JP2012038985A - Soldering device and magazine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable soldering of lead frames in large batches without human intervention.SOLUTION: A soldering device includes, inside a vacuum chamber 11, a pair of heater plates 12, 13 that heat a magazine 20 by holding the magazine 20 from both of its sides, and a pair of heat absorbing plates 14, 15. The heater plate 12 and the heat absorbing plate 14 are movable to come into contact with and separate from the other heater plate 13 and heat absorbing plate 15 respectively so as to press the magazine 20 against the other heater plate 13 and heat absorbing plate 15 during heating or cooling of the magazine 20. The magazine 20 includes a plurality of lead frames therein. Accordingly, heating the magazine 20 enables soldering of the lead frames included in the magazine 20 in large batches.

Description

  The present invention relates to a soldering apparatus for applying solder to an upper surface and heating a lead frame on which an electronic component is mounted to solder the electronic component to the lead frame, and to store and hold such a lead frame. Related to the magazine.

  In general semiconductor packages, semiconductors such as IGBTs (Insulated Gate Bipolar Transistors) and integrated circuit chips are joined on a lead frame by wire soldering, and are connected with wires such as gold, copper, and aluminum, followed by resin sealing. .

  In this case, chip attachment with solder has been performed by supplying wire solder to a die pad of a lead frame with a die bonder and mounting the chip there (see, for example, Patent Document 1). In the apparatus of Patent Document 1, wire solder is supplied to a lead frame conveyed by a heater rail, and a power transistor is mounted thereon, thereby soldering the power transistor to the lead frame. This method is a tact-oriented method and can perform soldering in a short time, but on the other hand, there are many voids in the solder, and there are many steps such as performing a void inspection during the production.

  On the other hand, in the case of a module such as a hybrid integrated circuit, a product in which a large number of chip parts such as integrated circuits, capacitors, resistors, and coils are mounted on solder applied by printing or the like is placed on a plate jig and placed in a soldering apparatus. There is a method of performing soldering with a hot plate in a vacuum. In this method, since soldering is performed in a vacuum, there is an effect of drawing out voids in the solder, and the void ratio can be reduced. However, in this soldering apparatus, since the products on the plate jig were manually arranged, the mass productivity was very low due to the increase in the man-hour and the increase in the man-hour work time. For this reason, since the processing time is long, it has not been adopted in lead frame type products such as discrete, which emphasize mass production.

  By the way, in the manufacture of a semiconductor using a lead frame, a magazine is used for transporting the lead frame between each process (for example, see Patent Documents 2 and 3). The magazine has a rectangular parallelepiped with elongated rectangular openings on both sides, and a plurality of partition steps extending in the horizontal direction between the openings are formed at predetermined intervals on the opposing inner walls of both side plates. Yes. A plurality of magazines can be stored by placing the lead frames horizontally on the partitioning steps. Thus, in each semiconductor manufacturing process, one lead frame is pulled out from the magazine and processed, and the processed lead frame is returned to the magazine. When the processing of all the lead frames stored in the magazine is completed, these lead frames are transported to the next process while being repaired in the magazine.

  Here, in the soldering process, in order to reduce the void ratio in the solder, when the above soldering apparatus is used, the lead frames are drawn one by one from the magazine and arranged on the plate jig, and the lead frames are arranged. The obtained plate jig is fed into a soldering apparatus. In the soldering apparatus, the plate jig is disposed on the hot plate in a vacuum atmosphere, and the lead frame is soldered collectively by being heated from the lower surface by the hot plate. When the soldering by the soldering device is finished, the plate jig is pulled out from the soldering device, and the lead frames are picked up one by one from the plate jig and stored in the magazine. When the lead frames are stored in the magazine, the lead frames are transported to the next manufacturing process while being stored in the magazine.

JP 2006-114649 A (paragraph [0023], FIG. 1) JP 9-36137 A Japanese Patent Laid-Open No. 9-237798

  However, when soldering the lead frame in a vacuum atmosphere in a batch with a hot plate, the lead frame is taken out from the magazine and arranged on the plate jig, and after the soldering is finished, it is picked up from the plate jig and returned to the magazine. Since the work is performed manually, it takes time and processing time, and there is a problem that mass productivity is very low.

