JPH11330161A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device, which can stably connect electrodes of a semiconductor element and electrodes of a circuit board with an nearly-constant connection resistance value at all times, and by which the device can easily mounted on the board, while eliminating the need for annoying adjustment of the element. SOLUTION: A resin sheet 13 is bonded onto a part of a circuit board 3, where a semiconductor element 7 is to be mounted. A conductive material 14 is attached onto positions of the sheet 13 opposite to projection electrodes of the board 3. The element 7 is positioned with respect to the board 3, the element 7 is pressed in such a direction as to near the board 3 under a heated condition to bring projection electrodes 9, embedded in the element 7 into contact substrate electrode parts 4 via the conductive material 14, whereby the element 7 and board 3 are bonded and encapsulated together, thus obtaining a semiconductor device 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device in which a semiconductor element mainly composed of a semiconductor bare chip is mounted on a circuit board.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a reduction in size and weight of electronic equipment, and accordingly, in a semiconductor device having a semiconductor element mounted on a circuit board, it is necessary to increase the mounting density of electronic circuits. For the purpose, a method of turning a semiconductor bare chip obtained by dividing a wafer into individual pieces upside down and mounting the semiconductor bare chips directly on a circuit board is often used. In particular, as a technology for assembling and mounting ultra-high pin count elements such as thermal head drivers, liquid crystal display drivers, and gate arrays, projecting electrodes are formed on the element electrode portion of a semiconductor bare chip by a ball bonding method using a wire bonder. 2. Description of the Related Art There is known a method of mounting a semiconductor bare chip on a circuit board by bonding to a substrate electrode portion of a substrate in an electrically connected state.

[0005] Next, as one line of a conventional method of manufacturing a semiconductor device, a manufacturing process of a liquid crystal display driver will be described. First, as shown in FIG. 4A, a conductive resin sheet 1 containing dispersed conductive particles 2 such as nickel metal fine powder is placed on the surface of the circuit board 3 on which the substrate electrode portion 4 is formed. paste. In this resin sheet 1, only the pressurized portions have conductivity. Subsequently, as shown in FIG. 1B, the mounting head 10 having the built-in head heater 11 has a semiconductor in which a two-stage projection electrode (stud bump) 9 is previously formed on the element electrode portion 8 by a ball bonding method. The semiconductor element 7 composed of a bare chip is sucked. Here, the semiconductor element 7 is pressed against the suction surface of the mounting head 10 against the surface on which the protruding electrodes 9 are not formed, and the air suction force of a vacuum pump (not shown) is applied to the air suction passage 12 of the mounting head 10. By acting through the mounting head, it is attracted to the mounting head 10.

[0004] A mounting head 10 to which a semiconductor element 7 is sucked.
After the semiconductor element 7 is positioned with respect to the circuit board 3 so that the element electrode portion 8, that is, the protruding electrode 9 faces the substrate electrode portion 4, the semiconductor element 7 descends as shown in FIG. Is placed on the resin sheet 1. Next, the mounting head 10 presses the semiconductor element 7 to press it against the resin sheet 1. Thereby, as shown in FIG. 2C, the protruding electrodes 9 are embedded in the resin sheet 1 and are electrically connected to the substrate electrode portions 4 of the circuit board 3 via the conductive particles 2. Contact. In addition, the mounting head 10 drives the head heater 11 to increase the heating temperature to 200 ° C. The resin sheet 1 is melt-hardened by the heat generated by the head heater 11 being transferred through the element electrode portions 8 and the protruding electrodes 9. The melt-cured resin sheet 1 firmly holds the joint between the protruding electrode 9 and the substrate electrode portion 4 and seals the gap between the semiconductor element 7 and the circuit board 3.

