KR20080090991A - Semiconductor device - Google Patents

Abstract

A semiconductor device is provided to reduce a stress concentration of a connector due to a temperature change although a substrate having a linear expansion coefficient difference is adhered and to reduce an initial stress in the connector immediately. A semiconductor device includes a minute pitch electrode and a connection structure. The minute pitch electrode is formed on a semiconductor element(1) to have a pitch less than 50 um. The connection structure connects a pad or a wire(21) formed on a substrate(20). The connection structure has a bump(11) and a structure. One side of the bump is connected to the minute pitch electrode. The other side of the bump has Young modulus ranging from 65 GPa to 600 GPa. The structure is connected to the pad or the wire formed on the substrate with a buffer layer(12) between. The buffer layer is formed of one selected from the group consisting of tin, aluminum, indium, or lead. A projection is formed on one of facing surfaces of the pad or the wire formed on the bump and the substrate.

Description

Semiconductor device {SEMICONDUCTOR DEVICE}

This application is based on Japanese Patent Application No. 2007-100777 filed April 6, 2007 and Japanese Patent Application No. 2007-299110, filed November 19, 2007, the contents of which are incorporated herein by reference. It is cited as.

TECHNICAL FIELD The present invention relates to a semiconductor device used for home appliances, consumer equipment, and industrial use.

The demand for high functionalization centering on portable electronic devices is increasing year by year, and with this, a high speed and a large capacity semiconductor device are needed. On the other hand, the miniaturization of devices is also a great need, and the development of the semiconductor package which made them compatible is performed. As a key technology for realizing this, flip chip mounting for connecting semiconductor elements by protrusion bumps has attracted attention, and has already been used in various packages. Flip chip mounting is a mounting method which connects a chip in which bumps are formed on a pad by face down on an electrode of a substrate.

Compared with the conventional wire bonding connection method, the flip chip mounting method has advantages such as shorter connection length, which can suppress delay of signal propagation and enable high-speed transmission, and miniaturization because the chip size is package size. Can be mentioned. The main flip chip mounting method is a solder bump connection method for connecting a chip and a substrate by solder bumps, an Au bump / solder connection method for connecting a stud bump and a board side wiring with solder after forming a gold stud bump on the chip side, After the gold stud bump is formed on the chip side, the ultrasonic connection method for connecting the stud bump and the board side wiring by ultrasonic connection (see FIG. 7), and the stud bump and the board side wiring are formed using silver paste or The contact connection system which connects resin materials, such as an anisotropic conductive film (ACF), mainly with the material mainly becomes the mainstream.

On the other hand, refinement of bump pitch is progressing, and connection of a 20 micrometer pitch is announced by the chip-to-chip connection of a chip | tip laminated package. It is currently limited to chip stack packages, but further miniaturization is expected in the future regarding chip / substrate connections. Patent Document 1 discloses a method for manufacturing an electrode bump and a connection method for use in chip stacking. The bump tip portion has a structure in which a stress change is formed larger than that of the bump base. We reduce.

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2005-243714

[Patent Document 2] Japanese Unexamined Patent Publication No. 2002-134541

In the case of finely connecting two or more members having a coefficient of linear expansion coefficient to 50 micrometers pitch or less in the above-described conventional connection method, the following problems can be given, respectively.

(1) solder bump connection method

At the time of connection, it is necessary to heat above the solder melting temperature. In the case of lead-free solder which is currently mainstream, the solder is heated to about 240 ° C. Therefore, when the temperature reaches room temperature after connection, deformation and distortion occur in the solder joint due to the difference in coefficient of linear expansion between the connection members, resulting in short between bumps and breakage of the joint due to high distortion. In the case of realizing a pitch of 50 micrometers or less, the solder bump is preferably 30 micrometers or less, but in the present process, the production of fine bumps is very difficult. Moreover, since the height between members after connection becomes about 20 micrometers, it becomes difficult to fill the underfill between members.

