JP4611429B2 - Method for filling metal into fine space - Google Patents

Description

  The present invention relates to a method of filling and hardening a molten metal in a fine space existing in a processing object.

  For example, in an electronic device typified by a semiconductor device, a micromachine, or the like, it may be necessary to form a fine conductor filling structure, junction structure, or functional structure having a high aspect ratio inside. In such a case, a technique for realizing a conductor filling structure, a joining structure, a functional structure, and the like by filling a fine space with a preselected filler is known. However, it is extremely difficult to sufficiently fill the bottom of the fine space having a high aspect ratio without causing voids or deformation after curing.

  For example, in the case of wafer processing used in the manufacture of semiconductor devices, the wafer is provided with a large number of fine spaces (holes) for forming electrodes and the like. For example, it is several tens of μm or less and is very small. Moreover, the thickness of the wafer is considerably larger than the minute space having such a minute hole diameter, and the aspect ratio of the minute space is often 5 or more. In order to form an electrode, it is necessary to reliably fill such a minute, high aspect ratio minute space with a conductive material so as to reach the bottom, and naturally, advanced filling technology is required. The

  As an electrode forming technique, a technique using a conductive paste in which a conductive metal component and an organic binder are mixed is also known, but metallurgy using a molten metal material having excellent conductivity, low loss, and excellent high frequency characteristics. Technology is attracting attention. Such a technique is disclosed in Patent Document 1 and Patent Document 2, for example.

  First, Patent Document 1 discloses a technique for filling a metal in a minute space (through hole) by a molten metal backfilling method. In the molten metal backfilling method, the atmosphere in which the object (wafer) is placed is depressurized, and then the object is inserted into the molten metal while maintaining the depressurized state, and then the ambient gas pressure of the molten metal , The molten metal is filled into the space by the atmospheric gas pressure difference before and after the metal is inserted, and then the object is pulled up from the molten metal tank and cooled in the atmosphere.

However, this molten metal backfilling method has the following problems.
(A) When the object is pulled up from the molten metal tank and cooled, the metal surface is recessed in a concave shape to a position lower than the surface of the object. For this reason, electrical continuity with the outside may be incomplete.
(B) In order to solve the above-described problems, the molten metal must be supplied again to fill the concave surface. Moreover, in order to fill the concave surface, it is necessary to make the surface of the supplied metal higher than the surface of the object. Therefore, a process for matching the surface of the metal with the surface of the object, for example, CMP (Chemical Mechanical Polishing) process is required. These cause factors such as complication of the process and a decrease in yield accompanying the process.
(C) A bigger problem is that, despite the complicated process as described above, a gap or the like inadequately filled with molten metal is generated in the fine space, particularly at the bottom.

  Next, Patent Document 2 discloses a differential pressure filling method. In this differential pressure filling method, an object in which a fine space is formed and a metal sheet are placed in a vacuum chamber, then the inside of the vacuum chamber is decompressed, the metal sheet is melted by heating means, and then the inside of the vacuum chamber is inactivated. Pressurize to atmospheric pressure or higher with active gas. Thereby, the molten metal is sucked into the fine space by vacuum. Next, the vacuum chamber is opened to remove the molten metal remaining on the sample surface, and then cooled to room temperature in the atmosphere.

  According to the description of Patent Document 2, since the heat capacity of the molten metal is smaller than that of the molten metal backfill method (Patent Document 1), the sample is not warped or cracked, and the excess metal is suppressed to a minimum. It is said that there are effects such as being able to reduce costs.

  However, in the differential pressure filling method described in Patent Document 2, the molten metal is not completely filled up to the bottom of the fine space, and voids are generated inside.

  Moreover, since the molten metal remaining on the sample surface is removed, a part of the molten metal (upper end side) filled in the minute gap is also scraped off in the process. For this reason, the problem of a concave surface still remains.

  In fact, the fact that the wafers manufactured by the differential pressure filling method and the devices using the wafers have not been provided to the market is proof that the above-mentioned problems have not been solved.

