JP2015051440A - Metal filing apparatus and metal filing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal filling apparatus and metal filling method capable of covering an entire surface to be treated with molten metal and reducing dissolved gas in the molten metal as much as possible by sufficiently ensuring fluidity of the molten metal and making uniform flow of the molten metal on the surface to be treated.SOLUTION: A metal filling apparatus 1 includes: a holding table H that holds a semiconductor wafer K in a state that a treatment surface of the semiconductor wafer K is inclined at 90° with respect to a horizontal direction; a cylindrical housing C; a piston P provided movably forward and backward; and the like. The semiconductor wafer K held on the holding table H, the housing C, and the piston P form an airtight treatment chamber 2. This metal filling apparatus 1 further includes: a decompression mechanism 10 reducing pressure inside the treatment chamber 2; a molten metal supply mechanism 15 supplying molten metal M into the treatment chamber 2; degasification mechanism 20 degasifying the molten metal M; and an exciting mechanism 30 applying high-frequency vibration to the molten metal M supplied into the treatment chamber 20.

Description

  The present invention relates to a metal filling apparatus and a metal filling method for filling molten metal into a minute space formed on the surface of a workpiece.

  2. Description of the Related Art In recent years, in a through silicon via (Through Silicon via) technique, a technique for filling a via or a through hole (hereinafter referred to as “microspace”) formed on a semiconductor wafer (object to be processed) with a metal is required. According to this silicon through electrode technology, it is possible to develop a chip stacking technology using the through electrode, and it is expected to realize a high-functional and high-speed semiconductor system by three-dimensional mounting.

  As described above, for example, an apparatus disclosed in JP 2010-283034 (hereinafter referred to as “conventional apparatus”) is proposed as an apparatus for filling a metal in a minute space on an object to be processed. ing.

  This conventional apparatus includes first and second supports, a molten metal supply unit, a pressure control unit, a pressurizing unit, and the like, so that a processing chamber is formed by the first support and the second support. It has become. The molten metal supply unit is configured to supply the molten metal into the processing chamber through a metal supply path provided in the second support, and the pressure control unit is configured to transmit pressure in the second support. The process chamber is configured to be depressurized, supplied with gas into the process chamber, and pressurized with gas. Further, the pressurizing means is configured to apply a pressing pressure to the second support, move the second support toward the first support, and apply pressure to the processing chamber.

  According to this conventional apparatus, first, an object in which a minute space is formed is placed on the upper surface of the first support, and the second support is combined with the first support so as to cover the object, A processing chamber is formed around the substrate. Next, after the processing chamber is depressurized by the pressure control unit, the molten metal is supplied into the processing chamber by the molten metal supply unit so that a metal thin film is formed on the surface of the object to be processed. As a result, the molten metal is filled in the minute space with a differential pressure. Thereafter, the filled molten metal is cured. At this time, pressure is applied to the molten metal until the molten metal is cured by the pressure control unit and the pressurizing means. Finally, the residual metal thin film on the object is removed to obtain the object filled with metal in the minute space.

JP 2010-283034 A

  By the way, in the said conventional apparatus, the wettability (affinity) of the molten metal with respect to a to-be-processed object is bad, in other words, the surface tension of the molten metal with respect to a to-be-processed surface is large, and the contact angle of the molten metal with respect to a to-be-processed surface becomes large. In this case, since the molten metal supplied into the processing chamber is deformed into an uneven shape or a spherical shape, the flow of the molten metal on the surface to be processed becomes non-uniform. As a result, entrainment of a gas component in the processing chamber, film breakage of the molten metal thin film, and the like occur, and as a result, there arises a problem that the molten metal cannot be uniformly filled in the minute space.

  In addition, the molten metal used for filling the metal in the minute space reacts with a very small amount of residual oxygen to form an oxide, so even if it is used in a vacuum state, the oxide in the molten metal It is very difficult to prevent formation. As a result of the formation of oxides in the molten metal, the fluidity of the molten metal is reduced, and in the same manner as described above, the flow of the molten metal becomes non-uniform, and entrainment of gas components and molten metal are caused. There arises a problem that defective filling due to a thin film breakage or the like occurs.

  In addition, when dissolved gas (micro gas phase) is present in the molten metal, the dissolved gas is simultaneously supplied by supplying the molten metal into the processing chamber, and the dissolved gas is in the processing chamber. There is also a problem of causing film breakage.

  The present invention has been made in view of the above circumstances, and by sufficiently ensuring the fluidity of the molten metal, the entire molten surface is melted by making the molten metal flow uniform on the surface. An object of the present invention is to provide a metal filling apparatus and a metal filling method that can be covered with metal and that can reduce dissolved gas in molten metal as much as possible.

The present invention for solving the above problems is as follows.
A metal filling device for filling molten metal supplied onto the surface of the object to be processed in a minute space formed so as to open on the surface of the object,
A processing unit main body comprising a holding unit for holding the object to be processed, and a processing chamber formed facing the surface of the object to be processed held by the holding unit;
A pressure reducing mechanism that includes an air passage having one end opened in the inner wall surface of the processing chamber, and that decompresses the processing chamber through the air passage;
A liquid flow path having one end opened to the inner wall surface of the processing chamber, and a storage tank that is connected to the other end of the liquid flow path and stores a molten metal are provided, and the treatment is performed via the liquid flow path. A molten metal supply mechanism for supplying molten metal into the room;
At least one excitation mechanism for applying high-frequency vibration to the molten metal;
A pressurizing mechanism for pressurizing the molten metal supplied into the processing chamber,
The molten metal supply mechanism relates to a metal filling apparatus configured to supply molten metal, to which high-frequency vibration is added by the vibration mechanism, into a processing chamber.

