JP3903769B2 - Semiconductor bonding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor bonding apparatus that heat-bonds a semiconductor component to a package, and more particularly to a semiconductor bonding apparatus that forms a low oxygen concentration atmosphere when bonding a semiconductor component to a package using a solder material that easily oxidizes.
[0002]
[Prior art]
Conventionally, in joining using a solder material that easily oxidizes, such as AuSn solder, it is necessary to perform the joining process in a low oxygen concentration atmosphere with an inert gas such as nitrogen. The inside is filled with an inert gas, or the inert gas is sprayed locally to the process part of joining, and the method of preventing oxidation is taken.
[0003]
[Problems to be solved by the invention]
However, when the inside of the apparatus of the prior art and the outside of the apparatus are shut off and filled with an inert gas, there is a problem that it takes a very long time to replace the air inside the apparatus with the inert gas. .
[0004]
In order to shorten the replacement time, there is a method in which the inside of the apparatus is first evacuated with a vacuum pump or the like to make it close to a vacuum, and then filled with an inert gas. Since a high degree of structure is required, a new problem that the cost of the apparatus rises arises.
[0005]
In addition, in the method of blowing an inert gas locally to the bonding process part, in order to prevent the inert gas to be blown from causing a temperature drop during bonding, it is necessary to heat the inert gas or to stabilize the atmosphere. Since a large amount of inert gas is blown onto the surface, the running cost increases.
[0006]
Furthermore, the method of spraying an inert gas locally on the bonding process part is indispensable for correcting the bonding position because the flow rate of the inert gas sprayed is large and the temperature distribution of the sprayed gas is uneven. There is a problem that there is a possibility of adversely affecting image recognition.
[0007]
Furthermore, in the method in which an inert gas is locally blown to the bonding process portion, since the local blowing is performed and only the bonding portion has a low oxygen concentration, the solder cannot be melted in advance. In many cases, the solder is melted after sandwiching the piece, or an external force such as ultrasonic vibration is applied to destroy the oxide film, etc., and the former takes a long time to join, and the latter has a new mechanism to give vibration. There was a problem that it was necessary.
[0008]
The present invention has been made in view of such a problem, and an object of the present invention is to form an inert gas atmosphere efficiently by the flow of a local inert gas, thereby reducing the cost at low cost. It is an object of the present invention to provide a semiconductor bonding apparatus capable of forming an environment having an oxygen concentration and easily using a solder material that is easily oxidized for bonding.
[0009]
Another object of the present invention is that, even in the recognition based on the image necessary for determining the bonding position of the semiconductor component, the adverse effect of the image fluctuation at the time of image observation due to the change in the air density due to the thermal expansion of the air at a high temperature is extremely reduced. It is to provide a semiconductor bonding apparatus that can be kept small.
[0010]
Still another object is to provide a semiconductor bonding apparatus capable of bonding semiconductor components after melting solder in advance and minimizing the bonding time by heating and pressing.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration. The gist of the invention described in claim 1 is a semiconductor bonding apparatus for bonding components, a first base on which the components are mounted, and a casing that surrounds the first base by providing a space. , An opening provided in the upper part of the first base, first supply means for supplying a first inert gas into the casing, and a second inert gas in the casing And a second supply means for supplying the gas in a swirling flow in the same plane as the surface on which the opening is formed .
According to a second aspect of the invention, the second supply means is provided with a plurality of ejection holes so that the second inert gas forms a swirling flow. Item exists in the semiconductor bonding apparatus according to Item 1 .
The gist of the invention described in claim 3 is that the slope of the area gradually decreasing toward the opening is formed on the inner periphery of the housing. Exists in the device .
According to a fourth aspect of the present invention, the first supply means supplies the first inert gas from a lower part than the first base. It exists in the semiconductor junction apparatus in any one .
According to a fifth aspect of the present invention, there is provided a control wall that prevents the second inert gas supplied by the second supply means from being supplied to a component mounted on the first base. It exists in the semiconductor junction apparatus in any one of the Claims 1 thru | or 4 characterized by the above-mentioned .
The gist of the invention described in claim 6 is that the Reynolds number of the inert gas in the opening is set to be lower than the space in the casing. It exists in the semiconductor junction apparatus as described above .
The gist of the invention of claim 7 resides in the semiconductor bonding apparatus according to any one of claims 1 to 6 , wherein the first base is a heater .
