JP3125874B2 - Surface treatment method and surface treatment device for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method and a surface treatment method for a semiconductor device in which an external lead terminal is plated mainly for a surface mount type semiconductor device in which external lead terminals are disposed on a semiconductor device body. It relates to a processing device.

[0002]

2. Description of the Related Art Conventionally, in this type of semiconductor device, the solderability of the tip of an external lead terminal determines the shape of a fillet at the time of mounting. Improvements have been made from various angles.

In general, there are two types of steps in a lead terminal arranging step of arranging external lead terminals on a semiconductor device body. That is, when the material of the external lead terminal does not require much mechanical strength depending on the type and application of the semiconductor device, the external lead terminal is formed and finished in the lead terminal forming step. A general-purpose case in which a certain mechanical strength is required for the material, a lead frame arranging step of embedding and enclosing a lead frame which is a base material of an external lead terminal in a semiconductor device body, and An outer plating step of outer plating the entire frame (including a case where the outer plating is performed in an electrolytic plating bath with an electrolytic plating solution), and a lead formed by cutting the lead frame after the outer plating into predetermined dimensions to form an external lead terminal. The external lead terminal is finished through a cutting step and a lead bending step of bending and forming the external lead terminal.

Incidentally, as a well-known technique related to a surface mounting type semiconductor device provided with such external lead terminals and a plating process for the external lead terminals, for example, a surface disclosed in Japanese Patent Application Laid-Open No. Hei 4-94563 is disclosed. Examples include a mounting type semiconductor device and a method of manufacturing the same, and a method of processing a surface of an external lead terminal in an electronic component disclosed in Japanese Patent Publication No. 7-3850.

[0005]

In the case of plating the external lead terminals in the above-mentioned general-purpose surface-mount type semiconductor device, the process of equalizing the entire potential by supplying power is performed by using a single contact contact. For simplicity, the plating process is usually performed before the lead cutting step of cutting the integrally connected lead frame that is the base material of the external lead terminals. In addition to the problem that the plating is thin near the cut surface of the terminal or the material is exposed at the tip, the corrosion resistance is degraded. In addition, for example, when the plating component is hard plating, the lead bending step is performed. Cracks easily occur in such cases, and in such a case, it is difficult to fill the cracks, so that the plating component is regulated. There is a problem.

Therefore, it has been considered to perform a plating process after the lead cutting step. However, a process of equalizing the entire potential by supplying power is performed on a large number of contact contacts for all the individual external lead terminals. Is not only complicated in the process, but also involves a risk that the external lead terminals may be deformed in the process, which is difficult to carry out.

[0007] Even if the lead frame is formed so as to be integrally connected at a position other than the front end thereof and then plated, the external lead terminals are deformed when the lead frame is cut in a subsequent lead cutting step. Therefore, such a configuration is difficult to adopt.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a technical problem that a plating device is not regulated and a plating process can be performed without a material exposed portion. To provide a surface treatment method and a surface treatment apparatus.

[0009]

According to the present invention, there is provided a surface treatment method for a semiconductor device after a lead terminal arranging step of arranging external lead terminals of a predetermined size at a predetermined position of a semiconductor device body. An electroless plating bath using an electroless plating solution comprising metal ions having excellent solder wettability in an acid or alkali aqueous solution in a state where the semiconductor device main body is housed in a housing so that terminals are released. A surface treatment method for a semiconductor device including an electrolytic plating bath step is obtained.

Further, according to the present invention, in the above method for treating a surface of a semiconductor device, a cleaning step of cleaning the semiconductor device body stored in the container after the electroless plating bath with cleaning water; And a drying step of drying the semiconductor device body housed in the container.

Further, in these methods for treating a surface of a semiconductor device, the step of arranging a lead terminal is a step of forming a lead terminal for forming and finishing an external lead terminal. A lead frame arranging step of incorporating and enclosing a lead frame which is a base material of an external lead terminal, an outer plating step of outer plating the entire lead frame, and cutting the lead frame after the outer plating to a predetermined size. Lead cutting process to
And a lead bending step of bending and forming the cut lead frame.

