JPH10340927A - Manufacture of semiconductor device and bonding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device and a bonding device, which can avoid connection failures caused by the warpage of a semiconductor chip and a circuit board to realize a semiconductor device having high reliability. SOLUTION: After starting pressurization on a semiconductor chip 1 and a circuit board 3 by means of a bonding tool 2, a resin on the side surface of the semiconductor chip 1 is subjected to ultraviolet irradiation. Then, the semiconductor chip 1 and the circuit board 3 are heated to thermally cure the resin. After the semiconductor chip 1, the circuit board 3 and a resin 9 returned to normal temperatures, the pressurization is removed, and the resin is cooled sufficiently so as to maintain the condition where the warpage of the semiconductor chip 1 is corrected, thus eliminating the occurrence of connection failures between a bump and a connection electrode.

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 by a flip-chip mounting method and a bonding apparatus used for the method.

[0002]

2. Description of the Related Art One of the mounting methods of a semiconductor chip is as follows.
There is a flip chip mounting method. The flip-chip mounting method mounts the semiconductor chip directly face down via bumps on the connection electrodes of a circuit board such as glass, ceramic, or silicon chip, so that a single semiconductor chip can be directly mounted without a package. This is a technology that can realize a small, thin, low-cost semiconductor device and a semiconductor device with excellent electrical characteristics.

FIG. 5 is a process diagram showing a manufacturing process of a conventional flip-chip mounting method, in which 30 is a semiconductor chip, 31 is a pad electrode, 32 is a bump, 33 is a circuit board, 34 is a board electrode, 35 is a bonding tool, 36
Is an ultraviolet curing resin, 37 is ultraviolet light, and 38 is an external electrode on the substrate, which is an electrode for electrical connection with an external device. In the figure, the configuration shown by the broken line is the semiconductor chip 30
For vacuum suction. Hereinafter, a conventional flip chip mounting method will be described.

First, as shown in FIG. 5A, bumps 32 are formed on pad electrodes 31 of a semiconductor chip 30, and the semiconductor chip 30 is vacuum-held face down by a bonding tool 35. The pad electrodes 31 of the semiconductor chip 30 are usually formed with bump electrodes called bumps 32. Gold (Au), solder, or the like is used for the bump material.
There are plating, vapor deposition, and ball bonding using a wire bonder.

In recent years, a technique of bonding semiconductor chips to each other by the flip-chip mounting method has also been put into practical use. In order to improve the operation speed and electric characteristics of a semiconductor device, electrodes are formed on one or both semiconductor chip elements. May be done. At this time, since the electrodes are formed on the element, it is necessary to connect both semiconductor chips at a low temperature and with a low load that do not affect the element characteristics. For this purpose, a metal material having a low melting point and a low hardness, such as indium (In), may be used as the bump material.

Next, as shown in FIG. 5B, after the bumps 32 of the semiconductor chip 30 and the bumps of the circuit board 33, which are fixed by suction to the bonding tool 35, are aligned,
An ultraviolet curable resin 36 is applied on the circuit board 33.

Next, as shown in FIG. 5C, the bonding tool 35 is lowered, and the semiconductor chip 30 and the circuit board 33 are heated and pressed for a predetermined time. As a result, the ultraviolet curable resin 36 interposed between the semiconductor chip 30 and the circuit board 33 is thermally cured and contracted by curing, so that the bumps 32 of the semiconductor chip 30 and the substrate electrodes 3 of the circuit board 33 are formed.
4 is electrically connected via the bumps 32 of the semiconductor chip 30. The optimum bonding method is set according to the material of the bump 32, the connection method, and the material of the substrate electrode 34 of the circuit board 33. The gap between the semiconductor chip 30 and the circuit board 33 is filled with the ultraviolet curing resin 36.

Next, as shown in FIG. 5D, in order to cure the ultraviolet curing resin 36 protruding from the side surface of the semiconductor chip 30, ultraviolet rays 37 are irradiated to irradiate the ultraviolet ray 37 between the semiconductor chip 30 and the circuit board 33. Thermal curing for completely curing the curable resin 36 is performed, and the flip chip mounting process is completed.

Conventionally, a semiconductor chip is flip-chip mounted on a substrate by the above-described steps.

[0010]

However, the conventional method has the following problems. In other words, the resin interposed between the semiconductor chip and the circuit board is heated and hardened by pressurizing and heating with a heated bonding tool. If the cured resin between the semiconductor chip and the circuit board is not sufficiently cooled, the resin softens, the elastic modulus becomes extremely low, and when the pressure on the bonding tool is released, the warpage returns, especially for large-area semiconductor chips. However, there has been a problem that a connection failure between the bump and the substrate electrode occurs, which lowers the yield and reliability of the manufactured semiconductor device.