The gist of the invention described in claim 8 is characterized in that a second base is provided around and protrudes from the lower portion of the first base around the first base. It exists in the semiconductor junction device in any one of Claim 1 thru | or 7 .
The gist of the invention according to claim 9 resides in the semiconductor bonding apparatus according to claim 8 , wherein the second base is a radiating fin .
The gist of the invention of claim 10 is that the first inert gas and the second inert gas are nitrogen gas or argon gas. Exists in the semiconductor bonding apparatus .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
(First embodiment)
FIG. 1 is a perspective view of a first embodiment of a semiconductor bonding apparatus according to the present invention, and FIG. 2 is a sectional side view of each of a circular heating stage, a nitrogen atmosphere forming mechanism, and an adiabatic cooling unit shown in FIG. FIG. 3 is an enlarged view of a side cross section in the vicinity of the nitrogen atmosphere forming mechanism shown in FIG. 1, and FIG. 4 is a cross section at the ejection hole formed in the nitrogen blowing nozzle of the nitrogen atmosphere forming mechanism shown in FIG. FIG. In addition, the arrow described in FIG. 1 thru | or FIG. 4 has shown the flow of nitrogen gas.
[0014]
Referring to FIG. 1, the first embodiment includes a circular heating stage 1, a nitrogen atmosphere forming mechanism 2, and an adiabatic cooling unit 3. Nitrogen that is an inert gas atmosphere by a nitrogen gas that is an inert gas. An atmosphere is formed, and the semiconductor component 25 is heated and bonded to the ceramic package 7 using AuSn solder.
[0015]
Referring to FIG. 2, the circular heating stage 1 includes a circular heater 4 that heats the ceramic package 7, a support member 5 that supports the circular heater 4, and radiating fins 6, and is attached to the heat insulating cooling unit 3. A piping path 11 is formed in the circular heater 4 and the support member 5, and the ceramic package 7 is directly vacuum-adsorbed on the circular heater 4 by using the piping path 11 to fix the heat of the circular heater 4 to the ceramic package. 7 directly communicate. Moreover, the radiation fin 6 preheats the nitrogen gas supplied to the upper surface of the circular heater 4 in order to form a nitrogen atmosphere.
[0016]
Referring to FIG. 2, the adiabatic cooling unit 3 includes a heat insulating pedestal 8 that fixes the circular heating stage 1, a heat insulating member 9 that performs heat insulation, and a cooling unit 10 that performs effective cooling. The member 9 has a function of vacuum suction from the piping path 11 in order to vacuum-suck the ceramic package 7 on the upper surface of the circular heater 4.
[0017]
2 to 4, the nitrogen atmosphere forming mechanism 2 includes a heater cover 13 having a lower nitrogen inlet 12, a nozzle cover 15 having an upper nitrogen inlet 14, a blowing nozzle 16 for blowing upper nitrogen, and an upper stage. The directional control wall 17 prevents turbidity between nitrogen and lower nitrogen. A heat insulating chamber 18 is formed by the lower surface of the heat radiating fin 6, the heat insulating pedestal 8, the heat insulating member 9, and the heater cover 13, and a nitrogen chamber 19 is formed by the upper surface of the circular heater 4 and the heat radiating fin 6 and the blowing nozzle 16. A spare chamber 20 is formed by the nozzle cover 15 and the blowing nozzle 16. The upper stage nitrogen is nitrogen gas supplied from the upper stage nitrogen inlet 14, and the lower stage nitrogen is nitrogen gas supplied from the lower stage nitrogen inlet 12.
[0018]
The blow nozzle 16 is formed with a slope 16 a that gradually decreases in area toward the upper opening 22 provided at the upper part of the circular heater 4. The diameter of the upper opening 22 is smaller than the diameter of the lower part of the nitrogen chamber 19. It is getting shorter. The blow nozzle 16 is formed with a plurality of blow holes 21 through which upper stage nitrogen is blown into the nitrogen chamber 19. The blow holes 21 are formed so as to blow above the direction control wall 17 in the nitrogen chamber 19. The upper stage nitrogen blown into the nitrogen chamber 19 is swirled in the nitrogen chamber 19 to form a swirling flow. Further, the upper stage nitrogen is blown into the nitrogen chamber 19 so as to form a swirling flow in the same plane as the surface where the upper opening 22 is formed.
