JPH04296723A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To offer the manufacture of a semiconductor device which surely and electrically connect plural electrodes of the semiconductor device to electrodes on a substrate. CONSTITUTION:An aluminum electrode 12 is formed on the surface of a liquid crystal driving IC 11 and a metallic bump electrode 13 is formed on the top surface of the aluminum electrode 12 by plating. The height of the metallic bump electrode 13 is made uniform by pressing the metallic bump electrode 13 as shown by an arrow P from above the liquid crystal driving IC 11 by a heated pressing jig 16 which has a flat pressure surface 15 as shown under conditions of 400-550 deg.C temperature, 50-150kg/pad pressure, and a 1.0 second pressure time.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a plurality of electrodes of a semiconductor element are reliably electrically connected to electrodes on a substrate.

0003

[Prior Art] Generally, in electronic devices in which a semiconductor element is mounted on a substrate, a face-down bonding method is known as a method for mounting the semiconductor element, in which a metal bump electrode on the semiconductor element is directly connected to an electrode on the substrate. ing.

[0004] A method of realizing high-density packaging at low cost by electrically connecting using an anisotropic conductive film containing conductive particles as a connection material was proposed, for example, in Japanese Patent Publication No. 62-6652. It is stated in the No.

The structure described in Japanese Patent Publication No. 62-6652 is, for example, as shown in FIG. Conductive particles 4 as conductive particles are mixed and dispersed in an insulating adhesive 3 disposed on a substrate 2 and a conductive lead layer 1 of this substrate 2, and have conductivity in the thickness direction and in the surface direction. The semiconductor device 7 includes an anisotropic conductive adhesive layer 5 having an insulating property, and a semiconductor element 7 which is placed and fixed on the anisotropic conductive adhesive layer 5 and has a pad 6 formed on its lower surface. Then, an anisotropic conductive adhesive layer 5 is inserted between the substrate 2 and the semiconductor element 7,
The substrate 2 and the semiconductor element 7 are bonded together, and the conductive lead layer 1 and the pad 6 are electrically connected by the conductive particles 4.

[0006] Furthermore, in order to increase the yield of connections,
Although metal bump electrodes 8 are often formed on the pads 6 of the semiconductor element 7 as shown in FIGS. 7 and 8, the heights of these metal bump electrodes 8 are not necessarily uniform. These metal bump electrodes 8 are usually made of metal and are often formed by a plating method. For example, in the case of a liquid crystal driving IC 11 with an output number of 160 as a semiconductor element as shown in FIG. 5, the number of electrode protrusions is For example 18
4, and the height of the metal bump electrode 8 with a height of 18 μm is
There is usually a height difference of about 6 μm.

[0007]

[Problems to be Solved by the Invention] Therefore, when a connection is made using an anisotropic conductive adhesive layer 5 in which the conductive particles 4 have a particle diameter of about 2 μm to 5 μm, the height increases as shown in FIG. A good connection is made at the high metal bump electrode 8, but at the low height metal bump electrode 8, the conductive particles 4 do not come into contact with the metal bump electrode 8 and the wiring electrode 1, resulting in an electrical open. occurs.

Therefore, as shown in FIG. 10, if conductive particles with a large particle size are used, it is possible to make a good connection to any of the metal bump electrodes 8 having different heights. The conductive particles 4 have a particle diameter of approximately 10 μm (±1.5 μm).
When a connection experiment was conducted using the anisotropic conductive adhesive layer 5 of m), no electrical open occurred. Note that the particle diameter range of the conductive particles 4 is, for example, 6μ.
It is effective in the range from m to 20 μm.

[0009] However, in semiconductor elements such as the liquid crystal driving IC 7, as the definition of liquid crystal devices progresses, the number of metal bump electrodes 8 to be connected is increasing, and the connection pitch is also becoming finer.

Therefore, good connections are made when large conductive particles 4 are used for metal bump electrodes 8 with height differences, but it is difficult to connect semiconductor elements 7 with narrow connection pitches and small spacing between adjacent bumps. If used, short circuits are likely to occur between the metal bump electrodes 8. Therefore, there is a problem in that when the metal bump electrodes 8 fall below a certain connection pitch, large conductive particles 4 cannot be used.

