JP2004214354A - Brazing material supplying nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the wettability of a brazing material to a substrate, in a nozzle for supplying the brazing material by contacting the tip end of the same with a heated substrate to melt and supply the same. <P>SOLUTION: A bulkhead bush 6 is provided in the cavity 5 of a nozzle main body 4, and a guide pipe 10 is fixed to a pipe member 9 provided below the nozzle main body 4. The guide pipe 10 is supported by a positioning member 12 and a cover member 13, which are arranged above the nozzle main body 4, and a supersonic oscillation providing means 18 pinching the piezo-electric ceramic oscillator 19 by a metallic body 20 and a free side metallic body 21 is arranged above the cover member 13. The brazing material drawn out of a feed roller 1 with the brazing material 2 wound thereon is penetrated through the guide pipe 10 and is provided with supersonic oscillation by a supersonic oscillation providing means 18. The brazing material 2 is projected out of the tip end of the guide pipe 10 by a predetermined size to contact the same with the heated substrate and melt the same to supply the brazing material 2 onto the substrate. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brazing material supply nozzle, and particularly to a method in which when a semiconductor chip (die) is bonded to a substrate such as a lead frame, the tip of a long brazing material is supplied by contact melting to a heated substrate. And a brazing material supply nozzle.
[0002]
[Prior art]
When the semiconductor chip (die) is fixed to a substrate such as a lead frame, and when it is not necessary to electrically connect the back surface of the semiconductor chip (die) to the substrate, a resin bond method using an insulating resin to fix the semiconductor chip (die) to the substrate However, in general, in order to electrically connect the back surface of the semiconductor chip (die) to the substrate and efficiently radiate heat generated during operation of the semiconductor chip (die) to the substrate. Next, as shown in FIG. 4, an electrode 31 is formed on the back surface of the semiconductor chip (die) 30, and this electrode 31 is formed on a substrate 33 such as a lead frame by using a conductive and good heat conductive brazing material 32. It is stuck to.
[0003]
As shown in FIG. 5 (A), for example, as shown in FIG. 5 (A), the substrate 33 such as the lead frame is used for bare bonding using a copper or copper-based substrate 33a having good electrical conductivity and good thermal conductivity. As shown in (B), a plating layer 33b that is hardly rusted, such as nickel, gold, and silver, and that is easily wetted by a brazing material is provided on both surfaces of a copper or copper-based substrate 33a having good electrical conductivity and good thermal conductivity. As shown in FIG. 5C, nickel, gold, silver, or the like is formed only at the bonding position of the semiconductor chip (die) on the copper or copper-based substrate 33a having good electrical conductivity and good thermal conductivity. A plating layer 33c which is not easily rusted and is easily wetted by a brazing material. As shown in FIG. 5 (D), copper or a copper-based substrate 33a having good electrical conductivity and good thermal conductivity is formed on both surfaces of nickel or the like. Forms a relatively inexpensive plating layer 33d that is less likely to rust And, further, gold, rust hardly such as silver, and such as the brazing material to form the easily-plated layer 33e wet is used only in the bonding position of the semiconductor chip (die) of the plating layer 33d.
[0004]
The method using the brazing material includes a hard soldering method using gold-silicon eutectic and the like, and a so-called soft soldering method using solder. The former hard soldering method has high reliability in fixing the semiconductor chip (die) to the substrate, but the brazing material is expensive, and the heating temperature of the tunnel furnace for melting the hard solder is high. Because of high cost, it is used only for special applications requiring high reliability.
[0005]
The latter soft soldering method is inexpensive because the brazing material is inexpensive and the heating temperature of the substrate for melting the brazing material is low, so that the cost is low and it is most widely used in consumer semiconductor devices. In this soft soldering method, a solder layer is formed in advance on the back surface of a semiconductor chip (die), and the semiconductor chip (die) is pressed against a heated substrate to melt and fix the solder layer. Method, a solder piece supply method that supplies solder pieces to a heated substrate and melts the solder pieces, inserts a solder wire drawn from a feeder roller around which a long solder wire is wound into a solder supply tool, and from the tip There is a solder wire supply method in which a predetermined length is protruded, and the tip is brought into contact with a heated substrate to be melted and supplied.
