JPS62293650A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To implement improvement in manufacturing efficiency and reliability and a low cost, by forming a lead plated layer on the side of a conductor member, which is connected for a bump electrode that is formed with a single composition of tin. CONSTITUTION:An oxide film 12 is formed on a semiconductor element 11. An electrode pad 13 is formed at a place where a bump electrode is to be formed, on the film 12. After a passivation film 14 is grown, a bump forming area is formed as a hole. A current conducting layer 15 is formed on the entire surface of the element 11. On the layer 15, a tightly contacted metal layer 16 and a diffused barrier plated layer 17 are formed. Thereafter, a part other than the bump electrode forming place is removed. A current is conducted to the layer 15, and a diffused barrier plated layer 19 is formed on the layer 17. Then, a tin plated layer 20 is formed on the layer 19. When the layer 20 is heated, a semispherical body is formed. Thus, a tin bump electrode 21 is obtained. The electrode 21 is thermally fused and fixed to a lead plated layer 33.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a semiconductor device in which a semiconductor element having a bump electrode is connected to a conductive member via the bump electrode. It is.

(Prior art) Conventionally, as a technology in this field, for example, Japanese Patent Application Laid-open No. 6
There was one described in Publication No. 0-224248. The configuration will be explained below using figures.

FIGS. 2(1) to 2(3) are manufacturing process diagrams showing a conventional method for manufacturing a semiconductor device. This semiconductor device is manufactured through the following steps.

■Process shown in FIG. 2 (1) Field oxidation l! formed on a semiconductor element 1 such as an integrated circuit (IC) chip! 2, an electrode pad 3 is formed at the location where the bump electrode is to be formed, and a rough passivation film (inactivation film) 4 is selectively formed, and then a current conductive layer 5 of aluminum Afl is deposited thereon. do. Next, an adhesion metal layer 6 of titanium Ti and a diffusion barrier plating layer 7 of platinum PT are selectively formed on the current conducting layer 5, and areas other than the areas where bump electrodes are to be formed are covered with a resistor film 8 for plating. A current is passed through the current conducting layer 4, and a diffusion barrier plating layer 9 of copper Cu or nickel Ni is formed by electroplating.
form. After that, a lead plating layer 10 and a tin plating layer 1
form 1.

(2) Process of FIG. 2(2) After removing the resist layer 8 with a solvent such as Accent, a part of the current conducting layer 5 is etched with a normal A or Q etching solution.

■Process shown in FIG. 2 (3) The hooking layer 10 and the tin plating layer 11 are melted by heat treatment, and lead Pb and tin Sn are alloyed to form a bump electrode 12 made of hemispherical solder. .

The bump electrode 12 thus produced is heat-sealed to a conductive member, for example a lead frame 13 of solder-plated or tin-plated copper CU foil on a film carrier.

In this type of manufacturing method, since a platinum diffusion barrier plating layer 7 is provided, a copper or nickel diffusion barrier plating layer 9 is provided.
No activator treatment of platinum is required to form the platinum. Furthermore, before forming the bump electrodes 12, the lead plating layer 10
Since the outside of the lead plating layer 10 is covered with the tin plating layer 11, the upper surface of the lead plating layer 10 is not attacked by the etching solution when a part of the current conducting layer 4 is etched. Therefore, activator treatment is not necessary, which not only simplifies the manufacturing process and provides a highly reliable barrier effect, but also enables hemispherical bump formation processing with high yield.

(Problems to be Solved by the Invention) However, the above manufacturing method has the following problems.

(i) A lead plating layer 10 is formed on the diffusion barrier plating layer 9.
Since two types of plating processes, ie, the tin plating layer 11 and the tin plating layer 11, are performed, not only the number of steps increases, but also two types of plating tanks must be managed and maintained, which increases manufacturing costs.

(ii) When removing a part of the current conductive layer 4 with an etching solution, the lead plating layer 1 in the part A of FIG.
Not only will the etching solution corrode, but there is a risk that the adhesion strength and reliability will decrease due to the infiltration of the etching solution.

(iii) Since heat treatment is required when alloying the lead plating layer 10 and the tin plating layer 11 to form the solder bump electrodes 12, it takes time and effort to control the heating temperature.

In addition, when alloying lead and tin, in order to achieve good results, flux is often applied or immersed and then heat treated. This increases the number of steps, leading to lower manufacturing efficiency and higher costs.