When a semiconductor chip is bonded to a circuit board coated with an ultraviolet-curable resin by pressing, the amount of resin spread from the entire periphery of the side surface of the semiconductor chip at the time of pressing depends on the amount of resin applied. This greatly differs, and it becomes extremely difficult to control the spread amount of the resin. As a result, as shown in FIG. 6, the ultraviolet curable resin 36 that has protruded from the entire periphery of the side surface of the semiconductor chip 30 and spreads extends onto the external electrodes 38 of the circuit board 33 where wire bonding is to be performed. As a result, not only the wire bonding to the external electrode 38 cannot be performed, but also the bonding strength is significantly reduced, and the reliability of the semiconductor device is reduced.

Further, as an ultraviolet curing resin used for connecting a semiconductor chip and a circuit board, a resin designed in consideration of a dielectric constant is used. For this reason, the resin properties are anaerobic, and the area in contact with oxygen in the air has curing characteristics such that it does not thermally cure, so that the resin interposed between the semiconductor chip and the circuit board is heated by heating, so the bonding tool requires a long time. There is also a problem in the process tact that heating and pressurization are required. Furthermore, in order to completely cure the resin protruding from the periphery of the side of the semiconductor chip, a photo-curing step by re-irradiating ultraviolet rays is required. There was also a problem that costs increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and a method of manufacturing a semiconductor device and a bonding apparatus capable of avoiding a connection failure due to warpage of a semiconductor chip and a circuit board and realizing a highly reliable semiconductor device. The purpose is to provide.

[0014]

In order to solve the above-mentioned conventional problems, a method of manufacturing a semiconductor device according to the present invention comprises the steps of starting the pressing of a semiconductor chip and a circuit board with a bonding tool and then applying an ultraviolet light to a side surface of the semiconductor chip. Irradiation is performed, and then the semiconductor chip and the circuit board are heated. Further, the bonding apparatus of the present invention is provided with a pulse heating mechanism for the bonding tool and the semiconductor chip, and a mechanism for irradiating the semiconductor chip with ultraviolet rays when the bonding tool is pressed, and has a function capable of sequencing these mechanisms in a predetermined time. is there. That is, on a stage of a bonding apparatus, a step of mounting a substrate having an electrode on the main surface with its electrode surface facing up, and a step of holding the main surface of the semiconductor chip facing the substrate and holding the same. A step of aligning a bump electrode provided on the main surface of the semiconductor chip with an electrode of the substrate; a step of applying an ultraviolet curable resin on the main surface of the semiconductor chip or the substrate; Connecting the electrodes to the electrodes on the substrate, pressing the semiconductor chip from the back side thereof to pressure-bond the bump electrodes and the electrodes on the substrate, and Irradiating ultraviolet light to a gap region between the semiconductor chip and the substrate to cure a resin surface formed in a side surface region of the semiconductor chip; and A step of said resin interposed in the gap between the conductor chip and the substrate is heat-cured, after which the semiconductor chip, substrate becomes normal temperature, and a step of releasing the pressurization of the semiconductor chip. Further, the irradiation time for irradiating the gap region between the semiconductor chip and the substrate with ultraviolet rays is shorter than the pressing time for pressing the semiconductor chip.

A bonding tool for holding a semiconductor chip, a stage for holding a substrate, a first heater provided on the bonding tool for heating the semiconductor chip, a bonding tool provided on the stage, A second heater for heating a substrate, and a semiconductor chip held by the bonding tool, which is pressure-bonded to the substrate, is provided near the stage to irradiate ultraviolet light to a side surface region of the semiconductor chip. And ultraviolet irradiation means.

According to the present invention, by the above means, the joining time between the semiconductor chip and the circuit board, that is, the step of curing the resin interposed between the semiconductor chip and the circuit board can be simplified and the productivity can be improved. Further, a connection failure due to warpage of the semiconductor chip and the circuit board can be avoided, and a highly reliable semiconductor device can be easily realized at low cost.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. First, an embodiment of a bonding apparatus used in the method for manufacturing a semiconductor device of the present invention will be described. FIG. 1 shows a bonding apparatus according to the present embodiment.