[0006]
In the pre-soldering method, since a solder layer is formed on the back surface of the semiconductor wafer, when the semiconductor chip (die) is cut and separated later by a dicing saw (diamond cutter) or the like, the soft solder is clogged, There is a problem that it is difficult to cut the solder layer. Further, the solder piece supply method has a problem that when supplying a minute solder piece, the supply position of the solder piece is not constant, so that high-precision die bonding cannot be performed. In the solder wire supply method, since the nozzle position can be controlled with high precision, the solder supply position can also be controlled with high precision, so that high-precision die bonding can be performed.
Therefore, recently, a solder wire supply system has been widely adopted.
[0007]
A solder supply tool used in a conventional solder wire supply system will be described.
As shown in FIG. 6, the solder supply tool 41 includes a guide pipe 42 into which a solder wire is inserted, a tool main body 43 holding the guide pipe 42, and a lower part of the tool main body 43. An outer fitting member 44 is fitted on the lower end of the pipe 42, and a tapered delivery head 45 is provided at the lower end of the guide pipe 42. The delivery head 45 is provided with a guide hole 46, and a solder wire is inserted from the upper end of the guide pipe 42 and guided by the guide hole 46 to be delivered.
[0008]
An inflow port 47 and an outflow port 48 for a cooling fluid are provided on a side portion of the tool main body 43, and a cooling fluid such as water or air introduced from the inflow port 47 is supplied to the guide pipe 42 and the tool. It flows through the inflow passage 49 formed between the main body 43 and the lower end of the guide pipe 42, and through a gap 50 formed between the tool main body 43 and the outer fitting member 44. , And is configured to flow out from the outlet 48. Accordingly, the lower end of the guide pipe 42, which is disposed above the heated lead frame and is exposed to the mixed gas in the tunnel furnace for heating the lead frame, can be cooled by the cooling fluid. . (For example, see Patent Document 1).
[0009]
In addition, a solder supply tool 51 as shown in FIG. 7 has been proposed to improve the cooling effect of the cooling fluid such as water or air. The solder supply tool 51 includes a guide pipe 52 into which the solder wire 32 pulled out from the feed roller 61 is inserted, a tool main body 53 holding the guide pipe 52, and a lower part of the tool main body 53. An outer fitting member 54 is fitted to the lower end of the guide pipe 52, and a tapered delivery head 55 is provided at the lower end of the guide pipe 52. The delivery head 55 is provided with a guide hole 56, and the solder wire is inserted from the upper end of the guide pipe 52 and guided by the guide hole 56 to be delivered. A plurality of heat pipes 57 are arranged along the outer peripheral surface of the guide pipe 52.
[0010]
The tool body 53 is provided with an inlet 58 and an outlet 59 for the cooling fluid. Cooling fluid, such as water or air, flowing from the inflow port 58 passes through the flow passage 60 formed between the tool body 53 and the heat pipe 57 and flows upward along the heat pipe 57. At the same time, it is configured to flow out from the outlet 59. Thus, the lower end of the guide pipe 52, which is disposed above the heated lead frame and is exposed to the mixed gas in the tunnel furnace for heating the lead frame, can be cooled by the cooling fluid. (For example, see Patent Document 1).
[0011]
As shown in FIG. 8A, the solder supply tools 41 and 51 are arranged above a tunnel furnace (not shown) that accommodates a substrate 33 such as a lead frame heated to a predetermined temperature in a mixed gas atmosphere. Then, the solder wire 32 is protruded by a predetermined dimension from the tip of the solder supply tools 41 and 51, and is lowered to bring the tip of the solder wire 32 into contact with the heated substrate 33 as shown in FIG. Then, as shown in FIG. 8C, a predetermined amount of the molten solder 32 is supplied onto the substrate 33.