Further, in the surface treatment method for a semiconductor device of the latter embodiment, in the exterior plating step, exterior plating is performed in an electrolytic plating bath using an electrolytic plating solution, and the plating components are different between the electrolytic plating solution and the electroless plating solution. As a pre-treatment prior to the electroless plating bath step after the lead bending step, the semiconductor device body housed in the container is immersed in a chemical solution to smooth the plating surface by the electrolytic plating bath. preferable.

On the other hand, according to the present invention, the semiconductor device main body having the external lead terminals disposed at the predetermined locations with the predetermined dimensions is immersed in the housing so that the external lead terminals are released. An electroless plating bath containing an electroless plating solution containing metal ions with excellent solder wettability in an acid or alkali aqueous solution for performing an electroless plating bath, and stored in a container after the electroless plating bath A washing tub for washing the semiconductor device body in the washed state with washing water, and a draining and drying tank for draining and drying the semiconductor device body stored in the container after washing are separated in this order. A surface treatment apparatus for a semiconductor device having an electroless plating tank disposed adjacently is obtained.

Further, according to the present invention, in the surface treatment apparatus for a semiconductor device, the external lead terminals are subjected to electrolytic plating in advance by an electrolytic plating bath with an electrolytic plating solution, and the ends are exposed by cutting. Thus, a surface treatment apparatus for a semiconductor device is obtained in which the electroplating solution and the electroless plating solution have different plating components.

Furthermore, according to the present invention, in the surface treatment apparatus for a semiconductor device, a chemical solution bath for storing a chemical solution for smoothing a plating surface by an electrolytic plating bath by a chemical treatment prior to the electroless plating bath. And a surface treatment apparatus for a semiconductor device provided with:

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First, the outline of the surface treatment method for a semiconductor device according to the present invention will be briefly described. This surface treatment method for a semiconductor device is performed after an existing lead terminal arranging step of arranging external lead terminals with a predetermined size at a predetermined position of a semiconductor device main body. Executing an electroless plating bath step of performing an electroless plating bath using an electroless plating solution in which metal ions having excellent solder wettability are present in an acid or alkali aqueous solution in a state where the apparatus main body is stored in a container. It is. A washing step of washing the semiconductor device body housed in the container after the electroless plating bath with cleaning water, and a drying step of drying the semiconductor device body housed in the container after washing. Is to execute.

However, also in this case, the lead terminal arranging step is performed in two steps, ie, the case where the external lead terminal is formed by a lead terminal forming step and the case where the external lead terminal is formed by a lead material forming step. A lead frame disposing step of incorporating and enclosing and disposing a certain lead frame; an external plating step of externally plating the entire lead frame (including a case where the external plating is performed in an electrolytic plating bath with an electrolytic plating solution); This includes both a lead cutting step of cutting the plated lead frame into predetermined dimensions to form an external lead terminal and a case of finishing the external lead terminal through a lead bending step of bending and forming the external lead terminal.

In a surface treatment apparatus to which such a method for treating a surface of a semiconductor device is applied, a semiconductor device main body having external lead terminals of a predetermined size at a predetermined location is housed in such a manner that the external lead terminals are released. An electroless plating solution comprising metal ions having excellent solder wettability, such as Sn and Pb, stored in an acid or alkali aqueous solution for performing an electroless plating bath by being immersed in a state stored in a (tray). An electroless plating bath, a cleaning bath for washing the semiconductor device body stored in the container after the electroless plating bath with cleaning water, and a semiconductor device body stored in the container after the cleaning. It requires an electroless plating tank (electroless plating apparatus), which is separated from a draining / drying tank for draining / drying in this order and is provided adjacent to the tank.

FIG. 1 is a partially cutaway view of a semiconductor device main body 1 housed in a tray 2 to be subjected to surface treatment by the surface treatment method and apparatus of the present invention. FIG.