(2) Au bump / solder connection method

Since the solder needs to be melted in the same way as the solder bump connection method, when it is brought to room temperature after connection, deformation and distortion occur in the solder joint due to the difference in the coefficient of linear expansion between the connecting members, resulting in short between bumps and breakage of the joint due to high distortion. There is a possibility. In particular, since the amount of solder is smaller than that of the solder bump connection, the breakage occurrence rate is expected to be high. In addition, stress concentration on the gold bumps / chip pads is also concerned. In addition, it is difficult to uniformly form a gold stud bump of 30 micrometers or less by suppressing the height variation.

(3) Ultrasonic Connection

In the case of the ultrasonic connection system, since the connection temperature is as low as 150 ° C. or less, short and breakage of the connection portion due to the temperature change as described above are unlikely to occur. However, since it is necessary to load a load at the time of connection, in a gold stud bump, a deformation | transformation arises at the time of a load load, and the short between adjacent bumps is concerned.

(4) contact connection method

In the contact connection method, the connection temperature is suppressed to about 150 ° C, but since the connection mode is a contact, the connection resistance becomes high and high-speed transmission becomes difficult. In addition, in the case of using a silver paste or ACF for fine connection, it is necessary to select a conductive particle product having a diameter of several micrometers and the cost is high.

As mentioned above, when adapting a prior art as it is regarding a micro connection, there are many subjects and the development of new technology is needed.

In Patent Literature 1, the tip of the bump can be deformed to absorb the load at the time of connection. However, the contact resistance is high in connection between members having different linear expansion coefficients because of contact contact, which is not suitable. Moreover, since heating at 150 degreeC-400 degreeC is required, deformation | transformation and distortion of a connection part resulting from a linear expansion coefficient difference become large, and there exists a problem in connection between material materials.

Accordingly, an object of the present invention is to provide a semiconductor device having a fine pitch electrode with a pitch of 50 micrometers or less, in which a pad or a wiring on a substrate is connected to each other. It is an object of the present invention to provide a semiconductor device capable of preventing connection breakage due to distortion or reducing contact resistance to cope with high reliability and high speed transmission.

The main aspect of the present invention relates to a structure in which a pad or wiring on a substrate is connected to a semiconductor element having a fine pitch electrode of 50 micrometers pitch or less, and the substrate and the semiconductor element have a Young's modulus (Young's modulus) of 65 GPa or more and 600 GPa. It is connected via the bump below and the buffer layer which has tin, aluminum, indium, or lead as a main component, and the processus | protrusion formed in at least one of the opposing surfaces of the pad or wiring on a bump and a board | substrate, It is characterized by the above-mentioned. It is a semiconductor device.

By forming the above projections, the stress in the transverse direction generated at the time of connection between the bump and the pad or the wiring can be alleviated, and the movement of the material constituting the buffer layer can be prevented or alleviated. In addition, low-temperature connection is enabled by connecting by ultrasonic waves.

The characteristics of the present invention are that it is easy to secure a stress buffer layer between the bumps and the wiring, the spacing (connection height h1) of the connection part is high, the stress buffer layer has, the hard bumps, low temperature connection such as ultrasonic connection This would be possible.

Thereby, even when the base material with a linear expansion coefficient difference is connected, the stress concentration of the connection part resulting from temperature change can be reduced. Moreover, since the temperature difference between connection temperature and room temperature is small, the initial stage stress to the connection part immediately after manufacture can be reduced. Moreover, since the space | interval of a connection part is wide, it is easy to inject underfill. In addition, since bumps are used as bumps, bump deformation due to load during connection is reduced, and short between bumps can be prevented.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

<Example 1>

1 is a schematic cross-sectional view of a connecting portion of a first embodiment of the present invention. Reference numeral 1 is a semiconductor element, 2 is a chip side pad, 11 is a bump, 12 is a buffer layer, 20 is a substrate, 21 is wiring, 22 is wiring plating, and 24 is underfill.