[0012]
As described above, the reason why the cooling means is provided in the solder supply tools 41 and 51 is that when the tip of the solder wire 32 is brought into contact with the substrate 33 such as a heated lead frame to be melted and supplied onto the substrate 33. In addition, the solder wire 32 is prevented from being melted more than necessary, the specific component (Sn) having a low melting point in the solder wire 32 is prevented from melting, and a secondary oxide film is not formed on the surface of the solder wire 32. That's why.
[0013]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-252032 ([0002] to [0021]; see FIGS. 1 to 3).
[0014]
[Problems to be solved by the invention]
By the way, recently, with the miniaturization of electronic components incorporating a semiconductor device, the size of a semiconductor chip (die) has been reduced, the bonding position of the semiconductor chip (die) to a substrate such as a lead frame has been increased, and the distance between the semiconductor chip (die) and the substrate has increased. Are required to have low electric resistance and low heat radiation resistance. For that purpose, the wettability of the solder to the substrate is an important factor. The wettability of the solder on the board is greatly influenced by the type and condition of plating on the board surface, the state of contamination on the surface, and the oxidation state.However, with a conventional solder supply tool, it is impossible to completely remove these disturbance factors. However, there is a problem to be solved such as deterioration of solder supply position accuracy, limitation of a small amount of coating, and delay of cycle time.
[0015]
In addition, the above “solder supply position accuracy” refers to whether or not the solder position after the molten solder supplied on the substrate flows and spreads on the substrate, exactly matches the intended supply position. Means precision. That is, as shown in FIG. 9A, the molten solder 32 supplied on the substrate 33 should originally flow concentrically on the substrate 33 and spread as shown by a two-dot chain line 32a. Depending on the surface condition of the substrate 33, the molten solder 32 does not flow concentrically and spreads, but moves on the substrate 33 as shown by a two-dot chain line 32b in FIG. The semiconductor chip (die) cannot be bonded to the correct position, or cannot be bonded to the correct position. If this is attempted, the amount of solder at that position will be insufficient, resulting in a problem that the above-described low electrical resistance and low heat radiation resistance between the semiconductor chip (die) and the substrate cannot be realized. Therefore, in order to eliminate such inconvenience, it is necessary to improve the accuracy of the solder supply position.
[0016]
The disturbance factor of the substrate 33 such as the lead frame depends on the removal by the cleaning effect by preheating the substrate 33 in a mixed gas atmosphere in the semiconductor manufacturing apparatus. This is due to the inability to remove disturbance factors that cause deterioration of position accuracy. Further, the conventional solder supply tools 41 and 51 control the supply amount of the solder, and have a problem to be solved that lacks a function of improving the wettability of the solder.
[0017]
Further, regarding the supply amount of the solder, the solder supply tool 41 in FIG. 6 has a large clearance between the guide pipe 42 and the solder wire, and the cooling effect of the solder wire is not sufficient, so that the supply amount of the solder is accurately controlled. However, as shown in FIG. 10A, the supply amount of the solder becomes larger than the normal supply amount 32 shown by the solid line as shown by the two-dot chain line 32 ′, and this excessive molten solder 32 When the semiconductor chip (die) 30 is supplied and pressurized, the excess solder 32 ′ exudes from the periphery of the semiconductor chip (die) 30 as shown in FIG. There has been a problem to be solved, such as swelling on the end face of the (die) 30 or, in extreme cases, creeping up to the upper surface of the semiconductor chip (die) 30 to cause a short circuit. Further, the solder supply tool 51 shown in FIG. 7 has a problem that it is expensive because the heat pipe 47 is used.
[0018]
Furthermore, if a liquid such as water is used as a cooling medium, not only does the sealing structure become complicated, but in the event of leakage, the die bonder itself or nearby equipment becomes wet, or the leaked liquid evaporates. There has been a problem in that the semiconductor chip (die) is contaminated by the vapor, causing characteristic fluctuation. Further, a chiller (constant-temperature liquid circulation device) for circulating cooling water must be provided, which has been a factor of cost increase.
