JP2012146802A - Method and apparatus for filling metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress filling defects of a metal filling a through hole of a substrate.SOLUTION: A method for filling a through hole 110, penetrating between an upper surface 101 and a lower surface 102 of a substrate 100, with a metal 120 includes: a process S40 in which a molten metal 31 is supplied to the upper surface 101; and processes S30 and S50 in which the through hole 110 is filled with the molten metal 31 by relatively lowering a pressure around an opening of the through hole 110 in the lower surface 102 than a pressure around the molten metal 31 supplied to the upper surface 101.

Description

  The present invention relates to a metal filling method and a metal filling apparatus for filling a through hole of a substrate with metal.

  A technique is known in which, after a silicon substrate having fine holes is immersed in a molten metal tank in a vacuum chamber that has been depressurized, the inside of the vacuum chamber is pressurized to fill the fine holes with molten metal (for example, Patent Document 1).

JP 2002-158191 A

  When the fine hole penetrates the substrate, the molten metal enters from both sides of the fine hole, so that a void is likely to occur near the center of the fine hole, and the metal is divided in the through hole, resulting in poor electrical reliability. There was a case.

  The problem to be solved by the present invention is to suppress poor filling of the metal into the through hole of the substrate.

  [1] A metal filling method according to the present invention is a method of filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate, wherein molten metal is applied to the first surface. Supplying the molten metal into the through hole by lowering the pressure around the opening of the through hole on the second surface relatively lower than the pressure around the molten metal. And a process.

  [2] A metal filling method according to the present invention is a method of filling a through hole penetrating between a first surface and a second surface of a substrate, and the through hole in the second surface. And a second step of immersing the substrate in molten metal in a state where the filling space is depressurized, and a first step of forming a filling space that is communicated with the opening and reduced in pressure relative to the atmospheric pressure. And a third step of pressurizing the molten metal and filling the through-hole with the molten metal while the substrate is immersed in the molten metal, and the first step comprises: It is characterized by decompressing the filling space after forming the filling space, or forming the filling space in a reduced pressure atmosphere.

  [3] In the above invention, the first step may include interposing a lattice-like member between the through hole and the filling space.

  [4] A metal filling method according to the present invention is a method of filling a through hole penetrating between a first surface and a second surface of a substrate, and the through hole in the second surface. A first step of forming a filling space adjacent to the opening of the substrate through a flexible film and having a reduced pressure compared to the atmospheric pressure; A second step of immersing, and a third step of filling the molten metal into the through-hole by pressurizing the molten metal in a state where the substrate is immersed in the molten metal, The first step includes forming the filling space in a reduced-pressure atmosphere.

  [5] In the above invention, the filling space may include a plurality of compartments partitioned from each other.

  [6] In the above invention, the third step may include exhausting the filling space.

  [7] A metal filling device according to the present invention is a device for filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate, and the molten metal is applied to the first surface. The molten metal is filled in the through hole by supplying the supply means and the pressure around the opening of the through hole on the second surface relatively lower than the pressure around the molten metal. And a differential pressure generating means.

  [8] A metal filling apparatus according to the present invention is an apparatus for filling a through hole penetrating between a first surface and a second surface of a substrate, and the through hole in the second surface. And a holding jig for holding the substrate, a metal melting tank in which a molten metal into which the substrate is immersed is stored, the holding jig, A chamber in which the metal melting tank is disposed; a transport unit that moves the holding jig in the chamber to immerse the substrate in the molten metal; a decompression unit that decompresses the chamber; and the chamber And pressurizing means for pressurizing the inside.

  [9] In the above invention, the holding jig may include a lattice-like member interposed between the through hole and the filling space.

[10] A metal filling device according to the present invention is a device for filling metal into a through hole penetrating between a first surface and a second surface of a substrate, and the through hole in the second surface. A holding jig for holding the substrate, and a holding jig for holding the substrate via the flexible film. Mounting means to be mounted on, a metal melting tank in which a molten metal into which the substrate is immersed is stored, the holding jig, the mounting means, a chamber in which the metal melting tank is disposed, and the holding jig. A conveying means for moving a tool in the chamber to immerse the substrate in the molten metal; a depressurizing means for depressurizing the interior of the chamber; and a pressurizing means for pressurizing the interior of the chamber. To do.
[11] In the above invention, the holding jig may have a partition wall that partitions the filling space into a plurality of partition chambers.
[12] In the above invention, the metal filling device may further include exhaust means for exhausting the inside of the filling space.

  According to the present invention, the pressure around the opening of the through-hole in the second surface is relatively lower than the pressure around the molten metal supplied on the first surface, so that the through-hole is melted. Since the metal is filled, the poor filling of the metal into the through hole of the substrate can be suppressed.

  Further, according to the present invention, the molten metal supplied to the first surface in a state where the space for filling around the opening of the through hole in the second surface is depressurized is pressurized to the molten metal in the through hole. Therefore, the filling failure of the metal into the through hole of the substrate can be suppressed.