The bump 11 has a metal having a longitudinal modulus of 65 kPa or more and 600 kPa or less as a main component. For example, the bump 11 has at least one of nickel, copper, aluminum, gold, and titanium as a main component. Moreover, if the longitudinal elastic modulus of the whole bump is 65 GPa or more, a composite may be sufficient, for example, the laminated structure of copper and nickel may be sufficient. Here, the longitudinal modulus of elasticity of the entire bump 11 is set to 65 GPa or more. In the structure in which materials having different linear expansion coefficients are connected to each other, the factor affecting the reliability of the connection is the shear distortion ε of the connection, and the shear distortion ε is When the distance L from the center, the connection height d, the linear expansion coefficient difference Δα and the temperature change amount ΔT of both members are ε = Δα · ΔT · L / d, the higher the connection height d, the smaller the distortion, that is, the reliability Increases. For this reason, in the connection structure of a present Example, when using single tin or solder (a Young's modulus of about 17-30 Mpa), height cannot be ensured, but the metal bump (For example, aluminum 68 kPa) whose final elastic modulus is 65 kPa or more. This is because the height can be ensured, and the reliability of the connection can be improved. Unevenness is formed at the tip of the bump 11.

The buffer layer 12 has any one of tin, indium, lead, and aluminum as a main component, and may be a material having a lower Young's modulus than the selected bump 11 material.

Even if the buffer layer 12 is formed on the bump 11 or the wiring 21, it is independent (not formed in any of the chip side bump and the board side wiring in advance, but is sandwiched between the bump and the wiring). It may be formed in the thickness of 2-3 micrometers. The buffer layer 12 has any one of tin, indium, lead, and aluminum as its main component, and may be a material having a lower Young's modulus than the selected bump 11 material.

The substrate 20 may be a resin substrate, a ceramic substrate, a silicon substrate, or the like. The wiring 21 and the plating on the wiring 22 are generally used in respective substrates. For example, in the case of a resin substrate, the wiring 21 is copper, and the wiring 22 is nickel, gold plating, or the like. Can be mentioned. In the first embodiment, the substrate 20 will be described as a printed substrate. Unevenness is formed in the bump 11 at the connection object side. In the first embodiment of FIG. 1, the unevenness of the mountain type is shown, but the unevenness formed in the bump 11 is at least one between the bump 11 and the wire-like plating 22 when connected to the wiring-like plating 22. The shape does not matter as long as the buffer layer 12 is secured above the position. In addition, the unevenness | corrugation formed in bump 11 may be formed in wiring-like plating 22, and may be formed in both bump 11 and wiring-like plating 22. As shown in FIG.

2 shows an example of a bump formation process on the semiconductor element 1 side in the first embodiment. In Figs. 2 and 3, the chip-side pad 2 is mainly composed of aluminum, the metal is mainly composed of nickel, the bumps 11 are mainly composed of metal, the metal is mainly composed of tin, and the wiring is mainly composed of copper. The metal plating on the wiring 22 will be described using gold plating as an example on a metal containing nickel as a main component.

The chip-side pad 2 and the wiring (not shown) are formed in the semiconductor element 1 as shown in FIG. As a pretreatment for plating nickel on the chip side pad 2, after the surface is etched, zinc substitution is performed. Thereafter, the resist 3 is coated, exposed and developed as shown in FIG. 2B to form an opening at a scheduled formation position of the bump 11 (FIG. 2C). As the resist 3, any of a negative resist and a positive resist may be used. Moreover, the thickness of the resist 3 shall be more than desired bump height. Nickel bumps are formed in the openings formed as described above by electroless plating (Fig. 2 (d)). The unevenness | corrugation of 1-15 micrometers is formed in the front-end | tip of the formed nickel bump. Examples of the method of forming the irregularities are described below.