[0019]
Therefore, the present invention solves the above-mentioned problems, and uses a wire brazing material such as a soft brazing material such as solder, a hard brazing material such as a Pb-Sn-Ag system, or a Pb-free solder substitute brazing material. It is an object of the present invention to provide a brazing material supply nozzle capable of supplying a predetermined amount to a predetermined position of a substrate with high precision.
[0020]
[Means for Solving the Problems]
The brazing material supply nozzle according to claim 1 of the present invention is configured to insert a brazing material drawn out from a feeder roller around which a long wire-shaped brazing material is wound, and to heat a tip end of the brazing material protruding from a lower end. In the brazing material supply nozzle adapted to be brought into contact with and melted, an ultrasonic vibration applying means for applying ultrasonic vibration to the inserted brazing material is provided.
[0021]
According to the above brazing material supply nozzle, the ultrasonic vibration is applied to the brazing material by the ultrasonic vibration applying means, so that the vibration of the longitudinal component of the ultrasonic wave and the frictional heat between the brazing material and the substrate such as the lead frame. The synergistic effect with this material breaks through the oxide film and contaminants on the substrate surface, exposing the pure substrate surface or plating surface, and activating the brazing material itself to improve the wettability of the brazing material to the substrate Is done. In addition, the effect of stirring the brazing material melted by the ultrasonic vibration is obtained, and a chemical reaction such as an oxidation-reduction reaction due to the stirring effect is promoted. Due to these synergistic effects, the wettability of the brazing material to the substrate is greatly improved, and the molten brazing material moves on the substrate due to an oxide film or a contaminant on the substrate surface, or flows unevenly from the supply position. In addition, the supply position accuracy of the brazing material is greatly improved, and the adhesiveness between the semiconductor chip (die) and the substrate is significantly improved. This makes it possible to bond a semiconductor chip (die) having high performance.
[0022]
Further, in the brazing material supply nozzle according to a second aspect of the present invention, the ultrasonic vibration applying means is a piezoelectric element.
[0023]
According to the brazing material supply nozzle described above, ultrasonic vibration can be applied to the brazing material by the piezoelectric element, and the above-described excellent effects can be obtained. As the piezoelectric element, a publicly-known piezoelectric element such as a piezoelectric ceramic can be used.
[0024]
Further, the brazing material supply nozzle according to claim 3 of the present invention is characterized in that the lower side of the ultrasonic vibration applying means is fixed by an active fixing member and the upper side is supported by a free side member. It is.
[0025]
According to the brazing material supply nozzle described above, the lower side of the ultrasonic vibration applying means is fixed by the active fixing member, and the upper side is supported by the free side member. The side member vibrates freely, and ultrasonic vibration can be effectively applied to the brazing material inserted through the free side member.
[0026]
A brazing material supply nozzle according to a fourth aspect of the present invention is characterized in that a cooling means for cooling the brazing material inserted is provided below the ultrasonic vibration applying means.
[0027]
According to the brazing material supply nozzle described above, the brazing material inserted into the nozzle can be appropriately cooled by the cooling means, so that the brazing material is heated and melted more than necessary and is excessively supplied onto a substrate such as a lead frame. Can be prevented, and the secondary surface oxidation of the brazing material can be prevented.
[0028]
Further, in the brazing material supply nozzle according to claim 5 of the present invention, the cooling means of the brazing material is an air cooling system using a cooling gas, and a supply port for supplying a cooling gas into the nozzle and a brazing material in the nozzle. And an exhaust port for exhausting a cooling gas obtained by cooling the gas.