  The technical difficulty that occurs when the molten metal is sufficiently filled into the fine space is not a problem only in the case of wafer processing for semiconductor devices. Other electronic devices, micromachines, and the like can be similarly problematic.

JP 2002-237468 A Japanese Patent Laid-Open No. 2002-368082

  An object of the present invention is to provide a method capable of filling a fine space with a metal filler without causing concave surface formation, voids, voids and the like.

  Another object of the present invention is to provide a method that does not require re-supply of molten metal after cooling, a CMP process, etc., and can contribute to simplification of the process and improvement of yield.

  In order to solve at least one of the above-described problems, the present invention applies a forced external force to the molten metal in the fine space when filling and hardening the molten metal in the fine space existing in the object to be processed. A step of cooling and hardening the molten metal while the voltage is applied;

  As described above, the method according to the present invention includes a step of cooling and hardening the molten metal while applying a forced external force to the molten metal in the fine space, so that the molten metal is finely divided by a forced external force applied from the outside. While sufficiently filling the bottom of the space, metal deformation due to heat shrinkage can be suppressed. For this reason, the fine space can be filled with the metal body without generating voids or voids.

  For the same reason, it is also possible to avoid the concave surface of the molten metal that occurs when cooled by a fine gap. For this reason, electrical continuity with the outside can be reliably ensured.

  Further, since the concave surface of the metal body can be avoided, there is no need to re-supply molten metal after cooling, a CMP process, etc., which can contribute to simplification of the process and improvement of yield.

  In the present invention, the forced external force means that a pressure applied when left undisturbed, typically, atmospheric pressure is not included. This forced external force is given as at least one selected from pressure, magnetic force or centrifugal force. The pressure may be applied as a positive pressure or a negative pressure. In the case of negative pressure, it becomes a suction force. Specifically, the pressure is given as a press pressure or a gas pressure.

  As another form of the forced external force, there is a form using an injection pressure by an injection machine. In this case, the molten metal is supplied onto the opening surface of the object by an injector, and the molten metal is cooled and hardened while a forced external force due to the injection pressure is applied.

  When a forced external force is applied, it is preferable that not only the static pressure but also the dynamic pressure is actively used in the initial stage of the curing process to perform a dynamic pushing operation by the dynamic pressure. According to this method, it is possible to reliably prevent the molten metal from reaching the bottom of the fine space and to generate an unfilled region at the bottom.

  In the present invention, at least a part of the process is performed in a reduced pressure atmosphere in a vacuum chamber. This is because the molten metal can be vacuum-sucked into a fine space by the reduced pressure atmosphere in the vacuum chamber. The reduced pressure atmosphere refers to an atmosphere having a lower pressure than the atmospheric pressure.

  Molten metal is preferably supplied such that the metal film forms on the open face. Thereby, the molten metal can be surely pushed into the fine space by the forced external force received by the metal thin film.

  When supplying molten metal so that the metal thin film is formed on the opening surface, after the molten metal is cured, the metal thin film on the opening surface is remelted and the remelted metal thin film is wiped off. be able to. The heat at the time of remelting is also applied to the hardened metal body inside the fine gap, but since the heat capacity of the hardened metal body is significantly larger than the heat capacity of the metal thin film, even if the metal thin film is remelted, It does not progress until remelting. For this reason, only a metal thin film can be wiped off and a flat surface without a concave surface portion can be formed.

4 is a flowchart illustrating a method according to the present invention. 2 is a cross-sectional SEM photograph of a semiconductor wafer (silicon wafer) obtained by omitting a curing step (pressure cooling) in the step shown in FIG. It is a cross-sectional SEM photograph of the semiconductor wafer (silicon wafer) obtained by the method based on this invention which has a hardening process (pressurization cooling). It is a figure which shows another example of application of the method which concerns on this invention. It is a figure which shows another example of application of the method which concerns on this invention. It is a figure which shows another example of application of the method which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Target object 21 Fine space 4 Molten metal 41 Filled molten metal 42 Metal film 40 Hardened metal body