  The present invention has been made in view of the above points, and can perform batch processing of a large number of batches of soldering of a lead frame on which a plurality of semiconductor chips and chip components are mounted without human intervention. An object is to provide a soldering apparatus and a magazine.

  In the present invention, in order to solve the above-described problems, both side surfaces of a magazine for holding a plurality of lead frames each having electronic components placed on each applied solder and maintaining a horizontal state at a predetermined interval in a vertical direction. At least one pair of heater plates capable of melting the solder and joining the electronic component to the lead frame by heating in contact with each other, and at least one of the heater plates is in contact with the side surface of the magazine. There is provided a soldering apparatus characterized by comprising a heating means that can be driven in a detachable manner and has a heater plate driving section that holds the magazine in a state of being heated.

  According to such a soldering apparatus, the magazine is heated while the lead frame is stored without taking out the lead frame from the magazine. Thereby, a lot of lead frames can be soldered together.

  The present invention is also a magazine for melting the solder applied to the lead frame housed inside by sandwiching the both side surfaces by the heater plate and soldering the electronic components placed thereon. Thus, a magazine is provided in which the top plate is provided with a vent hole.

  According to such a magazine, when being sandwiched and heated by the heater plate, the magazine is provided with a gas vent hole that guides the flux gasified when the uppermost lead frame is heated to the outside. As a result, the uppermost lead frame does not retain a temperature due to gas retention during heating, so that all the lead frames can be soaked.

  In the soldering apparatus having the above-described configuration, since the lead frame is soldered by directly heating the magazine in which the lead frame is stored, the lead frame is taken in and out of the magazine. Since there is no need to arrange them on a plate jig, a large amount of lead frames can be soldered together in a short time, which has the advantage that it can greatly contribute to cost reduction of products.

By setting the vacuum state during the melting of the solder, it becomes possible to reduce voids in the solder generated from the flux.
The magazine that solders the lead frame by heating it with the lead frame housed has a vent hole in the top plate, so that the gas component from the flux generated during the heat history does not stay inside. Since it can be pulled out to the outside, partial heating of the uppermost lead frame is avoided, and all the lead frames can be uniformly heated.

  The magazine can be adjusted in heat capacity from the side surface to the lead frame by slitting the side surface of the magazine, and the temperature distribution in the magazine can be made uniform.

It is a figure which shows the soldering apparatus which concerns on one embodiment of this invention. It is a figure explaining the manufacturing process of the semiconductor device formed by mounting an electronic component in a lead frame. It is a perspective view which shows the structural example of a magazine.

  Hereinafter, in the embodiment of the present invention, an example in which a semiconductor device that is a module such as a hybrid integrated circuit is manufactured by mounting a semiconductor chip and a plurality of electronic components that are chip components in one section that is a module of a lead frame. Detailed description will be given with reference to the drawings.

FIG. 1 is a view showing a soldering apparatus according to an embodiment of the present invention.
A soldering apparatus 10 according to the present invention includes a vacuum chamber 11 that can be evacuated. Although not shown, the vacuum chamber 11 includes an opening / closing mechanism that opens or seals the internal space in which the magazine 20 is installed, a vacuum pump that evacuates the internal space, a vacuum valve that is provided between the internal space and the vacuum pump, and the like. I have. Although not shown, the vacuum chamber 11 includes a mechanism that fills the internal space decompressed by a vacuum pump with an inert gas (for example, nitrogen gas).

  The inside of the vacuum chamber 11 has a heating zone on the side where the magazine 20 is supplied, and a cooling zone on the side where the magazine 20 is taken out. The heating zone is provided with a pair of heater plates 12 and 13 that sandwich and heat the magazine 20 supplied to the internal space from both sides. In the illustrated example, the heater plate 12 is installed so as to be able to contact and separate from a fixed heater plate 13. Thus, the heater plate 12 is retracted from the movement path of the magazine 20 when the magazine 20 is supplied and moved to the cooling zone, and operates to press the magazine 20 against the heater plate 13 when performing soldering. . Similarly, the cooling zone is provided with a pair of heat absorbing plates 14 and 15 that cool the magazine 20 by sandwiching it from both sides. In the example shown in the drawing, the heat absorbing plate 14 is installed so as to be able to contact and separate from the fixed heat absorbing plate 15. Thus, the heat absorption plate 14 is retracted from the movement path of the magazine 20 when the magazine 20 is supplied and moved out of the vacuum chamber 11, and the magazine 20 is pressed against the heat absorption plate 15 when cooling is performed. Operate.