FIG. 1A is a plan view showing a substrate in which a metal is filled in a through hole in the first embodiment of the present invention, and FIG. 1B is a IB-IB line in FIG. FIG. FIG. 2 is a cross-sectional view showing the overall configuration of the metal filling apparatus according to the first embodiment of the present invention. FIG. 3 is a view showing a molten metal supply apparatus that can be used in place of the crucible in the first embodiment of the present invention. FIG. 4A is a plan view showing the holding jig in the first embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the line IVB-IVB in FIG. FIG. 5 is a flowchart showing a metal filling method according to the first embodiment of the present invention. FIGS. 6A to 6C are cross-sectional views showing the steps in FIG. FIG. 7 is a cross-sectional view showing a modification of step S60 in FIG. FIG. 8A is a plan view showing a holding jig in the second embodiment of the present invention, and FIG. 8B is a cross-sectional view taken along the line VIIIB-VIIIB in FIG. FIG. 9 is a cross-sectional view showing a holding jig in the third embodiment of the present invention. FIG. 10 is a cross-sectional view showing the overall configuration of the metal filling apparatus according to the fourth embodiment of the present invention. FIG. 11 is a flowchart showing a metal filling method according to the fourth embodiment of the present invention. 12A to 12D are cross-sectional views showing the steps of FIG. FIG. 13 is a cross-sectional view showing a holding jig in the fifth embodiment of the present invention. FIG. 14 is a flowchart showing a modification of the metal filling method according to the fifth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< first embodiment >>
First, a substrate having a through hole filled with metal by a metal filling apparatus and a metal filling method according to the present embodiment will be described with reference to FIGS. 1 (A) and 1 (B). FIG. 1A and FIG. 1B are a plan view and a cross-sectional view showing a substrate in which a metal is filled in a through hole in this embodiment.

  As shown in FIGS. 1A and 1B, a large number of through holes 110 are formed in the substrate 100 in this embodiment. Then, by filling each through hole 110 with metal 120, for example, it is used as an interposer having a high aspect ratio through electrode. Note that the use of the substrate 100 is not limited to the interposer, but can be widely used for wiring of electronic devices and optical devices, structures of MEMS (Micro Electro Mechanical Systems) devices, and the like.

  The substrate 100 is a plate-like member made of a material excellent in heat resistance that is insoluble at the melting temperature of the molten metal 31 described later. Specific examples of the material constituting the substrate 100 include semiconductors such as silicon and gallium arsenide (GaAs), glass, ceramics, polytetrafluoroethylene, polyimide, and the like. In addition, although the board | substrate 100 in this embodiment has a single layer structure, it is not limited to this in particular, The board | substrate 100 is good also as a multilayer structure.

  The through hole 110 in the present embodiment penetrates between the upper surface 101 and the lower surface 102 of the substrate 100 and is bent in a crank shape in the substrate 100. Such through-holes 110 are formed by photoexcited electrolytic polishing, DRIE (Deep-Reactive Ion Etching) represented by ICP-RIE (Inductively Coupled Plasma-Reactive Ion Etching), wet etching using an etching solution, or microdrill. It can be formed by a machining method or the like.

  The photoexcited electrolytic polishing method is, for example, as described in JP-A-2003-347272, after forming a recess in one surface of a substrate by anisotropic etching in advance, In this method, a through hole is formed in the substrate by immersing the substrate and applying a current between the substrate and the cathode electrode while irradiating the other surface of the substrate with light.

  The shape of the through hole 110 is not limited to the crank shape, and may be, for example, a straight through hole or may be branched into a plurality of portions in the substrate 100. Further, the through hole 110 illustrated in FIG. 1B penetrates between the upper surface 101 and the lower surface 102 of the substrate 100, but is not particularly limited thereto. For example, the through hole may penetrate between the upper surface 101 and the side surface 103 of the substrate 100. Further, in FIG. 1A, 16 through holes 110 are arranged in a matrix in the substrate 100, but the number and arrangement of the through holes 110 are not particularly limited thereto. Note that the upper surface 101 in the present embodiment corresponds to an example of the first surface in the present invention, and the lower surface 102 and the side surface 103 in the present embodiment correspond to an example of the second surface in the present invention.

  Examples of the metal 120 filled in the through hole 110 include metals such as gold tin (AuSn), tin (Sn), and indium (In), or tin-lead (Sn—Pb), tin (Sn). Examples thereof include a solder of a group, a lead (Pb) group, a gold (Au) group, an indium (In) group, or an aluminum (Al) group.

  Next, the metal filling apparatus 1 that fills the through hole 110 of the substrate 100 described above with the metal 120 will be described with reference to FIGS.

  FIG. 2 is a cross-sectional view showing the overall configuration of the metal filling apparatus in the present embodiment. FIG. 3 is a view showing a molten metal supply apparatus that can be used in place of the crucible 30 in the present embodiment. 4B is a plan view and a cross-sectional view showing the holding jig in the present embodiment.

  As shown in FIG. 2, the metal filling device 1 according to the present embodiment includes a first chamber 10, a second chamber 20, a crucible 30, a transfer arm 40, and a holding jig 50. .

