions obtain electrons at the base island to generate zero-valent copper deposited on the base island to form a bonding enhancement layer. In some specific embodiments, the copper cyanide complex ions include: [Cu(CN) 2 ] - 、[Cu(CN) 3 ] 2- , or [Cu(CN) 4 ] 3- etc.

[0049] In some specific embodiments, forming the bonding enhancement layer further comprises: after the electrochemical reaction, removing the patterned mask layer by using an alkaline solution with a concentration of 0.1 to 2 mol / L. In some specific embodiments, removing the patterned mask layer by using a NaOH solution or a KOH solution with a concentration of 0.1 to 2 mol / L at 10° C. to 80° C.

[0050] In order to make the formed bonding enhancement layer have a polycrystalline structure, the electrochemical reaction is carried out in multiple times, and each reaction uses a copper salt solution of different concentrations or a solution containing copper cyanide complex ions of different concentrations or types as a reaction solution, and the reaction is carried out at the same or different current density.

[0051] In a specific embodiment, forming a bonding enhancement layer on the surface of the base island by electrochemical reaction includes: forming a patterned mask layer on the surface of the base island, the mask layer exposing an area where the bonding enhancement layer is formed; placing the lead frame in a film containing [Cu(CN)] with a concentration of 0.79 mol / L 2 ] - In the solution, the lead frame base island is used as the cathode and the metal copper is used as the anode. 2 The electrochemical reaction was carried out at a current density of 15s; the lead frame was placed in a KOH solution with a concentration of 0.9mol / L, and the patterned mask layer on the surface of the base island was removed at 50°C; the lead frame was cleaned; the thickness of the bonding enhancement layer formed on the surface of the base island was 0.1μm.

[0052] In some specific embodiments, forming the bonding enhancement layer on the surface of the base island of the lead frame includes: forming the bonding enhancement layer on the surface of the base island of the lead frame by 3D printing.

[0053] In some specific embodiments, 3D printing is performed on the surface of the base island to form a bonding enhancement layer, specifically comprising: using a 3D printing device to form a structure of the bonding enhancement layer on the surface of the base island using an ink containing 20wt% to 80wt% of copper; and curing the 3D printed structure of the bonding enhancement layer by heating or laser sintering to form a bonding enhancement layer.

[0054] In some specific embodiments, the 3D printed bonding enhancement layer structure is cured by heating to 80° C. to 800° C., thereby forming the bonding enhancement layer.

[0055] In some specific embodiments, a 0.1W to 50W laser is used to solidify the structure of the 3D printed bonding enhancement layer, thereby forming the bonding enhancement layer.

[0056] In some specific embodiments, the viscosity of the ink used for 3D printing is 1-1000 cp.

[0057] In some specific embodiments, the ink used for 3D printing contains 20 wt % to 80 wt % of copper and a polar or non-polar substance.

[0058] There are many printing methods for 3D printing. In some specific implementations, the bonding reinforcement layer is formed by one 3D printing.

[0059] In some specific embodiments, multiple printing layers are formed on the base island by multiple 3D printings, and the multiple printing layers constitute the bonding reinforcement layer. The same or different inks can be used for 3D printing of each printing layer; the formation process of each printing layer constituting the bonding reinforcement layer can be layer-by-layer printing and layer-by-layer curing, or layer-by-layer printing and then curing together. Different inks are used to print to form stacked layers or the bonding reinforcement layer is printed in different regions.

[0060] In a specific embodiment, a 3D printing device is used to print a polyurethane solution containing 50wt% of copper as ink, the viscosity of the ink is 6cp, and the structure of the bonding enhancement layer is printed. A 1.5W laser is used and the laser is moved at a moving speed of 5mm / s for sintering to form a bonding enhancement layer. The thickness of the bonding enhancement layer is 0.8μm.

[0061] In S13 , the material of the bonding enhancement layer formed on the surface of the base island of the lead frame is polycrystalline copper, that is, copper is a crystal with multiple crystal orientations.

[0062] In some specific embodiments, the bonding enhancement layer has a thickness of 0.1 μm to 5 μm.

[0063] In S14, the lead frame is subjected to oxidation pretreatment. The oxidation pretreatment includes placing the lead frame in an oxidation pretreatment liquid to provide a lead frame surface more suitable for reaction for subsequent oxidation treatment. In some specific embodiments, the oxidation pretreatment liquid includes a second modifier and a second additive, wherein the second modifier includes one or more of triazole, tetrazole, and imidazole, and the second additive includes an amine or a quaternary ammonium salt.

[0064] In some specific embodiments, the mass fraction of the second modifier is 1% to 10%, and the mass fraction of the second additive is 1% to 10%.