[0019]
Lower nitrogen enters the heater cover 13 from the lower nitrogen inlet 12, and heat is exchanged with the heat insulating pedestal 8 and the heat radiating fins 6 in the heat insulating chamber 18 to increase the temperature, and nitrogen is released from the gap between the heat radiating fins 6 and the heater cover 13. Blow out into chamber 19. Further, the direction is changed to the center of the circular heater 4 by the direction control wall 17 provided in the nitrogen chamber 19, and it directly hits the ceramic package 7 fixed on the circular heater 4. Nitrogen is injected into the ceramic package 7 while exchanging heat, and since the flow rate is small, the influence of the temperature drop due to direct injection is negligible.
[0020]
On the other hand, the upper stage nitrogen enters the preliminary chamber 20 from the upper stage nitrogen inlet 14 and blows out into the nitrogen chamber 19 from the ejection hole 21. The blown-up upper nitrogen is not mixed immediately with the lower nitrogen because of the direction control wall 17, and swirls around the slope 16 a of the blowing nozzle 16 and rises while swirling the surface of the slope 16 a by centrifugal force. Is released into the atmosphere from the upper opening 22 with the rising flow of.
[0021]
The upper stage nitrogen blown into the nitrogen chamber 19 does not directly hit the ceramic package 7 but also has a function of efficiently releasing the lower stage nitrogen injected into the ceramic package 7 from the upper opening 22 to the atmosphere together with the swirling flow of the upper stage nitrogen. . Further, since the upper stage nitrogen blown into the nitrogen chamber 19 is swirling, it can be isolated from the surroundings such as the atmosphere without involving external air from the upper opening 22 even if a certain amount of flow is applied. it can. The nitrogen concentration at the center of the heater can be increased by balancing the flow rates of the lower nitrogen and the upper nitrogen and designing the Reynolds number of the upper nitrogen to be low.
[0022]
Although it is possible to increase the nitrogen concentration efficiently if the upper opening 22 and the central opening of the direction control wall 17 are made as small as possible, the size is as large as necessary for supplying the ceramic package 7 and heating and bonding the semiconductor component 25. It is necessary to ensure. Specifically, it is necessary to secure at least the outer size of the ceramic package 7 and the semiconductor component 25, the size of the hand that supplies the ceramic package 7 and the semiconductor component 25, and the size in which the joining head 34 can be inserted.
[0023]
In the first embodiment, the required nitrogen flow rate is 10 liters / min or less when the upper opening 22 and the opening of the direction control wall 17 have a diameter of 40 mm and the upper nitrogen and the lower nitrogen are combined. By supplying nitrogen of about 10 liters / min, the oxygen concentration can be reduced to 500 ppm or less even in the state of FIG. Further, as shown in FIG. 6B, the oxygen concentration can be reduced to 100 ppm or less in a state where the bonding head 34 is inserted. Further, if the diameter of the opening of the upper opening 22 and the direction control wall 17 can be made smaller than the diameter of 40 mm, the oxygen concentration can be made 100 ppm or less even when the joining head is not inserted.
[0024]
Further, in the first embodiment, since the flow of nitrogen gas from the inside of the nitrogen chamber 19 to the outside is formed, air density unevenness due to thermal expansion of air at high temperatures is often a problem. The adverse effect of image fluctuations during image observation due to a phenomenon generally referred to as a hot flame can be minimized. For example, when the stage temperature is 250 ° C. and image recognition is performed with a CCD camera required for positioning, the image is fluctuated about 2 to 3% with respect to the visual field in the normal case. Then, it can be suppressed to about 0.2%.
[0025]
Next, the heat bonding operation of the first embodiment will be described in detail with reference to FIG. 5 and FIG.
FIG. 5 is a schematic diagram for explaining the bonding operation of the first embodiment of the semiconductor bonding apparatus according to the present invention, and FIG. 6 shows the first embodiment of the semiconductor bonding apparatus according to the present invention. It is a perspective view which shows the mode at the time of joining head insertion.
[0026]
First, the ceramic package 7 is supplied onto the circular heater 4 by some handling device or an operator, and the supplied ceramic package 7 is directly heated by the circular heater 4. The joint surface of the ceramic package 7 is Au plated.
[0027]
Next, the image recognition camera 23 is moved by the moving mechanism 26 while the semiconductor component 25 on the positioning stage 24 and the ceramic package 7 are image-recognized, and the image recognition camera 23 performs semiconductor recognition by the position correction mechanism 27 based on the image recognition result. The joining position between the component 25 and the ceramic package 7 is corrected.