(iv) When connecting the bump electrode 12 to the lead frame 13 made of tin-plated copper foil, for example, it is generally said that Sn plating generates a voice car (whisker); The thinner the tin plating thickness is, the easier it is to grow. For example, when the thickness is 5 μm or less, the growth rate becomes faster. If such a voice car is generated on the surface of the lead frame 13, the bump electrode 12
There is a risk of a connection failure when connecting or tampering with the

The present invention solves the problems that the prior art had, complicating the plating process, corroding the lead plating layer 10 and reducing adhesion strength, increasing the number of manufacturing steps due to flux formation, and poor connection due to voice car formation in the lead frame 13. The present invention provides a method for manufacturing a semiconductor device that solves the above problems.

(Means for Solving the Problems) In order to solve the above problems, the present invention forms bump electrodes on a semiconductor element such as an IC chip, and connects the bump electrodes to a conductive member, such as a lead frame of a film carrier. In a method of manufacturing a semiconductor device by heat-sealing, the bump electrode is formed into a predetermined shape by plating tin on the diffusion barrier plating layer and then melting the tin plating by heat treatment. A lead plating layer is previously formed on the surface of the lead frame, and the tin bump electrode is heat-sealed to this lead plating layer.

(Function) According to the present invention, as described above, it, 4+
Since four manufacturing methods are used, the tin plating layer having a single composition simplifies the plating process and improves etching resistance and adhesion strength. The tin bump electrodes prevent the generation of whiskers, and also form a solder alloy with the lead-plated layer of the conductive member when connected to the conductive member, thereby improving the connection strength.Thus, the above-mentioned problem can be solved. It is possible to remove points.

(Example) Figures (1) to (4) are manufacturing process diagrams of a semiconductor device showing an example of the present invention. This semiconductor device is manufactured through the following steps.

■ On the field film 12 formed on the semiconductor element 11 such as the process integrated circuit (IC) chip shown in FIG. niC
VD (Chemical Vapor Deposit)
After the passivation film 14 is grown using the ion method or the like, bump forming areas are opened on the electrode pads 13 using photolithography.

Next, a current conducting layer 15 made of ρ or the like is formed on the entire surface of the semiconductor element 11 by a vapor deposition method or the like, and an adhesion metal layer 16 such as titanium T1 and a diffusion barrier layer such as platinum Pt are formed on the current conducting layer 15. After forming the next layer 17, those adhesive metal layers 1
6 and the diffusion barrier plating layer 17 other than the portion where the bump electrode is to be formed are removed by photolithography. Here, the adhesive metal layer 16 has a function of adhering to the field oxide film 12 and the electrode pad 13.

Roughly, the vicinity of the outer edges of the adhesion metal layer 16 and the diffusion barrier plating layer 17 are covered with a resist film 18 for plating using photolithography, and then the current conducting layer 15 is energized to form a diffusion barrier plate by electroplating. A diffusion barrier plating layer 19 of copper CU, nickel Ni, etc. is formed on the plating layer 17 . The diffusion barrier plating layer 19 is formed to have a thickness of, for example, about 5 to 10 μm.

Subsequently, a tin plating layer 20 is formed on the diffusion barrier plating layer 19. Here, the diffusion barrier plating layer 17°19 is
It has a function of preventing mutual diffusion between the tin plating layer 20 and the electrode pad 13.

■ After removing the resist film 18 for process plating shown in FIG. 1 (2) with a solvent such as acetone, the outer edge of the current conducting layer 15 is etched with a mixture of phosphoric acid, nitric acid, glacial acetic acid, and water, for example. Remove by etching with liquid.

■Process in Figure 1 (3) For the purpose of spheroidizing the tin plating layer 20 and removing internal organic matter,
The tinned layer 20 is heated to a temperature of 34°C in an atmosphere such as N2.
Heat to about 0-350'C. Then, the tin plating layer 20 becomes hemispherical and a bump electrode 21 made of tin is obtained. The height of the bump electrode 21 is, for example, 25 μm to 100 μm.
It is formed to about m.

(4) Process A conductive member, such as a film carrier 30, to be connected to the process bump electrode 21 in FIG. 1(4) is prepared in advance.