[0029]
According to the brazing material supply nozzle described above, the cooling gas such as air supplied from the supply port circulates through the nozzle to cool the brazing material and is discharged from the exhaust port to cool the brazing material. Can be. In particular, since a cooling gas is used as a cooling fluid, compared with the case where a cooling liquid is used, the heat diffusion property is excellent, and the sealing of the connection portion and the like becomes easy, so that the configuration is simplified. Even if a cooling gas leak occurs, the die bonder itself equipped with a brazing filler nozzle, like a cooling liquid, wets nearby equipment and floors, or deteriorates the characteristics of semiconductor devices due to vapors from the leaked liquid. I can't.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a brazing material supply nozzle of the present invention will be described with reference to the drawings. 1A is a longitudinal sectional view of the brazing material supply nozzle of the present invention, and FIG. 1B is a bottom view of the brazing material supply nozzle of FIG. 1A. FIGS. 2A to 2D are cross-sectional views of the brazing material supply nozzle of FIG. 1A taken along line AA, cross-sectional views taken along line BB, and lines CC, respectively. Are a cross-sectional view and a plan view taken along the line.
[0031]
In FIG. 1, reference numeral 1 denotes a soft solder (Sn-Pb alloy) or a so-called solder (Pb-Sn-Ag type), which has been recently developed to solve the environmental pollution problem caused by Pb. A feed roller around which a wire-shaped brazing material 2 made of a Pb-free solder substitute brazing material (Sn-Zn-based, Sn-Ag-based, Sn-Ag-Cu-based, etc.) is wound, and 3 is inserted through the brazing material 2. This is a brazing material supply nozzle for supplying a substrate such as a lead frame. The brazing filler metal supply nozzle 3 includes a nozzle body 4 having a cavity 5 therein, a partition bush 6 of cooling gas provided in the cavity 5 of the nozzle body 4, and a nozzle body 4 partitioned by the partition bush 6. It has an inlet 7 provided at an upper portion for supplying a cooling gas, and an outlet 8 provided at a lower portion of the nozzle body 4 for exhausting a used cooling gas. A cooling gas supply pipe 7a and a cooling gas supply pipe 8a are connected to the inflow port 7 and the discharge port 8, respectively.
[0032]
The nozzle body 4 has an annular groove 4a on an inner peripheral surface corresponding to the inflow port 7.
As apparent from FIG. 2A, the partition bush 6 has a portion corresponding to the annular groove 4a radially having a plurality of horizontal holes 6a communicating with the central vertical hole. The horizontal hole 6a is easily aligned with the position of the inflow port 7, so that the assembly with the nozzle body 4 is facilitated. The partition bush 6 has a pipe portion 6b extending downward along the vertical hole.
[0033]
A copper pipe member 9 is attached to the lower surface of the nozzle body 4, and a stainless steel guide pipe 10 for guiding the brazing material 2 is inserted into the pipe part 6 b of the partition bush 6. The pipe member 9 has a flange portion 9a fixed to the lower surface of the nozzle body 4 and a pipe portion 9b forming a gap for guiding the cooling gas between the partition bush 6 and the flange portion 9a. As shown in FIGS. 3A and 3B, the lower end of the guide pipe 10 projects from the partition bush 9 by a predetermined size and is fixed by a silver solder 11.
[0034]
An intermediate portion of the guide pipe 10 is positioned concentrically with the center axis of the partition bush 6 by a positioning member 12, and the positioning member 12 is held at a predetermined position by a cover member 13. The upper end of the guide pipe 10 is larger than the cover member 13 so as to apply ultrasonic vibration to the brazing material 2 by an ultrasonic vibration applying means described later.
[0035]
Between the nozzle body 4 and the partition bush 6, between the lower surface of the nozzle body 4 and the flange portion 9a of the pipe member 9, between the upper surface of the nozzle body 4 and the lower surface of the positioning member 12, and between the positioning member 12 and the guide. Heat-resistant O-rings 14, 15, 16, 17 are interposed between the pipe 10 and the pipes 10, respectively, and are hermetically sealed.