Bump tip uneven | corrugated formation The 1st method is a method of forming uneven | corrugated by pressing in a mold | die. On the surface of the jig formed or surface coded from a material having a hardness higher than that of the bump 11, unevenness (1 to 15 µm) having a desired height to be formed on the bump 11 is formed. Although uneven | corrugated formation may use methods, such as a mechanical grinding | polishing, an etching, laser processing, plasma processing, cutting, etc., it is more preferable to select the method suitable for processing a zigzag material. Concave-convex is formed on the bump 11 by applying the load from above and opposing this jig of FIG. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the irregularities are formed on the bumps 11, gold is deposited on the nickel surface, or 0.01 µm to 5 µm is formed by sputtering or plating. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used. In addition, a formation method such as a bump transfer method or a bump formation method using a thin film formation process used in MEMS (Micro Electro Mechanical Systems) is not limited.

The bump-tip uneven | corrugated formation 2nd method is the method using dry etching. The dry etching method is a method of using a scientific reaction such as reactive gas etching, reactive ion etching, reactive ion beam etching, reactive laser beam etching, or the like, in which a scientific reaction and a physical reaction are simultaneously etched by collision of ions such as ion milling. You may use either. From the state of FIG. 2 (d), unevenness of 1 to 15 μm is formed on the bump 11 by any of the above methods. The convex portion may have any shape as long as at least one of the convex portions is formed on the bump 11 surface such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the unevenness is formed on the bump 11 by dry etching, gold is deposited on the nickel surface, or 0.01 μm to 5 μm is formed by sputtering or plating. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used.

The bump-tip uneven | corrugated formation 3rd method is the method using wet etching. The wet etching method is a process in which chemicals that corrode and dissolve metals or the like are processed into an arbitrary shape by infiltrating and spraying an object to be processed, and a large amount of processing can be realized at a low cost at a time. From the state of FIG. 2 (d), unevenness | corrugation of 1-15 micrometers is formed on bump 11 by the wet etching method. The convex portion may have any shape as long as at least one of the convex portions is formed on the bump 11 surface such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the unevenness is formed on the bump 11 by dry etching, gold is deposited on the nickel surface, or 0.01 μm to 5 μm is formed by sputtering or plating. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used. Although the bump formation method by a plating process was described here, formation methods, such as the bump transfer method and the bump formation method using a MEMS process, are not limited.

The bump-tip uneven | corrugated formation 4th method is the method using laser processing. The kind of laser can be selected according to target materials, such as a solid-state laser, such as a YAG laser, a ruby laser, a gas laser, such as a carbon dioxide laser, an argon ion laser, a helium neon laser, a liquid laser, a semiconductor laser, and a free electron laser. Since uneven formation using a laser can be finely processed, it can be processed into a complicated shape. From the state of FIG. 2D, unevenness | corrugation of 1-15 micrometers is formed on the bump 11 with a laser. The convex portion may have any shape as long as at least one of the convex portions is formed on the bump 11 surface such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the irregularities are formed on the bumps 11 by laser, gold is deposited on the nickel surface, or 0.01 µm to 5 µm is formed by sputtering, plating, or the like. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used.

Although the bump formation method by a plating process was described here, formation methods, such as the bump transfer method and the bump formation method using a MEMS process, are not limited. The fifth method of forming bump bump unevenness is a method using sputtering. Sputtering is a technique of surface processing and film-forming by colliding argon ionized in vacuum with a process surface. A method of forming an unevenness of 1 to 15 占 퐉 by forming a sample in the state of (d) in a vacuum chamber and processing the upper surface of the bump 11 with ionized argon, and a method of forming an arbitrary protrusion on the bump with a sputter film deposition apparatus. Can be mentioned. The convex portion may have any shape as long as at least one of the convex portions is formed on the bump 11 surface such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the irregularities are formed on the bumps 11 by laser, gold is deposited on the nickel surface, or 0.01 µm to 5 µm is formed by sputtering or plating. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used.