  The first chamber 10 is connected to a vacuum pump device 15 via a first pressure reducing pipe 12 having a first pressure reducing valve 11. The first chamber 10 is connected to a pressurized gas supply device 16 via a first pressurizing pipe 14 having a first pressurizing valve 13. In addition, as pressurized gas, inert gas, such as nitrogen gas, can be used, for example. Moreover, as an example of the pressurized gas supply apparatus 16, a nitrogen cylinder etc. can be illustrated, for example.

  Further, the first chamber 10 is provided with a hinge-type opening / closing lid 17 for carrying the substrate 100 into and out of the chamber 10. By opening the opening / closing lid 17, the substrate 100 can be carried into and out of the metal filling device 1. A heating device 18 for heating the substrate 100 is provided in the first chamber 10. As the heating device 18, for example, a heater or an infrared heating device can be used.

  Similarly, the second chamber 20 is connected to the vacuum pump 15 via a second pressure-reducing pipe 22 having a second pressure-reducing valve 21, and has a second pressure-increasing valve 23. The pressurized gas supply device 16 is connected via a pressurizing pipe 24.

  An opening 26 that can be opened and closed by a shutter 25 is formed between the first chamber 10 and the second chamber 20. The two chambers 10 and 20 can communicate with each other through the opening 26.

  In addition, the 1st and 2nd chambers 10 and 20, the vacuum pump 15, and the pressurized gas supply apparatus 16 in this embodiment are equivalent to an example of the differential pressure | voltage generating means in this invention. In addition, the first and second chambers 10 and 20 in the present embodiment correspond to an example of the chamber in the present invention, and the vacuum pump 15 in the present embodiment corresponds to an example of the decompression unit in the present invention. The pressurized gas supply device 16 corresponds to an example of a pressurizing unit in the present invention.

  A crucible 30 is provided in the second chamber 20. Inside the crucible 30, a molten metal 31 filling the through hole 110 of the substrate 100 is stored. A heater 32 for heating and melting the metal 31 is provided on the outer periphery of the crucible 30. The molten metal 31 filled in the through hole 110 is cured, whereby the above-described metal 120 is formed.

  Instead of the crucible 30, a molten metal supply device 80 as shown in FIG. 3 may be provided in the second chamber 20. The molten metal supply device 80 includes a metal melting part 81 that melts the metal 31, and a molten metal supply pipe 82 that guides the molten metal 31 from the metal melting part 81 and supplies the molten metal 31 onto the upper surface 101 of the substrate 100. Yes. Although not particularly shown, an auxiliary heating device for heating and melting the metal is provided on the outer peripheral portion of the metal melting portion 81. By using such a molten metal supply device 80 instead of the crucible 30, the amount of the molten metal 31 used can be reduced.

  The crucible 30 and the molten metal supply device 80 in the present embodiment correspond to an example of the supply means in the present invention, and the crucible 30 in the present embodiment corresponds to an example of the molten metal layer in the present invention.

  As shown in FIG. 2, the transfer arm 40 has a clamp 41 that holds a holding jig 50 that holds the substrate 100, and the holding jig 50 is three-dimensionally inside the first and second chambers 10 and 20. The clamp 41 can be tilted by rotating the joint 42. The transfer arm 40 immerses the substrate 100 in the molten metal 31 in the crucible 30 by putting the holding jig 50 into the crucible 30.

  As shown in FIGS. 4A and 4B, the holding jig 50 includes a main body portion 51 having a cylindrical side surface 511 and a bottom surface 512, and a partition wall provided upright on the bottom surface 512 of the main body portion 51. 52. The partition wall 52 is formed in an annular shape having an inner diameter slightly smaller than that of the substrate 100.

  When the substrate 100 is placed on the holding jig 50, all the through holes 110 of the substrate 100 are included inside the annular partition wall 52 (see FIG. 4A), and the upper surface 521 of the partition wall 52 is the substrate 100. A closed space 53 is formed between the holding jig 50 and the substrate 100. The sealed space 53 is defined by the lower surface 102 of the substrate 100, the partition wall 52 of the holding jig 50, and the bottom surface 512 of the holding jig 50, except that it is in communication with the through hole 110 of the substrate 100. It is a sealed space (room). The sealed space 53 in the present embodiment corresponds to an example of a filling space in the present invention.

  Next, the metal filling method in the present embodiment will be described with reference to FIGS.

  FIG. 5 is a flowchart showing a metal filling method according to the present embodiment, FIGS. 6A to 6C are cross-sectional views showing steps in FIG. 5, and FIG. 7 is a cross-sectional view showing a modification of step S60 in FIG. FIG. 6A shows step S10 in FIG. 5, FIG. 6B shows step S40 in FIG. 5, and FIG. 6C shows step S50 in FIG.

  First, in step S10 of FIG. 5, the substrate 100 is mounted on the holding jig 50 via the opening / closing lid 17 of the first chamber 10 as shown in FIG. 6A. At this time, the partition wall 52 comes into contact with the lower surface 102 of the substrate 100, thereby forming a sealed space 53 communicating with the through hole 110. The sealed space 53 communicates with the outside (the inside of the first chamber 10) only through the through hole 110.