[0065] In S15, at least a portion of the bonding enhancement layer is oxidized to form an oxide layer, which specifically includes: placing the lead frame in an oxidizing treatment solution for reaction; and cleaning the lead frame.

[0066] Oxidizing at least a portion of the bonding enhancement layer means that during the oxidation process of the bonding enhancement layer, it is not necessary to oxidize all of the bonding enhancement layer, nor is it necessary to form an oxide layer on all surfaces of the bonding enhancement layer. After the oxidation treatment, the bonding enhancement layer is located between the oxide layer and the surface of the base island, and does not affect the various performances of the lead frame for chip packaging.

[0067] In some specific embodiments, the oxidation treatment solution includes an oxidant, a first modifier and a first additive. In some specific embodiments, the oxidant includes one or more of hydrogen peroxide, sodium persulfate, and sodium chlorite. The addition of the first modifier and the first additive is used to control the speed of forming an oxide layer on a portion of the surface of the lead frame. In some specific embodiments, the first modifier includes one or more of triazole, tetrazole, and imidazole, and the first additive includes an amine or a quaternary ammonium salt.

[0068] In some specific embodiments, in the oxidation treatment solution, the mass fraction of the oxidant is 1% to 10%.

[0069] During the oxidation process, since the bonding enhancement layer includes a polycrystalline material of a metal, the metal is bonded with oxygen atoms in multiple directions to form an oxide of the metal, and thus, the oxide layer has an uneven surface.

[0070] In some specific embodiments, after the post-oxidation treatment, the ratio of the actual surface area of ​​the oxide layer to the area occupied by the oxide layer on the surface of the lead frame (S ratio) is 1 to 5. The actual surface area of ​​the oxide layer refers to the surface area of ​​the rough surface of the oxide layer, and the area occupied by the oxide layer on the surface of the lead frame refers to the area projected by the oxide layer on the surface of the lead frame. The ratio of the two (S ratio) is used to characterize the surface roughness of the oxide layer.

[0071] In some specific embodiments, after the post-oxidation treatment, the thickness of the oxide layer is Since the oxide layer has roughness, the thickness of the oxide layer refers to the average thickness of the oxide layer.

[0072] In S16, the lead frame is subjected to oxidation treatment to remove residual impurities on the oxide layer, such as metal oxides, metal salts or other contaminants, especially byproducts generated in the process of forming the oxide layer, so as to improve the purity of the oxide layer. Specifically, the lead frame is immersed in an oxidation post-treatment solution, wherein the oxidation post-treatment solution includes a complexing agent or a chelating agent.

[0073] In some specific embodiments, in the post-oxidation treatment solution, the mass fraction of the complexing agent or chelating agent is 1% to 10%.

[0074] In some embodiments, the complexing agent or chelating agent includes one or more of a nitrogen-containing compound, an oxygen-containing compound or a sulfur-containing compound. In some embodiments, the complexing agent can be a nitrogen-containing compound, such as one or more of ammonia, an ammonium salt (such as ammonium chloride), an amino acid (such as ethylenediaminetetraacetic acid). In some embodiments, the complexing agent can be an oxygen-containing compound, such as one or more of a compound containing a carboxyl group (such as oxalate, acetate) or a hydroxyl group (such as hydroxide, citrate, tartrate, lactate). In some embodiments, the complexing agent can be a sulfur-containing compound, such as thiosulfate, thiocyanate, mercaptan or mercaptocarboxylic acid (such as thiolactic acid).

[0075] In order to increase the reaction rate of the post-oxidation treatment and enhance the effect of the post-oxidation treatment, in some specific embodiments, while the lead frame is immersed in the post-oxidation treatment solution for reaction, ultrasound, spraying, heating, compressed air or other processes are applied to promote the relevant chemical reactions that occur to remove pollutants.

[0076] In S17, the lead frame is cleaned and dried, specifically including: performing post-cleaning on the lead frame to remove any metal complex, metal salt or other contaminant residues remaining in the oxidation treatment. In some specific embodiments, the post-cleaning includes: immersing the lead frame in a mixture of one or more of inorganic acid, sulfuric acid, hydrochloric acid, phosphorous acid, and nitric acid, and then rinsing with deionized water to remove the inorganic acid remaining on the surface of the lead frame. In some specific embodiments, the mass fraction of the inorganic acid is 1% to 10%.

[0077] After post-cleaning, the lead frame is dried. In some specific embodiments, the drying includes placing the lead frame in a warm and dry flowing air environment to gradually dry the lead frame.

[0078] In some embodiments, the temperature of the warm dry flowing air ranges from 60°C to 150°C.

[0079] In some specific embodiments, the lead frame is placed at the air outlet of a blower, and the lead frame is blown by the warm air blown by the blower to dry it.