[0005]

However, in the conventional method of manufacturing a semiconductor device, the electrical connection between the protruding electrode 9 and the substrate electrode portion 4 by the conductive particles 2 and the gap between the semiconductor element 7 and the circuit substrate 3 are not provided. Since the resin sheet 1 mixed with the conductive particles 2 is used for the purpose of performing sealing with a resin in a single step, the resin sheet 1 is interposed between the bump electrode 9 and the substrate electrode portion 4 in a mounted state. The number of the conductive particles 2 is small, and the number varies. As a result, the connection resistance value between the protruding electrode 9 and the substrate electrode portion 4 varies from one semiconductor device to another and is not constant, and there is a problem that the electrical characteristics of the manufactured semiconductor device change.

Further, in this manufacturing method, in order to keep the number of conductive particles 2 interposed between the protruding electrode 9 and the substrate electrode portion 4 as constant as possible, the circuit substrate 3 and the semiconductor element 7 are connected to each other. It is necessary to face each other with exact parallelism. Therefore, the plurality of two-step protruding electrodes 9 formed on one semiconductor element 7 are shaped into a flat surface by means such as pressing each tip against a leveling stage, and each height is adjusted to an accurate constant value. The semiconductor elements 7 on which the protruding electrodes 9 are formed need to be pressed against the circuit board 3 while maintaining an accurate parallelism. Therefore, the conventional manufacturing method requires complicated and difficult adjustments to the semiconductor manufacturing apparatus.

In view of the above, the present invention has been made in view of the above-mentioned conventional problems, and can stably connect a projecting electrode of a semiconductor element to a substrate electrode portion of a circuit board with a substantially constant connection resistance value at all times. It is an object of the present invention to provide a method of manufacturing a semiconductor device in which a semiconductor element can be easily mounted on a circuit board without requiring any adjustment.

[0008]

In order to achieve the above object, a first aspect of the present invention is to join a projecting electrode formed on a device electrode portion of a semiconductor device to a substrate electrode portion of a circuit board in an electrically connected state. According to the method for manufacturing a semiconductor device in which the semiconductor element is mounted on the circuit board, a gap between the circuit board and the semiconductor element is sealed at a position on the circuit board where the semiconductor element is to be mounted. Attaching a conductive material to a position of the resin sheet facing the projecting electrode, and placing the semiconductor element on the circuit board with the projecting electrode facing the conductive material. After positioning,
Under the heating state, the semiconductor element is pressurized in a direction approaching the circuit board, and the protruding electrode embedded in the resin sheet is applied to the substrate electrode portion via the conductive material pressed thereby. Contacting and sealing the semiconductor element and the circuit board by bringing them into contact with each other.

In this method of manufacturing a semiconductor device, a certain amount of a conductive material provided separately from the resin sheet surely intervenes between each of the plurality of protruding electrodes and the substrate electrode portion. The junction with the electrode portion is reliably electrically connected, and the connection resistance value is always stabilized at a constant value. In addition, since a conductive material provided separately from the resin sheet is interposed between the protruding electrode and the substrate electrode portion, there is no need to adjust the semiconductor element so as to face the circuit board with an accurate parallelism. Can be manufactured.

In the method of manufacturing a semiconductor device according to a second aspect of the present invention, a step of attaching a conductive material to a position of the substrate electrode portion where the bump electrode is to be joined, and a step of attaching the conductive material to the circuit board. Attaching a resin sheet for sealing a gap between the circuit board and the semiconductor element to a location where the semiconductor element is to be mounted, including a location, and providing the semiconductor with the bump electrode facing the conductive material. After positioning the element with respect to the circuit board, the semiconductor element is pressed in a direction approaching the circuit board under a heating state, and the protruding electrode embedded in the resin sheet is interposed through the conductive material. The circuit board and the semiconductor element by contacting the substrate electrode portion with the
Sealing step.

In this method of manufacturing a semiconductor device, the same effect as that of the first invention can be obtained by directly attaching the conductive material to the circuit board.