[0036]
The above constitutes the main part of the nozzle for supplying the brazing material. An ultrasonic vibration applying means 18 for applying ultrasonic vibration to the brazing material 2 is arranged on the nozzle main portion. The ultrasonic vibration applying means 18 has a piezoelectric ceramic vibrator 19 sandwiched between a lower active fixed metal body 20 and an upper free metal body 21. The piezoelectric ceramic vibrator 19 is obtained by subjecting a polycrystalline ceramic obtained by baking a high-purity raw material powder such as BaTiO ₃ , PZT, PbTiO ₃ or the like to a ring at a high temperature in a ring shape, and subjecting the upper and lower surfaces thereof to a metallizing method. The electrodes are formed by the following method. A connection bolt 22 is fixed to a center hole 19 a of the piezoelectric ceramic vibrator 19.
[0037]
The active fixed side metal body 20 is mounted on the cover member 13, and has a vertical hole 20 a through which the guide pipe 10 is inserted along a central axis, female screw portions 20 b and 20 c at lower and upper portions, and an upper outer periphery. The flange portion 20d is actively fixed to a member for fixing the nozzle 3 by O-rings 23 and 24, and the male screw portion of the cover member 13 is provided on the lower female screw portion 20b. The connecting bolt 22 is screwed to the upper female screw portion 20c.
[0038]
The free-side metal body 21 has a vertical hole 21a through which the guide pipe 10 is inserted along the central axis, and female screw portions 21b and 21c at the lower and upper portions. Are screwed, and the male screw part of the nozzle guide 25 is screwed to the upper female screw part 21c.
[0039]
Above the nozzle guide 25, a feed roller 1 around which the brazing material 2 is wound, and a back roller 26 as necessary, are arranged. The brazing material 2 drawn from the feed roller 1 is passed through the opening of the nozzle guide 25. The guide pipe 10 is inserted into the guide pipe 10 so that an appropriate pull-out resistance is applied to the guide pipe 10 so that the guide pipe 10 is fed out by a predetermined dimension.
[0040]
Next, the operation of the brazing material supply nozzle 3 will be described. First, the brazing material 2 is pulled out from the feed roller 1, the brazing material 2 is inserted into the guide pipe 10 from the opening of the nozzle guide 25, and is protruded from the lower end of the guide pipe 10 by a predetermined dimension.
[0041]
Then, a cooling gas such as cooling air is supplied into the nozzle body 4 from the inflow port 7.
Then, the cooling gas supplied into the nozzle body 4 passes from the annular groove 4a of the nozzle body 4 through the radial horizontal hole 6a of the partition bush 6, and flows between the inner peripheral surface of the pipe portion 6b and the outer peripheral surface of the guide pipe 10. It descends through the gap 27 formed, makes a U-turn after exiting from the lower end of the pipe portion 6b of the bulkhead bush 6, and in this time, the inner circumferential surface of the pipe member 9 and the inner circumferential surface of the bulkhead bush 6 It rises through the gap 28 formed and is discharged from the discharge port 8. Here, the guide pipe 10 is cooled mainly while the cooling gas descends through the gap 27 formed between the inner peripheral surface of the pipe portion 6b of the partition bush 6 and the outer peripheral surface of the guide pipe 10. The brazing material 2 inserted into the guide pipe 10 is cooled. The clearance between the guide pipe 10 and the brazing material 2 is small, the thermal diffusivity of air is 2.2 × 10 ⁻⁵ m ² / s, and the thermal diffusivity of water is 1.9 × 10 ⁻⁷ m ² / s. s is 116 times that of the water-cooled type, and the brazing material 2 can be effectively cooled in a short time.
[0042]
When electricity is supplied to the electrodes of the piezoelectric ceramic vibrator 19, the piezoelectric ceramic vibrator 19 vibrates ultrasonically, whereby the free-side metal body 21 vibrates, and longitudinal vibration is applied to the brazing material 2.