The bonding apparatus of this embodiment comprises a bonding tool 2 for pressurizing and heating a semiconductor chip 1 and a stage 4 for mounting a circuit board 3. The tip of the bonding tool 2 and the circuit board 3 are mounted. The stage 4 is provided with both pulse heaters 5a and 5b that generate heat when a pulse current is applied. Further, an optical fiber 6 is provided in the vicinity of the stage 4 so that the entire periphery of the side surface of the semiconductor chip 1 can be irradiated with ultraviolet rays while the semiconductor chip 1 is pressed by the bonding tool 2. In the drawing, the configuration shown by a broken line is a hole for vacuum suction.

The heating temperature and the heating time of the bonding tool 2 and the stage 4 can be arbitrarily set by changing the pulse current and the current application time of the respective pulse heaters 5a and 5b.
The setting is performed in a diagram showing a flowchart as shown in FIGS. 2 and 3 and a diagram showing a time chart. Further, it has a function capable of sequence-controlling the heating temperature and heating time of the bonding tool 2, the heating temperature of the stage 4, the heating time, and the ultraviolet irradiation time depending on each bonding condition.

Next, an embodiment of a method of manufacturing a semiconductor device according to the present invention will be described with reference to FIG. In FIG.
1 is a semiconductor chip, 2 is a bonding tool, 3 is a circuit board, 4 is a stage, 5a and 5b are pulse heaters, 6
Numeral denotes an optical fiber, which is the same as the configuration shown in FIG. 1, 7 is a bump, 8 is a connection electrode, 9 is an ultraviolet curable resin, 10 is an external electrode on a substrate, 11 is a resin fillet,
Reference numeral 12 denotes ultraviolet rays.

First, as shown in FIG. 4A, a semiconductor chip 1 is held by a bonding tool 2 having a pulse heater 5a of a bonding apparatus as shown in FIG. It is mounted on a stage 4 having a pulse heater 5b. Then, bumps 7 are formed on the pad electrodes of the semiconductor chip 1, and the semiconductor chip 1 is vacuum-adsorbed and held face down by the bonding tool 2. The formation of the bumps 7 is not limited to the semiconductor chip 1 side, but may be performed on the circuit board 3 side or on both sides of the semiconductor chip 1 and the circuit board 3. In this state, the alignment between the bumps 7 of the semiconductor chip 1 and the connection electrodes 8 of the circuit board 3 is performed. At this time, the alignment between the two is provided by providing a space between the semiconductor chip 1 and the circuit board 3 and inserting a camera (not shown) having an optical mechanism capable of simultaneously observing the bumps 7 and the connection electrodes 8 therebetween. Can be aligned.

Next, as shown in FIG. 4B, after the alignment between the bumps 7 of the semiconductor chip 1 and the connection electrodes 8 of the circuit board 3 is completed, an ultraviolet ray is applied to a region on the circuit board 3 where the semiconductor chip 1 is to be mounted. A fixed amount of the curable resin 9 is applied.

Next, as shown in FIG. 4C, the bonding tool 2 holding the semiconductor chip 1 by vacuum suction is gradually lowered, and a predetermined load is applied to the circuit board 3 on the stage 4 so that the semiconductor chip 1 is pressed. The connection between the bump 7 and the connection electrode 8 of the circuit board 3 is performed. At this time, the ultraviolet curable resin 9 applied on the circuit board 3 is pushed out to the side surface of the semiconductor chip 1 at the same time when the semiconductor chip 1 is pressed and formed around the entire periphery of the semiconductor chip 1 as a resin fillet 11.
Next, while applying pressure according to the flowchart shown in FIG. 2 described above, an ultraviolet ray is applied to the resin fillet 11 formed on the side surface of the semiconductor chip 1 by an optical fiber.
Irradiate 2. Then, a pulse current is applied to the bonding tool 2 and the pulse heaters 5 a and 5 b of the stage 4 to heat the semiconductor chip 1 and the circuit board 3.
A time chart for these series of flows is as shown in FIG.

As shown in FIG. 3, after a predetermined time t1 has elapsed after the semiconductor chip 1 has been pressurized by the tool, the ultraviolet rays 1
2 is irradiated for a predetermined time t2. After a predetermined time t3 has elapsed from the start of the ultraviolet irradiation, the bonding tool 2 and the stage 4 are heated for a predetermined time t4. The relationship between the pressing time t5 and the ultraviolet irradiation time t2 and the heating time t4 of the bonding tool 2 and the stage 4 is t2 ≦ t.
4 <t5, the heating of the bonding tool 2 and the stage 4 is terminated after at least the irradiation of the ultraviolet light 12 is completed, and further, the semiconductor chip 1 and the circuit board 3,
Further, the pressurization of the bonding tool 2 is released when the temperature of the UV-curable resin 9 reaches room temperature. That is, pressurization is performed for a time obtained by adding a predetermined time (delay time) for returning the semiconductor chip 1, the circuit board 3, and the ultraviolet curable resin 9 to room temperature.