Further, in the method of manufacturing a semiconductor device according to a third aspect of the present invention, there is provided a method of adhering a conductive material to a predetermined position in a resin sheet for sealing a gap between the circuit board and the semiconductor element; Positioning the conductive material with respect to the circuit board so as to face a position where the bump electrode is to be joined, and attaching the bump to a location on the circuit board where the semiconductor element is to be mounted; and After positioning the semiconductor element with respect to the circuit board by facing the conductive material, the semiconductor element was pressed in a direction approaching the circuit board under a heating state, and embedded in the resin sheet. By making the protruding electrode contact the substrate electrode portion via the conductive material,
Bonding and sealing the semiconductor element and the circuit board.

Also in this method of manufacturing a semiconductor device, the same effect as that of the first invention can be obtained by attaching a conductive material to the resin sheet in advance.

In each aspect of the invention, by using an adhesive containing a solder metal or a conductive filler as the conductive material, the bonding between the protruding electrode and the substrate electrode portion can be strengthened.

Further, as the resin sheet in each invention,
It is preferable to use a semiconductor element having a thermal expansion coefficient larger than that of the semiconductor element and smaller than that of the circuit board. Thereby, the stress due to the thermal expansion that tends to be applied to the resin sheet due to the thermal stress due to the difference in the thermal expansion coefficient between the semiconductor element and the circuit board can be reduced. Therefore, high reliability can be obtained in joining the protruding electrode of the semiconductor element and the substrate electrode portion through the conductive material.

Further, it is more preferable that the resin sheet of each invention has a coefficient of thermal expansion that gradually increases from a portion facing the semiconductor element to a portion facing the circuit board. This makes it possible to extremely effectively reduce the stress due to thermal expansion that is applied to the conductive material due to the thermal stress caused by the difference in the thermal expansion coefficient between the semiconductor element and the circuit board. A higher reliability can be obtained by bonding between the substrate and the substrate electrode portion via a conductive material.

[0017]

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

FIG. 1 is a schematic vertical sectional view showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps, and the same or equivalent parts as those in FIG. The description is omitted. In this embodiment, as shown in FIG. 1A, a simple resin sheet 13 containing no conductive particles is provided, and the resin sheet 13 is connected to a semiconductor element on the circuit board 3 as shown by a two-dot chain line. 7 is attached to a place to be mounted. The resin sheet 13 is preferably made of a thermosetting resin, for example, an epoxy resin, and has a thickness slightly larger than the height of the two-step projection electrode 9 provided on the semiconductor element 7, that is, 50 to 100 μm.
The thickness is formed.

Next, as shown in FIG. 1B, a predetermined position on the resin sheet 13 is
Are simultaneously supplied by a screen printing method or individually supplied by a dispensing method. Here, the predetermined position of the resin sheet 13 is such that each protruding electrode 9 of the semiconductor element 7 is
Are positions to be opposed to each other to make contact with the corresponding substrate electrode portions 4. Further, as the conductive material 14,
In this embodiment, fine powder of a conductive metal material such as gold or silver or a silver-palladium alloy is used as a conductive filler, and the conductive filler is formed by mixing a thermosetting resin, for example, an epoxy resin and a solvent. Use an adhesive.
In addition, a solder metal such as tin-lead can be used as the conductive material 14. In the case of a solder metal, it is individually supplied to and adhered to each predetermined position by a dispensing method.

Subsequently, as shown in FIG. 1C, the mounting head 10 having the built-in head heater 11 has a two-stage projecting electrode 9 previously formed on the element electrode portion 8 by a ball bonding method or a plating method. The semiconductor element 7 composed of the formed semiconductor bare chip is sucked. Here, in the semiconductor element 7, the suction surface of the mounting head 10 is pressed against the surface on which the protruding electrodes 9 are not formed, and the air suction force of a vacuum pump or the like acts via the air suction passage 12 of the mounting head 10. Thus, it is attracted to the mounting head 10. The mounting head 10 having the semiconductor element 7 attracted as described above.
After positioning the semiconductor element 7 with respect to the circuit board 3 so that the element electrode portion 8, that is, the protruding electrode 9 accurately faces the conductive material 14, the semiconductor element 7 is moved down while maintaining the positioning state under the heating state. Then, the semiconductor element 7 is pressed against the circuit board 3.