Although the bump formation method by a plating process was described here, formation methods, such as the bump transfer method and the bump formation method using a MEMS process, are not limited. Bump tip uneven | corrugated formation 6th method is the method using grinding | polishing. By grinding the sample in the state of FIG. 2 (d) with abrasive paper, unevenness of 1 to 15 μm is formed on the bump 11. In this case, abrasive paper having a particle size in which the unevenness falls within the above-described base range is used. It is a special feature that the grinding | polishing by grinding paper is very easy. Although the resist may be removed at the time of forming the projections, the resist can prevent damage to wirings or the like other than the bump 11 or prevent peeling of the bump 11 due to stress at the time of polishing. After the unevenness is formed on the bump 11 by polishing, gold is deposited on the nickel surface, or 0.01 μm to 5 μm is formed by sputtering or plating. Gold only needs to be formed when needed. Finally, as shown in FIG. 2F, the semiconductor element 1 having the bumps 11 formed by removing the resist 3 is obtained. In the present embodiment, the formation process by electroless plating has been described, but electrolytic plating may be used.

Although the bump formation method by a plating process was described here, formation methods, such as the bump transfer method and the bump formation method using a MEMS process, are not limited. In the above-mentioned concave-convex forming method, a method of forming the concave-convex on the semiconductor element 1 side is described, but the same effect is obtained even when the concave-convex is formed on the plating 22 on the wiring on the substrate 20 side. 3 shows an example of a process for forming the buffer layer 12 on the substrate 20 side of the first embodiment. In FIG. 3A, a copper wiring 21 and nickel plating are formed on the printed board 20. After that, after the resist 23 is applied, the openings are formed by exposure and development at the portions where the buffer layer 12 is formed (FIG. 3C). As the resist 23, any of a negative resist and a positive resist may be used. Finally, tin plating is formed in the openings by electroplating or electroless plating to form a printed board having the buffer layer 12. You may remove a resist as needed. The tin plating thickness formed in this embodiment is the sum h1 of the chip side pads 2, bumps 11, tin plating thickness and the thicknesses of the wirings 21 and 22 on the wirings 22 formed on the semiconductor element 1 side. It is formed so as to be longer than the chip side pad diameter h2. Here, h2 represents the dimension of the opening drilled in the film formed to cover the pad, inside the pad outer periphery formed on the semiconductor element. In addition, the shape of this opening part may be circular or rectangular, and in the former case, h2 shall refer to the diameter, and in the latter case, it shall refer to the length of a short side. In addition, tin plating may be formed by dip.

4 shows an example of a package forming process of the first embodiment. First, as shown in Fig. 4A, the buffer layer 12 on the substrate side and the chip bump 11 are aligned. The connection can be improved by cleaning the board | substrate side buffer layer 12 before connection. After positioning, ultrasonic connection is performed while heating and pressing are performed. Heating temperature is set so that connection part temperature may be room temperature or more and 150 degrees C or less. The expansion of the connection part at the time of ultrasonic application is shown in FIG. In the ultrasonic connection process, first, by applying a load, the distance between the contacted members is brought close, and after that, the ultrasonic wave is oscillated with the load applied, and the new surface is exposed by removing the oxide film and the contaminated film on the surface of the contacted body. The connection is secured by solid phase diffusion. By forming the protrusions on the bumps 11, the buffer layer 12 can be interposed between the bumps 11 and the wiring-plated plating 22 even when the initial load is applied. Therefore, a higher load can be loaded than when there is no protrusion, and the distance between the contacted members can be made closer. In addition, in the bump 11, the buffer layer 12, the buffer layer 12, and the plating 22 on the wiring, an oxide film on the buffer layer 12 is removed by ultrasonic application to expose the new surface, whereby solid phase diffusion connection is performed to make electrical connection. This is expected. Finally, the underfill 24 is interposed between the semiconductor element 1 and the substrate 20 to thereby reinforce the connecting portion and to prevent the contamination of the connecting portion, thereby completing the package.