The present invention also provides:
A processing unit main body including a processing chamber formed facing the surface of the object to be processed held in the holding unit;
A decompression mechanism for decompressing the processing chamber;
A molten metal supply mechanism for supplying the molten metal stored in the storage tank into the processing chamber via a liquid passage;
An excitation mechanism for applying high-frequency vibration to the molten metal;
Using a metal filling device provided with a pressurizing mechanism for pressurizing the molten metal supplied into the processing chamber,
A metal filling method of filling molten metal supplied onto the surface of the object to be processed in a minute space formed to open on the surface of the object to be processed,
A decompression step of decompressing the processing chamber;
A molten metal supply step of supplying the molten metal in the storage tank into the processing chamber via the liquid passage;
Performing a pressurizing step of pressurizing the molten metal supplied into the processing chamber;
The molten metal supply step relates to a metal filling method in which molten metal to which high-frequency vibration is added by the vibration mechanism is supplied into a processing chamber through the liquid passage.

  According to the metal filling device and the metal filling device, first, an object to be processed in which a minute space is formed on the surface (surface to be processed) is held by the holding unit. Next, the pressure in the processing chamber is reduced by exhausting the gas in the processing chamber through the ventilation path by the decompression mechanism.

  Next, substantially simultaneously with the operation of the vibration mechanism, the molten metal supply mechanism starts supplying molten metal stored in the storage tank into the processing chamber via the liquid flow path. After supplying a certain amount of molten metal, the supply of molten metal is stopped, and then the processing chamber is hermetically sealed and the molten metal supplied into the processing chamber is pressurized by a pressurizing mechanism, Is filled with molten metal. Note that the exhaust of the gas in the processing chamber through the ventilation path may be stopped before starting the supply of the molten metal into the processing chamber, or after the supply of the molten metal into the processing chamber is started, In order to prevent the molten metal from being sucked in, it may be stopped at an appropriate timing.

  As described above, in the metal filling apparatus according to the present invention, the molten metal in the storage tank is supplied into the processing chamber via the liquid flow path in a state where high-frequency vibration is added by the vibration mechanism. Yes.

  Here, since the high frequency vibration added to the molten metal is propagated while repeating partial compression and decompression, the dissolved gas expands by cavitation in the decompressed portion, and Because it gathers in the low pressure part, it grows while colliding with each other. And since dissolved gas floats to a liquid level by this bubble growth, the dissolved gas in the said molten metal is excluded. Therefore, in this metal filling apparatus, the dissolved gas of the molten metal supplied into the processing chamber can be reduced as much as possible.

  Moreover, in the said metal filling apparatus, as above-mentioned, compression and pressure reduction generate | occur | produce alternately by propagation of a high frequency vibration, and a cavitation generate | occur | produces in the pressure-reduced part. The inside of the bubble is molten metal vapor or dissolved gas, but if the bubble is a small amount before growth, the cavitation collapses due to the pressure fluctuation and melts due to the impact pressure generated by the cavitation collapse Solid metal crystals such as oxides formed in the metal and metal films made of these are pulverized into fine particles. Thereby, the fall of the fluidity | liquidity of the molten metal caused by a solid metal crystal or these metal films can be suppressed.

  Furthermore, the molten metal supplied into the processing chamber has a sliding effect on the interface between the surface to be processed and the molten metal, as the vibration propagates, the liquid surface vibrates and the contact angle with the surface to be processed is apparently reduced. Occurs. Accordingly, the fluidity of the molten metal is improved, the flow with respect to the surface to be processed becomes uniform, and the surface to be processed can be uniformly covered with the molten metal. In the metal filling method according to the present invention, the molten metal is added to the molten metal over time so that the vibration energy at the liquid surface of the molten metal becomes constant even when the amount of the molten metal in the processing chamber increases. It is preferable to gradually increase the output of the high frequency vibration.

  The vibration mechanism is preferably configured to directly apply high-frequency vibration to the molten metal. In this way, for example, the apparatus configuration becomes simpler than when the entire apparatus is vibrated or the substrate is vibrated, and less energy is required to give a sufficiently large vibration. can do.

  In the metal filling apparatus, the vibration mechanism is configured to directly apply high-frequency vibration in the same direction as the molten metal flows from the storage tank to the processing chamber to the molten metal. Is preferred. In this way, high-frequency vibration can be more efficiently propagated to the molten metal in the processing chamber.

  The vibration mechanism is disposed between one end side and the other end side of the liquid passage, and the high-frequency vibration is supplied to the molten metal that flows through the liquid passage and is supplied into the processing chamber. Can be added directly. Even if it does in this way, there exists a suitable effect.

  Further, the vibration mechanism may be configured to directly apply high-frequency vibration to the molten metal in the storage tank. Even if it does in this way, a suitable effect can be acquired. In this case, in order to prevent the added vibration from being attenuated and transmitted to the molten metal in the processing chamber, the liquid passage between the storage tank and the processing chamber may be shortened as much as possible. preferable.

  Furthermore, the metal filling device according to the present invention includes a first vibration mechanism and a second vibration mechanism, and the first vibration mechanism is disposed between one end side and the other end side of the liquid passage. The second vibration mechanism is configured to directly add high-frequency vibrations to the molten metal that flows through the liquid passage and is supplied into the processing chamber. It is preferable that the high frequency vibration is directly applied to the metal.

  In addition, when providing an excitation mechanism between the one end side and the other end side of the liquid flow path, the excitation mechanism includes an excitation unit having an excitation chamber formed so as to communicate with the outside. A horn disposed so that a tip portion is positioned in the vibration chamber, and a vibrator that vibrates the horn. The vibration tank includes the storage tank and a processing chamber that are connected to the vibration chamber. Is arranged between one end side and the other end side of the liquid flow path so as to communicate with each other via a horn, and directly applies high-frequency vibration to the molten metal flowing through the vibration chamber. It is preferable to configure so as to. And when comprised in this way, it is preferable to make the direction of the high frequency vibration added to the molten metal which distribute | circulates the said excitation chamber correspond with the direction which goes to the said process chamber from the said excitation chamber.