[0028]
Next, in the solder supply device 28, the AuSn solder piece 31 cut out to a predetermined length from the solder reel 29 by the cutter 30 is vacuum-sucked by the solder suction nozzle 33 at the tip of the solder supply head 32, and is circularly moved by the moving mechanism 26. Supply to the ceramic package 7 on the heater 4. At this time, since the low oxygen concentration atmosphere is already formed and the formation rate of the oxide film is slow, the temperature of the circular heater 4 can be increased to the temperature at which the solder pieces 31 on the ceramic package 7 melt.
[0029]
Next, in a state where the semiconductor component 25 is vacuum-adsorbed to the bonding head 34, the bonding head 34 is moved onto the ceramic package 7 by the moving mechanism 26, and the semiconductor component 25 is supplied to the ceramic package 7 and bonded to the molten solder piece 31. Then, the temperature of the circular heater 4 is lowered to the melting point of the solder piece 31 or lower and the fixing head 34 is raised after cooling and fixing.
[0030]
It takes time from the supply of the solder piece 31 to the joining of the semiconductor component 25, and there is a possibility that an oxide film may be formed during that time. If it is difficult to form a low oxygen concentration atmosphere, the temperature of the circular heater 4 is increased after the joining head 34 is inserted into the nitrogen chamber 19 as shown in FIG. Since there is no turbulence in the flow at the center, a further increase in the nitrogen concentration can be expected, a stable nitrogen gas atmosphere can be realized, and the temperature of the circular heater 4 is raised simultaneously with the start of insertion of the bonding head 34. After the solder piece 31 is melted and contacted, the temperature of the circular heater 4 is lowered and cooled, and the semiconductor component 25 is fixed to the ceramic package 7.
[0031]
Further, when the requirement of the joining position accuracy is not strict, the joining is completed without waiting for the solidification of the solder to raise the joining head 34, and then the temperature of the circular heater 4 is lowered to cool the semiconductor component 25. If it adheres to 7, the joining time can be shortened.
[0032]
In the first embodiment, nitrogen gas is used as the inert gas, but it goes without saying that the same effect can be obtained even if an inert gas such as argon gas is used. It is the same.
[0033]
As described above, according to the first embodiment, an inert gas atmosphere is efficiently formed by a local inert gas flow, thereby forming a low-cost and stable low oxygen concentration environment. Therefore, it is possible to easily use a solder material that easily oxidizes for bonding.
[0034]
Furthermore, according to the first embodiment, even in the recognition by the image necessary for determining the joining position of the semiconductor component, the fluctuation of the image at the time of image observation due to the change in the air density due to the thermal expansion of the air at a high temperature. There is an effect that the adverse effect can be suppressed extremely small.
[0035]
Furthermore, according to the first embodiment, the semiconductor components can be joined after the solder is melted in advance, and the joining time by heating and pressing can be minimized.
[0036]
(Second Embodiment)
7 is a perspective view of a second embodiment of the semiconductor bonding apparatus according to the present invention, FIG. 8 is a development view of the semiconductor bonding apparatus shown in FIG. 7, and FIG. 9 is a semiconductor according to the present invention. It is a schematic diagram for demonstrating joining operation | movement of 2nd Embodiment of a joining apparatus.
[0037]
Unlike the first embodiment, the second embodiment differs from the first embodiment in that a plurality of ceramic packages 7 are heated at the same time, and semiconductor components 25 can be sequentially joined to the individual ceramic packages 7. In order to join the semiconductor components 25 side by side with the ceramic packages 7, it is necessary to make a large opening at the top as shown in FIGS.
[0038]
Compared to the first embodiment, the upper opening is larger and the flow is complicated, so the performance of forming a nitrogen atmosphere is inferior. However, the protrusion 36 that narrows the area of the upper opening is provided on the side of the bonding head 34 to provide a larger size. The difference in nitrogen concentration between the elliptical long and short axes of the opening 37 can be reduced, and a sufficient low oxygen concentration atmosphere can be formed by supplying nitrogen also from the bonding head 34 side.
