An outer lead packaging structure of a plastic package device and a re-plating method

Abstract

The application discloses a plastic package device outer lead package structure and a re-plating method, which comprises the following steps: a plastic package device is arranged on a substrate; the substrate is fixed on a lead frame; the plastic package device comprises outer leads; the outer leads are symmetrically arranged on two sides of the plastic package device; the plastic package device is fixed on the substrate through a metal wire; and the metal wire fixes the substrate on the lead frame, so that the outer leads of the plastic package device are in conductive connection with the lead frame. The application avoids surface scratches and outer lead deformation and damage generated in the tumbling and falling process of the plastic package device in the drum re-plating method, and improves the quality and yield of the outer lead re-plating of the plastic package device.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of semiconductor integrated circuit package testing, and relates to a plastic package device external lead packaging structure and a re-plating method. BACKGROUND

[0002] The plastic package device external lead re-plating is usually applied to the situations of external lead plating layer contamination, damage, oxidation, falling off and abnormal solderability, so as to solve the problems of the appearance and solderability of the external lead plating layer, and belongs to a rework processing behavior. Since the plastic package device external lead re-plating is a rework processing on finished products, it is different from the plating rework processing of the matrix frame circuit in the packaging process, and needs to re-plate each external lead of each finished product. How to realize the conductive interconnection between the external leads and the efficient and high-quality re-plating is a difficulty in the plastic package device external lead re-plating processing.

[0003] At present, the main re-plating method in the industry is a drum re-plating method, and the specific technology is as follows: (1) the plastic package device needing re-plating is subjected to external lead defective plating layer stripping treatment, that is, the original metal plating layer is corroded away by using an acidic solution to immerse, so that the copper substrate of the plastic package device external lead is exposed; (2) the plastic package device after stripping is subjected to external lead deoxidation, activation and other pretreatments; (3) the re-plating is carried out by using a drum plating process, that is, a plurality of pretreated plastic package devices are placed in a drum plating equipment with plating solution, the drum rolls and falls at a certain speed, the external leads of the plastic package devices are connected with the cathode conductive device in the drum, the connection realizes instantaneous plating, and the cumulative multiple instantaneous plating achieves the set plating thickness; (4) the plastic package device is taken out, neutralized, washed with water and dried to complete the re-plating processing.

[0004] The drum re-plating method has certain limitations, mainly as follows: (1) during the drum rotation, the plastic package devices constantly roll and fall, which inevitably causes the mutual friction between the plastic package devices and other plastic package devices, and between the plastic package devices and the drum, resulting in the surface scratch and scratch problems of the plastic package devices; (2) for DIP (dual in-line package), SOP (small outline package), SSOP (shrink small outline package) and TSSOP (thin shrink small outline package) type plastic package devices, since the external lead thickness is thin, the pitch is small and the interval is narrow, the external lead loss and deformation are easily caused during the rolling and falling, resulting in the damage and scrap of the plastic package devices. For the plastic package devices with high quality and high yield re-plating requirements, the existing drum re-plating method is not applicable. SUMMARY

[0005] The application aims to solve the problem that the external lead of the plastic package device is easy to deform and causes surface scratch and scratch in the prior art, and provides a plastic package device external lead packaging structure and a re-plating method.

[0006] To achieve the above object, the present application adopts the following technical solutions to achieve the above object:

[0007] An outer lead package structure of a plastic package device comprises a plastic package device, a substrate, a metal wire and a lead frame.

[0008] The plastic package device is arranged on the substrate; the substrate is fixed on the lead frame; the plastic package device comprises outer leads; the outer leads are symmetrically arranged on two sides of the plastic package device; the plastic package device is fixed on the substrate by the metal wire; and the metal wire fixes the substrate on the lead frame.

[0009] The present application is further improved in that:

[0010] The plastic package device is fixed on the substrate by the metal wire, specifically, the plastic package device is attached to one side of the substrate; the metal wire is wound from the outer lead on one side of the plastic package device to the other side of the substrate, and then is wound back to the bottom of the outer lead on the other side of the plastic package device; the binding and winding of the bottom of all the outer leads are completed in sequence, and an ''S''-shaped winding path is formed on one side of the substrate; the plastic package device is fixedly bound on the substrate, and the outer leads are in mutual conduction.

[0011] The diameter of the metal wire is not more than 25% of the width of the surface of the outer lead.