  In the metal filling apparatus configured as described above, first, the horn is vibrated by operating the vibrator. When the horn is vibrated, supply of molten metal from the storage tank into the processing chamber is started almost simultaneously, and thereafter, the molten metal is filled into the minute space in the same manner as described above. Even if it does in this way, since a high frequency vibration can be directly given with respect to molten metal from a horn, the dissolved gas in molten metal can be excluded. In addition to being able to pulverize solid metal crystals, etc., it is possible to obtain a sliding effect and a contact angle reducing effect between the surface to be processed and the molten metal, and the fluidity of the molten metal is uniform. Then, the entire surface to be treated can be covered with a uniform molten metal by preventing film breakage.

  In addition, it is preferable that this metal filling apparatus is further provided with the collection | recovery mechanism which collect | recovers the molten metals in the said vibration chamber. If it does in this way, after performing a metal filling process, the molten metal which stays in a vibration chamber can be collect | recovered. Therefore, it is possible to prevent the molten metal staying in the vibration chamber from being hardened and hindering the operation of the horn, or preventing the molten metal staying in the molten metal supplied into the processing chamber from being mixed in the next processing. it can.

  Further, in the metal filling apparatus, the holding unit is configured to hold the object to be processed such that a surface of the surface to be processed is inclined with respect to a horizontal direction, and the ventilation path includes the object to be processed. It is preferable to be configured to open at a height position above the uppermost end of the surface to be processed and above the opening of the liquid passage.

  In this way, since the molten metal is gradually filled into the processing chamber from the lower end side of the surface to be processed, the molten metal is supplied at least until the liquid level of the molten metal reaches above the upper end of the surface to be processed. By continuing, the gas component remaining in the processing chamber can be collected above the liquid surface of the molten metal, the residual gas component can be kept away from the surface to be processed, and the entire surface to be processed can be covered with the molten metal.

  Moreover, in the said metal filling apparatus, it is preferable that the inclination | tilt angle of the to-be-processed surface with respect to a horizontal direction shall be 30 degrees-150 degrees. In this way, when the molten metal is supplied into the processing chamber, the residual gas component can be more reliably collected above the liquid surface of the molten metal.

  In the present invention, the size of the minute space formed on the object to be processed is typically assumed to have a diameter of 0.1 μm to several tens of μm, but is limited to this range. It is not a thing.

  As described above, according to the metal filling apparatus and the metal filling method of the present invention, vibration is added to the molten metal supplied into the processing chamber, so that the dissolved gas in the molten metal is efficiently removed. can do. In addition, solid metal crystals and metal films in the molten metal can be pulverized, and a sliding effect and a contact angle reducing effect can be obtained between the surface to be processed and the molten metal. Sufficient fluidity can be secured to prevent film breakage due to flow non-uniformity, and the entire surface to be treated can be covered with a uniform molten metal, thereby reducing defective filling.

  In addition, when the structure directly applies vibration to the molten metal, the apparatus structure can be made relatively simple, and sufficient vibration can be obtained without requiring large energy. Can be added to the molten metal.

It is sectional drawing which showed schematic structure of the metal filling apparatus which concerns on one Embodiment of this invention. It is sectional drawing which showed the structure of the vibration excitation mechanism. It is sectional drawing seen from the arrow AA direction in FIG. It is explanatory drawing for demonstrating the process in which the vibration propagated from a high frequency vibrator is amplified. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is explanatory drawing for demonstrating the process filled with a molten metal with the metal filling apparatus which concerns on one Embodiment. It is sectional drawing which showed schematic structure of the metal filling apparatus which concerns on other embodiment of this invention. It is explanatory drawing for demonstrating the process in which the molten metal is supplied in the process chamber in the metal filling apparatus which concerns on other embodiment. It is explanatory drawing for demonstrating the process in which the molten metal is supplied in the process chamber in the metal filling apparatus which concerns on other embodiment.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In the following description, “right” and “left” indicate the right side and the left side, respectively, as viewed in the drawing.

[1. Configuration of metal filling equipment]
As shown in FIG. 1, the metal filling apparatus 1 of this example is a metal that fills a molten metal M in a minute space formed so as to open on the surface (surface to be processed) of a semiconductor wafer (object to be processed) K. In this filling apparatus, the semiconductor wafer K is formed with a holding table H in which the surface to be processed is tilted by 90 ° with respect to the horizontal direction, an internal space is formed, and the right end surface faces the holding table H. The cylindrical housing C disposed in this manner, the piston P provided so as to be able to advance and retreat with respect to the surface to be processed of the semiconductor wafer K held by the holding table H, and the holding table H are moved toward and away from the housing C. A moving mechanism 5 and an advancing / retracting mechanism 6 for moving the piston P back and forth are provided. The holding table H, the housing C, and the piston P function as a processing unit main body, and the semiconductor wafer K and the housing C held by the holding table H And the piston P is airtight. Chamber 2 is formed. In addition, the to-be-processed surface of the semiconductor wafer K refers to the part in which the minute space which should be filled with molten metal was formed, and is not restricted to the whole surface of a to-be-processed object.

  In addition, the metal filling apparatus 1 includes a decompression mechanism 10 that exhausts the gas in the processing chamber 2 to decompress the processing chamber 2, and a molten metal supply mechanism 15 that supplies the molten metal M into the processing chamber 2. The deaeration mechanism 20 that degass the molten metal M, the vibration mechanism 30 that applies vibration to the molten metal M supplied into the processing chamber 2, the moving mechanism 5, the advance / retreat mechanism 6, the decompression mechanism 10, the melting And a control device 59 for controlling the operation of the metal supply mechanism 15, the deaeration mechanism 20 and the vibration excitation mechanism 30.

  The holding table H has a workpiece holding mechanism such as a vacuum chuck or an electrostatic chuck that can be held on the holding table H without deforming the semiconductor wafer K against the pressure reduction in the processing chamber 2. The semiconductor wafer K can be held on the holding surface facing the housing C. The holding table H is moved by the moving mechanism 5. The holding table H is moved in a direction approaching the housing C (left direction), and the semiconductor wafer K held on the holding table H is moved. By bringing the surface into contact with the right end surface of the housing C and the airtight seal 9 provided on the right end surface of the housing C, an airtight processing chamber 2 is formed.