The present invention was developed in view of the above-mentioned problems, and in the face-down bonding method, a good connection can be made even to electrode protrusions with fine pitches and height differences, and short circuits are less likely to occur between adjacent electrodes. The purpose is to provide a method for manufacturing semiconductor devices with high reliability and high yield.

[Configuration of the invention]

[0013]

[Means for Solving the Problems] The method for manufacturing a semiconductor device of the present invention uses a jig having a flat pressurizing surface and heated to a temperature of 190° C. or more and 550° C. or less. The height of the electrode projections within the semiconductor element is made uniform by pressing the electrode projections.

[0014]

[Function] The present invention allows electrode protrusions formed on a semiconductor element to be pressed at a flat pressure surface and at a temperature of 190°C or higher, which is the temperature that occurs during connection, and at a temperature of 550°C, which is a temperature that does not destroy the semiconductor element. Pressing is performed with a jig heated to a temperature of 0.degree. C. or less to equalize the height of the electrode protrusions within the semiconductor element.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 5, reference numeral 11 denotes a liquid crystal driving IC 11, which is a semiconductor element and has 160 outputs, and has a size of approximately 5 mm×9 mm. And I for liquid crystal drive
On the surface of C11 is an aluminum electrode 12, and on the upper surface of this aluminum electrode 12, for example, titanium (Ti),
A barrier metal layer (not shown) made of nickel (Ni) and gold (Au) in this order is formed. On this barrier metal layer, a metal bump electrode 13 as an electrode projection made of, for example, gold (Au) is formed by a plating method or the like.

For example, in the case of the liquid crystal driving IC 11 having 160 outputs, the number of metal bump electrodes 13 is, for example, 184, the size is about 60 μm square, the connection pitch is 100 μm, and the average of the metal bump electrodes 13 is approximately 60 μm square. The height is 18
There is usually a height difference of about 6 μm.

In this state, as shown in FIG. 1(a), a heated pressing jig 16 with a flat pressing surface 15 is used to press the liquid crystal driving I.
From above C11 in the direction of arrow P, temperature 400℃~5
50℃, pressure 50-150kg/pad, pressure time 1
．． When the metal bump electrode 13 formed on the liquid crystal driving IC 11 was pressed for 0 seconds, the average initial height was 18 μm, the maximum value was 20 μm, and the minimum value was 14 μm. As shown in FIG. 1(b), the subsequent height has an average value of approximately 14 μm, a maximum value of 14 μm, and a minimum value of 13 μm.

Note that even when pressurization was applied under the above conditions, no malfunction of the liquid crystal driving IC 11 occurred at all. Further, the pressing force varies depending on the size, number, hardness, and conditions under which the metal bump electrodes 13 are formed, and is determined as appropriate.

[0020] Furthermore, in the case of connection using an anisotropic conductive film,
Since the temperature when the liquid crystal driving IC 11 is connected reaches 190°C, it is effective when applying pressure at a temperature of 190°C or higher. If the temperature during pressurization exceeds 550°C, the metal bump electrode 13
Regardless of the material, there is a high probability that the semiconductor will be damaged, so it is necessary to control the temperature to 550° C. or lower. For example, a metal bump electrode 13 made of plated gold (Au)
In order to sufficiently equalize the height of the pressure, the pressurizing temperature must be raised to at least 400°C or higher. According to experiments, when pressurized at room temperature, even if a pressure of 150 kg/pad was applied, the material could only be crushed by 2 μm, and sufficient uniformity could not be achieved.Furthermore, even if the pressure was increased, no further deformation occurred.

Further, from the viewpoint of cost and life, the pressurizing jig 16 is made of a high-melting point metal alloy such as molybdenum (M
o) The base material is an alloy, and the pressurizing surface 15 is made of a material with high impact resistance and heat resistance, such as artificial diamond, brazed to it. Furthermore, when using an anisotropic conductive film suitable for fine pitch connections with a particle diameter of about 2 μm to 5 μm,
It is desirable to keep the flatness of the pressing surface 15 of the pressing jig 16 within ±0.5 μm.

