JP2002289650A - Semiconductor device tape carrier and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor device tape carrier having high reliability by protecting an excess deposit of tin produced at a side of a lead when conducting electroless tin plating. SOLUTION: In the method for manufacturing the semiconductor device tape carrier, a wiring pattern including a lead 8 of copper is formed by patterning a copper foil 3 on a polyamide resin film 1 via a spattered nickel layer 2, and a tin plated layer 4 is formed on its wiring pattern by a substitution deposit type of electroless plating using a plating solution containing complex agent of copper. As the pretreatment of tin plating, a part 2a of the spattered nickel layer 2 squeezed off from the lower part of the lead 8 of copper is peeled off with pretreatment agent, thereby, the excess deposit of tin can be protected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape carrier for a semiconductor device which is a precision electronic component, and more particularly to a semiconductor device in which a tin plating layer is formed on a conductor pattern of a copper foil formed on a polyimide resin via a nickel sputtering layer. The present invention relates to a tape carrier and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a tape carrier for a semiconductor device on which an IC for driving a liquid crystal display or the like is mounted, as a method of applying a copper coating to a polyimide resin, a method of pasting a polyimide resin and a copper foil with an adhesive has conventionally been adopted. I was That is, the structure of the conventional tape carrier is shown in FIG.
As shown in FIG.
Then, the copper foil 3 is bonded through the intermediary, and the copper foil is patterned to form a wiring pattern including the copper lead 8. Then, in order to give the copper lead 8 a stable bonding property,
This is a structure in which an electroless tin plating layer 4 is provided on a wiring pattern.

However, with this structure, the heat resistance of the tape carrier as a whole is limited to the performance of the adhesive even though a polyimide resin having excellent heat resistance is used. Therefore, recently, a method of directly coating a copper foil on the polyimide resin surface without using an adhesive has been developed and implemented. In this method, a copper coating layer is directly formed on a polyimide resin surface by sputtering or the like.

[0004] However, the method of directly coating the surface of the polyimide resin with copper by sputtering or the like is inferior in adhesion between the copper foil and the resin film. Therefore, recently, from the viewpoints of high density, fine pitch, and light weight of mounting technology, FIG.
As shown in (1), a material has been developed in which a nickel sputter layer 2 is formed on a polyimide resin film 1 and then a copper foil 3 is formed by an electrolytic method.

The operation of mounting the tape carrier on a semiconductor device will be described with reference to FIG. 2 according to an embodiment of the present invention. The semiconductor device (IC chip) 5 is arranged so as to be located in a device hole. Then, after aligning the inner lead of the lead 8 protruding into the device hole with the electrode of the semiconductor element 5, it is pressure-bonded by a bonding tool. Gold bumps 6 are formed on the electrodes of the semiconductor element 5, and when pressed against the copper leads 8 in a heated state, the tin plating melts, a gold-tin alloy is formed, and the electrodes and the inner leads are joined. You.

[0006]

However, such a material, that is, a polyimide resin film 1 as shown in FIG.
The material on which the copper foil 3 was formed by the electrolytic method via the nickel sputter layer 2 was subjected to substitution deposition type electroless plating using a plating solution containing a copper complexing agent to form the electroless tin plating layer 4. When applied, at the interface between the nickel sputtered layer 2 and the copper on the side surface 8a of the lead 8, abnormal precipitation of tin appears as shown in a copy of the photograph of FIG.

In general, electroless tin plating is precipitated by substitution with copper. In this case, since the nickel sputtered layer 2 exists,
It is considered that a potential difference occurs at the interface between copper and nickel during precipitation, causing an abnormal reaction.

Further, the tin plating generated in this portion does not melt the tin at the time of inner lead bonding, so that the gold-tin bonding becomes insufficient and the bonding may be defective.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to prevent excessive precipitation of tin on the side surface of a lead when performing electroless tin plating, and to provide a highly reliable tape carrier for a semiconductor device and a method of manufacturing the same. Is to provide.

[0010]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as follows.

(1) A tape carrier for a semiconductor device according to the first aspect of the present invention forms a wiring pattern including copper leads by patterning a copper foil provided on a polyimide resin via a nickel sputter layer. In a semiconductor tape carrier in which a tin plating layer is formed on a pattern,
It is characterized in that the nickel spattered layer protruding from under the copper lead is removed by the pretreatment of tin plating.