  The piston P is advanced and retracted in the axial direction by an advance / retreat mechanism 6 inside the housing C. Two airtight seals 7 and 8 are interposed between the outer peripheral surface of the piston P and the inner peripheral surface of the housing C.

  The advance / retreat mechanism 6 is, for example, a hydraulic cylinder mechanism or the like that provides a driving force for moving the piston P back and forth, and can move the piston P forward and backward toward the semiconductor wafer K with a predetermined pressing force.

  The decompression mechanism 10 is provided through the upper side wall on the right end side of the housing C, a pipe 12 having a buffer portion 12a formed in an opening on the housing C side, and a vacuum connected to the processing chamber 2 by the pipe 12. It consists of a pump 11 and a control valve 13 provided between the vacuum pump 11 and the processing chamber 2 in the pipe 12. The air in the processing chamber 2 is exhausted by the vacuum pump 11 to depressurize the processing chamber 2. It is a mechanism to do. The operation of the vacuum pump 11 and the opening / closing of the control valve 13 are controlled by a control device 59.

  The molten metal supply mechanism 15 passes through the storage tank 16 in which the molten metal M is stored and the lower side wall on the right end side of the housing C, and is provided so that the opening thereof faces the buffer portion 12 a of the pipe 12. The piping 17a that connects a vibration unit 31 of the vibration mechanism 30 to be described later and the processing chamber 2, the piping 17b that connects the storage tank 16 and the vibration unit 31, and the storage tank 16 of the piping 17b The control valve 18 interposed between the vibration unit 31 and the supply pump 19 with a pressure control function interposed between the storage tank 16 and the control valve 18, with a predetermined supply pressure, This is a mechanism for supplying the molten metal M from the storage tank 16 into the processing chamber 2 via an excitation chamber 32 formed in the excitation unit 31. The control valve 18 is an on-off valve capable of controlling the flow rate, and the operation of the supply pump 19 and the operation of the control valve 18 are controlled by the control device 59.

  In the storage tank 16, the molten metal M used for metal filling is heated at a temperature higher than its melting point and stored in a liquid state. In this example, the molten metal M used for metal filling is lead-free solder having a melting point of about 200 ° C. However, the type of the molten metal M is not limited to solder, Depending on the function, any material such as Au, Ag, Cu, Pt, Pd, Ir, Al, Ni, Sn, In, Bi, Zn, and alloys thereof can be adopted.

  The deaeration mechanism 20 includes a vacuum pump 21 connected to the storage tank 16 by a pipe 22, and is a mechanism that exhausts the air in the storage tank 16 and degass the molten metal M in the storage tank 16. is there.

  The vibration mechanism 30 is disposed between the processing chamber 2 and the control valve 18 in a state where the pipes 17a and 17b are connected to the molten metal M supplied from the storage tank 16 to the processing chamber 2. It is a mechanism that adds vibration. As shown in FIGS. 1 to 3, the vibration mechanism 30 includes a vibration unit 31 having a vibration chamber 32 formed therein, a horn 40 disposed in the vibration chamber 32, and a high frequency. The vibrator 51, a drive device 50 that vibrates the high-frequency vibrator 51, and a recovery device 55 that recovers the molten metal M staying in the vibration chamber 32.

  As shown in FIGS. 2 to 4, the horn 40 is a member having a circular cross-sectional shape, and a horn main body to which a vibration unit 40 a disposed in the excitation chamber 32 and a high-frequency vibrator 51 are connected. 40b and three parts of the flange part 40c formed between the vibration part 40a and the horn main body 40b.

  The vibration part 31 is composed of a rectangular parallelepiped vibration part main body 31a and a cover body 31b fixed to one surface of the vibration part main body 31a. The vibration unit 40a of the horn 40 has a vibration chamber 32 into which the vibration unit 40a is inserted, and the vibration unit is arranged in a plane parallel to the surface on which the cover body 31b is fixed so as to communicate with the vibration chamber 32 and the outside. The first through-hole 33 penetrating along the direction parallel to the vibration direction of 40a, and orthogonally to the surface on which the cover 31b is fixed so as to communicate the excitation chamber 32 and the outside, and Second and third through holes 34 and 35 penetrating along the direction perpendicular to the axis of the first through hole 33 are formed on two mutually parallel surfaces. The pipe 17a is connected to the first through hole 33, the pipe 17b is connected to the second through hole 34, and the molten metal M stored in the storage tank 16 is supplied to the pipe 17b, The second through hole 34, the vibration chamber 32, the first through hole 33 and the pipe 17 a are circulated and supplied into the processing chamber 2. In addition, while forming the 1st through-hole 33 in the position which does not remove | deviate from the in-plane position of the front end surface of the vibration part 40a of the horn 40, the axis line is parallel to the vibration direction of the vibration part 40a of the horn 40. It is desirable to use a straight pipe to smoothly propagate the vibration into the processing chamber 2.

  The horn 40 is inserted from the surface where the cover body 31b of the vibration portion main body 31a is fixed in a state where a gap 32a is left between the vibration portion 40a and the inner wall surface of the vibration chamber 32. By fixing the body 31b, the flange portion 40c is sandwiched between the vibration portion main body 31a and the cover body 31b, and movement thereof is restricted. Seal members 41 and 42 are interposed between the flange portion 40c and the vibration portion main body 31a and the cover body 31b, respectively, so that sealing performance is ensured and the flange portion 40c and the vibration portion are excited. The main part 31a and the cover body 31b are not in direct contact with each other.

  The driving device 50 is a mechanism that applies a predetermined voltage to the high-frequency vibrator 51 that can generate high-frequency oscillation using, for example, the piezoelectric effect, and causes the high-frequency vibrator 51 to generate vibration. When a predetermined voltage is applied by the driving device 50, vibration is generated in the high-frequency vibrator 51, and the horn 40 connected to the high-frequency vibrator 51 vibrates along the axial direction.