As a result, the protruding electrodes 9 are buried in the resin sheet 13 while pressing down the corresponding conductive materials 14 as shown in FIG. Then, the substrate electrode portion 4 is electrically connected to the substrate electrode portion 4 via the conductive material 14. The mounting head 10 has a heating temperature of 200 head heaters 11.
Control so as to raise the temperature to ° C. Thereby, the resin sheet 1
3 is melted by transferring the heat generated by the head heater 11 through the element electrode portion 8 and the projecting electrode 9, and is slightly pressurized through the semiconductor element 7 to be slightly lower than the height of the projecting electrode 9. Since it has a large thickness, it is deformed so as to completely fill the gap between the circuit board 3 and the semiconductor element 7. The conductive material 14 and the resin sheet 13 are melted and hardened to strengthen the bonding state between the protruding electrodes 9 and the substrate electrode portions 4, and firmly bond the semiconductor element 7 and the circuit board 3 to each other. .

On the other hand, when a solder metal is used as the conductive material 14, the conductive material 14
1. The protruding electrode 9 and the substrate electrode portion 4 are electrically and mechanically firmly connected by being heated and melt-hardened by the generated heat, and the protruding electrode 9 and the substrate are hardened by the electro-conductive material 14 being melt-hardened. The electrode part 4 is firmly joined.

FIG. 2 is a schematic longitudinal sectional view showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps. In this embodiment, the method is different from that of the first embodiment. Only the sequence of some of the steps is different. That is, as shown in FIG. 3A, the conductive material 14 is simultaneously supplied to the portion of each circuit board electrode portion 4 of the circuit board 3 to which the protruding electrode 9 is to be joined by the screen printing method or individually by the dispensing method. I do. Next, the mounting head 10 having the built-in head heater 11 attracts the semiconductor element 7 composed of a semiconductor bare chip having the projection electrode 9 formed on the element electrode section 8 in advance, and the element electrode section 8, that is, the projection electrode 9 becomes conductive. After the semiconductor element 7 is positioned with respect to the circuit board 3 so as to accurately face the conductive material 14, the semiconductor element 7 is lowered while maintaining the positioning state, and the semiconductor element 7 is pressed against the circuit board 3. As a result, the protruding electrodes 9 are embedded in the resin sheet 13 while pushing down the corresponding conductive material 14 as shown in FIG. The substrate 14 is in electrical contact with the substrate electrode portion 4 via the line 14.

At this time, in this embodiment, the mounting head 10 drives the head heater 11 to raise the temperature to a heating temperature of 200 ° C. Therefore, the resin sheet 13
Since the heat generated by the head heater 11 is melted by being transferred through the element electrode portion 8 and the protruding electrode 9, the protruding electrode 9 is smoothly embedded in the melted resin sheet 13. As shown in (1), the substrate electrode portion 4 is electrically connected to the substrate electrode portion 4 via the corresponding conductive material 14.

As in the first embodiment, the resin sheet 13 is pressed and heated via the semiconductor element 7 so as to fill the gap between the circuit board 3 and the semiconductor element 7 without any gap. After being deformed, it hardens, and the joint between the protruding electrode 9 and the substrate electrode portion 4 with the conductive material 14 interposed therebetween is sealed therein, and the joined state is firmly maintained.
The semiconductor element 7 and the circuit board 3 are firmly joined to each other.

FIG. 3 is a schematic vertical sectional view showing a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps. In this embodiment, the steps are different from those of the first embodiment. Only the order of some of them is different. That is, as shown in FIG. 2A, the protruding electrode 9 and the substrate electrode portion 4 are provided on one surface of the resin sheet 13 before being attached to the circuit board 3.
The conductive material 14
Are simultaneously supplied by a screen printing method or individually supplied by a dispensing method. In this way, the resin sheet 13 to which the conductive material 14 has been previously attached is placed in a state where the conductive material 14 is positioned upward as shown in FIG.
The conductive material 14 serves as the protruding electrode 9 in the substrate electrode portion 4.
And bonded to the circuit board 3. After that, as shown in FIGS. 3C and 3D, the semiconductor device 7 is mounted on the circuit board 3 through the same steps as in the first embodiment, and
7 is manufactured. That is, FIGS. 1C and 1D show FIGS.
This is the same step as (c) and (d).