[0012] A method for re-plating outer leads of a plastic package device, comprising:

[0013] The plastic package device is subjected to a de-plating treatment to remove the original plating layer of the outer leads on the plastic package device, and is subjected to pure water cleaning and drying;

[0014] The substrate combined with the lead frame and bound with the plastic package device is placed in a de-oxidation solution for de-oxidation treatment, and is subjected to pure water flushing after the oxidation treatment;

[0015] The substrate combined with the lead frame and bound with the plastic package device after the treatment is placed in an activation solution, and then is placed in an electroplating solution for re-plating treatment;

[0016] The substrate combined with the lead frame and bound with the plastic package device after the treatment is placed in a neutralization solution, is subjected to pure water flushing and drying of water stains;

[0017] The substrate combined with the lead frame and bound with the plastic package device is unbound, and the plastic package device is removed, to complete the re-plating process flow.

[0018] The substrate bound with the plastic package device, specifically, the plastic package device is attached to one side of the substrate; the metal wire is wound from the outer lead on one side of the plastic package device to the other side of the substrate, and then is wound back to the bottom of the outer lead on the other side of the plastic package device; the binding and winding of the bottom of all the outer leads are completed in sequence, and an ''S''-shaped winding path is formed on one side of the substrate; the plastic package device is fixedly bound on the substrate, and the outer leads are in mutual conduction.

[0019] The deoxidizing solution is Na2S2O8 solution, the concentration is 200±20g / L, the processing temperature is 30±3℃, and the processing time is 30±5S.

[0020] The activating solution is methyl sulfonic acid, the concentration is 12.5±2.5%, the processing temperature is 30±3℃, and the processing time is 10±5S.

[0021] The re-plating treatment is placed in the electroplating solution, specifically, the substrate with the plastic package device treated by the activating solution is placed in the electroplating line equipment to perform the electroplating re-plating treatment. The electroplating solution is a methyl sulfonic acid system, the current is 50±3A, the electroplating temperature is 35℃, and the electroplating time is 300±30S.

[0022] The neutralizing solution is trisodium phosphate, the concentration is 20±5g / L, the processing temperature is 45±3℃, and the processing time is 15±5S.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] The present application uses a metal wire to back paste the plastic package device on the substrate, uses the metal wire to bind and interconnect the outer lead of the plastic package device, and sequentially completes the back binding and fixing of multiple plastic package devices. The outer lead of each plastic package device is interconnected by the metal wire, and the outer leads between the plastic package devices are also interconnected by the metal wire. The substrate with multiple plastic package devices is bound on the packaging lead frame. The present application avoids the problems of surface scratches and deformation damage of the outer lead of the plastic package device in the tumbling and falling process in the drum re-plating method, and improves the quality and yield of the re-plating of the outer lead of the plastic package device.

[0025] Further, the present application selects the diameter of the metal wire according to the width of the outer lead to prevent excessive marks from being generated in the process of winding the metal wire around the outer lead and exceeding the control requirements of the industry standard. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0027] Figure 1 The schematic diagram for binding the substrate with multiple plastic package devices on the lead frame;

[0028] Figure 2 The schematic diagram for binding the back of the plastic package device;

[0029] Figure 3 The schematic diagram for binding the front of the plastic package device to the substrate;

[0030] Figure 4 Fig. 1 is a schematic diagram of a plurality of plastic encapsulated devices back bonding to a substrate;

[0031] Figure 5 Fig. 2 is a schematic diagram of a wire wrap outer lead;

[0032] Figure 6 Fig. 3 is a schematic diagram of a wire wrap outer lead with a resulting wire wrap indentation.

[0033] Wherein: 1 - plastic encapsulated device, 2 - substrate, 3 - wire, 4 - outer lead bottom, 5 - plastic encapsulated device front, 6 - outer lead top, 7 - indentation, 8 - lead frame, 9 - outer lead. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0036] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0037] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0038] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0039] In the description of the embodiments of the present application, it also needs to be explained that, unless explicitly specified and limited, if the terms "arrange", "install", "connect", "connect" appear, they should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] The present application will be further described in detail below with reference to the accompanying drawings:

[0041] Referring to Figure 1 The present application discloses a plastic package device external lead packaging structure, comprising: a plastic package device 1, a substrate 2, a metal wire 3 and a lead frame 8.