  In step S <b> 10, the substrate 100 is carried into the first chamber 10 via the opening / closing lid 17 with the opening 26 closed by the shutter 25 so that the second chamber 20 is not directly exposed to the atmosphere.

  In addition, when it takes time to depressurize the first chamber 10 to be described later, for example, the holding jig is used in a state where the inside of the first chamber 10 is depressurized using the mounting arm 70 described in the fourth embodiment. The substrate 100 may be mounted on 50.

  Next, in step S <b> 20, after closing the opening / closing lid 17 and sealing the inside of the first chamber 10, the substrate 100 is heated to a predetermined temperature by the heating device 18.

  When the temperature difference between the molten metal 31 in the crucible 30 and the substrate 100 is large, the molten metal 31 may be hardened when contacting the substrate 100. On the other hand, in this embodiment, before the substrate 100 is immersed in the molten metal 31, the substrate 100 is preheated by the heating device 18 to prevent the molten metal 31 from being cured when the substrate 100 is immersed. Can do.

  If the temperature difference between the molten metal 31 and the substrate 100 is not large, the heating device 18 may be omitted and step S20 may be omitted.

  Next, in step S30, the first pressure reducing valve 11 is opened, and the inside of the first chamber 10 is roughly evacuated by the vacuum pump 15 via the first pressure reducing pipe 12.

Next, after the shutter 25 is opened and the first chamber 10 and the second chamber 20 are communicated with each other through the opening 26, the second decompression valve 21 is opened, and the first and second chambers 10 are opened. , 20 is vacuumed by the vacuum pump 15 via the second decompression pipe 22 to reduce the vacuum pressure to about 10 ⁻² to 10 ⁻³ [Pa]. Due to this decompression, the inside of the sealed space 53 is also decompressed through the through hole 110.

  The pressure at the time of depressurization in step S30 is not particularly limited to the above value as long as it is a pressure relatively lower than the atmospheric pressure. Moreover, step S20 and step S30 mentioned above may be performed simultaneously, and step S30 may be performed prior to step S20.

  Next, in step S <b> 40, as shown in FIG. 6B, the holding jig 50 on which the substrate 100 is mounted is moved to the crucible 30 by the transfer arm 40, and the substrate 100 is immersed in the molten metal 31.

  In addition, since the internal diameter of the through-hole 110 of the board | substrate 100 is small, only the board | substrate 100 was immersed in the molten metal 31 with the surface tension of the molten metal 31, and the interface tension of the molten metal 31 and the through-hole 110 (state of step S40) ), The molten metal 31 does not enter the through hole 110.

Next, in step S50, as shown in FIG. 6C, the first and second pressurization valves 13 and 23 are opened while the substrate 100 is immersed in the molten metal 31, and the pressurized gas supply device is opened. The pressurized gas is introduced into the first and second chambers 10 and 20 through the first and second pressurizing pipes 14 and 24 from the first and second chambers 10 and 20, and the inside of the first and second chambers 10 and 20 is The pressure is increased to about 5 × 10 ⁵ [Pa].

  In addition, the pressure at the time of pressurization in this step S50 will not be specifically limited if it is a pressure relatively higher than the pressure at the time of pressure reduction in said step S30.

  This pressurization causes a pressure difference between the inside of the first and second chambers 10 and 20 and the inside of the sealed space 53, so that the molten metal 31 is pushed into the through hole 110 as shown in FIG. The molten metal 31 is filled in the through hole 110.

  When the molten metal 31 is difficult to enter the through hole 110, a metal film may be formed on the opening periphery of the through hole 110 to reduce the interfacial tension between the molten metal 31 and the through 110.

  Next, in step S <b> 60, the substrate 100 is pulled up from the molten metal 31 by the transfer arm 40 and the substrate 100 is air-cooled, whereby the metal filling operation into the through hole 110 is completed. In this embodiment, in this embodiment, the holding jig 50 is pulled up from the molten metal 31 with the clamp 41 of the transfer arm 40 inclined. Thereby, the residue of the molten metal 31 on the substrate 100 can be removed.

  As shown in FIG. 7, a squeegee 90 may be provided in the vicinity of the crucible 30 and residues on the substrate 100 may be removed by the squeegee 90.

  As described above, in this embodiment, the pressure around the opening of the through hole 110 on the lower surface 102 of the substrate 100 is relatively lower than the pressure around the molten metal 31 supplied on the upper surface 101 of the substrate 100. By doing so, the molten metal 31 is filled in the through hole 110. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent a void (filling failure) from occurring in the through hole 110, and the metal in the through hole 110. 120 is not divided and has excellent electrical reliability.

  In the present embodiment, the substrate 100 is immersed in the molten metal 31 in a state where the sealed space 53 communicating with the through hole 110 is decompressed, and the molten metal 31 is pressurized in this state. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

<< Second Embodiment >>
FIGS. 8A and 8B are a plan view and a cross-sectional view showing a holding jig according to the second embodiment of the present invention. In the present embodiment, the configuration of the holding jig 50B is different from that of the first embodiment, but other configurations are the same as those of the first embodiment. In the following, the second embodiment will be described only with respect to differences from the first embodiment, and the same reference numerals will be given to portions having the same configuration as the first embodiment, and description thereof will be omitted.