FIG. 1 is a flow chart illustrating a method according to the present invention. Referring to the figure, the method shown in this embodiment includes a preparation process, a pouring process, a curing process, and a post-process. However, the distinction between these steps is merely a matter of convenience for explanation. Hereinafter, it demonstrates in order of a process.
(A) Preparation Step First, the object 2 to be processed is placed on the support 3 provided inside the vacuum chamber 1. The object 2 has a fine space 21. The fine space 21 needs to be open on the outer surface of the object 2, but its mouth shape, path, number, etc. are arbitrary. The through hole shown in the figure does not need to be a non-through hole. Alternatively, it may be a complicated shape that extends not only in the illustrated vertical direction but also in a horizontal direction perpendicular thereto. The minute space 21 is not limited to the one formed intentionally. It may have occurred unintentionally.

  A typical example of the object 2 is a semiconductor device wafer, but is not limited thereto. The present invention can be widely applied when it is necessary to fill the solid space 21 in the object 2 with molten metal and solidify it. For example, in other electronic devices, micromachines, etc., a fine conductor inside The present invention can be widely applied when forming a filling structure, a bonding structure, or a functional part. In some cases, the present invention can be applied to devices having a normal size other than electronic devices and micromachines.

  In addition, the object 2 may be a metal, an alloy, a metal oxide, a ceramic, glass, a plastic, a composite material thereof, or a laminate thereof as long as it has heat resistance against heat dissipated from the molten metal. It can be widely used regardless of whether it is different. Furthermore, the outer shape of the object 2 is not limited to a flat plate shape, and can take any shape. The flat plate shape shown is merely an example selected for convenience of explanation.

  When a wafer is selected as the target object 2, its physical properties, structure, and the like vary depending on the type of target device. For example, in the case of a semiconductor device, a Si wafer, a SiC wafer, an SOI wafer, or the like is used. In the case of a passive electronic circuit device, it may take the form of a dielectric, a magnetic material or a composite thereof. Also in the manufacture of MRAM (Magnetoresistive Random Access Memory), MEMS (Micro Electro Mechanical Systems), or optical devices, wafers having physical properties and structures that meet the requirements are used. In the wafer, the fine space 21 is generally referred to as a through hole, a non-through hole (blind hole), or a via hole. The fine space 21 has, for example, a pore diameter of 10 μm to 60 μm. The thickness of the wafer itself is usually several tens of μm. Therefore, the fine space 21 has a considerably high aspect ratio. This is a major reason for causing problems when the molten metal 4 is filled in the fine space 21.

Next, the vacuum chamber 1 is evacuated, and the internal pressure of the vacuum chamber 1 is reduced to, for example, a degree of vacuum of about 10 ⁻³ Pa. However, this degree of vacuum is an example, and the present invention is not limited to this.
(B) Pouring Step Next, in the casting step, the molten metal 4 is poured into the fine space 21 from the opening surface where the fine space 21 is open. This pouring step is basically performed in a reduced pressure atmosphere inside the vacuum chamber 1. Thereby, the molten metal 4 is sucked into the fine space 21 by vacuum, and the filled molten metal 41 is generated inside the fine space 21.

  The composition of the metal material constituting the molten metal 4 is selected according to the type of the object 2 and its purpose. The molten metal 4 is generally not composed of a single metal element, but contains a plurality of metal elements premised on alloying. For example, if the object 2 is a semiconductor wafer and the purpose is to form a conductor in the minute space 21, Ag, Cu, Au, Pt, Pd, Ir, Al, Ni, Sn, In A metal component containing at least one metal element selected from the group consisting of Bi, Zn and Zn can be used. In order to obtain a bonded structure, a metal component is selected in consideration of the bonding property with the objects to be bonded.

  The metal component described above preferably has a nanocomposite structure. Here, the nanocomposite structure refers to a polycrystal having a particle size of preferably 500 nm or less. The advantage of using a metal component having a nanocomposite structure is that the melting point of the molten metal 4 as a whole can be lowered.