Therefore, the semiconductor device 17 obtained by this manufacturing method can obtain exactly the same effects as in the first embodiment. In addition, this manufacturing method has an advantage that the process can be simplified because the resin sheet to which the conductive material is previously attached is attached to the circuit board.

On the other hand, as shown in FIG. 3A, a resin sheet 13 on which a conductive material 14 is previously adhered to one surface is arranged in such a manner that the conductive material 14 is located on the lower side as shown in FIG. 3B. The conductive material 14 may be positioned so as to correspond to the joint portion of the protruding electrode 9 in the substrate electrode portion 4, and may be attached to the circuit board 3. After that, as shown in FIGS. 2C and 2D, the semiconductor device 7 is mounted on the circuit board 3 through the same steps as in the second embodiment to manufacture the semiconductor device 17. The semiconductor device 17 obtained by this manufacturing method can obtain exactly the same effects as in the second embodiment.

In each of the first to third embodiments, the coefficient of thermal expansion of the resin sheet 13 is larger than the coefficient of thermal expansion of the semiconductor element 7 and smaller than the coefficient of thermal expansion of the circuit board 3. Is set. Specifically, when the thermal expansion coefficient of a general semiconductor element 7 is 3 ppm / K, and the thermal expansion coefficient of the circuit board 3 is a ceramic substrate, it is 6 ppm / K.
Since the resin substrate is 14 ppm / K, the coefficient of thermal expansion of the resin sheet 13 is set at a value between 3 ppm / K and 6 ppm / K, or between 3 ppm / K and 14 ppm / K.

As a result, the stress due to the thermal expansion applied to the resin sheet 13 due to the thermal stress due to the difference in the thermal expansion coefficient between the semiconductor element 7 and the circuit board 3 can be reduced. Therefore, high reliability can be obtained in joining the protruding electrode 9 of the semiconductor element 7 and the substrate electrode portion 4 with the conductive material 14 interposed therebetween.

On the other hand, in each of the above-described first to third embodiments, the coefficient of thermal expansion of the resin sheet 13 gradually increases from the side facing the semiconductor element 7 toward the side facing the circuit board 3. It can also be set to change to a state. In setting the coefficient of thermal expansion of the resin sheet 13 in this case, there is no particular restriction on the coefficient of thermal expansion specific to the semiconductor element 7 and the circuit board 3. A resin sheet 13 whose coefficient of thermal expansion gradually changes from 3 ppm / K to 6 ppm / K or 14 ppm / K of the coefficient of thermal expansion of the circuit board 3 is used. By using such a resin sheet 13, stress due to thermal expansion that is applied to the conductive material 14 due to thermal stress due to a difference in thermal expansion coefficient between the semiconductor element 7 and the circuit board 3 is extremely effectively reduced. Therefore, it is possible to obtain higher reliability in joining the protruding electrode 9 of the semiconductor element 7 and the substrate electrode portion 4 via the conductive material 14.

[0032]

As described above, according to the method of manufacturing a semiconductor device of the present invention, the conductive material provided separately from the resin sheet between each of the plurality of protruding electrodes and the substrate electrode portion can be reliably fixed. Since it can be interposed by the amount, the junction between the protruding electrode and the substrate electrode can be reliably electrically connected,
The connection resistance value can be stabilized at a constant value. Further, since a conductive material provided separately from the resin sheet is interposed between the protruding electrode and the substrate electrode portion 4, there is no need to adjust the semiconductor element so as to face the circuit board with an accurate parallelism. It can be easily manufactured.