  Here, the state of vibration in the high-frequency vibrator 51 and the horn 40 will be described with reference to FIG. The upper diagram of FIG. 4 shows the amplitude amounts in the respective portions of the high-frequency vibrator 51 and the horn 40, and the lower diagram shows the configuration of the high-frequency vibration 51 and the horn 40.

  As shown in FIG. 4, the vibration in the high-frequency vibrator 51 is propagated to the vibration section 40a while being amplified by a booster structure or the like provided in the horn main body 40b, and is susceptible to heat. A vibration having a predetermined magnitude can be applied to the molten metal M in a state where a sufficient distance is left between the molten metal M and the high-temperature molten metal M. Further, the flange portion 40c of the horn 40 is provided so that the position thereof is located at the node of the amplitude, so that no significant vibration is generated in the flange portion 40c. Therefore, as described above, by sandwiching the flange portion 40c by the vibration portion main body 31a and the cover body 31b via the seal members 41 and 32, energy loss is suppressed as much as possible, and vibration is efficiently generated. Can be propagated to. Note that the length of the horn 40 may be any length as long as the high-frequency vibrator 51 is not affected by heat from the high-temperature molten metal M (thermal isolation is possible).

  The recovery mechanism 55 includes a recovery tank 56 whose inside is appropriately depressurized by a vacuum pump, a third end formed at the vibration exciter body 31 through a pipe joint 38 with one end connected to the recovery tank 56 and the other end. The pipe 57 connected to the through hole 35 and the control valve 58 of the pipe 57 interposed between the vibration unit main body 31 and the recovery tank 56, and the molten metal M staying in the vibration chamber 32. It is a mechanism to collect. The operation of the vacuum pump and the opening / closing of the control valve 58 are controlled by a control device 59.

[2. Metal filling process]
Next, with reference to FIGS. 5-10, the process of filling the molten metal M in a micro space with the metal filling apparatus 1 of this example is demonstrated.

  According to the metal filling apparatus 1 of the present example, first, in a state where the holding base H is moved in the direction away from the housing C (right direction) by the moving mechanism 5, the semiconductor wafer K is moved to the housing C side. Is held on the holding surface of the holding base H (see FIG. 5). Next, the holding mechanism H is moved in the direction approaching the housing C (leftward) by the moving mechanism 5, and the right end surface of the housing C and the airtight seal 9 provided on the right end surface of the housing C are pushed onto the surface of the semiconductor wafer K. The treatment chamber 2 is formed by applying and contacting.

  In order to minimize the amount of molten metal M supplied into the processing chamber 2, the piston P is moved toward the semiconductor wafer K by the advance / retreat mechanism 6 so that the volume of the processing chamber 2 becomes as small as possible. It is preferable to keep it.

  Next, the vacuum pump 11 is operated and the control valve 13 is opened to decompress the inside of the processing chamber 2 and the minute space (see FIG. 6).

  Next, a voltage having a predetermined magnitude is applied to the high-frequency vibrator 51 to cause the high-frequency vibrator 51 to oscillate at a high frequency, and the horn 40 is vibrated in the direction along the axis via the booster 52. . The vibration frequency may be about 20 to 40 kHz, and the amplitude may be about 50 to 100 μm. These values are the size of the apparatus, the viscosity and density of the molten metal M, or the required amount of vibration. It is preferable to set appropriately according to the above.

  At substantially the same time as the horn 40 is vibrated, as shown in FIG. 7, the control valve 13 is closed, the control valve 18 is opened, and the supply pump 19 is used to enter the processing chamber 2 from the storage tank 16. The supply of molten metal M is started. The supply of the molten metal M into the processing chamber 2 is performed in a state adjusted to an appropriate supply speed by the control valve 18. Moreover, the molten metal M in the storage tank 16 is in a degassed state, and the gas component in the molten metal M supplied into the processing chamber 2 is reduced as much as possible.

  Further, in the metal filling apparatus 1 of this example, the molten metal M supplied into the processing chamber 2 is directly subjected to vibration from the horn 40 along the direction of flow into the processing chamber 2 in the vibration chamber 32. By applying vibration, cavitation occurs in the molten metal M, and bubbles grow. Thereby, since dissolved gas floats to a liquid level, the dissolved gas in the molten metal M is excluded. Therefore, the molten metal M is supplied into the processing chamber 2 with a very small gaseous component.

  In addition, since an impact pressure is generated when the cavitation generated in the molten metal M is crushed, the solid metal crystal or the like formed in the molten metal M is pulverized into fine particles by the impact pressure, and the fluidity of the molten metal M. Can be suppressed.

  Then, the molten metal M flowing through the vibration chamber 32 gradually fills the processing chamber 2 from below the processing chamber 2. At this time, the vibration from the horn 40 toward the processing chamber 2 is propagated to the molten metal M supplied into the processing chamber 2 via the molten metal M in the pipe 17a. The molten metal M vibrates and cavitation occurs in the molten metal M, and the dissolved gas phase is eliminated and the metal made of a solid metal crystal such as an oxide in the molten metal M, as described above. The membrane is crushed to fine particles. Therefore, in the metal filling apparatus 1, the molten metal M can be filled into the processing chamber 2 while eliminating the gas component in the molten metal M and suppressing the decrease in fluidity of the molten metal M.

  Furthermore, since the liquid level of the molten metal M is vibrated by the propagation of vibration to the molten metal M, a sliding effect is obtained between the surface to be processed of the semiconductor wafer K and the molten metal M, and the surface to be processed. And the contact angle between the molten metal M and the fluidity of the molten metal M with respect to the surface to be processed increases.

  As described above, by eliminating the molten metal M supplied into the processing chamber 2 or the dissolved gas of the molten metal M supplied into the processing chamber 2 and ensuring the fluidity, it is caused by the gas phase and the flow non-uniformity. The inside of the processing chamber 2 is filled with the molten metal M in a state where the molten metal thin film to be cut is effectively prevented.