  Another technique for reducing the melting point is to combine a high melting point metal component (Ag, Cu, Au, Pt, Pd, Ir, Al, Ni) and a low melting point metal component (Sn, In, Bi). .

  The molten metal material preferably contains bismuth (Bi). The advantage of containing bismuth (Bi) can contribute to the formation of a metal conductor free from voids and voids in the fine space 21 by utilizing the volume expansion characteristics of bismuth (Bi) during cooling. It is in.

  Furthermore, when the bottom of the fine space 21 is closed by a conductor, the step of supplying the precious metal nanoparticles into the fine space 21 before pouring the above-described molten metal 4 and thereafter pouring the molten metal 4 is performed. Taking it is also effective. By passing through this step, the oxide film that may be formed on the conductor can be reduced by the catalytic action of the noble metal nanoparticles, and a junction with low electrical resistance can be formed between the molten metal 4 and the conductor. . Precious metals include gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru) and osmium (Os). Among these elements, it is preferable to include at least one selected from gold (Au), platinum (Pt), and palladium (Pd).

  In pouring the molten metal 4, the above-described metal material is melted in advance outside the vacuum chamber 1 and supplied to the object 2 inside the vacuum chamber 1 or installed inside the vacuum chamber 1. A heating mechanism is attached to the support 3 and the metal material is dissolved in the vacuum chamber 1. Although the temperature for melt | dissolution is an example, it can set in the range of 200-300 degreeC. As described above, the melting temperature can be adjusted or lowered by selecting a combination of metal components and nanonization.

  The metal material may be supplied in the form of powder, or a metal thin plate corresponding to the outer shape of the object 2 is prepared in advance using the metal material described above, and this metal thin plate is used as the object. 2 may be superposed on one surface and dissolved.

  Unlike the above pouring method, a step of immersing the object 2 in a molten metal tank in a reduced pressure atmosphere and then pulling it up can be employed.

  The casting step can include a step of pressurizing the molten metal 4. In this step, it is preferable to apply not only static pressure but also dynamic pressure to the molten metal. This is because the molten metal 4 can be forced into the fine space 21 by the dynamic pushing action of the dynamic pressure. The pressurization may be applied as a press pressure using a mechanical pressing means, or may be applied as an indentation force using a stencil and a squeegee, and the atmospheric gas pressure in the vacuum chamber 1 is increased from a reduced pressure state. It may be given by pressing. So-called differential pressure filling is executed by the increased pressure from the reduced pressure state.

When the gas pressure inside the vacuum chamber 1 is increased, an inert gas such as N ₂ gas is supplied into the vacuum chamber 1 to increase the gas pressure while preventing oxidation of the molten metal material. Is preferred. Although the gas pressure in the vacuum chamber 1 is an example, it can be set in the range of 0.6 to 1 kgf / cm ² . A suitable dynamic pressure can be generated by controlling the pressure rise-time characteristic until the gas pressure is reached.

  Further, the pouring step may include a step of injecting the molten metal 4 by an injection machine installed outside the vacuum chamber 1 to fill the fine space 21. This step may be combined with the pressurizing means described above, or may be an independent means.

  In the pouring step, it is preferable to supply the molten metal 4 so that the metal thin film 42 is formed on the opening surface of the minute space 21 of the object 2 that opens. That is, the molten metal 4 is supplied so as to be larger than the total volume of the fine space 21. By performing such a process, the pushing operation can be surely generated by using the dynamic pressure applied to the metal thin film 42.

  Furthermore, in the pouring step, filling using ultrasonic vibration, filling using magnetic force, and filling using centrifugal force can be performed. In ultrasonic vibration filling, it is conceivable to apply ultrasonic vibration to the object 2, apply ultrasonic vibration to the press means, or apply ultrasonic vibration to the stencil and squeegee. However, it is necessary to appropriately select the vibration frequency from the viewpoint of improving the vibration efficiency and avoiding the overflow of the molten metal 4 due to the resonance action of the object 2.