Here, the semiconductor device main body 1 in which the external lead terminals 1a are formed at predetermined positions and in predetermined dimensions by the existing lead terminal arranging process is placed in a tray 2 which is a storage container in a state where the external lead terminals 1a are released. In the state stored in the storage device. As the semiconductor device here, an IC (integrated circuit) can be exemplified, and the tray 2 may be, for example, a plating-only device or a shipping device, regardless of the intended use.
The semiconductor device body 1 is molded with a molding material before the lead terminal arranging step.

FIG. 2 shows an electroless plating tank 1 used in a surface treatment apparatus to which the surface treatment method for a semiconductor device of the present invention is applied.
FIG. 2 is a perspective view illustrating a basic configuration of the No. 0.

The electroless plating bath 10 conforms to the basic configuration described above, and includes an electroless plating bath 10a
One washing tub (the number of tubs may be arbitrary) 10b, 10c
And the draining / drying tank 10d are separated from each other and arranged adjacent to each other. However, in this case, the semiconductor device body 1 is used in a state where the external lead terminals 1a are housed in a predetermined number of units on the tray 2 (a predetermined number is stacked and stacked) so that each external lead terminal 1a is released. In the plating bath 10a, a number of semiconductor device main bodies 1 (the external lead terminals 1a) are immersed in an electroless plating solution for a predetermined time to be subjected to an electroless plating bath, and each of the cleaning baths 10b and 10c and the drainage drying bath 1
Even at 0d, many semiconductor device bodies 1 are washed and drained and dried. In the electroless plating bath, a base material exposed portion such as a cut surface of the external lead terminal 1a in each semiconductor device body 1 is plated by replacement of the electroless plating solution.

The respective semiconductor device main bodies 1 which have been subjected to the respective processes of the electroless plating bath, washing and draining and drying using the electroless plating tank 10 are supplied for shipment as finished products at that time. You.

FIG. 3 is a simplified side view showing a manufacturing process including a surface treatment step of a semiconductor device by a surface treatment apparatus using the electroless plating tank 10 for each step. FIG. FIG. 4B relates to an external plating step, FIG. 5C relates to a lead cutting step, FIG. 5D relates to a lead bending step, and FIG. It relates to a plating bath process.

Here, FIGS. 3A to 3D show the above-described existing lead terminal disposing steps. To explain in order, in a lead frame disposing step, as shown in FIG. 3A, a lead frame 1a ', which is a base material of the external lead terminals 1a, is incorporated and enclosed in the semiconductor device main body 1, and disposed. In the exterior plating step, as shown in FIG.
The entire lead frame 1a 'is exterior-plated M in an electrolytic plating bath with an electrolytic plating solution and molded, and in the lead cutting step, as shown in FIG. The external lead terminal 1a is formed by cutting at the dimensions, and FIG.
As shown in FIG. 3, the external lead terminal 1a is bent and formed. In the electroless plating bath step, as shown in FIG. 3 (e), the cut surface of the external lead terminal 1a is exposed by the electroless plating bath. A tip plating M 'is applied to the portion.

That is, in the conventional lead terminal disposing process, the lead frame 1a 'is electrolytically plated and then the lead is cut to obtain the external lead terminal 1a. At this point, the end of the external lead terminal 1a is exposed. However, in this case, the end of the external lead terminal 1a is subjected to electroless plating again after the subsequent bending and forming of the external lead terminal 1a, so that there is no portion where the material is exposed.

FIG. 4 is a side view illustrating the detailed configuration of the electrolytic plating bath applied in the exterior plating step described with reference to FIG. 3B.

Referring to this electrolytic plating bath, the exterior plating of the semiconductor device main body 1 is usually performed in an electrolytic plating bath using an electrolytic plating solution. In the electroless plating bath, the cathode (cathode) plate 4 is connected to the external power supply 3 and is formed by the semiconductor device body 1 provided with the lead frame 1a '.
And Sn-Pb plate by anode (positive electrode) plate 5 Sn ⁺
The electrode plate is immersed in an electrolytic plating solution filled with ions and Pb ⁺ ions, and Sn ⁺ ions and Pb ⁺ ions are forcibly deposited on the cathode plate 4 as a product by externally applying a voltage to each electrode plate. Has become. here,
Since the driving energy for deposition is supplied from the outside, very high-speed plating is possible, and a large plating thickness can be obtained.