(2) In the method of manufacturing a tape carrier for a semiconductor device according to the second aspect of the present invention, a wiring pattern including copper leads is formed by patterning a copper foil provided on a polyimide resin via a nickel sputtering layer. In a method for manufacturing a tape carrier for a semiconductor in which a tin plating layer is formed on a wiring pattern thereof by a substitution precipitation type electroless plating using a plating solution containing a complexing agent, as a pretreatment for tin plating, the copper The nickel sputtered layer protruding from below the lead is removed by a pretreatment agent.

(3) The invention according to claim 3 is a method for manufacturing a tape carrier for a semiconductor device according to claim 2, wherein the pretreatment agent is a film dissolving agent, an oxidizing agent, a stabilizer, a corrosion inhibitor, and a surfactant. It is characterized by comprising at least one of an agent, an additive, a complexing agent, and an amine compound.

(4) The invention according to claim 4 is a method for manufacturing a tape carrier for a semiconductor device according to claim 3, wherein the film dissolving agent is a cyanide, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid. , Chromic acid, citric acid, and formic acid.

(5) The invention of claim 5 is the invention of claim 3 or 4
The method for manufacturing a tape carrier for a semiconductor device according to the above aspect, wherein the oxidizing agent includes at least one of hydrogen peroxide, sodium nitrobenzenesulfonate, peroxosulfate, nitro compound, and nitrate.

(6) The invention of claim 6 provides the above-mentioned claims 3 to
5. The method for manufacturing a tape carrier for a semiconductor device according to any one of the items 5, wherein the additive contains any one of mercaptobenzothiazole and dithiocarbamic acid.

(7) The invention according to claim 7 is the method for manufacturing a tape carrier for a semiconductor device according to claim 2, wherein the pretreatment agent is nitric acid, hydrogen peroxide, ethylenediamine, sodium nitrobenzenesulfonate, mercaptobenzothiazole. It is characterized by being composed of a pickling solution constructed in a bath.

(8) The invention according to claim 8 is the method for manufacturing a tape carrier for a semiconductor device according to claim 2, wherein the pretreatment agent has a composition of ethylenediamine, citric acid, sodium nitrobenzenesulfonate, and dithiocarbamic acid. It is characterized by being composed of a bathed pickling solution.

<Function> In the so-called substitution deposition type electroless plating in which metal ions in a plating solution are deposited on the surface of a plating object by a substitution reaction, electrons generated by elution of the plating object as cations in the plating solution. And the ions of the plating metal present in the plating solution are combined to form a metal film on the object to be plated. That is, the deposition of the substitution deposition type electroless plating film is accompanied by elution of the plating object into the plating solution as a cation.

Usually, in such a substitution precipitation reaction, the ionization tendency of the object to be plated must not be larger than that of the plating metal. For example, when the object to be plated is copper and the plating metal is tin, the substitutional precipitation of tin does not occur theoretically. However, even in such a case, by including a copper complexing agent such as thiourea in the electroless plating solution, copper is forcibly eluted from the object to be plated into the solution as cations, and tin ions are converted into metal. It can be deposited as tin.

At the time of the above-mentioned substitutional precipitation of tin, there is no change in the fact that copper is eluted as a cation from the object to be plated as described above. In this case, the elution of copper selectively occurs from a portion of the object to be plated having a physically unstable shape. In other words, elution at the interface between the plating object and the polyimide resin or at the edge of the plating object occurs preferentially, and particularly when there is a slight gap at the interface between the heterogeneous substance composite such as copper and the polyimide resin. When the composite is exposed to a corrosive atmosphere, such as a plating solution containing a copper complexing agent, the tendency for copper present at the interface with the polyimide to elute due to crevice corrosion increases.

For this reason, a copper foil provided on a polyimide resin via a nickel sputter layer is patterned to form a wiring pattern including copper leads, and a plating solution containing a complexing agent is applied on the wiring pattern. In the case of a tape carrier for semiconductors in which a tin plating layer is formed by displacement deposition type electroless plating used, the presence of a nickel sputter layer induces abnormal deposition of tin at the interface between the nickel sputter layer and copper on the side surface of the lead. become.

Therefore, in the present invention, as a method for preventing excessive tin plating generated at the interface between the nickel sputter layer on the side surface of the lead and the copper, a pretreatment of tin plating is performed by using a pretreatment such as a mixed solution of nitric acid and hydrogen peroxide. By performing the pretreatment using the treatment liquid, the nickel sputtered layer remaining on the side surface of the lead is removed, and the abnormal reaction of tin is suppressed. This makes it possible to reduce bonding defects during inner lead bonding due to tin plating melting defects. Here, in order to prevent the dissolution of copper, it is desirable that the pretreatment agent be added as an inhibitor to the additive, either mercaptobenzothiazole or dithiocarbamic acid.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

In FIG. 1, first, a copper foil 3 provided on a polyimide resin film 1 with a nickel
Is patterned by etching to form a wiring pattern including the copper lead 8 (FIG. 1A). At this time, the copper is etched during the copper etching on the lead side surface 8a, so that a part of the nickel sputtered layer 2 remains from the lower part of the copper lead 8 as the protruding portion 2a.