  The heater plates 12 and 13 can be configured by embedding a heating element in a heat conductor. The heating element can generate heat at a temperature corresponding to the supplied current, and it is preferable that a plurality of rod-shaped heating elements are appropriately spaced apart from each other in the heat conductor. In this case, an appropriate temperature gradient can be provided on the heating-side surface of the heat conductor so that the lead frame accommodated in the magazine can be heated uniformly by controlling the heat generation temperature of each rod-shaped heat generator. . For example, a temperature gradient may be provided according to the distribution of heat capacity of the magazine 20 to be heated. Therefore, a rod-shaped heating element may be disposed close to the thick portion of the magazine 20, or the heating temperature of the rod-shaped heating element may be set higher. Or you may set the heat_generation | fever temperature of a rod-shaped heat generating body low in the upper part of the magazine with which heat_generation | fever tends to accumulate | store.

  The heat absorbing plates 14 and 15 are constituted by a heat conductor provided so that a passage through which the cooling water flows is meandering, and connected to a heat exchanger (not shown) provided outside the vacuum chamber 11 so that the cooling water Is circulated with a pump. Thereby, a circulating cooling device of a system in which cooling water is circulated between the heat exchanger and the heat absorbing plates 14 and 15 is configured, and the heat absorbing plates 14 and 15 can continuously cool the magazine 20. . That is, the circulating cooling water is radiated to the atmosphere by a fan by a heat exchanger and cooled, and is supplied to the heat absorbing plates 14 and 15 where it absorbs heat from the magazine 20, thereby becoming a high temperature and again being a heat exchanger. It is repeated in the cycle of being returned to and cooled here.

  The movable heater plate 12 and the heat absorption plate 14 are configured by, for example, an electric actuator so as to be able to contact and separate from the heater plate 13 and the heat absorption plate 15. In this electric actuator, the heater plate 12 or the heat absorption plate 14 is urged in the direction of the heater plate 13 or the heat absorption plate 15 by an urging spring, for example, and is driven in a direction away from the heater plate 13 or the heat absorption plate 15 by an electric motor. It is configured. The urging springs have an urging force such that when the heater plate 12 or the heat absorbing plate 14 presses the magazine 20 against the heater plate 13 or the heat absorbing plate 15, they are in close contact with each other. The electric actuator may be configured by a single mechanism common to the heater plate 12 and the heat absorption plate 14 on the movable side, and the heater plate 12 and the heat absorption plate 14 may be driven simultaneously.

  In the soldering apparatus 10 having the above configuration, when soldering an electronic component mounted on a lead frame to the lead frame, first, the vacuum chamber 11 is opened, and the heater plates 12 and 13 only receive the magazine 20. They are separated to have a gap. Next, the magazine 20 is pushed into the vacuum chamber 11 with the lead frame stored therein, and is stopped in the gap between the heater plates 12 and 13.

  Thereafter, the vacuum chamber 11 is driven, the inside is sealed and filled with an inert gas, the heater plate 12 is driven, the magazine 20 is pressed against the heater plate 13, and the heater plates 12, 13 start heating. When the heater plates 12 and 13 reach a high temperature, the heat is transmitted to the magazine 20 and further transmitted from the magazine 20 to the lead frame to melt the solder applied to the lead frame. The vacuum chamber 11 is evacuated at an appropriate timing until the solder reaches the melting point. Thereby, when the solder is melted beyond the melting point, voids generated in the inside due to gasification of the flux are reduced by evacuation, thereby preventing a decrease in the bonding strength of the solder.

  After the solder is melted, the heating of the heater plates 12 and 13 is stopped, and the evacuation in the vacuum chamber 11 is stopped. Thereafter, the heater plate 12 is driven away from the magazine 20, and the magazine 20 is moved from the heating zone to the cooling zone using an appropriate moving means. At this time, the heat absorption plates 14 and 15 are separated so as to have a gap enough to receive the magazine 20. When the magazine 20 is moved between the endothermic plates 14, 15, the endothermic plate 14 is driven to press the magazine 20 against the endothermic plate 15, and cooling water is circulated through the endothermic plates 14, 15 to cool the magazine 20. Start. The magazine 20 is sandwiched between the heat absorbing plates 14 and 15 in a close contact state so that the magazine 20 efficiently absorbs the temperature and lowers the temperature, and accordingly, the lead frame housed therein is also cooled. When the temperature of the magazine 20 is lowered to a predetermined temperature, the heat absorbing plate 14 is driven in a direction away from the magazine 20, the vacuum chamber 11 is opened, and the magazine 20 is taken out from the vacuum chamber 11 using an appropriate moving means.