FIG. 5 is a local plan view showing the state transition of the lead terminals in the exterior plating step described in FIG. 3B and the lead cutting step described in FIG. 3C. FIG. 4B shows the state before the lead is cut, and FIG.

Usually, the electrolytic plating bath can be performed only before cutting the lead. The reason is that the lead frame 1a 'exposed from the semiconductor device main body 1 is externally connected before the lead cutting shown in FIG. On the other hand, after cutting the lead shown in FIG. 5 (b), the lead frame 1a 'is cut to a predetermined size including the connection portion to become the external lead terminals 1a. Are electrically independent, and therefore need to be individually contacted for the whole.

Therefore, if the electroless plating bath is performed after the lead is cut, since the electroless plating bath utilizes the ionization tendency of the metal element itself, the electroless plating bath does not require an external power supply and is simple. Can be plated.

FIG. 6 is a side view illustrating the detailed configuration of the electroless plating bath 10a applied in the electroless plating bath process described with reference to FIG. 3 (e).

Referring to the electroless plating bath 10a, when the external lead terminal 1a is made of copper (Cu), since the electroless plating solution contains Sn ions and Pb ions, the outer plating M is applied. When the semiconductor device main body 1 having the external lead terminals 1a is immersed in an electroless plating solution,
The exposed copper, which is the material of the external lead terminal 1a, emits electrons to be ionized and melts out in the electroless plating solution. Conversely, Sn ions and Pb ions receive the emitted electrons and deposit on the exposed copper surface. Thereby, the exposed surface of the copper is completely covered with the Sn / Pb film, and the tip plating M 'is applied.

By the way, when a semiconductor device is manufactured through such an electroless plating bath, washing and draining and drying, use of a transport mechanism enables automation.

FIG. 7 is a side view showing a simplified structure of the entire surface treatment apparatus for a semiconductor device including a transport mechanism in addition to the electroless plating tank 10 'different from that described in FIG.

In this transport mechanism, the semiconductor device body 1 (product) having the external lead terminals 1a is connected to the external lead terminals 1a.
The tray 2 housed in a state where the is released is fixed to the basket 6 and hangs on the beam 7 at the loading position E1, the beam 7 is raised to the rising position E2, and then the basket 6 is pushed out by a pusher in the horizontal direction to the moving position. Move to E3.

Thereafter, when the beam 7 is lowered to the lowering position E4, the basket 6 is immersed in the chemical solution in the chemical solution bath 10e of the electroless plating tank 10 ', and is kept in this state for a predetermined time to perform chemical treatment. The plating surface is smoothed by an electrolytic plating bath. During this time, if the next basket 6 is hung on the beam 7 at the loading position E1, continuous processing becomes possible, and the product can be processed in each tank by repeating such operations.

The electroless plating bath 10 'is a chemical bath 10'.
e, an electroless plating bath 10a is provided, and the cleaning bath 10b, 1 is disposed adjacent to the electroless plating bath 10a.
0c and a draining / drying tank 10d are arranged in this order.

The electroless plating solution is stored in the electroless plating bath 10a, and the product is immersed therein for a predetermined time to perform the electroless plating bath. Washing tub 10
Cleaning water is stored in b, and the product is immersed in this cleaning water once after the electroless plating bath to perform initial cleaning. The washing tub 10c is provided with a shower section 8, and the product is washed again with washing water from the shower section 8. An air blow section 9 is provided in the draining / drying tank 10d, and the product is drained by blowing air from the air blow section 9.

Finally, after removing the basket 6 from the beam 7 at the unloading position E5, the basket 6 is dried and dry-pack baked in an oven before being provided for shipment. The detailed configuration of the electroless plating tank 10 'is freely combined in accordance with the process, and is not limited to the illustrated one.