[0080] The lead frame is processed by the processing method of S11 to S17, and the bonding enhancement layer composed of the metal polycrystalline material is oxidized to obtain an oxide layer. The oxide layer is formed on the polycrystalline metal material, so its surface is uneven and has a certain roughness.

[0081] Due to the molding process of the lead frame, usually, the copper in the lead frame material is arranged in a single crystal direction. After the copper is oxidized, oxygen combines with copper to grow on the surface of the lead frame to form copper oxide. Since copper is a single crystal, the direction in which the copper oxide grows is relatively consistent, resulting in the bonding strength with the packaging material may not meet the requirements, and over time, the packaging material and the lead frame may be delaminated, resulting in packaging failure; especially when the silver-plated area is large, delamination is more likely to occur.

[0082] The oxide layer formed by the polycrystalline material of the metal included in the bonding enhancement layer of the lead frame treated by the treatment methods of S11 to S17 has a greater roughness than the oxide layer formed by the single crystal material. The lead frame treated by the treatment methods of S11 to S17 is applied to chip packaging, and the chip and at least part of the lead frame are packaged by the packaging material. During the packaging process, the packaging material enters the gap or recess on the oxide layer on the base island of the lead frame. After the packaging material is solidified, the oxide layer has a good bonding force with the packaging material, thereby improving the strength and reliability of the package.

[0083] An embodiment of the present disclosure further provides a lead frame. Figure 2 A side view of the lead frame of an embodiment of the present disclosure is shown, referring to Figure 2 The lead frame includes: a base island 1, which includes an area 11 for placing a chip; a bonding enhancement layer 2, which is located on the surface of the base island 1, and the bonding enhancement layer 2 covers the area 11 for placing the chip, and the bonding enhancement layer 2 includes a metal polycrystalline material; an oxide layer 3, which is located on the surface of the bonding enhancement layer 2.

[0084] In some specific embodiments, the bonding enhancement layer 2 includes polycrystalline copper, in which the copper is in the form of polycrystalline crystals; the oxide layer 3 includes copper oxide, for example, one or more of copper oxide or cuprous oxide.

[0085] In some specific embodiments, the lead frame is made of copper alloy or copper.

[0086] In some specific embodiments, the thickness of the oxide layer 3 is

[0087] In some specific embodiments, the ratio of the actual surface area of ​​the oxide layer 3 to the area occupied by the oxide layer 3 on the surface of the lead frame is 1-5.

[0088] When the lead frame of the embodiment of the present disclosure is used for chip packaging, the packaging material enters the gaps or recesses on the oxide layer 3 on the base island 1 of the lead frame during the packaging process. After the packaging material is solidified, the oxide layer 3 has good bonding force with the packaging material, thereby improving the strength and reliability of the packaging.

[0089] An embodiment of the present disclosure also provides a chip packaging product, which includes: a lead frame of the above embodiment; a chip mounted on a base island of the lead frame; bonding wires electrically connecting the chip to the lead frame; and packaging material, wherein the packaging material encapsulates the chip, the bonding wires, and at least a portion of the lead frame.

[0090] In some embodiments, the encapsulation material includes epoxy resin.

[0091] An oxide layer is formed on the base island of the lead frame. In some specific embodiments, the thickness of the oxide layer is

[0092] In some specific embodiments, the ratio of the actual area of ​​the surface of the oxide layer to the area occupied by the oxide layer 3 on the surface of the lead frame is 1-5.

[0093] The chip packaging product of the embodiment of the present disclosure has good packaging strength and high packaging reliability because the oxide layer formed on the base island of the lead frame has good bonding strength with the packaging material.

[0094] The above is only an exemplary embodiment used to illustrate the principle of the present disclosure, and is not intended to limit the scope of protection of the present disclosure. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also within the scope of protection of the present disclosure.

Claims

1. A method for processing a lead frame, characterized in that: include: Providing a lead frame, the lead frame comprising a base island, the base island being used for placing a chip; A bonding enhancement layer is formed on the surface of the base island of the lead frame, the bonding enhancement layer covers the area for placing the chip, and the bonding enhancement layer includes a metal polycrystalline material.

2. The lead frame processing method according to claim 1, characterized in that: Before forming the bonding enhancement layer, a patterned mask layer is formed on the surface of the base island of the lead frame to expose the area where the bonding enhancement layer is to be formed.

3. The lead frame processing method according to claim 2, characterized in that: The forming of the bonding enhancement layer includes forming the bonding enhancement layer on the surface of the base island of the lead frame by electrochemical reaction.

4. The lead frame processing method according to claim 3, characterized in that: The electrochemical reaction comprises: using a copper salt solution with a concentration of 0.1 to 2 mol / L or a solution containing copper cyanide complex ions with a concentration of 0.1 to 2 mol / L as a reaction solution, using the lead frame as a cathode, and reacting at 0.1 to 100 A / dm 2 The electrochemical reaction was carried out at a current density of .