  The surface to be processed of the semiconductor wafer K in the processing chamber 2 is completely covered with the molten metal M, in other words, until the liquid level of the molten metal M is located above the upper end of the surface to be processed. Then, the operation of the supply pump 19 is stopped (see FIG. 8). It should be noted that during the period from the start of supply of the molten metal M to the stop of supply, the vibration energy on the liquid surface of the molten metal M is kept constant, and the sliding effect and contact angle between the surface to be processed of the semiconductor wafer K and the molten metal M are maintained. In order to obtain a sufficient reduction effect, it is preferable to gradually increase the voltage applied to the high-frequency vibrator 51 over time, that is, gradually increase the output of the high-frequency vibration.

  In the metal filling apparatus 1 of the present example, the molten metal M is supplied from the lower side of the processing chamber 2 and is gradually filled from the lower side of the processing chamber 2. Even if there is a residual gas component, the residual gas component is collected above the liquid surface of the molten metal M. And after providing the buffer part 12a and trapping a residual gas component in the said buffer part 12a, the to-be-processed surface of the semiconductor wafer K in the process chamber 2 is covered with the molten metal M, It is prevented that the space | gap consisting of a residual gas component contacts a to-be-processed surface. Further, as described above, since the fluidity of the molten metal M is ensured, it is difficult for the molten metal thin film to be broken.

  Thereafter, as shown in FIG. 9, the piston P is moved toward the semiconductor wafer K to a predetermined position by the advance / retreat mechanism 6. At this time, excess molten metal M in the processing chamber 2 is pushed back to the storage tank 16 while the molten metal M is appropriately pressurized by the flow rate control function of the control valve 18 or the pressure control function of the supply pump 19. At the same time, the molten metal M is pressurized and filled in the minute space.

  Then, it cools until the temperature of the molten metal M with which it filled in micro space becomes below melting | fusing point, and waits until the molten metal M cools and hardens | cures. Then, after the molten metal M is cured, as shown in FIG. 10, the holding table H is moved rightward by the moving mechanism 5 to open the processing chamber 2, and the semiconductor wafer K is removed from the holding part of the holding table H. .

  Then, when the apparatus is stopped after repeating the above metal filling operation, the control valve 58 is opened, and the molten metal M staying in the vibration chamber 32 in the recovery tank 56 whose inside is appropriately depressurized by a vacuum pump. Recover. By doing in this way, it can prevent that the molten metal M which stayed and deteriorated in the vibration chamber 32 at the next driving | operation is mixed in the newly supplied molten metal M, and also the vibration chamber 32 It is possible to prevent the molten metal M staying inside from being hardened and hindering the operation of the horn 40.

  Thus, according to the metal filling apparatus 1 of this example, since the molten metal M supplied into the processing chamber 2 is directly vibrated, the dissolved gas in the molten metal M is reduced as much as possible. The amount of gas that is supplied into the processing chamber 2 together with the molten metal M can be reduced. Further, by giving vibration to the molten metal M, the solid metal crystal or metal film in the molten metal M can be pulverized into fine particles, and between the surface to be processed of the semiconductor wafer K and the molten metal M. Since the sliding effect and the contact angle reduction effect can be obtained, the fluidity of the molten metal M can be secured and the film breakage caused by the non-uniform flow of the molten metal M can be prevented. The occurrence of defects can be suppressed.

  Further, in the metal filling apparatus 1 of this example, vibration is directly applied to the molten metal M supplied into the processing chamber 2. Therefore, for example, the apparatus configuration can be simplified as compared with the case where vibration is applied to the entire apparatus or vibration is applied to the substrate, and sufficient vibration can be obtained with less energy. Can be added to the molten metal M, and the effect produced by the addition of the vibration can be sufficiently obtained. In addition, when the entire apparatus is vibrated or the substrate is vibrated, the portion corresponding to the vibration node does not vibrate, and thus there is a problem that vibration is not added to the molten metal M in the portion. In the filling device 1, it is possible to reliably add vibration to the molten metal M without such a problem.

  As mentioned above, although one Embodiment of this invention was described, the specific aspect which this invention can take is not limited to this at all.

  For example, in the above example, the vibration device 30 is disposed between the piping 17a and the piping 17b that are liquid passages, and the molten metal M vibrates directly while flowing from the storage tank 16 into the processing chamber 2. However, instead of the vibration device 30, a vibration device that directly applies vibration to the molten metal M in the storage tank 16 may be provided. Even if it does in this way, there exists a suitable effect similarly to the above. In this case, the piping between the storage tank 16 and the processing chamber 2 is shortened as much as possible in order to prevent the added vibration from being attenuated and transmitted to the molten metal M in the processing chamber 2. Is preferred.

  Further, in addition to the vibration device 30 (first vibration device), a vibration device (second vibration device) that applies vibration to the molten metal M in the storage tank 16 may be further provided. In this way, the dissolved gas in the molten metal M in the storage tank 16 can be removed in advance, and the dissolved gas in the molten metal M supplied into the processing chamber 2 can be reduced to an infinite extent. it can. Moreover, the solid metal crystal in the molten metal M stored in the storage tank 16 can be pulverized in advance to fine particles, and the fluidity of the molten metal M can be more easily ensured.

  In the above example, as a preferred embodiment, in the vibration chamber 32, the molten metal M supplied into the processing chamber 2 is aligned with the flowing direction of the molten metal M into the processing chamber 2. Although the vibration is added, the vibration is not necessarily required along the direction of flow to the processing chamber 2. Specifically, when the vibration propagates to the inside of the processing chamber 2 due to reasons such as the length of the pipe being short, the vibration does not have to be along the direction of flowing into the processing chamber 2.

  Furthermore, in the above example, the configuration is such that excess molten metal M in the processing chamber 2 is pushed back to the storage tank 16, but the control valve 58 is a control valve with a flow rate control function, and the molten metal M is appropriately pressurized. You may make it collect | recover the excess molten metal M to the collection | recovery tank 56 with the state kept.