[0043]
Then, the brazing material 2 protruding from the lower end of the guide pipe 10 is brought into contact with a substrate such as a heated lead frame. Then, the tip of the brazing material 2 slides on the surface of the substrate by ultrasonic vibration to peel off the oxide film and contaminants on the substrate surface, thereby exposing the pure surface of the substrate and the brazing material 2 The tip is melted by heat conduction from the substrate and is supplied onto the substrate. Ultrasonic vibration is applied to the molten brazing material supplied on the substrate through the brazing material 2, so that the molten brazing material is agitated, and oxides and contaminants contaminate the surface of the molten brazing material. Prevent covering. Due to the synergistic effect of the exposure of the pure surface of the substrate surface and the stirring action of the molten brazing material, the molten brazing material is supplied to a predetermined position on the substrate with high precision as shown by the solid line in FIG. can do.
[0044]
Moreover, as described above, since the oxide film and contaminants on the substrate surface are removed and the surface of the molten brazing material is not covered with oxides and contaminants, the molten braze supplied on the substrate is The flow of the brazing material is concentrically spread from the above-mentioned supply position without moving or unevenly spreading the flow, so that the supply position accuracy of the brazing material is significantly improved.
[0045]
Further, since the brazing material 2 in the nozzle 3 is appropriately cooled by the cooling gas, the supply amount of the brazing material 2 onto the substrate can be accurately controlled to a predetermined amount. Therefore, when a semiconductor chip (die) is supplied and pressurized on the molten brazing material, it becomes possible not only to bond the semiconductor chip (die) to a predetermined position on the substrate with high accuracy, but also to supply the brazing material. Since the amount is controlled to a predetermined value, as shown in FIG. 10B, there is a problem that the excess brazing material rises on the side surface of the semiconductor chip (die) or flows on the upper surface of the semiconductor chip (die). Therefore, a high-quality semiconductor device having low electric resistance and low heat radiation resistance can be obtained.
[0046]
The above embodiment has been described for one embodiment of the present invention, and the present invention is of course not limited to this embodiment.
[0047]
For example, in the above-described embodiment, the positioning member 12 and the cover member 13 are mounted on the nozzle main body 4 so that the ultrasonic vibration applying means 18 can be used in common with the type in which the ultrasonic vibration applying means 18 is not mounted. However, the nozzle body 4 or the metal body 20 may have the functions of the positioning member 12 and the cover member 13.
[0048]
Further, as shown in FIGS. 3A and 3B, the guide pipe 10 is not limited to projecting from the lower end of the pipe member 9, but may be made to coincide with the lower end of the pipe member 9 or the lower end of the partition bush 9. It may be slightly recessed from the part.
[0049]
【The invention's effect】
The brazing material supply nozzle of the present invention inserts a brazing material drawn from a feeder roller wound with a long wire-shaped brazing material, and contacts and melts the tip of the brazing material protruding from the lower end with the heated substrate. In the brazing material supply nozzle adapted to supply the brazing material, ultrasonic vibration applying means for applying ultrasonic vibration to the inserted brazing material is provided. By sliding the surface of a substrate such as a lead frame with a brazing material to which ultrasonic vibrations have been applied, oxide films and contaminants on the substrate surface are removed, and the pure surface of the substrate is exposed. Since the wettability of the brazing material is improved, the molten brazing material supplied on the substrate does not move on the substrate or spread eccentrically from the initial supply position, and also spread on the substrate. The stirring effect of the supplied brazing filler metal by ultrasonic vibration prevents the surface of the molten brazing filler metal from being covered with oxides and contaminants, significantly improving the wettability of the brazing filler metal with respect to the substrate. Can be supplied to a predetermined position with high precision. Therefore, the bonding position accuracy of the semiconductor chip (die) can be improved, and the electric resistance and the heat radiation resistance of the brazing material can be reduced.
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional view of a brazing material supply nozzle according to an embodiment of the present invention,
(B) is a bottom view of the brazing material supply nozzle of (A).
FIG. 2A is a cross-sectional view of the brazing material supply nozzle of FIG. 1 taken along line AA.