Furthermore, a protective passivation film 14 made of silicon nitride (SiN) or the like is formed on the upper surface of the liquid crystal driving IC 11, which also covers a part of the upper surface of the aluminum electrode 12.

On the other hand, wiring electrodes 22 are formed at predetermined positions on a glass substrate 21 of a liquid crystal display device as a semiconductor device. The wiring electrode 22 has a surface layer made of aluminum (Al) or a metal or metal multilayer film mainly composed of aluminum. In this embodiment, the wiring electrode 22 is made of chromium (Cr) and aluminum, and the film thicknesses of chromium and aluminum are respectively The wavelengths are set to 70 nm and 400 nm.

Furthermore, 26 is an anisotropic conductive adhesive layer as an anisotropic conductive film, and this anisotropic conductive adhesive layer 26 is made of an adhesive 27 made of, for example, an epoxy thermosetting resin, and is made of, for example, nickel. Conductive particles 28, which are conductive particles made of aluminum, are dispersed and included. Note that the anisotropic conductive adhesive layer 2
The film thickness of No. 6 is approximately 30 μm. Further, the conductive particles 28 do not have to be completely spherical, and may be, for example, chestnut-shaped, and the diameter is set to about 2 μm to 5 μm.

Next, a method for electrically connecting the metal bump electrodes 13 of the liquid crystal driving IC 11 to the wiring electrodes 22 on the glass substrate 21 by face-down bonding will be described with reference to FIGS. 2 to 5.

First, the outer shape of the anisotropic conductive adhesive layer 26 is punched out using a die to be slightly larger than the liquid crystal driving IC 11.

Then, as shown in FIG. 2, a glass substrate 2
An anisotropic conductive adhesive layer 26 is placed on the glass substrate 21, and the anisotropic conductive adhesive layer 26 is attached onto the glass substrate 21 as shown in FIG.

Next, using the automatic bonding tool 31 shown in FIG. 4, pressurize (approximately 50 g/pad) and heat (tool temperature 190° C.) with approximately 8 kg from the back side of the liquid crystal driving IC 11.
) and hold for about 30 seconds. At this time, the glass substrate 21
is placed on a stage (not shown) heated to about 60° C., and heated from the back side of the glass substrate 21.

Then, when the bonding tool 31 is separated from the liquid crystal driving IC 11, as shown in FIG.
The liquid crystal driving IC 11 is bonded to the glass substrate 2 by the conductive particles 28 in the anisotropic conductive adhesive layer 26.
The metal bump electrode 13 of the liquid crystal driving IC 11 is electrically connected to the first wiring electrode 22 .

[0030] All of the above steps are automated,
The liquid crystal driving IC 11 is mounted on a glass substrate 21 .

[0031] The adhesive 27 used in the above embodiment is as follows:
At the time of connection, the film is held at 190° C. for about 30 seconds to advance curing, and it firmly adheres to the passivation film 14, which is the surface protection layer of the liquid crystal driving IC 11, and the glass substrate 21. Therefore, the entire liquid crystal driving IC 11 is firmly mounted on the glass substrate 21, and the subsequent step of resin reinforcement by bonding is also unnecessary.

[0032] Also, -30°C (30 minutes)/85°C (30 minutes)
500 cycles of thermal shock test (0 minutes), 1000 hours of high temperature and high humidity storage test at 65°C and 95% humidity, 1000 hours of high temperature storage test at 85°C, 5 cycles from -10°C to 65°C at 95% humidity The liquid crystal display device according to the present invention was evaluated through various reliability tests such as a temperature/humidity cycle test, an operation test, a mechanical test such as a vibration test, and an impact test.
There were no occurrences of opens or shorts caused by connection points.

In the above embodiment, the metal bump electrode 13 of the liquid crystal driving IC 11 is made of gold. However, the metal bump electrode 13, which is softer than nickel particles and into which nickel particles penetrate easily, can be made of, for example, lead-tin (Pb-Sn). ) type or lead-indium (Pb-In) type solder bump electrodes.

