JP2017001014A - Method for forming thin film conductive layer and sintering device for thin film conductive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thin film conductive layer having good conductive characteristic on a base plate.SOLUTION: A method for forming a thin film conductive layer has: a process in which a metal microparticle coating layer, in which metal microparticle on a surface of which a surface coating molecular layer is provided is dispersed as a dispersoid in a liquid phase dispersion medium containing an organic solvent, is coated on a base plate thereby forming a metal microparticle dispersion liquid coating film layer; a process in which the organic solvent is evaporated to form a dried metal microparticle coating layer; a process in which a specified pressure load is given to the dried metal microparticle coating layer from a surface of said coating layer; and a process in which charged particle beams are sequentially radiated onto the metal microparticle coating layer in which pressure load has been treated thereby forming a chain-like connection structure.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a method for forming a thin film conductor layer and a sintering apparatus for the thin film conductor layer.

  Along with the miniaturization of various electronic devices and electronic components, further miniaturization of the wiring pattern formed on the wiring board is desired. For this reason, there is a method of forming a conductor layer by using a conductive metal paste capable of directly drawing a desired wiring pattern in place of a conductor layer produced by a conventional plating method for forming a wiring pattern. It is being advanced.

For example, using a conductive metal paste using metal nanoparticles with a surface coating molecular layer, not only a normal wiring pattern with a width of several mm, but also a fine wiring pattern with a minimum line width / interval of 20 μm / 20 μm. Manufacturing with good reproducibility with stable current-carrying characteristics is in progress.
When a dispersion containing metal nanoparticles having a surface coating molecular layer is used, a fine wiring pattern can be drawn with high drawing accuracy and reproducibility.

  By using a technique for producing a dense sintered body layer of metal nanoparticles from metal nanoparticles with a surface coating molecular layer contained in this coating film layer, a fine wiring pattern can be formed with good reproducibility. It is known that a conductor layer can be formed. At that time, it is necessary to remove the coating molecular layer on the surface from the metal nanoparticles having the surface coating molecular layer, and then proceed with the sintering of the metal nanoparticles, and at least 200 ° C., usually about 250 ° C. Heat treatment at temperature is required.

  Regarding the substrate material used for the wiring board, for example, a so-called Pb-free solder material is used for solder bonding, and the use of a material having a heat resistance of about 250 ° C. is also progressing. In addition to the heating step in the solder bonding step, these heat resistant substrate materials are further subjected to heat treatment at about 250 ° C in order to sinter the metal nanoparticles, so that the substrate material is thermally deteriorated. It becomes the factor which raises the frequency which causes.

  Therefore, in the step of forming a sintered body-type conductor layer using a dispersion containing metal nanoparticles with a surface coating molecular layer, the heat treatment temperature is selected to be at least 200 ° C. Development of a technique capable of proceeding with the removal of the layer and the subsequent sintering of the metal nanoparticles is desired.

If the sintered body type conductor layer can be formed from the metal nanoparticles having the surface-coated molecular layer while the heat treatment temperature is suppressed to 200 ° C. or lower, the types of substrate materials that can be used are greatly expanded.
Conventionally, due to the problem of heat resistance, the use of a sintered body-type conductor layer is also opened for various fields in which a conductive thin film layer has been produced using a plating method or the like.

  However, when copper, which is an inexpensive metal, is used as the metal particles, there is a problem that the wiring resistance increases due to the formation of surface copper oxide when the direct-drawing patterning wiring using the metal particles is formed. The following has been proposed as a technique for reducing the resistance of a thin film conductor layer (Patent Documents 1 to 4).

  In Patent Document 1, the conductor composition is negatively charged as a step of applying the conductor composition on a substrate with at least one component selected from the group consisting of metal particles, metal precursors, and mixtures thereof. A method is disclosed in which a conductor is produced by changing the component into a metal by sintering while being exposed to an ionic reducing gas.

  Further, in Patent Document 2, a patterning wiring using nano copper metal particles is formed on a substrate by a direct drawing method, and the metal surface oxide film is reduced by atomic hydrogen and / or organic substances are removed from the wiring. A method for performing the above process is disclosed.

  In Patent Document 3, after removing surface coating molecules from metal fine particles having a surface coating molecular layer contained in the coating layer, energy rays are irradiated from the surface of the coating layer when the metal fine particles are sintered at low temperature. After that, heat treatment is performed at a low temperature of 150 ° C. or less to promote the removal of surface coating molecules, and the metal itself exhibits good conductivity by rapidly proceeding with the sintering of the metal fine particles. A method of forming a fine particle sintered body is disclosed.

  In Patent Document 4, a metal dispersion containing metal nanoparticles having a particle size of about 0.5 nm to 200 nm is coated and dried on the entire surface of the substrate, and a laser beam that generates light having a wavelength of 300 nm to 550 nm is locally applied to the metal particles. A method of forming a desired wiring on a substrate by removing the unnecessary portion of the metal dispersion liquid by brushing and cleaning the wiring pattern by bonding together.

<Problem 1>
In Patent Document 4, in which metal fine particles are sintered using the energy of a focused laser beam or a focused charged particle beam, small square regions of several hundred nm to several tens of μm are vertically and horizontally connected to form a wide square region. Sintering is required. The ratio of the metal in the metal fine particle dispersion liquid dispersed in the liquid phase dispersion medium containing the organic solvent is approximately 20 to 70% by weight depending on the type of the metal fine particles. Then, the pattern volume becomes small. Therefore, as shown in FIG. 13, the adjacent portion of the region A where the sintering is performed first and the region B where the sintering is performed next is irradiated twice to cause a large volume shrinkage. As shown in an enlarged manner, there is a problem that a crack occurs and the pattern is disconnected.