As described above, the pressure release of the bonding tool 2 is performed after the ultraviolet curing resin 9 between the semiconductor chip 1 and the circuit board 3 is sufficiently cooled, so that the warpage of the semiconductor chip 1 is corrected. Can be maintained, and a connection failure between the bump 7 on the semiconductor chip 1 and the connection electrode 8 does not occur.

Further, pressure is applied by the bonding tool 2,
Since the resin fillet 11 formed on the side surface of the semiconductor chip 1 is irradiated with ultraviolet rays 12 in the pressurized state to cure the resin, the spread amount of the ultraviolet curing type resin 9 can be quantitatively reduced, and the wire bonding can be performed. The resin contamination of the external electrodes 10 of the circuit board 3 to be performed can be eliminated. The same effect can be obtained by heating the semiconductor chip 1 and the circuit board 3 by heating either the bonding tool 2 or the pulse heaters 5a and 5b of the stage 4. UV curable resin 9
Is not limited to an ultraviolet curable resin, and a thermosetting resin can also be used.

Next, as shown in FIG. 4D, a series of these flows is completed, and the bonding tool 2 is raised.
When the pressure is released, the manufacturing process of the semiconductor device of the present embodiment is completed.

In this embodiment, the ultraviolet curable resin 9 is used.
Was applied to the circuit board 3 side, but may be applied to the semiconductor chip 1 side. Potting is possible for the application method. Further, in the present embodiment, the semiconductor chip 1
Is held by the bonding tool 2 and the semiconductor chip 1
Although the method of pressing and pressing from the back side of the above has been described, the semiconductor chip 1 and the circuit board 3 may be joined by pressing against the circuit board 3 side. That is, the object to be held by the bonding tool 2 may be a semiconductor chip or a circuit board, and the direction in which they are subjected to a pressure treatment by pressing may be on either the semiconductor chip side or the circuit board side. In particular, in the future, if the circuit board becomes smaller and thinner and becomes the same size as a semiconductor chip,
The object to be held may be a semiconductor chip or a circuit board. Further, although the joining of the semiconductor chip 1 and the circuit board 3 has been described as a representative, the joining is not limited to the joining of the semiconductor chip and the board, but the joining between the two semiconductor chips, that is, the first semiconductor chip and the first The same can be applied to the case of bonding with the second semiconductor chip.

As described in the present embodiment, in the method of manufacturing a semiconductor device, the pressure release of the bonding tool 2 during the flip-chip mounting is performed by the ultraviolet curing type between the semiconductor chip 1 and the circuit board 3. After the resin 9 is sufficiently cooled, that is, after the temperature is lowered to room temperature, the warpage of the semiconductor chip 1 is corrected, the bumps are normally performed, and the connection between the bumps 7 and the connection electrodes 8 is performed. The occurrence of defects can be eliminated.

In the bonding apparatus used in the method for manufacturing a semiconductor device according to the present embodiment, the pulse heaters 5a, 5a, which generate heat when a pulse current is applied to the tip of the bonding tool 2 and the stage 4 on which the circuit board 3 is installed.
5b are provided together, and the bonding tool 2
The optical fiber 6 is provided in the vicinity of the stage 4 so that the entire periphery of the side surface of the semiconductor chip 1 can be irradiated with ultraviolet rays in a state where the semiconductor chip 1 is pressurized. UV irradiation can also be performed. That is, pressure is applied by the bonding tool 2,
In the pressurized state, the resin fillet 11 formed around the entire side surface of the semiconductor chip 1 can be irradiated with ultraviolet rays 12 to cure the resin, and the resin spread on the circuit board substrate regardless of the amount of the resin applied. The amount can be quantitatively reduced, and the resin contamination of the external electrodes 10 of the circuit board 3 for performing wire bonding is eliminated. Therefore, a reduction in wire bonding strength is prevented, and highly reliable wire bonding can be performed, so that the reliability of the manufactured semiconductor device can be improved.

[0031]

As described above, the effects of the present invention are as follows. In flip-chip mounting, the pressure release of the bonding tool is performed after the cured resin between the semiconductor chip and the circuit board is sufficiently cooled. Since the warped state is maintained, a connection failure between the bump and the connection electrode does not occur. Therefore, the yield and reliability of the manufactured semiconductor device can be improved.