Features of this embodiment are easy to ensure a stress buffer layer between the bump and the wiring, a high gap (connection height h1) of the connection portion, having a stress buffer layer, having a hard bump, low temperature connection such as ultrasonic connection This would be possible. It is easy to ensure a stress buffer layer, so that the initial load can be increased, and the distance between the contacted bodies can be made close, so that the oxide film and the contaminated film are easily removed at the time of ultrasonic application. Moreover, when a connection part space is large, even when the base material with a linear expansion coefficient difference is connected, there exists an advantage that the stress concentration of a connection part resulting from a temperature change can be reduced, and an underfill is easy to be injected. By having a stress buffer layer, the stress generate | occur | produced in a manufacturing and use environment can be alleviated by a connection part compared with a normal ultrasonic connection system. By having hard bumps, bump deformation due to the load at the time of connection is reduced, and short between bumps can be prevented. Since it is low temperature connection, such as an ultrasonic connection, since the temperature difference of connection temperature and room temperature is small, the initial stress to the connection part immediately after manufacture can be reduced.

As described above, according to the present embodiment, a semiconductor device having various effects and having a highly reliable connection structure can be realized. In the first embodiment, an example in which nickel bumps and gold plating are formed on the semiconductor element 1 side and a tin buffer layer is formed on the substrate side has been described. However, nickel bumps may be formed on the substrate side, and tin may be formed on the semiconductor element 1. You may form in the side). As the buffer layer 12, an alloy containing aluminum as a main component may be used.

<Example 2>

6 is a schematic sectional view of the second embodiment. Reference numeral 1 is a semiconductor element, 2 is a chip side pad, 11 is a bump, 12 is a buffer layer, 20 is a substrate, 21 is wiring, 22 is wiring plating, and 24 is underfill.

The bump 11 has a metal having a longitudinal modulus of 65 kPa or more and 600 kPa or less as a main component. For example, the bump 11 has at least one of nickel, copper, aluminum, gold, and titanium as a main component. Moreover, if the longitudinal elastic modulus of the whole bump is 65 GPa or more, a composite may be sufficient, for example, the laminated structure of copper and nickel may be sufficient.

The buffer layer 12 has any one of tin, indium, lead, and aluminum as a main component, and may be a material having a lower Young's modulus than the selected bump 11 material. The substrate 20 may be a resin substrate, a ceramic substrate, a silicon substrate, or the like.

The wiring 21 and the plating on the wiring 22 are generally used in respective substrates. For example, in the case of a resin substrate, the wiring 21 is copper, and the wiring 22 is nickel, gold plating, or the like. Can be mentioned. In the second embodiment, the substrate 20 is a printed substrate, and the structure is formed with irregularities on the substrate wiring side.

The first method of forming the unevenness in the plating 22 on the wiring is a pressing method with a mold. On the surface of the jig formed or surface-coated with a material having a higher hardness than the wiring-like plating 22, unevenness (1 to 15 mu m) having a desired height to be formed on the wiring-like plating 22 is formed. Although any method, such as mechanical polishing, etching, laser processing, plasma processing, or cutting, may be used for forming the unevenness, it is more preferable to select a method suitable for processing the zigzag material. Concave-convex is formed on the plating 22 on the wiring by opposing this jig with the substrate of Fig. 3A and applying a load from above. If a resist is formed, damage to wirings or the like other than the plating 22 on the wirings can be prevented. After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. This tin may be formed on the bump 11 side.

The second method of forming irregularities in the plating 22 on the wiring is a method using dry etching. The dry etching method is a method of using a scientific reaction such as reactive gas etching, reactive ion etching, reactive ion beam etching, reactive laser beam etching, or the like, in which a scientific reaction and a physical reaction are simultaneously etched by collision of ions such as ion milling. You may use either. From the state of FIG. 3A, unevenness | corrugation of 1-15 micrometers is formed on wiring plating 22 by any one of the above-mentioned methods. The convex portion may have any shape as long as at least one of the convex portions is formed on the surface of the plated plating 22 such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to the wirings other than the plating 22 on the wirings can be prevented by the resist. After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. This tin may be formed on the bump 11 side.