Next, as a pre-treatment for tin plating, a nickel pre-treatment layer such as a mixed solution of nitric acid and hydrogen peroxide is used to treat the nickel sputter layer remaining as the protrusion 2a on the side surface of the lead. Peel and remove (FIG. 1B).

Next, a tin plating layer is formed on the wiring pattern by substitution deposition type electroless plating using a plating solution containing a copper complexing agent (FIG. 1 (c)).

The pretreatment agent comprises at least one of a film dissolving agent, an oxidizing agent, a stabilizer, a corrosion inhibitor, a surfactant, an additive, a complexing agent, and an amine compound. Here, the film dissolving agent may be any one containing at least one of a cyanide, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, chromic acid, citric acid, and formic acid. The oxidizing agent may be any one containing at least one of hydrogen peroxide, sodium nitrobenzenesulfonate, peroxosulfate, nitro compound, and nitrate. The additive may include any one of mercaptobenzothiazole and dithiocarbamic acid.

As described above, if the nickel spatter layer 2 protruding from below the copper lead 8 is removed from the lead side surface 8a as a pretreatment for tin plating, the nickel on the side surface of the lead may be removed when tin plating is performed by electroless plating. Excessive tin plating generated at the interface between the sputtered layer and copper can be prevented.

FIG. 2 shows an embodiment of mounting the tape carrier manufactured as described above on a semiconductor element (IC chip). This is an example of application as a TAB tape for COF (Chip On Film), in which a semiconductor element (IC chip for driving a liquid crystal display) 5 is disposed so as to be located in a device hole, and a lead 8 projecting into the device hole is provided. After aligning the inner lead and the electrode of the semiconductor element 5,
Crimping with a bonding tool. Gold bumps 6 are formed on the electrodes of the semiconductor element 5, and when pressed against the copper leads 8 in a heated state, the tin plating is melted to form a gold-tin alloy, and the electrodes and the inner leads are formed well. Joined.

[0031]

<Example 1> First, a predetermined resist was applied to a tape carrier on which a copper foil 3 (copper film) was formed by electrolytic copper plating on a polyimide resin film 1 via a nickel sputtering layer 2. After drying, exposure and development were performed through a photomask having a predetermined wiring lead pattern, and then etching was performed to produce a wiring pattern including the leads 8.

Thereafter, the copper surface was normalized by degreasing and pickling. Here, 200 ml of 35% nitric acid is used as the pickling solution.
/ L, hydrogen peroxide 50ml / l, ethylenediamine 20
0 ml / l, sodium nitrobenzenesulfonate 50
g / l, 0.6 g / l mercaptobenzothiazole in a bath, a solution temperature of 55 ° C., a treatment time of 0 s,
0 s, 20 s, 40 s, and 60 s were processed.

Next, a tin plating layer 4 was formed on the wiring pattern by substitution deposition type electroless plating using a plating solution containing a copper complexing agent. The electroless tin plating was performed using 580M manufactured by Ishihara Chemical Co., at a liquid temperature of 70 ° C. for a processing time of 3 minutes and 40 seconds.

The tape carrier thus produced was observed on the side surface of the lead with a scanning electron microscope (SEM) to confirm the presence or absence of abnormal deposition and to measure the length of the bent portion. The presence or absence of abnormal deposition was determined as follows: No abnormal deposition on the entire surface of the lead: O, presence of the lead portion: Δ, Abnormal deposition on the entire lead: X. The results are shown in Table 1 (Pickling conditions and abnormal deposition of tin plating).

[0035]

[Table 1]

From the results shown in Table 1, if the pickling time is 20 s or longer, abnormal precipitation of tin does not occur on the side surfaces of the leads.

<Example 2> As in Example 1, the pickling solution was mixed with 120 ml / l of ethylenediamine and 90 g of citric acid.
/ L, sodium nitrobenzenesulfonate 90g /
l, using a mixed solution prepared with a composition of 0.6 g / l of dithiocarbamic acid, a liquid temperature of 55 ° C., a treatment time of 0 s, 10 s,
After treating for 20 s, 40 s, and 60 s, the electroless tin plating layer 4 was formed by substitution deposition type electroless plating using a plating solution containing a copper complexing agent, and the abnormal deposition property was evaluated.