In the magnetic filling, the molten metal 4 is made to contain a magnetic component, a magnetic field is applied from the outside, and the magnetic force acting on the magnetic component is used to draw the molten metal 4 into the fine space 21. . In centrifugal force filling, centrifugal force generated when the object 2 is rotated may be used.
(C) Curing process Next, the process proceeds to a curing process. The processing content in this curing step is one of the major features of the present invention. In the curing step, after the molten metal 4 is poured into the fine space 21 by the above-described casting step, the filled molten metal 41 in the fine space 21 is cooled and cured in a state where a forced external force F1 exceeding the atmospheric pressure is applied. Let The forced external force F1 is continuously applied until the curing is completed. The cooling is basically slow cooling at room temperature, but a temperature condition lower than room temperature may be set, or in some cases, a temperature condition higher than room temperature may be set. Furthermore, a cooling method may be adopted in which the temperature is lowered continuously or stepwise with time.

The magnitude of the forced external force F1 is determined in consideration of the mechanical strength of the object 2, the aspect ratio of the minute space 21, and the like. As an example, when the target object 2 is a silicon wafer, the forced external force F1 is preferably set in the range of greater than atmospheric pressure to ² kgf / cm ² or less. When the mechanical strength of the object 2 and the aspect ratio of the fine space 21 are large, a higher pressure can be applied.

  The forced external force F1 applied in the curing step is given by at least one selected from a press pressure, an injection pressure, a gas pressure, or a rolling pressure. When these pressures are used, in the initial stage of the curing process, not only the static pressure but also the dynamic pressure can be positively used to perform a dynamic pushing operation by the dynamic pressure. Thereby, while suppressing generation | occurrence | production of a space | gap and a void more reliably, it can operate so that the filling molten metal 41 may reach the bottom part of the fine space 21 still more reliably.

  The pressing pressure can be applied by mechanical pressing means, and the injection pressure can be applied by an injection machine. The gas pressure can be applied by increasing the atmospheric gas pressure while holding the object 2 in the vacuum chamber 1 or in a processing chamber prepared separately. Even in the gas pressure, by controlling the temporal pressure rise characteristic, the dynamic pressure can be actively used in the initial stage of the curing process, and a dynamic pushing operation by the dynamic pressure can be performed. Also in the curing step, ultrasonic vibration filling, magnetic force filling, and centrifugal force filling can be used.

  The pressurization by the forced external force in the curing process may be executed independently of the pressurization process in the pouring process, or may be executed in a continuous relationship. When executed in a continuous relationship, both pressurization steps are absorbed as one pressurization step. A typical example is when the gas pressure in the vacuum chamber 1 is increased to a level exceeding the atmospheric pressure, and when the molten metal 4 is supplied onto the opening surface of the object 2 by an injector, and a forced external force is generated by the injection pressure. This is a case where the molten metal is cooled and hardened while the voltage is applied. However, it is preferable to adjust the applied pressure as one pressurizing step even when they are integrated.

  As described above, the present invention includes a curing step of cooling and hardening the filled molten metal 41 in the fine space 21 while the forced external force F1 is applied to the molten metal 4 in the fine space 21. The filled molten metal 41 is reliably filled in the space 21, and when the filled molten metal 41 is thermally contracted during the cooling process, deformation of the metal due to the thermal contraction can be suppressed by the applied forced external force F1. For this reason, the fine space 21 can be filled with the hardened metal body 40 up to the bottom thereof without generating voids or voids. For the same reason, it is possible to avoid the concave surface to be generated when the hardened metal body 40 is cooled in the fine space 21.

  Furthermore, since the concave surface of the hardened metal body 40 in the fine space 21 can be avoided, there is no need to re-supply molten metal after cooling, a CMP process, etc., which contributes to simplification of the process and improvement of yield. Can do.