Further, the circuit board substrate is pressurized by a bonding tool, and the resin fillet formed around the entire side surface of the semiconductor chip is irradiated with ultraviolet rays to cure the resin under the pressurized state. It is possible to quantitatively reduce the spread amount of the resin on the top, and there is no resin contamination of the external electrodes of the circuit board where the wire bonding is performed, so that the wire bonding strength is not reduced and highly reliable wire bonding can be performed. Thus, the reliability of the manufactured semiconductor device can be improved.

Also, since the resin fillet formed on the side surface of the semiconductor chip can be irradiated with ultraviolet rays and cured by a pressing step using a bonding tool, the ultraviolet rays are separately irradiated as a separate step. The step of photo-curing is unnecessary. As a result, it is possible to reduce the number of steps and to reduce the production cost by improving the productivity.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a process flow chart showing steps from the start of pressurization to the release of pressurization by a bonding tool according to an embodiment of the present invention.

FIG. 3 is a diagram showing a process required time from the start of pressurization to the release of pressurization by a bonding tool according to an embodiment of the present invention.

FIG. 4 is a process diagram showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 5 is a process chart showing a conventional method for manufacturing a semiconductor device.

FIG. 6 is a sectional view showing a problem in a conventional method of manufacturing a semiconductor device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor chip 2 bonding tool 3 circuit board 4 stage 5 pulse heater 6 optical fiber 7 bump 8 connection electrode 9 ultraviolet curing resin 10 external electrode 11 resin fillet 12 ultraviolet

Claims (5)

[Claims] 1. A step of mounting a substrate having an electrode on a main surface thereof on a stage of a bonding apparatus with the electrode surface of the substrate facing upward, and holding the semiconductor chip with the main surface of the semiconductor chip facing the substrate. And aligning the bump electrode provided on the main surface of the semiconductor chip and the electrode of the substrate,
Applying a UV-curable resin on the main surface of the semiconductor chip or the substrate, connecting the bump electrodes of the semiconductor chip to the electrodes on the substrate, and pressing the semiconductor chip from the back side thereof, A step of press-bonding the bump electrode and the electrode on the substrate, and irradiating the gap region between the semiconductor chip and the substrate with ultraviolet light in a state where the semiconductor chip is pressed, to a side surface region of the semiconductor chip. A step of curing the formed resin surface, a step of thermally curing the resin interposed in the gap between the semiconductor chip and the substrate while the semiconductor chip is being pressed, and the semiconductor chip and the substrate are at room temperature. Releasing a pressurization of the semiconductor chip. 2. The method of manufacturing a semiconductor device according to claim 1, wherein an irradiation time for irradiating the gap region between the semiconductor chip and the substrate with ultraviolet rays is shorter than a pressing time for pressing the semiconductor chip. 3. A step of mounting a first semiconductor chip having an electrode on a main surface on a stage of a bonding apparatus with its electrode surface facing up, and a second semiconductor chip with respect to the first semiconductor chip. Holding the main surfaces of the semiconductor chip in opposition to each other, aligning the bump electrodes provided on the main surface of the second semiconductor chip with the electrodes of the first semiconductor chip, The main surface of the semiconductor chip or the second surface
Applying an ultraviolet-curable resin to the semiconductor chip, connecting the bump electrodes of the second semiconductor chip to the electrodes on the first semiconductor chip, and removing the second semiconductor chip from the back side. Pressurizing and joining the bump electrode and the electrode on the first semiconductor chip by pressing, and pressing the second semiconductor chip and the second semiconductor chip while pressing the second semiconductor chip. Irradiating ultraviolet light to a gap region between the first semiconductor chip and the first semiconductor chip in a state where the second semiconductor chip is pressurized; Thermally curing the resin interposed in the gap between the first semiconductor chip and the second semiconductor chip, and releasing the pressurization of the second semiconductor chip after the first and second semiconductor chips reach room temperature. Having The method of manufacturing a semiconductor device according to claim. 4. The irradiation time for irradiating the gap region between the first semiconductor chip and the second semiconductor chip with ultraviolet light is shorter than the pressing time for pressing the second semiconductor chip. 4. The method for manufacturing a semiconductor device according to item 3. 5. A bonding tool for holding a semiconductor chip, a stage for holding a substrate, a first heater provided on the bonding tool for heating the semiconductor chip, and a heater provided on the stage for heating the substrate. A second heater and an ultraviolet light provided in the vicinity of the stage for irradiating ultraviolet light to a side surface region of the semiconductor chip in a state where the semiconductor chip held by the bonding tool is pressure-bonded to the substrate. A bonding apparatus comprising irradiation means.