[0042] The substrate 2 is provided with the plastic package device 1; the substrate 2 is fixed on the lead frame 8; the plastic package device 1 comprises external leads 9; the external leads 9 are a plurality of leads, symmetrically arranged on both sides of the plastic package device 1; the external leads 9 are in conductive interconnection with the lead frame 8.

[0043] The plastic package device 1 is fixed on the substrate 2 by winding the metal wire 3; the metal wire 3 fixes the substrate 2 on the lead frame 8, realizing the conductive interconnection of the external leads 9 of the plastic package device with the lead frame 8.

[0044] The plastic package device 1 is fixed on the substrate 2 by winding the metal wire 3, specifically: the plastic package device 1 is attached to one side of the substrate 2, the metal wire 3 is wound from the external lead 9 on one side of the plastic package device 1 to the other side of the substrate 2, and then is wound back to the bottom of the external lead 9 on the other side of the plastic package device 1, and the binding and winding of the bottom of all the external leads 9 are completed in turn, forming an "S" shaped winding path on one side of the substrate 2; the plastic package device 1 is fixedly bound on the substrate 2, and the external leads 9 are in conductive interconnection with each other.

[0045] The diameter of the metal wire 3 is not more than 25% of the width of the surface of the external lead. When the metal wire 3 is wound around the external lead 9, it will generate a pressing force on the corners of the external lead 9, and the size of the pressing force is proportional to the diameter (Φ) of the metal wire 3. Therefore, the area (S) of the indentation is proportional to the diameter (Φ) of the metal wire 3 (S∝Φ). The external lead 9 covered by the indentation 7 area is difficult to form a plating layer in the subsequent plating process, and appears as a depression on the surface of the lead. According to the "3.3.5 lead" clause in the standard method 2009.1 of GJB548B-2005, "the diameter of the indentation or the width of the depression on the lead (the diameter is calculated for circular leads) is more than 25% of the width of the lead", which is unqualified. The maximum value of the width of the indentation 7 is not more than the diameter of the metal wire 3. Therefore, the diameter of the metal wire 3 is not more than 25% of the width of the surface of the external lead 9.

[0046] A method for re-plating outer leads of a plastic package device, comprising:

[0047] The plastic package device 1 is subjected to a stripping treatment to strip the original plating layer of the outer leads 9 of the plastic package device 1, and is subjected to a pure water cleaning and drying treatment.

[0048] The substrate 2 with the plastic package device 1 and the lead frame 8 combination is placed in a deoxidizing solution for a deoxidizing treatment, and is subjected to a pure water rinsing after the deoxidizing treatment; the deoxidizing solution is a Na2S2O8 solution with a concentration of 200±20g / L, a treatment temperature of 30±3℃, and a treatment time of 30±5S.

[0049] The treated substrate 2 with the plastic package device 1 and the lead frame 8 combination is placed in an activating solution, and then is placed in an electroplating solution for a re-plating treatment; the activating solution is a methyl sulfonic acid with a concentration of 12.5±2.5%, a treatment temperature of 30±3℃, and a treatment time of 10±5S.

[0050] The re-plating treatment in the electroplating solution is specifically: the substrate 2 with the plastic package device 1 and the lead frame 8 combination treated by the activating solution is placed in an electroplating line equipment for an electroplating re-plating treatment; the electroplating solution is a methyl sulfonic acid system, an electric current is 50±3A, an electroplating temperature is 35℃, and an electroplating time is 300±30S.

[0051] The treated substrate 2 with the plastic package device 1 and the lead frame 8 combination is placed in a neutralizing solution, is subjected to a pure water rinsing and drying treatment; the neutralizing solution is a trisodium phosphate with a concentration of 20±5g / L, a treatment temperature of 45±3℃, and a treatment time of 15±5S.

[0052] The substrate 2 with the plastic package device 1 and the lead frame 8 combination is unbundled, and the plastic package device 1 is removed, thereby completing the re-plating process.

[0053] The substrate 2 with the plastic package device 1 is specifically: the plastic package device 1 is attached to one side of the substrate 2, the metal wire 3 is wound from one side of the plastic package device 1 to the other side of the substrate 2, and then is wound back to the bottom of the outer lead 9 on the other side of the plastic package device 1, and the binding and winding of the bottom of all the outer leads 9 is completed in sequence, thereby forming an "S" shaped winding path on one side of the substrate 2; the plastic package device 1 is fixedly bound to the substrate 2, and the outer leads 9 are mutually conductive.

[0054] The metal wire 3 is wound from the bottom of the outer lead 4, does not shield and interfere with the top of the outer lead 6, and does not affect the plating layer appearance and quality of the top of the outer lead 6 after re-plating.

[0055] The method of back-bonding the molding device 1 on the substrate 2 is to place the back of the molding device outward, with the front 5 of the molding device against the substrate 2, and then use a metal wire 3 to wrap from the bottom 4 of the outer lead of the molding device 1 to the other side of the substrate 2. Then the metal wire 3 is wrapped to the bottom 4 of the outer lead on the other side of the molding device 1, and so on until all the outer leads 9 are wrapped and interconnected.

[0056] Example 1:

[0057] For the re-plating of the external leads of SOP16L molded devices with a lead width of 400um, the specific implementation steps are as follows:

[0058] Step 1: Place multiple SOP16L molded devices that need to be replated in a 43% nitric acid solution and strip the original plating layer of the outer leads at room temperature, exposing the copper substrate completely.

[0059] Step 2: Clean and dry the multiple SOP16L molded devices after deplating with pure water;

[0060] Step 3: Attach an SOP16L molded device to a 3mm wide and 200mm long wooden substrate. Secure it by wrapping a 50µm diameter metal wire around one side of the substrate. Then, arrange the metal wire according to the attached... Figure 2 Appendix Figure 3 The SOP16L molded device is bonded to the substrate in this manner;

[0061] Step 4: Follow the attached... Figure 4 The same metal wire was used to bind another 7 SOP16L molded devices to the substrate.

[0062] Step 5: Attach the substrate with 8 SOP16L molded devices to the SOP16 lead frame and secure it with the same metal wire.

[0063] Step 6: Place the substrate with the plastic-encapsulated device and the lead frame assembly in a Na2S2O8 solution with a concentration of 196g / L, perform deoxidation treatment at 30℃ for 30s, and then rinse with pure water.

[0064] Step 7: Place the conjugate treated in Step 6 in a 12.5% ​​methanesulfonic acid solution and activate it at 30°C for 10 seconds.

[0065] Step 8: Place the composite material treated in Step 7 onto the electroplating line equipment for electroplating re-plating. The electroplating solution is a methanesulfonic acid system, the current is 50A, the electroplating temperature is 35℃, and the electroplating time is 300S.

[0066] Step 9: Place the conjugate treated in Step 8 in a 20 g / L trisodium phosphate solution and neutralize it at 45°C for 15 seconds.

[0067] Step 10: rinse the combination treated in step 9 with pure water and blow dry the water stains.

[0068] Step 11: unbind, remove the plastic encapsulated device, and check the appearance of the re-plated layer quality under a microscope.

[0069] Example 2:

[0070] For DIP8L plastic encapsulated device outer lead re-plating, the outer lead width is 1000um, and the specific implementation steps are as follows:

[0071] Step 1: Place multiple DIP8L plastic encapsulated devices that need to be re-plated in a 43% nitric acid solution, and remove the original plating layer of the outer lead at room temperature, so that the outer lead is completely exposed to the copper matrix;

[0072] Step 2: Clean the multiple DIP8L plastic encapsulated devices after stripping with pure water and dry them;

[0073] Step 3: Attach one DIP8L plastic encapsulated device to a wooden substrate with a width of 5.5mm and a length of 200mm, wrap a 100um diameter wire on one side of the substrate to fix it, and then bind the DIP8L plastic encapsulated device on the substrate in the manner shown in the attached Figure 2 , and Figure 3 ;

[0074] Step 4: According to the attached Figure 4 , bind the other 5 DIP8L plastic encapsulated devices on the substrate with the same wire;

[0075] Step 5: Bind the substrate with 5 DIP8L plastic encapsulated devices to the DIP8L lead frame with the same wire and fix it.

[0076] Step 6: Place the combination of the substrate with plastic encapsulated devices and the lead frame in a 200g / L Na2S2O8 solution, and perform deoxidation treatment at 30°C for 30S, and then rinse it with pure water.

[0077] Step 7: Place the combination treated in step 6 in a 12.5% methanesulfonic acid solution and perform activation treatment at 30°C for 10S.