  In the metal filling apparatus 1, the piston P is moved toward the semiconductor wafer K so as to press the molten metal in the processing chamber 2. However, the mechanism for pressing the molten metal M is limited to this. It is not something that can be done. For example, when it is not necessary to push back or discharge excess molten metal M, the control valve 18 is closed and the piston P is fixed so as not to move, and then pressurized gas is supplied into the processing chamber 2. A mechanism that pressurizes the molten metal M with a pressurized gas can be used.

  Furthermore, in this example, the semiconductor wafer K is configured to be held in a state where the surface to be processed is inclined by 90 ° with respect to the horizontal direction, but the inclination angle of the surface to be processed with respect to the horizontal direction is not necessarily limited to 90 °. It is not something that can be done. That is, when the molten metal is supplied into the processing chamber, the molten metal fluidity, the surface property of the object to be processed, the surface property of the piston P, etc. are gradually filled with the molten metal from below the processing chamber. Accordingly, a predetermined angle may be set as appropriate. This will be described below using a metal filling device 60 according to another embodiment shown in FIG. 11 as an example.

  As shown in FIG. 11, the metal filling device 60 includes a holding base H ′ that holds the semiconductor wafer K in a state in which the surface to be processed is inclined by an angle θ with respect to the horizontal direction, and a space is formed therein. A cylindrical housing C ′ having one end face opposed to the holding table H ′, and a piston P provided so as to be movable back and forth with respect to the surface to be processed of the semiconductor wafer K held by the holding table H ′. And a moving mechanism (not shown) for moving the holding base H ′ toward and away from the housing C ′ and an advancing / retreating mechanism (not shown) for moving the piston P ′ back and forth, and is held by the holding base H ′. An airtight processing chamber 62 is formed by the semiconductor wafer K, the housing C ′, and the piston P ′.

  In the metal filling device 60, an airtight seal 67 is interposed between the outer peripheral surface of the piston P ′ and the housing C ′, and the space between both is sealed by the airtight seal 67.

  Further, similarly to the metal filling device 1, the metal filling device 60 includes a decompression mechanism 70 that depressurizes the inside of the processing chamber 62, a molten metal supply mechanism 75 that supplies the molten metal M into the processing chamber 62, and a removal of the molten metal M. A deaeration mechanism (not shown) for performing gas, a vibration mechanism 80 for applying high-frequency vibration to the molten metal M supplied into the processing chamber 62, and a control device (not shown) for controlling the operation of each mechanism. ing.

  The pressure reducing mechanism 70 includes a vacuum pump 71, a pipe 72 having a buffer portion 72a formed therein, and a control valve 73. The pressure reducing mechanism 70 has substantially the same configuration as the pressure reducing mechanism 10 in the metal filling apparatus 1, but the pipe 72 has a housing C ′. It is provided so as to penetrate the side wall on the other end side.

  Also, the molten metal supply mechanism 75 has substantially the same configuration as the molten metal supply mechanism 15 in the metal filling device 1, and includes a storage tank 76, pipes 77 a and 77 b, a control valve 78, and a supply pump 79. The pipe 77a is provided so as to penetrate the side wall on one end side of the housing C ′, and the opening of the pipe 72 on the processing chamber 62 side is above the opening of the pipe 77a and of the processing chamber 62. It is located further above the top.

  The vibration mechanism 80 also has substantially the same configuration as the vibration mechanism 30 in the metal filling device 1, and includes a vibration unit 81 having a vibration chamber 82 formed therein, a horn 90, a booster, a high-frequency vibrator, and the like. And a recovery mechanism 95 that recovers the molten metal M staying in the vibration chamber 82, and the pipes 77 a and 77 b penetrate the first and second penetrations of the vibration portion 81. Connected to the hole.

  Next, the process of supplying the molten metal M into the processing chamber 62 in the metal filling device 60 will be described with reference to FIGS.

  According to this metal filling device 60, like the metal filling device 1, after forming the processing chamber 62 with the semiconductor wafer K held on the holding base H ′, the vacuum pump 71 is operated and the control valve 73 is opened. Then, the gas in the processing chamber 62 is exhausted, and the pressure in the processing chamber 62 and the minute space is reduced to a substantially vacuum state.

  Next, as shown in FIG. 12, the control valve 73 is closed, the control valve 78 is opened, the supply pump 79 is operated, and the supply of the molten metal M from the storage tank 76 into the processing chamber 62 is started. .

  Also in the metal filling device 60, the molten metal M supplied into the processing chamber 2 is directly subjected to high frequency vibration from the horn 90 in the vibration chamber 82. Accordingly, as described above, cavitation occurs in the molten metal M, and dissolved gas in the molten metal M is forcibly foamed and eliminated, and the molten metal is caused by the impact pressure generated by the collapse of the generated cavitation. The metal film formed in M is crushed. Furthermore, the vibration is propagated to the molten metal M, whereby the liquid level of the molten metal M vibrates, and a sliding effect and a contact angle reducing effect are obtained between the surface to be processed and the molten metal M.

  Further, since the molten metal M is supplied from the lower side of the processing chamber 62 and is gradually filled from the lower side of the processing chamber 62, the residual gas is present even if there is a residual gas component in the processing chamber 2. The component is collected above the liquid level of the molten metal M.

  Then, after supplying the molten metal M until the surface to be processed of the semiconductor wafer K in the processing chamber 62 is completely filled with the molten metal M, the control valve 78 is closed as shown in FIG. The operation of 79 is stopped.

  Thus, even if the surface to be processed is inclined by the angle θ with respect to the horizontal direction, the residual gas component is collected above the liquid surface of the molten metal M, and the entire surface to be processed can be covered with the molten metal M. In addition, since the high frequency vibration is directly applied to the molten metal M, the same effects as described above can be obtained. In order to collect the residual gas component above the liquid level of the molten metal M more reliably, the value of the angle θ is preferably set to a value within the range of 30 ° to 150 °.