  As shown in FIGS. 8A and 8B, the holding jig 50B in the present embodiment includes a plurality of regions surrounded by the annular partition wall 52 as compared with the holding jig 50 in the first embodiment. It has the partition wall 54 partitioned into. The partition wall 54 has substantially the same height as the partition wall 52 as shown in FIG. Further, the partition wall 54 has a cross shape in a plan view, and divides the inside of the annular partition wall 52 into four.

  In the present embodiment, when the substrate 100 is mounted on the holding jig 50B, the upper surface 521 of the partition wall 52 comes into contact with the lower surface 102 of the substrate 100 as in the first embodiment, and the holding jig 50B and the substrate 100 are separated. A sealed space 53 is formed therebetween. At this time, in this embodiment, since the upper surface 541 of the partition wall 54 also contacts the lower surface 102 of the substrate 100, the sealed space 53 is partitioned into four partition chambers 55 by the partition wall 54. Four through-holes 110 are assigned to each.

  Here, if there is a large difference in the flow resistance of the molten metal 31 between the plurality of through holes 110, the molten metal 31 is preferentially filled into some of the through holes 110 having a low flow resistance, and the through holes 110. In some cases, the sealed space 53 is filled with the molten metal 31 and the remaining through-holes 110 are not filled with the molten metal 31. In such a case, as the number of through-holes communicating with the same space increases, the number of through-holes 110 that are not filled with the molten metal 31 increases, and the non-uniformity of metal filling among the plurality of through-holes 110 increases. growing.

  On the other hand, in the present embodiment, by dividing the sealed space 53 into a plurality of compartments 55 by the partition wall 54, the number of through holes 110 communicating with the same compartment 55 is reduced. For this reason, the filling probability of the molten metal 31 to the through hole 110 is increased, and the metal filling between the plurality of through holes 110 can be made uniform.

  In the present embodiment, the sealed space 53 is divided into four compartments 55 by the partition walls 54, but the shape of the partition walls 54 and the number of the compartments 55 are not particularly limited thereto. As the number of compartments 55 is increased, the metal filling between the plurality of through holes 110 is more uniform.

  In the present embodiment, as in the first embodiment, the pressure around the opening of the through hole 110 in the lower surface 102 of the substrate 100 is more relative to the pressure around the molten metal 31 supplied on the upper surface 101 of the substrate 100. By making it low, the molten metal 31 is filled in the through hole 110. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

  In the present embodiment, similarly to the first embodiment, the substrate 100 is immersed in the molten metal 31 in a state where the sealed space 53 communicating with the through hole 110 is decompressed, and the molten metal 31 is pressurized in this state. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

<< Third Embodiment >>
FIG. 9 is a sectional view showing a holding jig in the third embodiment of the present invention. In the present embodiment, the configuration of the holding jig 50C is different from that of the second embodiment, but other configurations are the same as those of the second embodiment. In the following, the third embodiment will be described only with respect to differences from the second embodiment, and the same reference numerals will be given to portions having the same configuration as the second embodiment, and description thereof will be omitted.

  As shown in FIG. 9, the holding jig 50 </ b> C in this embodiment has a filter 56 extending between the upper part of the partition wall 52 and the upper part of the partition wall 54, as compared with the holding jig 50 </ b> B in the second embodiment. The upper opening of each compartment 54 is covered with a filter 56.

  The filter 56 is a lattice-like member obtained by processing a metal foil such as an aluminum foil, a titanium foil, or a stainless steel foil into a mesh shape by a photolithography technique. The mesh size of the filter 56 is preferably smaller than the opening of the through hole 110 of the substrate 100. As a result, the gas can pass through the filter 56, but the molten metal 31 cannot pass through the filter 56 due to the surface tension. The filter 56 in the present embodiment corresponds to an example of a grid member in the present invention.

  In the present embodiment, when the substrate 100 is mounted on the holding jig 50C, a plurality of (four in this example) are provided between the holding jig 50C and the substrate 100 by the partition wall 52 and the partition wall 54, as in the second embodiment. ) Compartments 55 are formed. At this time, in this embodiment, the filter 56 is interposed between the opening of the through hole 110 in the lower surface 102 of the substrate 100 and each compartment 55.

  Here, as described above, if there is a large difference in the flow resistance of the molten metal 31 between the plurality of through holes 110, the molten metal 31 may not be filled in some of the through holes 110.

  On the other hand, in this embodiment, since the sealed space 53 is divided into a plurality of compartments 55 by the partition wall 54 as in the second embodiment, the metal filling is uniform between the plurality of through holes 110. Can be achieved.

  Furthermore, in the present embodiment, the molten metal 31 is preferentially filled into the through hole 110 having the lowest flow resistance. When the molten metal 31 reaches the filter 56, the molten metal 31 is blocked by the filter 56. Next, the molten metal 31 is filled into the through hole 110 having a low flow resistance. Since this process is repeated until all the through holes 110 communicating with the same compartment 55 are filled with the molten metal 31, it is possible to promote uniform metal filling between the plurality of through holes 110. it can.