In particular, in the pouring process, when the molten metal 4 is supplied on the outer surface of the object 2 so that the metal thin film 42 is generated, the metal thin film 42 receives pressure and is filled in the fine space 21. Since the film thickness changes depending on the form of the filled molten metal 41, the deformation due to the heat shrinkage of the hardened metal body 40 filled and hardened in the fine space 21 and the concave surface are surely suppressed. be able to.
(D) Post-process Next, the metal thin film 42 on the outer surface of the object 2 is remelted, and the remelted metal thin film 42 is wiped off with, for example, a squeegee 5. According to this post-process, the outer surface of the object 2 can be flattened. Moreover, a simple operation such as wiping is required, and unlike the conventional case, there is no need to re-supply the molten metal 4 after cooling the molten metal and the CMP process, which contributes to simplification of the process and improvement of the yield. it can. If necessary, a step of repressurizing F2 and then cooling may be performed in accordance with the curing step. However, since this post-process is for removing the metal thin film 42 and flattening one surface of the object 2, it can be omitted if flattening is not necessary.

  The heat at the time of remelting is also applied to the hardened metal body 40 that is hardened inside the fine gap 21. However, since the heat capacity of the hardened metal body 40 is significantly larger than the heat capacity of the metal thin film 42, the metal thin film 42 is regenerated. Even if it melts, it does not progress until remelting of the hardened metal body 40. For this reason, only the metal thin film 42 can be wiped off.

  Through the series of steps described above, the object 2 in which the fine space 21 is filled with the hardened metal body 40 is obtained. Note that not all of the above-described steps need be performed in the vacuum chamber 1. The curing process and the post-process include processes that may be performed outside the vacuum chamber 1.

Next, the effect of the present invention will be demonstrated by SEM (Scanning Electron Microscope) photographs. 2 is a cross-sectional SEM photograph of a semiconductor wafer (silicon wafer) obtained by omitting the curing step (pressure cooling) in the step shown in FIG. 1, and FIG. 3 is a book having a curing step (pressure cooling). It is a cross-sectional SEM photograph of the semiconductor wafer (silicon wafer) obtained by the method which concerns on invention. Except for the presence or absence of a curing step (pressure cooling), both SEM photographs show a cross section of a semiconductor wafer obtained under the same process conditions. The process conditions are as follows.
(A) Preparatory step Vacuum degree in vacuum chamber: 10 ⁻³ (Pa)
Object: 300 mm × 50 μm silicon wafer with glass protective film Fine space: Opening diameter 15 μm, bottom hole diameter 10 μm
(B) Casting step (1) An identical thin metal plate was placed on the silicon wafer and dissolved.
Composition of thin metal plate: Sn, In, Cu, Bi
Melting temperature: 250 ° C
(2) Next, N ₂ gas was introduced into the vacuum chamber, and the gas pressure was set to 0.6 kgf / cm ² (pressurization).
(C) Curing step (only in the case of the present invention)
A pressure of 2.0 kgf / cm ² was applied to the molten metal with a press machine, and the molten metal was gradually cooled.
(D) Melting temperature for remelting the post-process: 250 ° C.
Wiping and re-pressurizing with a squeegee: A pressure of 2.0 kgf / cm ² is applied by a press machine. First, looking at the SEM photograph in FIG. 2, the hardened metal filled in the minute space 21 of the wafer 2 as the object. A concave surface portion P1 is formed on the upper end side of the body 40, and a void portion P2 that is not filled with the hardened metal body 40 is formed on the bottom portion. The presence of voids is also observed between the periphery of the hardened metal body 40 and the inner surface of the fine space 21.

  On the other hand, when the SEM photograph of FIG. 3 according to the application of the present invention is seen, the upper end surface of the hardened metal body 40 filled in the minute space 21 of the wafer 2 is continuous with the upper surface of the wafer 2. It is a continuous flat surface, and no concave surface is observed. The lower end surface of the hardened metal body 40 is in close contact with the bottom of the fine space 21, and the bottom gap is not visible. Furthermore, the outer peripheral surface of the hardened metal body 40 is in close contact with the inner surface of the fine space 21, and the presence of voids is not recognized.

  FIG. 4 shows another application of the method according to the invention. This example shows that the present invention can be applied not only to a fine space having a simple linear structure but also to a fine space having a curved path. Referring to FIG. 4A, the object 2 has two fine spaces 211 and 213 extending in the vertical direction at different positions, and these fine spaces 211 and 213 extend in the horizontal direction. Is continuous through.

  Even in the fine space structure as shown in FIG. 4A, by applying the method according to the present invention described with reference to FIG. 1, as shown in FIG. , 212, 213 to form a continuous hardened metal body 40. Although illustration is omitted, the hardened metal body 40 can be formed by applying the present invention even in a fine space having a more complicated shape.

  In FIG. 4, the object 2 can take the form of a metal, an alloy, a metal oxide, ceramics, glass, plastic, a composite material thereof, or a laminate thereof. Furthermore, the outer shape of the object 2 is not limited to a flat plate shape, and can take any shape. The shape shown is merely an example selected for convenience of explanation.

  FIG. 5 shows a further application of the method according to the invention. This example shows a case where the present invention is applied to the field of bonding technology. Referring to the figure, the fine space 21 generated between the first member 201 and the second member 202 is filled with the hardened metal body 40. The hardened metal body 40 is filled and hardened according to the method described with reference to FIG. The flowing direction of the molten metal may be any of a direction orthogonal to the paper surface or a direction parallel to the paper surface. The shapes of the first member 201 and the second member 202 are arbitrary, and the drawing is merely an example. Further, the first member 201 and the second member 202 may be the same type of metal material or different types of metal materials.

  Even if the first member 201 and the second member 202 cannot be separated and a general welding technique such as brazing cannot be applied, welding can be performed by applying the present invention.

  FIG. 6 shows a further application of the method according to the invention. In this application example, the hard metal body 40 is filled in the minute space 21 generated between the two cylinders 201 and 201 arranged in the same cylindrical shape. Such an application scene may occur not only in the technical field to which electronic devices and micromachines belong, but also in the technical field that handles larger mechanical components. That is, the application range of the present invention is not necessarily limited to the manufacturing process of a microelectronic device or a micromachine. Although not shown, the present invention may be applied as a means for filling cracks and gaps generated in an object.

  Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications and other applications not described will be apparent to those skilled in the art based on the basic technical idea and teachings of the present invention. It is obvious that the technical field can be conceived.

Claims (10)

A method of filling and hardening a molten metal in a minute space present in an object that is a wafer ,
The fine space has one end opened on one surface in the thickness direction of the object,
The object is placed on a support with the other end of the fine space closed.
Pressing pressure from the one surface of the fine the object to the molten metal filled in the space of the object, the injection pressure or by cooling the molten metal while applying a compaction and cured,
A method comprising the steps.   The method of claim 1, wherein the molten metal comprises Bi.   The method according to claim 1 or 2, wherein the molten metal is at least one selected from the group consisting of Ag, Cu, Au, Pt, Pd, Ir, Al, Ni, Sn, In, and Zn. A method comprising a metal element.   The method according to any one of claims 1 to 3, wherein a thin metal plate is disposed on the opening surface of the object and the pressure in the vacuum chamber is reduced before the molten metal is cooled and hardened. Dissolving the sheet metal in an atmosphere to produce the molten metal.   5. The method according to claim 4, comprising the step of increasing the atmosphere in the vacuum chamber from a reduced pressure state and pouring the molten metal into the fine space before cooling and hardening the molten metal. .   4. The method according to claim 1, wherein the molten metal is placed on the opening surface of the object placed in a reduced pressure atmosphere in a vacuum chamber before the molten metal is cooled and hardened. A method comprising the step of increasing the pressure in the vacuum chamber after supplying molten metal.   The method according to claim 1 or 2, wherein the molten metal is supplied onto the opening surface of the object by an injection machine, and the molten metal is cooled while applying a forced external force by the injection. A method comprising the step of curing.   The method according to claim 1, wherein the molten metal is supplied so that the metal thin film is formed on an opening surface where an opening of the fine space exists.   The method according to claim 8, comprising curing the molten metal, re-melting the metal thin film on the opening surface, and wiping the re-melted metal thin film.   The method according to claim 1, wherein the object is a semiconductor wafer.