The results of evaluating the abnormal precipitation of the TAB tape material thus produced are shown in Table 2 (Pickling conditions and abnormal deposition of tin plating).

[0039]

[Table 2]

From the results shown in Table 2, as in the case of Example 1, if the pickling time is 20 s or longer, abnormal precipitation of tin does not occur on the side surfaces of the leads.

[0041]

As described above, according to the present invention, the following excellent effects can be obtained.

According to the present invention, when a tape carrier formed by electrolytic copper plating on a polyimide resin film via a nickel sputter layer is subjected to electroless tin plating, the nickel sputter layer remaining on the side surfaces of the leads is As a pre-treatment agent, for example, a film dissolving agent, an oxidizing agent, a stabilizer, a corrosion inhibitor, a surfactant, an additive, a complexing agent, and a mixed solution composed of at least one of an amine compound are used to remove the mixture. In addition, it is possible to prevent abnormal deposition occurring on the side surface of the lead during tin plating.

Thus, it is possible to reduce bonding defects at the time of inner lead bonding due to defective tin plating. Here, the dissolution of copper can be effectively prevented by adding any one of mercaptobenzothiazole and dithiocarbamic acid to the pretreatment agent as an additive as an inhibitor.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method for manufacturing a tape carrier of the present invention.

FIG. 2 is an assembly diagram in which an IC chip is mounted on the tape carrier of the present invention to configure a semiconductor device.

FIG. 3 is a sectional view showing the structure of a conventional tape carrier.

FIG. 4 is a cross-sectional view showing the structure of a conventional tape carrier.

FIG. 5 is a copy of an SEM photograph of an abnormal tin plating portion deposited on the side of a copper lead induced by the presence of a nickel sputter layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyimide resin film 2 Nickel sputter layer 2a Protruding part 3 Copper foil 4 Electroless tin plating layer 5 Semiconductor element (IC chip) 6 Gold bump 7 Adhesive layer 8 Lead 8a Side surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K022 AA02 AA32 AA41 BA21 BA35 CA14 CA15 CA22 CA23 CA29 DA03 DB04 DB08 5F044 MM03 MM23 MM25 MM48

Claims (8)

[Claims] 1. A semiconductor tape carrier comprising a wiring pattern including a copper lead formed by patterning a copper foil provided on a polyimide resin via a nickel sputtering layer, and forming a tin plating layer on the wiring pattern. A tape carrier for a semiconductor device, wherein a nickel sputtered layer protruding from under a copper lead is removed by a pretreatment of tin plating. 2. A wiring pattern including a copper lead is formed by patterning a copper foil provided on a polyimide resin via a nickel sputtering layer, and a plating solution containing a copper complexing agent is coated on the wiring pattern. In the method for manufacturing a tape carrier for a semiconductor in which a tin plating layer is formed by substitution deposition type electroless plating used, as a pretreatment for tin plating, a nickel spatter layer protruding from below the copper lead is removed by a pretreatment agent. A method for manufacturing a tape carrier for a semiconductor device, comprising: 3. The pretreatment agent comprises at least one of a film dissolving agent, an oxidizing agent, a stabilizer, a corrosion inhibitor, a surfactant, an additive, a complexing agent, and an amine compound. The method for manufacturing a tape carrier for a semiconductor device according to claim 2, wherein: 4. The method according to claim 1, wherein the film dissolving agent is a cyanide, nitric acid,
4. The method for manufacturing a tape carrier for a semiconductor device according to claim 3, wherein the tape carrier comprises at least one of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, chromic acid, citric acid, and formic acid. 5. The tape for a semiconductor device according to claim 3, wherein the oxidizing agent contains at least one of hydrogen peroxide, sodium nitrobenzenesulfonate, peroxosulfate, nitro compound, and nitrate. Carrier manufacturing method. 6. The method of manufacturing a tape carrier for a semiconductor device according to claim 3, wherein said additive contains any one of mercaptobenzothiazole and dithiocarbamic acid. 7. The method according to claim 1, wherein the pretreatment agent is nitric acid, hydrogen peroxide, ethylenediamine, sodium nitrobenzenesulfonate,
3. The method for producing a tape carrier for a semiconductor device according to claim 2, wherein the method comprises a pickling solution bathed with a composition of mercaptobenzothiazole. 8. The tape carrier for a semiconductor device according to claim 2, wherein the pretreatment agent comprises an acid washing solution having a composition of ethylenediamine, citric acid, sodium nitrobenzenesulfonate, and dithiocarbamic acid. Production method.