  Further, in the holding jig 50 </ b> C according to the present embodiment, the adhesion of the molten metal 31 to the lower surface 102 of the substrate 100 can be suppressed by the filter 56, so that post-processing can be simplified.

  In the present embodiment, as in the second embodiment, the pressure around the opening of the through-hole 110 on the lower surface 102 of the substrate 100 is more relative to the pressure around the molten metal 31 supplied on the upper surface 101 of the substrate 100. By making it low, the molten metal 31 is filled in the through hole 110. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

  In the present embodiment, similarly to the second embodiment, the substrate 100 is immersed in the molten metal 31 in a state where the sealed space 53 communicating with the through hole 110 is decompressed, and the molten metal 31 is pressurized in this state. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

  In addition, you may provide the filter 56 in this embodiment in the holding jig 50 demonstrated in 1st Embodiment.

<< Fourth embodiment >>
FIG. 10 is a cross-sectional view showing the overall configuration of the metal filling apparatus according to the fourth embodiment of the present invention. The metal filling apparatus 1D according to the present embodiment is different from the metal filling apparatus 1 according to the first embodiment in that the metal filling apparatus 1D includes a mounting arm 70 and a film 57 is interposed between the substrate 100 and the holding jig 50D. However, the other configuration is the same as that of the first embodiment. Below, difference with 1st Embodiment is demonstrated about metal filling apparatus 1D in 4th Embodiment, the same code | symbol is attached | subjected about the part similar to 1st Embodiment, and description is abbreviate | omitted. Note that the holding jig 50D in the present embodiment has the same configuration as the holding jig 50B in the second embodiment, and is a holding jig having a partition wall 54.

  In the metal filling apparatus 1 </ b> D in the present embodiment, a mounting arm 70 is provided in the first chamber 10 as shown in FIG. 10. The mounting arm 70 can hold the substrate 100 and the film 57, and can move the substrate 100 and the film 57 in the first chamber 10 three-dimensionally.

  The film 57 is a flexible film and is made of a metal material that is insoluble at the melting temperature of the molten metal 31 and has excellent heat resistance. The film 57 corresponds to an example of a flexible film in the present invention, and the mounting arm 70 in the present embodiment corresponds to an example of a mounting means in the present invention.

  Next, the metal filling method in the present embodiment will be described with reference to FIGS. 11 and 12A to 12D.

  FIG. 11 is a flowchart showing a metal filling method according to this embodiment, and FIGS. 12A to 12D are cross-sectional views showing the steps of FIG. 12A shows step S130 in FIG. 11, FIG. 12B shows step S150 in FIG. 11, and FIGS. 12C and 12D show step S160 in FIG.

  First, in step S <b> 110 of FIG. 11, the substrate 100 and the film 57 are carried into the first chamber 10 through the opening / closing lid 17. In step S110, the substrate 100 and the film 57 are carried into the first chamber 10 with the opening 26 closed by the shutter 25 so that the second chamber 20 is not directly exposed to the atmosphere.

  Next, in step S120, the first pressure reducing valve 11 is opened, and the inside of the first chamber 10 is roughly evacuated by the vacuum pump 15 via the first pressure reducing pipe 12.

Next, after the shutter 25 is opened and the first chamber 10 and the second chamber 20 are communicated with each other through the opening 26, the second decompression valve 21 is opened, and the first and second chambers 10 are opened. , 20 is vacuumed by the vacuum pump 15 via the second decompression pipe 22 to reduce the vacuum pressure to about 10 ⁻² to 10 ⁻³ [Pa].

  The pressure at the time of depressurization in step S120 is not particularly limited to the above value as long as the pressure is relatively lower than the atmospheric pressure.

  Next, in step S130, the mounting arm 70 mounts the substrate 100 and the film 57 on the holding jig 50D while the inside of the first chamber 10 is decompressed. As a result, as shown in FIG. 12A, the substrate 100 is mounted on the holding jig 50D via the film 57, and the sealed space 58 is decompressed compared to the atmospheric pressure (see FIG. 12B). Is formed between the film 57 and the holding jig 50D. The sealed space 58 is adjacent to the opening of the through hole 110 in the lower surface 102 of the substrate 100 through the film 57.

  In step S130, the mounting arm 70 may simultaneously mount the substrate 100 and the film 57 on the holding jig 50D, or after the film 57 is mounted on the holding jig 50D, the substrate is placed on the film 57. 100 may be placed.

  Next, in step S140, the holding jig 50D on which the substrate 100 is mounted is moved to the heating device 18 by the transfer arm 40, and the substrate 100 is heated to a predetermined temperature by the heating device 18. If the temperature difference between the molten metal 31 and the substrate 100 is not large, the heating device 18 may be omitted and step S140 may be omitted.

  Next, in step S150, as shown in FIG. 12B, the holding jig 50D on which the substrate 100 is mounted is moved to the crucible 30 by the transfer arm 40, and the substrate 100 is immersed in the molten metal 31.