[0039]
A work tray 39 is installed on the heater 38 and moved to the nitrogen atmosphere forming mechanism 41 side by the table 40. By pressing the upper and lower tables 42 against the nitrogen atmosphere forming mechanism 41 from below, a nitrogen atmosphere is formed on the ceramic package 43 on the work tray 39. When the solder piece 31 is supplied in this state and the bonding head 34 is lowered, the oxygen concentration decreases, and stable bonding is possible.
[0040]
Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.
[0041]
【The invention's effect】
The semiconductor bonding apparatus of the present invention can form an inert gas atmosphere efficiently by a local inert gas flow, thereby forming a stable low oxygen concentration environment at low cost and oxidizing the bonding. There is an effect that an easy solder material can be used easily.
[0042]
Furthermore, the semiconductor bonding apparatus according to the present invention also has an adverse effect of image fluctuations during image observation due to a change in air density due to thermal expansion of air at a high temperature, even in image recognition necessary for determining the bonding position of semiconductor components. There is an effect that it can be kept extremely small.
[0043]
Furthermore, the semiconductor bonding apparatus according to the present invention can bond the semiconductor components after melting the solder in advance, and has an effect that the bonding time by heating and pressing can be minimized.
[Brief description of the drawings]
FIG. 1 is a perspective view of a first embodiment of a semiconductor bonding apparatus according to the present invention.
2 is a cross-sectional side view of each of a circular heating stage, a nitrogen atmosphere forming mechanism, and an adiabatic cooling unit shown in FIG.
FIG. 3 is an enlarged view of a side cross section in the vicinity of the nitrogen atmosphere forming mechanism shown in FIG.
4 is a cross-sectional view of an ejection hole formed in a nitrogen blowing nozzle of the nitrogen atmosphere forming mechanism shown in FIG.
FIG. 5 is a schematic diagram for explaining a bonding operation of the first embodiment of the semiconductor bonding apparatus according to the present invention.
FIG. 6 is a perspective view showing a state when the bonding head is inserted in the first embodiment of the semiconductor bonding apparatus according to the present invention.
FIG. 7 is a perspective view of a second embodiment of a semiconductor bonding apparatus according to the present invention.
8 is a development view of the semiconductor bonding apparatus shown in FIG.
FIG. 9 is a schematic diagram for explaining the bonding operation of the second embodiment of the semiconductor bonding apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circular heating stage 2 Nitrogen atmosphere formation mechanism 3 Thermal insulation cooling unit 4 Circular heater 5 Support member 6 Radiation fin 7 Ceramic package 8 Thermal insulation base 9 Thermal insulation member 10 Cooling unit 11 Piping path 12 Lower nitrogen inlet 13 Heater cover 14 Upper nitrogen inlet 15 Nozzle cover 16 Outlet nozzle 17 Direction control wall 18 Heat insulation chamber 19 Nitrogen chamber 20 Preliminary chamber 21 Ejection hole 22 Upper opening

Claims (10)

A semiconductor bonding apparatus for bonding components,
A first base on which components are mounted;
A housing surrounding the first base by providing a space on the outer periphery;
An opening provided in the upper part of the first base;
First supply means for supplying a first inert gas into the housing;
And a second supply means for supplying the second inert gas in a swirl flow in the same plane as the surface on which the opening is formed. apparatus. The said 2nd supply means is equipped with the several injection hole so that the said 2nd inert gas may form a swirl | vortex flow. 1 The semiconductor bonding apparatus as described. The semiconductor bonding apparatus according to claim 1, wherein a slope that gradually decreases in area toward the opening is formed on an inner periphery of the housing. 4. The semiconductor bonding apparatus according to claim 1, wherein the first supply unit supplies the first inert gas from a lower part than the first base. 5. 2. The control wall according to claim 1, further comprising a control wall that prevents the second inert gas supplied by the second supply means from being supplied to a component mounted on the first base. 4. The semiconductor bonding apparatus according to any one of 4 above. 6. The semiconductor bonding apparatus according to claim 1, wherein a Reynolds number of the inert gas at the opening is set to be lower than a space in the housing. The semiconductor bonding apparatus according to claim 1, wherein the first base is a heater. The second base is provided around the first base so as to be located at a lower portion of the first base and to be protruded. Semiconductor bonding equipment. 9. The semiconductor bonding apparatus according to claim 8, wherein the second base is a heat radiating fin. The semiconductor bonding apparatus according to claim 1, wherein the first inert gas and the second inert gas are nitrogen gas or argon gas.

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