  In the above embodiment, one magazine 20 is heated and cooled in each of the heating zone and the cooling zone in the vacuum chamber 11, but the present invention is not limited to this. For example, three heater plates may be provided, and a magazine may be sandwiched between the middle fixed heater plate and the outer movable heater plate. In this case, the same configuration is adopted also in the cooling zone, and movable endothermic plates are provided so as to press the magazines on both sides of the fixed endothermic plate provided in the center. In the above embodiment, the heating zone and the cooling zone are formed in the vacuum chamber 11, but they are not necessarily in the vacuum chamber 11 and may be provided in the atmosphere.

FIG. 2 is a diagram for explaining a manufacturing process of a semiconductor device formed by mounting electronic components on a lead frame.
In the semiconductor device manufacturing process, first, a strip-shaped lead frame 30 is prepared (S1). Although not shown in the drawing, the lead frame 30 is die-cut into a predetermined pattern, and a part on which a semiconductor chip or chip component is placed, an inner lead, an outer lead, and the like are formed in advance. Such a lead frame 30 is accommodated in the magazine 20 and conveyed to the next manufacturing process.

  In the next manufacturing process, the lead frames 30 are pulled out from the magazine 20 one by one, and the solder paste 40 is applied or printed at a predetermined position of the lead frame (S2). The lead frame 30 to which the solder paste 40 is applied is stored in the magazine 20 again and conveyed to the next manufacturing process. In this embodiment, the solder paste 40 is used as the bonding material, but the present invention is not limited to this, and other bonding materials such as plate solder and silver paste can be used.

  In the next manufacturing process, the lead frames 30 are pulled out from the magazine 20 one by one, and the semiconductor chip 50 and the chip component 51 are mounted on the solder paste 40 applied to the lead frame 30 (S3). The lead frame 30 on which the semiconductor chip and the chip component are mounted is stored again in the magazine 20 and conveyed to the next manufacturing process.

  In the next manufacturing process, with the lead frame 30 stored in the magazine 20, the magazine 20 is put into the soldering device 10 described above to heat and cool the lead frame 30, and then put into a cleaning device. The lead frame 30 is cleaned (S4). In the cleaning apparatus, the lead frame 30 is immersed in a cleaning solution and subjected to ultrasonic cleaning, and flux and the like are removed. As described above, in the heating, cooling, and cleaning steps, batch processing can be performed in a lump while the lead frame 30 is not removed from the magazine 20 and is still in the magazine 20. When the cleaning of the lead frame 30 is completed, the magazine 20 is transported to the next manufacturing process.

  In the next manufacturing process, the lead frames 30 are pulled out one by one from the magazine 20, wire bonding is performed by a wire bonder (S <b> 5), and the lead frame 30 is stored again in the magazine 20 and conveyed to the next manufacturing process.

  In the next manufacturing process, the lead frames 30 are pulled out from the magazine 20 one by one, placed in a molding device, and resin sealing is performed (S6). The lead frame 30 that has been resin-sealed is stored in the magazine 20 again in order to be transported to the next manufacturing process such as cutting of the lead frame 30 and lead processing.

FIG. 3 is a perspective view showing a configuration example of a magazine.
The magazine 20 is formed of a material that is heat resistant and can withstand the cleaning liquid because the soldering device 10 is heated and cooled while the lead frame 30 is inserted, and the cleaning device performs cleaning. Yes. Further, the magazine 20 can secure a sufficient heat distribution, and is formed of a material having such characteristics that the molten solder does not adhere to the inside of the magazine when scattered due to the burst of the void. The material of such a magazine 20 can be stainless steel or aluminum. In particular, aluminum is suitable as a material having the above characteristics.