Next, in step S160, with the substrate 100 immersed in the molten metal 31, the first and second pressurization valves 13 and 23 are opened, and the first and second pressurization pipes are opened from the pressurization gas supply device 16. The pressurized gas is introduced into the first and second chambers 10 and 20 through 14 and 24, and the inside of the first and second chambers 10 and 20 is increased to about 2 to 5 × 10 ⁵ [Pa]. Press.

  In addition, the pressure at the time of pressurization in step S150 is not particularly limited as long as it is relatively higher than the pressure at the time of depressurization in step S120.

  This pressurization causes a pressure difference between the inside of the first and second chambers 10 and 20 and the inside of the sealed space 58, so that the molten metal 31 enters the through hole 110 as shown in FIG. Extruded to fill the through hole 110 with molten metal.

  Here, as described above, when there is a large difference in the flow resistance of the molten metal 31 between the plurality of through holes 110, the molten metal 31 is preferentially filled into the through hole 110 having the lowest flow resistance.

  At this time, in this embodiment, as shown in the figure, since the inside of the sealed space 58 is depressurized, the film 57 is bent toward the sealed space 58 and the molten metal 31 reaches the film 57. As a result, the opening of the through hole 110 in the lower surface 102 of the substrate 100 is closed by the molten metal 31, so that the molten metal 31 fills the through hole 110 having the next lowest flow resistance as shown in FIG. Is done. This process is repeated until all the through-holes 110 adjacent to the same compartment 55 are filled with the molten metal 31, so that the metal filling between the plurality of through-holes 110 can be made more uniform. Can do.

  Next, in step S170, the substrate 100 is lifted from the molten metal 31 by the transfer arm 40, and the substrate 100 is air-cooled, whereby the metal filling operation into the through hole 110 is completed. During the pulling up, the holding jig 50D is pulled up from the molten metal 31 with the clamp 41 of the transport arm 40 inclined. Thereby, the residue of the molten metal 31 on the substrate 100 can be removed. Note that the residue of the molten metal 31 on the substrate 100 may be removed by a squeegee as in the first embodiment.

  As described above, in this embodiment, the pressure around the opening of the through hole 110 on the lower surface 102 of the substrate 100 is relatively lower than the pressure around the molten metal 31 supplied on the upper surface 101 of the substrate 100. By doing so, the molten metal 31 is filled in the through hole 110. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

  Moreover, in this embodiment, the board | substrate 100 is immersed in the molten metal 31 in the state which pressure-reduced the sealed space 58 adjacent to the through-hole 110 via the film 57, and the molten metal 31 is pressurized in this state. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 120. Excellent electrical reliability without any problems.

  The film 57 in this embodiment may be interposed between the holding jig 50 and the substrate 100 described in the first embodiment.

<< Fifth Embodiment >>
FIG. 13 is a cross-sectional view showing a holding jig in the fifth embodiment of the present invention. In the present embodiment, the configuration of the holding jig 50E is different from that of the first embodiment, but other configurations are the same as those of the first embodiment. In the following, the fifth embodiment will be described only with respect to differences from the first embodiment, and the same reference numerals will be given to portions having the same configuration as the first embodiment, and description thereof will be omitted.

  As shown in FIG. 13, in the holding jig 50 </ b> E in the present embodiment, a vacuum pump 59 is connected to an area surrounded by an annular partition wall 52 via an exhaust pipe 592 having an exhaust valve 591.

  In this embodiment, when the substrate 100 is mounted on the holding jig 50E, the upper surface 521 of the partition wall 52 abuts on the lower surface 102 of the substrate 100 as in the first embodiment, and the holding jig 50E and the substrate 100 are separated. A sealed space 53 is formed therebetween. The sealed space 53 communicates with the vacuum pump 59 through the exhaust pipe 592. The vacuum pump 59 in this embodiment corresponds to an example of a differential pressure generating unit and an exhaust unit in the present invention.

  In the present embodiment, the molten metal 31 is filled into the through hole 110 of the substrate 100 in the same procedure as the metal filling method in the first embodiment described with reference to FIG. 5, but in step S50 of FIG. When pressurizing the interiors of the first and second chambers 10 and 20, the vacuum pump 59 is also activated to exhaust the sealed space 53. Thereby, when the pressure required for metal filling is insufficient by the pressure difference between the inside of the first and second chambers 10 and 20 and the inside of the sealed space 53, the shortage can be compensated.

  When the holding device 50E in the present embodiment is used, the molten metal 31 can be filled into the through hole 110 by the method shown in FIG. FIG. 14 is a flowchart showing a modification of the metal filling method according to the fifth embodiment of the present invention.

  First, in step S210 of FIG. 14, the substrate 100 is mounted on the holding jig 50E located in the first chamber 10, and after sealing the first chamber 10 in step S220, the substrate 100 is mounted by the heating device 18. Heat.

  Next, without reducing the pressure in the first and second chambers 10 and 20, in step S230, the holding jig 50E on which the substrate 100 is mounted is moved to the crucible 30 by the transfer arm 40, and the substrate 100 is molten metal. Immerse in 31.