The third method of forming the unevenness in the plating 22 on the wiring is a method using wet etching. The wet etching method is a process in which chemicals that corrode and dissolve metals and the like are penetrated and sprayed into an object to be processed into an arbitrary shape, and a large amount of processing can be realized at a low cost at a time. From the state of FIG. 3A, the unevenness | corrugation of 1-15 micrometers is formed on the plating 22 on wiring wiring by the wet etching method. The convex portion may have any shape as long as at least one of the convex portions is formed on the surface of the plated plating 22 such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to the wirings other than the plating 22 on the wirings can be prevented by the resist. After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. This tin may be formed on the bump 11 side.

The fourth method of forming the unevenness in the plating 22 on the wiring is a method using laser processing. The kind of laser can be selected according to target materials, such as a solid-state laser, such as a YAG laser, a ruby laser, a gas laser, such as a carbon dioxide laser, an argon ion laser, a helium neon laser, a liquid laser, a semiconductor laser, and a free electron laser. Since uneven formation using a laser can be finely processed, it can be processed into a complicated shape. From the state of FIG. 3A, unevenness | corrugation of 1-15 micrometers is formed on bump 11 with a laser. The convex portion may have any shape as long as at least one of the convex portions is formed on the surface of the plated plating 22 such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to wirings or the like other than the bump 11 can be prevented by the resist. After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. You may form in the tin bump 11 side.

A fifth method of forming irregularities in the plating 22 on the wiring is a method using sputtering. Sputtering is a technique of surface processing and film-forming by colliding argon ionized in vacuum with a process surface. A method of forming irregularities of 1 to 15 µm by processing the upper surface of the plated plating 22 with ionized argon by placing the sample in the state of FIG. 3A in a vacuum chamber and ionizing argon, and using any sputter film forming apparatus. The method of forming on a bump is mentioned. The convex portion may have any shape as long as at least one of the convex portions is formed on the surface of the plated plating 22 such as a circle, a square, a polygon, a sphere, an ellipse, or the like. Although the resist may be removed at the time of forming the protrusions, damage to the wirings other than the plating 22 on the wirings can be prevented by the resist. After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. This tin may be formed on the bump 11 side.

The sixth method of forming the unevenness in the plating 22 on the wiring is a method using polishing. By grinding the sample in the state of FIG. 3A with abrasive paper, unevenness of 1 to 15 mu m is formed on the plating 22 on the wiring. In this case, abrasive paper having a particle size in which the unevenness falls within the above-described base range is used. It is a special feature that the grinding | polishing by grinding paper is very easy. Although the resist may be removed at the time of formation of the projections, damage to wiring or the like other than the wiring 22 on the wiring can be prevented by the resist, or peeling of the wiring 22 on the wiring due to the stress at the time of polishing can be prevented.

After the irregularities are formed on the plating 22 on the wirings, tin is formed on the nickel surface. This tin may be formed on the bump 11 side. In the first and second embodiments, the irregularities are formed on the bump 11 side and the wiring plating 22 side, respectively, but the bumps 11 and the wiring plating 22 may be formed on both the bumps 11 and the wiring wiring 22, respectively. .

In addition, the formation process of 2nd Example may be a process similar to 1st Example. In the second embodiment, in addition to the features of the first embodiment, since the unevenness is not formed on the semiconductor element 1 side, the semiconductor process can be simplified, and since the unevenness is present on the plating 22 side on the wiring, the buffer layer The thing which is easy to capture (12) is mentioned.

In addition, when the thickness of the buffer layer 12 is 5 micrometers or more, although it can manufacture by the process similar to Example 1, 2 mentioned above, when the buffer layer 12 becomes thick, the stress buffer function improves and is used. In the environment, the compound at the connecting interface continues to grow, but the stress buffer layer is maintained for a long time because the initial buffer layer is thick. As a result, it becomes a more reliable connection structure and can implement | achieve a highly reliable semiconductor.