Furthermore, although a semiconductor element with a metal bump electrode formed by forming a barrier metal on the aluminum electrode 12 by a plating method has been described, the structure of the barrier metal may be platinum/titanium (Pt/Ti), for example. It's okay to have it, and it's okay to not have it. Furthermore, the present invention can also be applied to cases where bump electrodes are formed by methods other than plating methods, such as dipping methods and ball bonding methods.

Further, although the wiring electrode 22 of the extraction electrode formed on the glass substrate 21 is made of chromium/aluminum, the wiring electrode 22 may be a metal or a metal multilayer film, and the material of the surface layer may be other than aluminum or aluminum alloy. ,
For example, it can be applied even when a thin metal is formed on aluminum or an aluminum alloy. An example of this is a wiring electrode 22 in which molybdenum (Mo), aluminum (Al), and molybdenum (Mo) are sequentially formed on a glass substrate 11. Note that the respective film thicknesses are, for example, 70 nm, 400 nm, and 50 nm.

Further, since the above device has a highly reliable connection part, it is not necessary to cover the back side of the liquid crystal driving IC 11 with a sealing resin, but it may be covered with a sealing resin.

Furthermore, the driving method is not limited to a simple matrix method or a TFT (thin film transistor) method.
It can be applied to any type of liquid crystal display device.

Although the above embodiments have been explained using a liquid crystal display device as an example, the invention is not limited to liquid crystal display devices and can be applied to any electronic device in which a semiconductor device such as an IC is mounted on a substrate. be.

[0039]

[Effects of the Invention] The present invention provides an electrode protrusion formed on a semiconductor element with a flat pressurizing surface and with a 19°
Does not destroy semiconductor elements at temperatures above 0°C55
By pressing with a jig heated to a temperature of 0°C or less, the height of the electrode protrusions within the semiconductor element can be made uniform, and in particular, in the face-down bonding method, the conductive particles of the anisotropic conductive film can be made small. As a result, a good connection can be made even to metal protrusions with fine pitches and height differences, and a reliable connection with high reliability and high yield is possible in which short circuits are less likely to occur between adjacent electrode protrusions.

[Brief explanation of drawings]

FIG. 1(a) is a cross-sectional view showing a method for forming a semiconductor element according to an embodiment of the present invention. (b) It is a sectional view showing a semiconductor element after formation same as the above.

FIG. 2 is a sectional view showing the process of attaching the liquid crystal driving IC to the substrate.

[Figure 3] Diagram 2 of attaching the same liquid crystal driving IC to the board
It is a sectional view showing the next process.

[Figure 4] Diagram 3 of attaching the same liquid crystal driving IC to the board
It is a sectional view showing the next process.

[Figure 5] Diagram 4 of attaching the above liquid crystal driving IC to the board
It is a sectional view showing the next process.

FIG. 6 is a sectional view showing a state in which a conventional liquid crystal driving IC is attached to a substrate.

FIG. 7 is a cross-sectional view showing the process of attaching the liquid crystal driving IC to the substrate.

[Figure 8] Figure 7 of attaching the above liquid crystal driving IC to the board
It is a sectional view showing the next process.

FIG. 9 is a cross-sectional view showing a state in which a liquid crystal driving IC is attached to a substrate using small-diameter conductive particles with metal bump electrodes having different heights.

FIG. 10 is a sectional view showing a state in which a liquid crystal driving IC is attached to a substrate using large-diameter conductive particles using metal bump electrodes having different heights.

[Explanation of symbols]

11 Liquid crystal driving IC13 as a semiconductor element
Metal bump electrode 15 as an electrode protrusion Pressure surface 16 Pressure jig

Claims (1)

[Claims] 1. An electrode protrusion formed on a semiconductor element is pressed with a jig having a flat pressing surface and heated to a temperature of 190° C. or more and 550° C. or less, and the electrode protrusion is pressed within the semiconductor element. A method of manufacturing a semiconductor device characterized by making the height uniform.