  Next, in step S240, the inside of the sealed space 53 is exhausted through the exhaust pipe 591 by the vacuum pump 59. As a result, the pressure around the opening of the through hole 110 in the lower surface 102 of the substrate 100 is relatively lower than the pressure around the molten metal 31 supplied on the upper surface 101 of the substrate 100, and the through hole 110 is melted. Metal 31 is filled. For this reason, since the molten metal 31 is filled from one end of the through hole 110 toward the other end, it is possible to prevent voids from being generated in the through hole 110, and the metal 120 is divided in the through hole 110. It has excellent electrical reliability.

  In addition, you may provide the filter 56 demonstrated in 3rd Embodiment, and the film 57 demonstrated in 4th Embodiment in the holding jig 50E in this embodiment. Further, a vacuum pump 59 may be connected to each compartment 55 of the holding jig 50B described in the second embodiment via an exhaust pipe 591.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1D ... Metal filling apparatus 10 ... 1st chamber 15 ... Vacuum pump apparatus 16 ... Pressurized gas supply apparatus 20 ... 2nd chamber 30 ... Crucible 31 ... Molten metal 40 ... Transfer arm 50, 50B, 50C, 50D, 50E ... Holding jig 52 ... Bulkhead 53 ... Sealed space 54 ... Partition wall 55 ... Partition chamber 56 ... Filter 57 ... Film 58 ... Sealed space 59 ... Vacuum pump 70 ... Mounting arm 80 ... Molten metal supply device 90 ... Squeegee 100 ... Substrate DESCRIPTION OF SYMBOLS 101 ... Upper surface 102 ... Lower surface 110 ... Through-hole 120 ... Metal

Claims (12)

A method of filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
Supplying molten metal to the first surface;
Filling the molten metal into the through-hole by making the pressure around the opening of the through-hole in the second surface relatively lower than the pressure around the molten metal. The metal filling method characterized by the above-mentioned. A method of filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
A first step of forming a filling space communicating with the opening of the through hole in the second surface and reduced in pressure compared to atmospheric pressure;
A second step of immersing the substrate in molten metal in a state where the space for filling is decompressed;
A third step of filling the molten metal into the through-hole by pressurizing the molten metal in a state where the substrate is immersed in the molten metal,
The metal filling method according to claim 1, wherein the first step includes reducing the filling space after forming the filling space or forming the filling space under a reduced pressure atmosphere. The metal filling method according to claim 2,
The metal filling method according to claim 1, wherein the first step includes interposing a lattice-like member between the through hole and the filling space. A method of filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
A first step of forming a filling space adjacent to the opening of the through hole in the second surface via a flexible film and having a reduced pressure compared to atmospheric pressure;
A second step of immersing the substrate in molten metal in a state where the space for filling is decompressed;
A third step of filling the molten metal into the through-hole by pressurizing the molten metal in a state where the substrate is immersed in the molten metal,
The metal filling method according to claim 1, wherein the first step includes forming the filling space in a reduced pressure atmosphere. A metal filling method according to any one of claims 2 to 4,
The metal filling method, wherein the filling space has a plurality of compartments partitioned from each other. A metal filling method according to any one of claims 2 to 5,
The metal filling method according to claim 3, wherein the third step includes exhausting the inside of the filling space. An apparatus for filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
Supply means for supplying molten metal to the first surface;
Differential pressure generating means for filling the molten metal in the through hole by lowering the pressure around the opening of the through hole in the second surface relatively lower than the pressure around the molten metal; A metal filling apparatus comprising: An apparatus for filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
A holding jig for holding the substrate, including an annular partition wall that forms a filling space communicating with the opening of the through hole in the second surface;
A metal melting tank in which a molten metal in which the substrate is immersed is stored;
A chamber in which the holding jig and the metal melting tank are disposed;
Transport means for immersing the substrate in the molten metal by moving the holding jig in the chamber;
Pressure reducing means for reducing the pressure in the chamber;
And a pressurizing means for pressurizing the inside of the chamber. The metal filling device according to claim 8,
The holding jig includes a lattice member interposed between the through hole and the filling space. An apparatus for filling a metal into a through-hole penetrating between a first surface and a second surface of a substrate,
A holding jig for holding the substrate, having an annular partition that forms a space for filling adjacent to the opening of the through hole in the second surface via a flexible film;
Mounting means for mounting the substrate on the holding jig via the flexible film;
A metal melting tank in which a molten metal in which the substrate is immersed is stored;
A chamber in which the holding jig, the mounting means, and the metal melting tank are disposed;
Transport means for immersing the substrate in the molten metal by moving the holding jig in the chamber;
Pressure reducing means for reducing the pressure in the chamber;
And a pressurizing means for pressurizing the inside of the chamber. The metal filling device according to any one of claims 8 to 10,
The holding jig has a partition wall that partitions the filling space into a plurality of partition chambers. The metal filling device according to any one of claims 8 to 11,
The metal filling apparatus further comprising exhaust means for exhausting the inside of the filling space.

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