By the way, in a semiconductor device manufactured through such a surface treatment, the combination of the material of the external lead terminal 1a of the semiconductor device main body 1 and the plating alloy can adjust the ionization tendency by using a complexing material. , Can be set freely. For example, the material of the external lead terminal 1a may be an iron-based alloy such as Fe-42% Ni in addition to copper.
The plating alloys are not limited to Sn-Pb, but lead-free plating (S
n, Bi, Ag, In, Zn, or the like, or an alloy of any combination thereof). Also, if the electroplating solution used for the electroplating bath or the electroless plating solution used for the electroless plating bath is made of an alloy with different plating components, the plating characteristics can be controlled, and the wettability and reliability can be improved. . Further, the drying step after the electroless plating bath step can be used also as the PKG drying step (dry pack baking) before shipping.
In addition, the external lead terminals 1
In the process of eliminating the electroplating bath in which a is formed and finished in the lead terminal forming step, the overall plating thickness becomes thinner, and there is a concern that the wettability may be slightly deteriorated. Time) increase and cost increase can be avoided.

[0043]

As described above, according to the present invention, the semiconductor device body provided with the external lead terminals obtained in the existing lead terminal arranging step is housed so that the external lead terminals are released. In a state where the product is stored in a container, an electroless plating bath using an electroless plating solution made of metal ions having excellent solder wettability in an acid or alkali aqueous solution is performed, and then the product is shipped after washing and draining and drying. Therefore, even when the tip of the external lead terminal has an exposed portion due to cutting, the exposed portion is plated to eliminate the exposed portion, and the manufactured product can have excellent corrosion resistance. In this case, in particular, the external lead terminals are preliminarily electrolytically plated with an electrolytic plating solution and subjected to electrolytic plating, and even when the tip is exposed by cutting, the electrolytic plating solution used for the electrolytic plating bath or the electroless plating is used. The plating characteristics can be controlled by applying an electroless plating solution to the bath with an alloy of different plating components, improving wettability and reliability, and exposing the material other than the tip of the external lead terminal (tie bar portion and plating crack portion). , An embedding effect can be obtained. In addition, prior to the electroless plating bath, the plating surface of the electrolytic plating bath is subjected to chemical treatment with a chemical solution and smoothed, so that the plating can be accurately performed when plating is performed by the electroless plating bath.

On the other hand, in the case where the electrolytic lead bath is not required in the lead terminal arranging step so that the external lead terminal is formed and finished in the lead terminal forming step, the lead is cut by performing the electroless plating bath. This eliminates the need for contact in the lead unit, which is a drawback of the above, and makes it extremely simple to manufacture because only immersion is required.
The problem of increase in T and increase in cost can be avoided.

In any case, since the electroless plating bath is performed in the final step following the existing manufacturing step, deterioration of wettability due to lead contamination and scratches can be prevented, and the shape of the solder fillet at the tip of the lead in the mounting step is excellent. As a result, the absorption of the solder paste is excellent and high connection reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a semiconductor device main body in a state of being housed in a tray to be manufactured by a surface treatment method and a surface treatment apparatus for a semiconductor device according to the present invention, partially cut away.

FIG. 2 is a perspective view illustrating a basic configuration of an electroless plating tank used in a surface treatment apparatus to which a surface treatment method for a semiconductor device according to the present invention is applied.

FIGS. 3A and 3B are simplified side views each showing a manufacturing process including a surface treatment step of a semiconductor device using a surface treatment apparatus using the electroless plating bath shown in FIG. 2, for each step; FIG. (B) relates to the exterior plating step, (c) relates to the lead cutting step,
(D) relates to the lead bending step, and (e) relates to the electroless plating bath step.

FIG. 4 is a side view illustrating a detailed configuration of an electrolytic plating tank applied in the exterior plating step described in FIG. 3B.