The film carrier 30 has a film tape 31 with a hole for chip attachment, and a lead frame 32 made of copper foil or the like is formed on the film tape 31, and an inner lead portion 32a of the lead frame 32 is formed on the film tape 31. It has a structure that protrudes into the hole. Conventionally, the surface of the inner lead portion 32a is plated with solder or tin, but in this embodiment, a lead plating layer 33 is formed on the surface of the inner lead portion 32a.

Then, the inner lead portion 32a is applied to the bump electrode 21, and heat treatment is performed at a temperature of, for example, about 340 to 350'C. Then, the tin of the bump electrode 21 and the lead plating @33 of the inner lead portion 32a are melted and alloyed to form a solder layer 40, and this solder layer 40 connects the bump electrode 21 and the inner lead portion 32a. Connected. Thereafter, a desired semiconductor device is obtained through steps such as cutting the film tape 32 at predetermined locations and sealing the semiconductor element 11 including the solder layer 40 with resin.

This embodiment has the following advantages.

(a) In the process of FIG. 1(2), when the outer edge of the current conducting layer 15 is removed with an etching solution, the tin plating layer 20 is not attacked by the etching solution, so the adhesion of the tin plating layer 20 is strong. does not decrease, thereby improving reliability. Moreover, since the tin plating layer 2o is formed of a single composition of tin, the plating process is simple.

(b) In the process of FIG. 1 (3), the tin bump electrode 2
1 has a large height, for example, about 20 to 100 μm,
Moreover, since the tin plating is heat-treated to make it spherical and the plating stress present in the tin plating is released, voice ker is less likely to occur. Similarly, in the process shown in FIG. 1(4), since the plating layer 33 formed on the inner lead portion 32a is lead-plated, no voice car occurs. In this manner, since no voice car is generated on the bump electrode 21 side and the inner lead portion 32a side, problems such as poor connection do not occur when connecting these two.

Moreover, since the solder layer 40 is used at the connection point between the bump electrode 21 and the inner lead portion 32a, connection at a low melting point is possible, and high adhesive strength can be obtained.

In the above embodiments, it is possible to change the material and shape of each layer on the semiconductor element side, the shape of the bump electrode 21, and the shape, structure, material, etc. of the conductive member other than those shown in the drawings. I'll go.

(Effects of the Invention) As described above in detail, according to the present invention, the bump electrode is formed with a single composition of tin, and a lead plating layer is formed on the side of the conductive member connected thereto, so that the bump electrode can be formed. simplification of the plating process when etching a part of the current conductive layer, improvement of the etching resistance of the tin plating layer and prevention of decrease in adhesion strength, prevention of whisker generation, Adhesion at a low melting point and improvement of its strength can be achieved. Therefore, the effects of improved manufacturing efficiency, reliability, and cost reduction can be expected.

[Brief explanation of the drawing]

Figures 1 (1) to (4) are old manufacturing process diagrams showing an embodiment of the present invention, and Figures 2 (1) to (3) are conventional manufacturing process diagrams. 11...Semiconductor element, 12...Field oxide film, 13...-electrode pad, 14...
... Passivation film, 15 ... Current conduction layer, 16 ... Adhesion metal layer, 17.19 ...
...Diffusion barrier plating layer, 18...Resist film, 18°20...Tin plating layer, 21...
・Bump electrode, 30...Film carrier, 3
2... Lead frame, 33... Lead plating layer, 40... Solder layer. Applicant's agent: Takashi Kakimoto Diagram of Jaku LD in August from Narimoto Figure 1 Figure 1 Figure 2 Figure 2

Claims (1)

[Claims] Covering the semiconductor element with an insulating film other than the part where the bump electrode is to be formed, plating a current conducting layer on the semiconductor element including the insulating film, and then adhering and diffusing the part where the bump electrode is to be formed. After forming a metal layer for a barrier and applying current to the current conducting layer to form a diffusion barrier plating layer on the metal layer, a bump electrode of a predetermined shape is formed on the diffusion barrier plating layer. In a method for manufacturing a semiconductor device in which a bump electrode is heat-sealed to a conductive member, the bump electrode is formed by plating tin on the diffusion barrier plating layer and then melting the tin plating by heat treatment. A method for manufacturing a semiconductor device, characterized in that a tin bump electrode is thermally fused to a lead-plated layer previously formed on the surface of the conductive member.