[Brief description of the drawings]

FIGS. 1A to 1D are schematic longitudinal sectional views sequentially showing steps of a method of manufacturing a semiconductor device according to a first embodiment of the present invention.

FIGS. 2A to 2D are schematic longitudinal sectional views sequentially showing steps of a method of manufacturing a semiconductor device according to a second embodiment of the present invention.

FIGS. 3A to 3D are schematic longitudinal sectional views sequentially showing steps of a method of manufacturing a semiconductor device according to a third embodiment of the present invention.

4A to 4C are schematic longitudinal sectional views sequentially showing steps of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Circuit board 4 Substrate electrode part 7 Semiconductor element 8 Element electrode part 9 Protruding electrode 13 Resin sheet 14 Conductive material 17 Semiconductor device

Claims (7)

[Claims] 1. A semiconductor device having the semiconductor element mounted on the circuit board by bonding a projecting electrode formed on an element electrode section of the semiconductor element to a substrate electrode section of a circuit board in an electrically connected state. In the method, a step of attaching a resin sheet for sealing a gap between the circuit board and the semiconductor element to a portion of the circuit board where the semiconductor element is to be mounted; and opposing the protruding electrodes in the resin sheet. A step of attaching a conductive material to a position to be made, and after positioning the semiconductor element with respect to the circuit board with the protruding electrode facing the conductive material, the semiconductor element is placed on the circuit board under a heated state. The protruding electrode buried in the resin sheet by pressing in a direction to approach the substrate electrode portion via the conductive material pressed thereby. A step of bonding and sealing the semiconductor element and the circuit board by contacting the semiconductor element with the semiconductor device. 2. A semiconductor device having the semiconductor element mounted on the circuit board by bonding the protruding electrode formed on the element electrode section of the semiconductor element to the substrate electrode section of the circuit board in an electrically connected state. In the method, a step of attaching a conductive material to a position of the substrate electrode portion where the protruding electrode is to be joined, and a place where the semiconductor element is to be mounted including a place where the conductive material is attached on the circuit board. Affixing a resin sheet for sealing a gap between the circuit board and the semiconductor element; heating the semiconductor element with respect to the circuit board after positioning the semiconductor element with the protruding electrode facing the conductive material; Under the condition, the semiconductor element is pressed in a direction approaching the circuit board, and the protruding electrodes embedded in the resin sheet are connected to the base via the conductive material. A step of joining and sealing the circuit board and the semiconductor element by bringing the semiconductor element into contact with a plate electrode portion. 3. A semiconductor device having the semiconductor element mounted on the circuit board by bonding the protruding electrode formed on the element electrode section of the semiconductor element to the substrate electrode section of the circuit board in an electrically connected state. In the method, a step of attaching a conductive material to a predetermined position in a resin sheet for sealing a gap between the circuit board and the semiconductor element; and bonding the resin sheet to the projecting electrode with the conductive material. Positioning the semiconductor element on the circuit board so as to face a position to be mounted, and attaching the semiconductor element on the circuit board at a place where the semiconductor element is to be mounted; and After positioning with respect to the circuit board, the semiconductor element is pressed in a direction approaching the circuit board under a heated state, and the protrusion embedded in the resin sheet is pressed. A method of manufacturing a semiconductor device, comprising: a step of joining and sealing the semiconductor element and the circuit board by bringing an electrode into contact with the substrate electrode portion via the conductive material. . 4. The method according to claim 1, wherein the conductive material is a solder metal.
A method for manufacturing a semiconductor device according to claim 3. 5. The method for manufacturing a semiconductor device according to claim 1, wherein the conductive material is an adhesive containing a conductive filler. 6. The resin sheet according to claim 1, wherein the resin sheet has a larger coefficient of thermal expansion than a semiconductor element and a smaller coefficient of thermal expansion than a circuit board. Of manufacturing a semiconductor device. 7. A resin sheet having a coefficient of thermal expansion that gradually increases from a portion facing the semiconductor element to a portion facing the circuit board is used as the resin sheet. The method for manufacturing a semiconductor device according to any one of the above.