5. The lead frame processing method according to claim 4, characterized in that: The forming of the bonding enhancement layer further comprises: after the electrochemical reaction, removing the patterned mask layer by using an alkaline solution with a concentration of 0.1 to 2 mol / L.

6. The lead frame processing method according to claim 1, characterized in that: Forming the bonding enhancement layer includes: forming the bonding enhancement layer on the surface of the base island of the lead frame by 3D printing.

7. The lead frame processing method according to claim 6, characterized in that: The 3D printing comprises: performing 3D printing on the surface of the base island with ink containing 20wt% to 80wt% of copper, wherein the viscosity of the ink is 1 to 1000cp.

8. The method for processing a lead frame according to any one of claims 1 to 7, characterized in that: The bonding enhancement layer includes polycrystalline copper.

9. The method for processing a lead frame according to any one of claims 1 to 7, characterized in that: The thickness of the bonding enhancement layer is 0.1 μm to 5 μm.

10. The method for processing a lead frame according to any one of claims 1 to 7, characterized in that: After forming the bonding enhancement layer, the method further includes: performing oxidation treatment on at least a portion of the bonding enhancement layer to form an oxide layer.

11. The lead frame processing method according to claim 10, characterized in that: The oxidation treatment comprises: Immersing the lead frame in an oxidation treatment solution to form an oxide layer on a portion of the surface of the lead frame, wherein the oxidation treatment solution comprises an oxidant, a first modifier and a first additive, and the mass fraction of the oxidant is 1% to 10%; The lead frame is cleaned.

12. The lead frame processing method according to claim 11, characterized in that: The first modifier includes one or more of triazole, tetrazole, and imidazole, the first additive includes amine or quaternary ammonium salt, and the oxidant includes one or more of hydrogen peroxide, sodium persulfate, and sodium chlorite.

13. The method for processing a lead frame according to claim 10, characterized in that: Before performing the oxidation treatment, the method further includes: performing oxidation pretreatment on the lead frame; The oxidation pretreatment comprises: placing the lead frame in an oxidation pretreatment solution, wherein the oxidation pretreatment solution comprises: a second modifier and a second additive, wherein the mass fraction of the second modifier is 1% to 10%, and the mass fraction of the second additive is 1% to 10%.

14. The method for processing a lead frame according to claim 13, characterized in that: The second modifier includes one or more of triazole, tetrazole, and imidazole, and the second additive includes amine or quaternary ammonium salt.

15. The method for processing a lead frame according to claim 10, characterized in that: After the oxidation treatment is performed, the method further includes: performing post-oxidation treatment on the lead frame; The post-oxidation treatment comprises: placing the lead frame in a post-oxidation treatment solution, wherein the post-oxidation treatment solution comprises a complexing agent or a chelating agent, and the mass fraction of the complexing agent or the chelating agent is 1% to 10%.

16. The method for processing a lead frame according to claim 15, characterized in that: The complexing agent or chelating agent includes one or more of nitrogen-containing compounds, oxygen-containing compounds or sulfur-containing compounds.

17. The method for processing a lead frame according to claim 15, characterized in that: After the post-oxidation treatment, the ratio of the actual surface area of ​​the oxide layer to the area occupied by the oxide layer on the surface of the lead frame is 1-5.

18. The method for processing a lead frame according to claim 15, characterized in that: After the post-oxidation treatment, the thickness of the oxide layer is 19. A lead frame, characterized in that: include: A base island, suitable for placing chips; A bonding enhancement layer, located on the surface of the base island, the bonding enhancement layer covers the area for placing the chip, and the bonding enhancement layer includes a metal polycrystalline material; An oxide layer is located on the surface of the bonding enhancement layer.

20. The lead frame according to claim 19, wherein: The bonding enhancement layer includes polycrystalline copper.

21. The lead frame according to claim 19, wherein: The lead frame is made of copper alloy or copper.

22. The lead frame according to any one of claims 19 to 21, characterized in that: The thickness of the oxide layer is 23. The lead frame according to any one of claims 19 to 21, characterized in that: The ratio of the actual area of ​​the surface of the oxide layer to the area occupied by the oxide layer on the surface of the lead frame is 1-5.

24. A chip packaging product, characterized in that: include: The lead frame according to any one of claims 19 to 23; A chip mounted on the base island of the lead frame; bonding wires electrically connecting the chip to the lead frame; A packaging material is provided to encapsulate the chip, the bonding wires, and at least a portion of the lead frame.

25. The chip packaging product according to claim 24, characterized in that: The packaging material includes epoxy resin.

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