While various embodiments in accordance with the present invention have been illustrated and described, it is not intended to be limited to the details shown and described herein but are not limited thereto and are intended to be included in the appended claims without departing from the scope of the present invention. It is intended to include all such changes and modifications.

1 is an enlarged cross-sectional view of a fine connecting portion of a first embodiment of the present invention;

2 is a cross-sectional view of one example of a bump forming process on a semiconductor device of the present invention.

3 is a cross-sectional view of an example of a buffer layer forming process on a substrate of the present invention.

4 is a cross-sectional view of one example of an assembly process of the present invention.

5 is an enlarged cross-sectional view of the micro connection part in the ultrasonic application process of the present invention.

6 is an enlarged cross-sectional view of a fine connection part of a second embodiment of the present invention;

7 is an enlarged cross-sectional view of a conventional joint using gold stud bumps.

<Explanation of symbols for main parts of the drawings>

1: semiconductor device

2: chip side pad

3: resist

11: bump

12: buffer layer

20: substrate

21: wiring

22: plating on wiring

24: underfill

Claims (13)

A semiconductor device having a connection structure for connecting a fine pitch electrode of 50 micrometers pitch or less formed on a semiconductor element and a pad or wiring formed on a substrate on which the semiconductor element is mounted, One side of the connection structure is connected to the fine pitch electrode, and the other is a buffer layer including a bump having a Young's modulus (Young's modulus) of 65 GPa or more and 600 GPa or less, and tin, aluminum, indium, or lead as a main component. It includes a structure connected to the pad or wiring formed on the substrate via the, A semiconductor device having a projection shape on at least one surface of a surface where the bumps and pads or wirings formed on the substrate face each other. The method of claim 1, The height of the connection between the surface of the semiconductor element on which the fine pitch electrode is formed and the surface of the substrate on which the pad or wiring is formed is h1. A semiconductor device having a relationship of h1? H2 when the connection diameter or the short side length of the bump is h2. The method of claim 1, A semiconductor device, characterized in that the bump is composed of a plurality of layers. The method of claim 1, The bumper main material is any one of nickel, copper, aluminum, gold, and titanium. The method of claim 1, The buffer layer is formed on the bumps or on the pads or wirings. The method of claim 1, And the buffer layer is formed by electroplating or electroless plating. The method of claim 1, The buffer layer is formed by using the metal foil inserted between the bumps, the pads, or the wirings. The method of claim 1, A connection between any one of the semiconductor element and the bump or the buffer layer and the pad is connected by applying ultrasonic waves. The method of claim 8, Said connection is performed at the temperature of room temperature or more and 150 degrees C or less, The semiconductor device characterized by the above-mentioned. A semiconductor device having a connection structure for connecting a fine pitch electrode of 50 micrometers pitch or less formed on a semiconductor element and a pad or wiring formed on a substrate on which the semiconductor element is mounted, One side of the connection structure is connected to the fine pitch electrode, and the other is a buffer layer including a bump having a Young's modulus (Young's modulus) of 65 GPa or more and 600 GPa or less, and tin, aluminum, indium, or lead as a main component. A semiconductor device having a structure connected to a pad or a wiring formed on said substrate via a gap. A semiconductor device having a connection structure for connecting a fine pitch electrode of 50 micrometers pitch or less formed in a semiconductor element and a pad or wiring on a substrate, The connection structure includes a bump, a buffer layer having a lower Young's modulus than the bump, and a wiring thickness, and a connection height h1 between the semiconductor element and the substrate which is a sum of the height of the bump, the height of the buffer layer, and the wiring thickness. And the relationship between the width (or connection diameter) h2 of the bumps are formed such that h1 ≧ h2, The buffer layer is formed on the bump or on the pad. The method of claim 11, The height of the said buffer layer is 5 micrometers or more, The semiconductor device characterized by the above-mentioned. The method of claim 11, The main component of the buffer layer is any one of tin, aluminum, indium and lead.

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