  The magazine 20 has a bottom plate 21, a top plate 22, and side plates 23 and 24, and has a rectangular parallelepiped shape. At both ends in the longitudinal direction, vertically long and narrow rectangular openings are formed, and an entrance through which the lead frame 30 is inserted and removed is configured. A plurality of U-shaped engaging grooves 25 extending in the horizontal direction are formed on the opposing inner walls of the side plates 23 and 24 at a predetermined interval in the height direction. The lead frame 30 is stored and held in the magazine 20 by being inserted along the locking groove 25. In the magazine 20 of the illustrated embodiment, 20 lead frames 30 can be stored.

  The magazine 20 has a plurality of vent holes 26 in its top plate 22. The vent holes 26 reduce radiant heat from the top plate 22 to the lead frame 30 accommodated in the uppermost stage, and lead the gasified flux to the outside of the magazine 20 when the uppermost lead frame 30 is heated. Is to do. Without the gas vent hole 26, gas stays during heating and the temperature of the lead frame 30 becomes too high. If it is too large, the temperature of the lead frame 30 becomes low due to the flow of gas. It will pass. Therefore, the size, position, number, etc. of the vent holes 26 are selected to such an extent that the solder paste 40 can be held at an appropriate temperature during heating. In the magazine 20 of the illustrated embodiment, a lead frame 30 having 12 module forming sections per sheet is targeted, and in this case, the vent hole 26 is a ratio of one per two module forming sections. It is formed with.

  Since the magazine 20 has a gas vent hole 26 in the top plate 22 and not in the bottom plate 21, whether the magazine 20 is upright or not is determined whether there is a gas vent hole 26 or not. Judgment can be made easily just by checking.

  The magazine 20 also has a plurality of slits 27 extending horizontally on the side plates 23 and 24 thereof. The slit 27 is formed between the locking grooves 25 formed in the side plates 23 and 24. This slit 27 is used in the case where the heat capacity of the magazine 20 becomes too large when the side plates 23 and 24 are made thick in order to ensure the required strength of the magazine 20 and heating takes a long time. 20 is provided for the purpose of reducing the heat capacity. The slit 27 also contributes to improving the cleaning performance in the cleaning process of the lead frame 30 as compared with the case where the side plates 23 and 24 are completely covered.

DESCRIPTION OF SYMBOLS 10 Soldering apparatus 11 Vacuum chamber 12, 13 Heater plate 14, 15 Endothermic plate 20 Magazine 21 Bottom plate 22 Top plate 23, 24 Side plate 25 Locking groove 26 Gas vent hole 27 Slit 30 Lead frame 40 Solder paste 50 Semiconductor chip 51 Chip component

Claims (9)

A magazine that holds a plurality of lead frames on which electronic components are placed on each applied solder while maintaining a horizontal state at a predetermined interval in the vertical direction is melted by contacting and heating both sides of the magazine. And at least one pair of heater plates capable of joining the electronic component to the lead frame;
A heater plate driving unit capable of driving at least one of the heater plates so as to be able to contact with and separate from a side surface of the magazine and holding the magazine during heating; and
A soldering apparatus comprising heating means having   2. The soldering apparatus according to claim 1, wherein the lead frame has a plurality of the electronic components, which are semiconductor chips and chip components, mounted in one section of the module.   The soldering apparatus according to claim 1, wherein the heater plate is configured by embedding a plurality of heating elements that generate heat at a temperature corresponding to a supplied current in a heat conductor. A pair of endothermic plates;
An endothermic plate driving unit capable of driving at least one of the endothermic plates so as to be able to contact with and separate from a side surface of the magazine and holding the magazine during cooling; and
The soldering apparatus according to claim 1, further comprising a cooling means having   The soldering apparatus according to claim 4, wherein the heat absorbing plate is formed by a heat conductive material so that a passage through which cooling water flows is meandering.   The soldering apparatus according to claim 4, wherein the heating unit and the cooling unit are installed in a vacuum chamber.   The soldering apparatus according to claim 6, wherein the vacuum chamber includes a mechanism that fills an internal space with an inert gas. A magazine for soldering electronic components placed thereon by melting solder applied to a lead frame housed inside by sandwiching both side surfaces by a heater plate,
A magazine characterized in that the top plate has a vent hole.   The magazine according to claim 8, wherein the side plates on both side surfaces have slits.

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