(B) is a cross-sectional view of the brazing material supply nozzle of FIG. 1 along the line BB,
(C) is a cross-sectional view of the brazing material supply nozzle of FIG. 1 along the line CC,
(D) is a plan view of the brazing material supply nozzle of FIG. 1.
FIG. 3A is an enlarged vertical sectional view of a tip end of the brazing material supply nozzle of FIG. 1;
(B) is a cross-sectional view of the brazing material supply nozzle of (A) taken along the line DD.
FIG. 4 is a front view of a semiconductor device in which a semiconductor chip (die) is brazed to a substrate.
FIG. 5 shows various forms of a substrate such as a lead frame;
(A) is an enlarged vertical sectional view of a bare bonding substrate exposing the base material,
(B) is an enlarged vertical cross-sectional view of the entire plating substrate having plating layers formed on both surfaces of the base material,
(C) is an enlarged vertical sectional view of a partially plated substrate in which a plating layer is formed only at a bonding position of a semiconductor chip (die) on a substrate;
(D) is an enlarged vertical cross-sectional view of a substrate in which plating layers are formed on both surfaces of a substrate, and another plating layer is formed only at a bonding position of a semiconductor chip (die).
FIG. 6 is a longitudinal sectional view of a conventional brazing material supply tool.
FIG. 7 is a longitudinal sectional view of another conventional brazing material supply tool.
FIG. 8A is an enlarged vertical sectional view of the brazing material supply tool in a standby state,
(B) is an enlarged vertical sectional view showing a state where the brazing material supply tool is lowered and the brazing material contacts the substrate;
(C) is an enlarged longitudinal sectional view of a state where the brazing material is supplied to the substrate by the brazing material supply tool.
FIG. 9A is a plan view of a state in which solder supplied on a substrate flows concentrically and spreads;
(B) is a plan view explaining the problem that the molten solder supplied depending on the surface state of the substrate moves on the substrate or flows unevenly.
FIG. 10A is a front view of a state in which excessive solder is supplied on a substrate,
(B) is a front view explaining a problem in the case where a semiconductor chip (die) is bonded by pressing on an excessive solder of (A).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Feed roller 2 Brazing material 3 Brazing material supply nozzle 4 Nozzle body 4a Annular groove 5 Cavity 6 Partition bush 6a Side hole 6b Pipe portion 7 Cooling gas inflow port 8 Cooling gas outlet 9 Pipe member 9a Flange portion 9b Pipe portion 10 Guide pipe 12 Positioning member 13 Cover members 14 to 17, 23, 24 O-ring 18 Ultrasonic vibration applying means 19 Piezoelectric element (piezoelectric ceramic vibrator)
Reference Signs List 20 Active fixed metal body 21 Free metal body 22 Connecting bolt 25 Nozzle guide 26 Backup roller 27, 28 Clearance

Claims (5)

A brazing material supply in which a brazing material drawn out from a feeder roller wound with a long wire-like brazing material is inserted, and the tip of the brazing material protruding from the lower end is brought into contact with the heated substrate to be melted and supplied to the substrate. At the nozzle
An ultrasonic vibration applying means for applying ultrasonic vibration to the inserted brazing material is provided. The brazing material supply nozzle according to claim 1, wherein the ultrasonic vibration applying means is a piezoelectric element. 3. The brazing material supply nozzle according to claim 1, wherein the lower side of the ultrasonic vibration applying means is fixed by an active fixing member, and the upper side is supported by a free side member. The brazing material supply nozzle according to any one of claims 1 to 3, further comprising a cooling unit provided below the ultrasonic vibration applying unit to cool the brazing material inserted therein. The brazing material cooling means is an air cooling system using a cooling gas, and has an inlet for supplying a cooling gas into a nozzle, and an exhaust port for exhausting a cooling gas that has cooled the brazing material in the nozzle. The brazing material supply nozzle according to claim 4.

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