DESCRIPTION OF SYMBOLS 1 Metal filling apparatus 2 Processing chamber 5 Movement mechanism 6 Advance / retreat mechanism 10 Decompression mechanism 11 Vacuum pump 12 Piping 13 Control valve 15 Molten metal supply mechanism 16 Storage tank 17a, 17b Piping 18 Control valve 19 Supply pump 20 Deaeration mechanism 21 Vacuum pump 22 Piping 30 Exciting mechanism 31 Exciting unit 32 Exciting chamber 33 First through hole 34 Second through hole 35 Third through hole 36, 37, 38 Fitting 40 Horn 40a Vibrating unit 40b Horn body 40c Flange unit 41, 42 Seal Member 50 Drive device 51 High frequency vibrator 52 Booster 55 Recovery mechanism 56 Recovery tank 57 Piping 58 Control valve H Holding stand C Housing P Piston

Claims (15)

A metal filling device for filling molten metal supplied onto the surface of the object to be processed in a minute space formed so as to open on the surface of the object,
A processing unit main body comprising a holding unit for holding the object to be processed, and a processing chamber formed facing the surface of the object to be processed held by the holding unit;
A pressure reducing mechanism that includes an air passage having one end opened in the inner wall surface of the processing chamber, and that decompresses the processing chamber through the air passage;
A liquid flow path having one end opened to the inner wall surface of the processing chamber, and a storage tank that is connected to the other end of the liquid flow path and stores a molten metal are provided, and the treatment is performed via the liquid flow path. A molten metal supply mechanism for supplying molten metal into the room;
At least one excitation mechanism for applying high-frequency vibration to the molten metal;
A pressurizing mechanism for pressurizing the molten metal supplied into the processing chamber,
The molten metal supply mechanism is configured to supply molten metal, to which high-frequency vibration is added by the vibration mechanism, into a processing chamber.   2. The vibration mechanism is configured to directly apply high-frequency vibration in the same direction as the direction of the molten metal flowing from the storage tank to the processing chamber to the molten metal. Metal filling equipment.   The vibration mechanism is disposed between one end side and the other end side of the liquid flow path, and directly applies high-frequency vibration to the molten metal that flows through the liquid flow path and is supplied into the processing chamber. 3. The metal filling device according to claim 1, wherein the metal filling device is configured to be added. The vibration mechanism is
Inside, a vibration unit having a vibration chamber formed to communicate with the outside,
A horn disposed such that a tip portion is located in the vibration chamber;
A vibrator that vibrates the horn,
The vibration unit is disposed between one end side and the other end side in the liquid flow path so that the storage tank and the processing chamber communicate with each other via the vibration chamber.
4. The metal filling apparatus according to claim 3, wherein high-frequency vibration is directly added to the molten metal flowing through the vibration chamber through a horn.   The metal filling device according to claim 1, wherein the excitation mechanism is configured to directly apply high-frequency vibration to the molten metal in the storage tank. A first vibration mechanism and a second vibration mechanism;
The first vibration mechanism is disposed between one end side and the other end side of the liquid passage, and the high-frequency vibration is supplied to the molten metal that flows through the liquid passage and is supplied into the processing chamber. Is configured to add directly,
3. The metal filling device according to claim 1, wherein the second vibration mechanism is configured to directly apply high-frequency vibration to the molten metal in the storage tank. The first vibration mechanism is
Inside, a vibration unit having a vibration chamber formed to communicate with the outside,
A horn disposed such that a tip portion is located in the vibration chamber;
A vibrator that vibrates the horn,
The vibration unit is disposed between one end side and the other end side in the liquid flow path so that the storage tank and the processing chamber communicate with each other via the vibration chamber.
7. The metal filling apparatus according to claim 6, wherein high-frequency vibration is directly applied to the molten metal flowing in the vibration chamber through a horn.   The metal filling apparatus according to claim 4 or 7, wherein a direction of high-frequency vibration added to the molten metal flowing in the vibration chamber is coincident with a direction from the vibration chamber toward the processing chamber.   The metal filling apparatus according to claim 4, 7 or 8, further comprising a recovery mechanism for recovering molten metal in the vibration chamber. The holding unit is configured to hold the object to be processed such that a surface of the object to be processed is inclined with respect to a horizontal direction.
The air passage is opened at a height position above the uppermost end of the surface to be processed of the workpiece and above the opening of the liquid passage. Any of the metal filling devices described.   The metal filling apparatus according to claim 10, wherein an inclination angle of the surface to be processed with respect to the horizontal direction is 30 ° to 150 °. A processing unit main body including a processing chamber formed facing the surface of the object to be processed held in the holding unit;
A decompression mechanism for decompressing the processing chamber;
A molten metal supply mechanism for supplying the molten metal stored in the storage tank into the processing chamber via a liquid passage;
An excitation mechanism for applying high-frequency vibration to the molten metal;
Using a metal filling device provided with a pressurizing mechanism for pressurizing the molten metal supplied into the processing chamber,
A metal filling method of filling molten metal supplied onto the surface of the object to be processed in a minute space formed to open on the surface of the object to be processed,
A decompression step of decompressing the processing chamber;
A molten metal supply step of supplying the molten metal in the storage tank into the processing chamber via the liquid passage;
Performing a pressurizing step of pressurizing the molten metal supplied into the processing chamber;
In the molten metal supply step, the molten metal to which high-frequency vibration is added by the vibration mechanism is supplied into a processing chamber through the liquid passage.   In the molten metal supply step, the molten metal to which the high-frequency vibration in the same direction as the molten metal flows from the storage tank to the processing chamber is directly added so that the high-frequency vibration is propagated to the molten metal in the processing chamber. 13. The metal filling method according to claim 12, wherein the metal is supplied into the processing chamber through a liquid path.   The metal filling method according to claim 12 or 13, wherein, in the molten metal supply step, the molten metal is supplied into the processing chamber so that the molten metal is filled from below the processing chamber. The metal filling method according to any one of claims 12 to 14, wherein, in the molten metal supply step, the output of high-frequency vibration added to the molten metal is increased with time.

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