FIG. 5 shows an exterior plating step described with reference to FIG.
5A is a local plan view showing a state transition of a lead terminal in a lead cutting step described in FIG. 5C, in which FIG.

FIG. 6 is a side view illustrating a detailed configuration of an electroless plating bath applied in the electroless plating bath process described with reference to FIG.

FIG. 7 is a side view showing a simplified configuration of the entire surface treatment apparatus of a semiconductor device including a transport mechanism in addition to an electroless plating tank different from that shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor device main body 1a External lead terminal 1a 'Lead frame 2 Tray 3 External power supply 4 Cathode (cathode) plate 5 Anode (anode) plate 6 Basket 7 Beam 8 Shower part 9 Air blow part 10, 10' Electroless plating tank 10a Electroless Plating bath 10b, 10c Washing bath 10d Draining / drying bath 10e Chemical bath M Exterior plating M 'Tip plating

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 23/50 C23C 18/16 H01L 21/288

Claims (10)

(57) [Claims] In a method for treating a surface of a semiconductor device after a lead terminal arranging step of arranging external lead terminals with predetermined dimensions at predetermined positions of a semiconductor device main body, the semiconductor device is so arranged that the external lead terminals are released. An electroless plating bath step of performing an electroless plating bath with an electroless plating solution in which metal ions having excellent solder wettability are present in an acid or alkali aqueous solution in a state where the apparatus main body is housed in a container. A method for treating a surface of a semiconductor device. 2. The surface treatment method for a semiconductor device according to claim 1, wherein the semiconductor device main body housed in the housing after the electroless plating bath is washed with washing water; Drying the semiconductor device main body stored in the storage device. 3. The semiconductor device surface treatment method according to claim 1, wherein said lead terminal arranging step is a lead terminal forming step of forming and finishing said external lead terminal. Surface treatment method. 4. The semiconductor device surface treatment method according to claim 1, wherein, in the lead terminal disposing step, a lead frame which is a base material of the external lead terminals is incorporated and enclosed in the semiconductor device main body. A lead frame arranging step, an external plating step of externally plating the entire lead frame, a lead cutting step of cutting the lead frame after the external plating at a predetermined size, and the lead frame after the cutting. And a lead bending step of bending and forming the surface of the semiconductor device. 5. The surface treatment method for a semiconductor device according to claim 4, wherein, in the exterior plating step, the exterior plating is performed in an electrolytic plating bath using an electrolytic plating solution. 6. The surface treatment method for a semiconductor device according to claim 5, wherein a plating component is different between the electrolytic plating solution and the electroless plating solution. 7. The semiconductor device body according to claim 5, wherein the semiconductor device main body is housed in the housing as a pretreatment prior to the electroless plating bath step after the lead bending step. A surface treatment method for a semiconductor device, comprising: immersing the substrate in a chemical solution to smooth the plating surface by the electrolytic plating bath. 8. An electroless plating bath is carried out by immersing a semiconductor device body having external lead terminals of a predetermined size at predetermined positions in a housing so that the external lead terminals are released. An electroless plating bath containing an electroless plating solution containing metal ions having excellent solder wettability in an acid or alkali aqueous solution for causing the electroless plating bath to be stored in the container after the electroless plating bath. A washing tub for washing the semiconductor device body with washing water and a draining / drying tank for draining and drying the semiconductor device body stored in the container after the washing are separated in this order. A surface treatment apparatus for a semiconductor device, comprising: an electroless plating tank disposed adjacently. 9. The surface treatment apparatus for a semiconductor device according to claim 8, wherein the external lead terminals are subjected to electrolytic plating by being subjected to an electrolytic plating bath with an electrolytic plating solution in advance, and the tip is exposed by cutting. And wherein the electrolytic plating solution and the electroless plating solution have different plating components. 10. The chemical treating bath according to claim 9, wherein a chemical solution for smoothing a plating surface of said electrolytic plating bath by chemical treatment prior to said electroless plating bath is stored. A surface treatment apparatus for a semiconductor device, comprising: