TWI749886B - Method for roughening surface of lead frame and electrochemical device - Google Patents

Abstract

A method for roughening the surface of a lead frame includes the following steps: performing surface roughening treatment on the lead frame to increase the surface roughness of the lead frame, and the surface roughening treatment includes sequentially using a copper-containing ion plating solution and a Nickel ion electroplating solution, palladium-containing ion electroplating solution and gold ion-containing electroplating solution perform electrochemical treatment procedures on the lead frame. Each electrochemical treatment procedure is carried out in an electrochemical device including a tank, an electrode plate, a conveying unit and a power supply device. Each electrochemical treatment procedure is carried out in sequence for the first stage treatment and 15 to 30 times for the second stage. Phase processing. The electrochemical treatment procedures are performed on the lead frame in the electrochemical device by respectively using the electroplating solution, so that the lead frame subjected to the surface roughening treatment has a rough surface.

Description

Method for roughening surface of lead frame and electrochemical device

The invention relates to a method and device for surface treatment, in particular to a method and an electrochemical device for roughening the surface of a lead frame.

In the current lead frame packaging process, in order to solve the problem that the bonding force between the surface of the lead frame and the metal wire is not good, the joint between the two is cracked, and the bonding force between the surface of the lead frame and the sealing compound is not good, so that the joint between the two is not good. The existing solution to the problem of cracks is to use a surface roughening agent to etch the surface of the lead frame before the wire bonding process and the sealing process, so that the etched lead frame has a rough surface to improve and Bonding force between metal wires or sealing materials.

However, the above method of roughening the surface of the lead frame by etching causes the thickness of the lead frame to become thinner, so that the mechanical strength of the lead frame is reduced and it is easy to break.

Therefore, an object of the present invention is to provide a method for roughening the surface of the lead frame.

Therefore, the method for roughening the surface of a lead frame of the present invention includes the following steps: performing surface roughening treatment on a lead frame so that the surface roughness of the lead frame after the surface roughening treatment is greater than that of the lead frame through the surface The roughness of the surface before the roughening treatment, and the surface roughening treatment includes sequentially using copper ion-containing electroplating solution, nickel-containing ion electroplating solution, palladium-containing ion electroplating solution, and gold-containing ion electroplating solution to electrochemically the lead frame respectively The treatment procedure, and the pickling procedure of cleaning the lead frame with an acidic solution before each electrochemical treatment procedure; wherein, each electrochemical treatment procedure is carried out in an electrochemical device, and the electrochemical device includes a defined Two oppositely arranged trough bodies with openings for the lead frame to pass through, one electrode plate arranged in the trough body and lying flat on the bottom of the trough body, and one arranged above the electrode plate for placing and conveying the lead wire A conveying unit that passes through the openings, and a power supply device that is electrically connected to the lead frame and the electrode plate and used to control the lead frame and the electrode plate to have opposite electrical properties; and each electrochemical treatment process is in sequence Carry out 1 first stage treatment and 15 to 30 second stage treatments. In the first stage treatment, the power supply device controls the lead frame and the electrode plate as a cathode and an anode respectively, and provides a current density ranging from 1 to 3 The current of A/dm ² and the processing time are 5 seconds to 25 seconds. In the second stage of processing, the power supply device first controls the lead frame and the electrode plate as a cathode and an anode, respectively, and provides a current density ranging from 1 to 3 A/dm ² electric current and the processing time is 5 seconds to 25 seconds, and then control the lead frame and the electrode plate as anode and cathode respectively and provide a current density ranging from 5 to 10 A/dm ² and the processing time is 3 Seconds to 15 seconds.

In addition, another object of the present invention is to provide an electrochemical device.

Therefore, the electrochemical device of the present invention is suitable for a lead frame for surface roughening treatment. The electrochemical device includes a tank, an electrode plate, a conveying unit, and a power supply device. The groove defines two opposite openings for the lead frame to pass through. The electrode plate is arranged in the tank and lays flat on the bottom of the tank. The conveying unit is arranged above the electrode plate and used for placing and conveying the lead frame through the openings. The power supply device is electrically connected with the lead frame and the electrode plate and is used for controlling the lead frame and the electrode plate to have opposite electrical properties.

The effect of the present invention is that the method of the present invention to roughen the surface of the lead frame is achieved by using a copper ion-containing electroplating solution, a nickel ion-containing electroplating solution, a palladium ion-containing electroplating solution, and a gold ion-containing electroplating solution, respectively, in the electrochemical device Perform the electrochemical treatment procedures on the lead frame, through the cooperation of the first-stage treatment and the second-stage treatment, especially in the second-stage treatment, the power supply device is used to control the lead frame to alternately serve as a cathode and The anode causes the surface of the lead frame to alternately undergo reduction and oxidation reactions, and metal atoms are continuously generated and dissolved, so that the lead frame treated with the surface roughening has a rough surface, and then the surface roughened The lead frame has a better bonding force with the metal wire or the sealing material in the subsequent packaging process. In addition, the thickness of the lead frame after the surface roughening treatment becomes thicker, and it has better mechanical strength and is not easy to break.

Another effect of the present invention is that the electrochemical device of the present invention allows the lead frame to continuously perform the surface roughening treatment through the openings of the tank body through the mutual cooperation of the electrode plate and the conveying unit.

The method for roughening the surface of the lead frame of the present invention is to perform surface roughening treatment on a lead frame so that the surface roughness of the lead frame after the surface roughening treatment is greater than that of the lead frame before the surface roughening treatment Surface roughness.

The surface roughening treatment includes electrochemical treatment procedures for the lead frame using copper ion-containing electroplating solution, nickel ion-containing electroplating solution, palladium ion-containing electroplating solution, and gold ion-containing electroplating solution in sequence, and each electrochemical treatment Use acidic solution to clean the lead frame before the pickling process.

It should be noted that the effect of the surface roughening treatment is to form a plurality of protrusions on the surface of the lead frame after the surface roughening treatment, and the average particle size of the protrusions ranges from 0.05 μm to 5 μm , And the surface roughness of the lead frame subjected to the surface roughening treatment ranges from 1.4 μm to 2.6 μm.

Each electrochemical treatment process is carried out in an electrochemical device. Referring to Figure 1, the electrochemical device includes a tank 1, an electrode plate 2, a conveying unit 3, a power supply device 4, and an unwinder 5. And a winder 6.

The tank body 1 defines an accommodating space 11 and two opposite openings 12 for the lead frame 9 to pass through. The accommodating space 11 is used to contain the electroplating solution used in the electrochemical treatment process. The solution is the above-mentioned copper ion-containing electroplating solution, nickel ion-containing electroplating solution, palladium ion-containing electroplating solution or gold ion-containing electroplating solution. Wherein, the composition of the copper ion-containing electroplating solution includes copper sulfate, the composition of the nickel-containing ion electroplating solution includes nickel sulfamate, the composition of the palladium-containing ion electroplating solution includes palladium cyanide, and the composition of the gold ion-containing electroplating solution Including gold cyanide.

The electrode plate 2 is disposed in the accommodating space 11 of the tank body 1 and lays flat on the bottom of the tank body 1. The electrode plate 2 is, for example, an insoluble electrode plate, a soluble electrode plate, or a combination of the two. When the electrode plate 2 is a soluble electrode plate, the material of the electrode plate 2 is matched with the electroplating liquid used in the electrochemical treatment procedure. For example, when the electroplating solution is the copper ion-containing electroplating solution, the electrode plate 2 When the electroplating solution is the nickel-containing ion electroplating solution, the material of the electrode plate 2 is nickel; when the electroplating solution is the palladium ion-containing electroplating solution, the material of the electrode plate 2 is palladium; When the electroplating solution is the gold ion-containing electroplating solution, the material of the electrode plate 2 is gold. The insoluble electrode plate is, for example, but not limited to, an insoluble electrode plate containing titanium or an insoluble electrode plate containing platinum.

The conveying unit 3 is arranged above the electrode plate 2 and is used to place and convey the lead frame 9 so that the lead frame 9 is conveyed from one of the openings 12 of the tank 1 to the other of the openings 12 One. The specific aspect of the conveying unit 3 is not particularly limited, such as one conveying belt and a plurality of conveying rollers arranged at intervals. In the embodiment shown in FIG. 1, the conveying unit 3 includes a plurality of conveying rollers 31 arranged at intervals.

The power supply device 4 is electrically connected to the lead frame 9 and the electrode plate 2, and is used to control the lead frame 9 and the electrode plate 2 to have opposite electrical properties. For example, when the power supply device 4 controls the lead frame 9 to be a cathode, the electrode plate 2 is an anode. Conversely, when the power supply device 4 controls the lead frame 9 to be an anode, the electrode plate 2 is a cathode. . The specific aspect of the power supply device 4 is not particularly limited, and can be any reversing electroplating power supply device used in a reversing electroplating process or a periodic reversing electroplating process.

The unwinder 5 and the winder 6 are arranged on opposite sides of the tank 1, and the unwinder 5 is used to transport the lead frame 9 through one of the openings 12 of the tank 1 to enter The electrochemical treatment is performed in the tank body 1, and the winder 6 is used to make the lead frame 9 after the electrochemical treatment pass through the other of the openings 12 of the tank body 1 and leave the tank body 1 .

Among these electrochemical treatment procedures, each electrochemical treatment procedure is to perform the first-stage treatment once and 15 to 30 second-stage treatments in sequence.

In the first stage of processing, the lead frame 9 and the electrode plate 2 are controlled by the power supply device 4 as a cathode and an anode, respectively, and provide a current with a current density ranging from 1 to 3 A/dm ² and the processing time is from 5 seconds to For 25 seconds, a reduction reaction occurs on the surface of the lead frame 9 at this time, and the metal ions to be plated (ie, copper, nickel, palladium or gold ions) accept electrons to form metal atoms and then precipitate out of the surface of the lead frame 9.

In the second stage of processing, the power supply device 4 first controls the lead frame 9 and the electrode plate 2 as the cathode and the anode, respectively, and provides a current with a current density ranging from 1 to 3 A/dm ² and the processing time is 5 seconds To 25 seconds, a reduction reaction occurs on the surface of the lead frame 9 at this time, and the metal ions to be plated (that is, copper ions, nickel ions, palladium ions or gold ions) accept electrons to form metal atoms and then precipitate out of the surface of the lead frame 9. Then, the power supply device 4 controls the lead frame 9 and the electrode plate 2 as anode and cathode, respectively, and provides a current with a current density ranging from 5 to 10 A/dm ² and the processing time is from 3 seconds to 15 seconds. An oxidation reaction occurs on the surface of the lead frame 9, so that the metal atoms formed on the surface of the lead frame 9 lose electrons and dissolve into metal ions. The method of the present invention to roughen the surface of the lead frame is through the cooperation of the first-stage treatment and the second-stage treatment, especially in the second-stage treatment, reduction reactions and oxidations occur repeatedly on the surface of the lead frame 9 The reaction causes the continuous generation and dissolution of metal atoms on the surface of the lead frame 9 so that the surface of the lead frame 9 subjected to the surface roughening treatment forms the protrusions.

The acidic solutions used in these pickling procedures are, for example, hydrochloric acid and sulfuric acid. In the present invention, the lead frame 9 is cleaned with sulfuric acid before each electrochemical treatment process to remove the dirt and rust on the surface of the lead frame 9.

More specifically, in the method for roughening the surface of the lead frame of the present invention, the step sequence of the surface roughening treatment is as follows: (1). Carry out a pickling procedure; (2). Use a copper ion-containing electroplating solution for the electroplating The SEM image of Fig. 2 shows the surface state of the lead frame after the electrochemical treatment process; (3). Perform a pickling process; (4). Use a nickel-containing ion plating solution to perform the electrochemical process. The treatment procedure, wherein the SEM image of Fig. 3 shows the surface state of the lead frame after the electrochemical treatment procedure; (5). Carry out a pickling procedure; (6). Carry out the electrochemical treatment with a palladium-containing ion plating solution The procedure, wherein, the SEM image of FIG. 4 is the surface state of the lead frame after the electrochemical treatment procedure; (7). Perform a pickling procedure; and (8). Use a gold ion-containing electroplating solution to perform the electrochemical treatment The procedure, wherein, the SEM image of FIG. 5 is the surface state of the lead frame after the electrochemical treatment procedure. The conditions of the electrochemical treatment procedure and the acid washing procedure are as described above, and will not be repeated here. The above-mentioned SEM images of FIGS. 2 to 5 are obtained through a scanning electron microscope (manufacturer: JEOL; model: JSM-6010PLUS/LA) of the lead frame processed by various electrochemical treatment procedures.

It is worth mentioning that, in some embodiments of the present invention, when the lead frame 9 is to be subjected to continuous surface roughening treatment, it is possible to use a plurality of electrochemical devices arranged at intervals as described above and A plurality of electrochemical equipment of the pickling device (not shown) arranged at intervals from the electrochemical devices, so that the electroplating solution contained in the accommodating space 11 of the tanks 1 is set in the tanks 1 Without the need to replace the electrode plate 2 and cooperate with the unwinder 5 and the winder 6 to complete the continuous surface roughening treatment. In the electrochemical device, the electroplating solution contained in the accommodating space 11 of the tank body 1 of each electrochemical device may be the same or different.

To sum up, the method of the present invention to roughen the surface of the lead frame uses electroplating solutions containing copper ions, nickel ions, palladium ions, and gold ions to match the corresponding electrode plates 2 and apply In the electrochemical device, the electrochemical treatment procedures are performed on the lead frame 9 through the interaction of the first-stage treatment and the second-stage treatment, especially the surface of the lead frame 9 is repeated during the second-stage treatment. Reduction and oxidation reactions occur and metal atoms continue to be generated and dissolved, so that the surface of the lead frame 9 subjected to the surface roughening treatment forms the protrusions, that is to say, the surface of the wire subjected to the surface roughening treatment The frame 9 has a rough surface, so that the lead frame 9 subjected to the roughening of the surface has a better bonding force with the metal wire or the sealing material in the subsequent packaging process. In addition, compared with the conventional lead frame that has been etched and reduced in thickness, the protrusions also make the lead frame 9 after the surface roughening process have a thicker thickness, which in turn has better mechanical strength and is not easy to fracture. On the other hand, the electrochemical device of the present invention allows the electrode plate 2, the conveying unit 3, the unwinder 5, and the rewinder 6 to cooperate with each other, so that the lead frame 9 can pass through the trough 1 The surface roughening treatment is continuously performed by the opening 12, so the object of the invention can be achieved.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to Within the scope covered by the patent of the present invention.

1: tank 11: accommodating space 12: opening 2: Electrode plate 3: Conveying unit 31: Conveying roller 4: power supply unit 5: Unwinder 6: Winder 9: Lead frame

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: Figure 1 is a schematic diagram illustrating the electrochemical device of the present invention; 2 is a SEM image illustrating the surface state of a lead frame after the electrochemical treatment process is performed on a lead frame through a copper-containing ion plating solution and an electrode plate made of copper by the method of the present invention to roughen the surface of the lead frame; 3 is an SEM image illustrating the surface state of a lead frame after the electrochemical treatment process is performed on a lead frame through a nickel-containing ion electroplating solution and an electrode plate made of nickel by the method of the present invention to roughen the surface of the lead frame; 4 is an SEM image illustrating the surface condition of a lead frame after the electrochemical treatment process is performed on a lead frame through a palladium-containing ion plating solution and an electrode plate made of palladium by the method of the present invention to roughen the surface of the lead frame; and FIG. 5 is an SEM image illustrating the surface state of a lead frame after the electrochemical treatment process is performed on a lead frame through a gold ion plating solution and an electrode plate made of gold by the method of the present invention to roughen the surface of the lead frame.

1: tank

11: accommodating space

12: opening

2: Electrode plate

3: Conveying unit

31: Conveying roller

4: power supply unit

5: Unwinder

6: Winder

9: Lead frame

Claims (5)

A method for roughening the surface of a lead frame, comprising the following steps: performing surface roughening treatment on a lead frame so that the surface roughness of the lead frame after the surface roughening treatment is greater than that of the lead frame after the surface roughening treatment The previous surface roughness, and the surface roughening treatment includes electrochemical treatment procedures for the lead frame by sequentially using a copper-containing ion plating solution, a nickel-containing ion plating solution, a palladium-containing ion plating solution, and a gold-containing ion plating solution, respectively, And before each electrochemical treatment process, an acidic solution is used to clean the lead frame. The copper-containing ion electroplating solution includes copper sulfate, the nickel-containing ion electroplating solution includes nickel sulfamate, and the palladium-containing ion electroplating solution Including palladium cyanide, the gold-containing ion electroplating solution includes gold cyanide; wherein, each electrochemical treatment procedure is performed in an electrochemical device, and the electrochemical device includes a defining two opposite settings for the The slot body with the opening through which the lead frame passes, an electrode plate arranged in the slot body and lying flat on the bottom of the slot body, and a conveying unit arranged above the electrode plate for placing and conveying the lead frame through the openings , And a power supply device that is electrically connected to the lead frame and the electrode plate and is used to control the lead frame and the electrode plate to have opposite electrical properties; and each electrochemical treatment procedure sequentially performs the first stage treatment and 15 to 30 second-stage treatments. In the first-stage treatment, the power supply device controls the lead frame and the electrode plate as a cathode and an anode, respectively, and provides a current with a current density ranging from 1 to 3A/dm ² and the treatment time It is 5 seconds to 25 seconds. In the second stage of processing, the power supply device first controls the lead frame and the electrode plate as a cathode and an anode, respectively, and provides a current with a current density ranging from 1 to 3 A/dm ² and the processing time is 5 seconds to 25 seconds, and then control the lead frame and the electrode plate as an anode and a cathode respectively and provide a current with a current density ranging from 5 to 10 A/dm ² for 3 seconds to 15 seconds. The method for roughening the surface of a lead frame according to claim 1, wherein a plurality of protrusions are formed on the surface of the lead frame after the surface roughening treatment, and the average particle size of the protrusions is in the range of 0.05 μm to 5μm. The method for roughening the surface of a lead frame according to claim 1, wherein the surface roughness of the lead frame subjected to the surface roughening treatment ranges from 1.4 μm to 2.6 μm. An electrochemical device suitable for surface roughening treatment for a lead frame. The electrochemical device comprises: a tank defining two oppositely arranged openings for the lead frame to pass through; and an electrode plate arranged on the lead frame. The tank body is placed flat on the bottom of the tank body; a conveying unit is arranged above the electrode plate and used to place and convey the lead frame through the openings; and a power supply device electrically connected to the lead frame and the electrode plate And it is used to control the lead frame and the electrode plate to have opposite electrical properties. The electrochemical device according to claim 4, further comprising an unwinder and a winder provided on opposite sides of the tank, the unwinder is used to transport the lead frame through the openings of the tank One of them is to enter the tank body to perform the electrochemical treatment, and the winder is used to make the lead frame after the electrochemical treatment pass through the other one of the openings of the tank body to leave the tank body.

Images