[0078] Step 8: Place the combination treated in step 7 in an electroplating line device and perform electroplating re-plating treatment. The electroplating solution is a methanesulfonic acid system, the current is 52A, the electroplating temperature is 35°C, and the electroplating time is 310S.

[0079] Step 9: Place the combination treated in step 8 in a 20g / L trisodium phosphate solution and perform neutralization treatment at 45°C for 15S.

[0080] Step 10: rinse the combination treated in step 9 with pure water and blow dry the water spots.

[0081] Step 11: unbind, remove the plastic package device, and check the appearance of the re-plating layer quality under a microscope.

[0082] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A plastic-encapsulated device external lead packaging structure, characterized in that, include: Plastic encapsulated device (1), substrate (2), metal wire (3) and lead frame (8); A molding device (1) is disposed on the substrate (2); the substrate (2) is fixed on the lead frame (8); the molding device (1) includes external leads (9); the external leads (9) are a plurality of wires, symmetrically arranged on both sides of the molding device (1); the molding device (1) is fixed on the substrate (2) by winding metal wires (3); the metal wires (3) fix the substrate (2) on the lead frame (8); The molding device (1) is fixed to the substrate (2) by winding a metal wire (3). Specifically, the molding device (1) is attached to one side of the substrate (2), and the metal wire (3) is wound from the outer lead (9) on one side of the molding device (1) to the other side of the substrate (2), and then wound back to the bottom of the outer lead (9) on the other side of the molding device (1). The binding and winding of the bottom of all the outer leads (9) is completed in sequence, forming an "S"-shaped winding path on one side of the substrate (2); so that the molding device (1) is fixedly bound to the substrate (2), and each outer lead (9) is interconnected.

2. The external lead packaging structure for a plastic-encapsulated device according to claim 1, characterized in that, The diameter of the metal wire (3) does not exceed 25% of the surface width of the outer lead (9).

3. A method for re-plating external leads of a plastic-encapsulated device, characterized in that, include: The plastic-encapsulated device (1) is stripped of its original plating layer on the external lead (9) and then cleaned with pure water and dried. The substrate (2) with the plastic encapsulated device (1) attached and the lead frame (8) are placed in a deoxidation solution for deoxidation treatment, and then rinsed with pure water after oxidation treatment. The substrate (2) with the plastic-encapsulated device (1) and the lead frame (8) after processing are placed in an activation solution and then placed in an electroplating solution for re-plating. The substrate (2) with the encapsulated device (1) and the lead frame (8) after processing are placed in a neutralization solution, rinsed with pure water, and dried. The substrate (2) with the plastic encapsulated device (1) is unbound from the lead frame (8) assembly, the plastic encapsulated device is removed, and the replating process is completed. Specifically, the substrate (2) with the encapsulated device (1) attached is as follows: the encapsulated device (1) is attached to one side of the substrate (2), and the metal wire (3) is wound from the outer lead (9) on one side of the encapsulated device (1) to the other side of the substrate (2), and then wound back to the bottom of the outer lead (9) on the other side of the encapsulated device (1). The binding and winding of the bottom of all the outer leads (9) is completed in sequence, forming an "S"-shaped winding path on one side of the substrate (2); so that the encapsulated device (1) is fixedly attached to the substrate (2), and each outer lead (9) is interconnected.

4. The method for re-plating external leads of a plastic-encapsulated device according to claim 3, characterized in that, The deoxidation solution is a Na2S2O8 solution with a concentration of 200±20 g / L, a treatment temperature of 30±3℃, and a treatment time of 30±5 s.

5. The method for re-plating external leads of a plastic-encapsulated device according to claim 3, characterized in that, The activation solution is methanesulfonic acid with a concentration of 12.5±2.5%, the treatment temperature is 30±3℃, and the treatment time is 10±5s.

6. The method for re-plating external leads of a plastic-encapsulated device according to claim 3, characterized in that, The process of placing the substrate in the electroplating solution for back plating specifically involves placing the substrate with the encapsulated device, which has been treated with an activation solution, into the electroplating line equipment for back plating. The electroplating solution is a methanesulfonic acid system, the current is 50±3A, the electroplating temperature is 35℃, and the electroplating time is 300±30s.

7. The method for re-plating external leads of a plastic-encapsulated device according to claim 3, characterized in that, The neutralization solution is trisodium phosphate with a concentration of 20±5 g / L, the treatment temperature is 45±3℃, and the treatment time is 15±5 s.

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