<Problem 2>
In general, fine metal particles having an average particle diameter of several nanometers to several tens of nanometers are referred to as metal nanoparticles, and a temperature significantly lower than the melting point of the metal material (for example, silver, a clean surface). It is known that the nanoparticles possessed are sintered at 200 ° C. or less. This is because in metal fine particles, if the particle diameter is sufficiently reduced, the proportion of the atoms in the high energy state existing on the particle surface will increase, and the surface diffusion of metal atoms will become so large that it cannot be ignored. . As a result, due to this surface diffusion, the interface between the particles is stretched and sintered. In order to obtain good current-carrying characteristics (low resistance characteristics) for the conductor layer, it depends on how clean the nanoparticle surface is before the sintering step. For example, in the case of copper particles, the oxide film on the surface significantly increases the resistance characteristics of the conductor layer.

Precious metals such as silver and gold are not easily oxidized, but copper is more easily oxidized than silver and gold. After drawing the wiring pattern, a heat treatment (about 150 to 300 ° C.) for evaporating the organic solvent and adhering the copper particles to each other is necessary.
However, the copper surface is oxidized during the heat treatment. Since the ratio of atoms in the surface portion of nano metal particles is large, there is a problem that the wiring resistance increases due to the formation of surface copper oxide.

<Problem 3>
In Patent Document 2, a patterning wiring using nano-copper metal particles is formed on a substrate by a direct drawing method, and the metal surface oxide film is reduced by atomic hydrogen or an organic substance is removed from the wiring. How to do is shown. This is effective if the thickness of the patterning wiring is about 1 μm because the reduction by atomic hydrogen is performed on the patterning surface. However, for example, in a pattern with a thickness of several tens of μm, atomic hydrogen does not reach the inside, so that it cannot be satisfactorily reduced and the wiring resistance increases.

<Problem 4>
In Patent Document 3, after removing surface coating molecules from metal fine particles having a surface coating molecular layer contained in the coating layer, energy rays are irradiated from the surface of the coating layer when the metal fine particles are sintered at low temperature. Then, heat treatment is performed at a low temperature of 150 ° C. or lower. This heat treatment promotes the removal of coating molecules on the surface, and the method of forming a metal fine particle sintered body exhibiting good conductivity by allowing the metal fine particle sintering itself to proceed rapidly by such low temperature heating is shown. ing.

  Intermolecular bonding force similar to the coordination bond between the coating molecule and the surface metal atom by injecting negative charges into the metal fine particles by irradiating energy beam such as electron beam and ultraviolet ray from the surface of the coating layer Is greatly reduced. Simultaneously with this decrease, a part of the energy of the irradiated energy beam is locally converted into the intramolecular vibrational energy of the coating molecule and the lattice vibrational energy of the metal microparticles. It promotes the release and removal of molecules. However, control of energy beam irradiation is difficult for conversion to intramolecular vibrational energy of coating molecules and lattice vibrational energy of metal fine particles in a state where the irradiation surface state cannot be detected.

  Therefore, an object of the present invention is to obtain a thin film conductor layer having good current-carrying characteristics on a substrate.

  In order to solve the above-mentioned problems, the invention described in claim 1 is a method of forming a thin film conductor layer of a metal fine particle sintered body on a substrate, comprising a dispersant on the surface of the metal fine particles The metal fine particle dispersion with the surface coating molecular layer is dispersed in a liquid phase dispersion medium containing an organic solvent as a dispersoid, and the substrate is coated with a metal fine particle dispersion to form a metal fine particle dispersion coating film layer. A step of evaporating the organic solvent to form a dried metal fine particle coating layer, a step of applying a predetermined pressing load from the surface of the coating layer to the dried metal fine particle coating layer, and pressing And a step of sequentially irradiating the load-treated metal fine particle coating layer with a charged particle beam to form a chain-like connection structure.

  According to the present invention, a thin film conductor layer having good current-carrying characteristics can be obtained on a substrate.

(A) is an example of the wiring pattern 100, (b) shows an enlarged view of the square region 101 of the wiring pattern 100 shown in (a), and (c) shows an enlarged view of (b). . It is a figure which shows an example of the scanning of a charged particle beam. It is a figure shown in the case of a copper particle as the surface of patterning wiring (metal fine particle application layer) after dry processing. It is a scanning electron micrograph. It is an external appearance perspective view of a surface pressing jig. It is an example of a hardware block diagram of a thin film conductor layer sintering apparatus using an electron beam as a charged particle beam. It is an example of the functional block diagram of the sintering apparatus shown in FIG. It is an example of the drive block diagram of a control apparatus. 7 is an example of a blanking signal, a second deflection circumferential direction signal, a second deflection radial direction signal, and a first deflection circumferential signal of the sintering apparatus shown in FIG. 6. It is an example of a scanning electron micrograph. It is an example of the flowchart for demonstrating the formation method of the thin film conductor layer of this invention. It is a figure which shows embodiment of the baking process using an electron beam as a charged particle beam. It is another example of a scanning electron micrograph. FIG. 14 is an enlarged view of the scanning electron micrograph shown in FIG. 13. It is another example of the drive block diagram of a control apparatus. It is an example of the signal diagram of the control apparatus shown in FIG.

<Embodiment 1>
Hereinafter, the first embodiment will be described in detail.
[Constitution]
In the present invention, for example, in the case of an ink jet method, nano copper metal particles are contained in an organic solvent as a dispersoid and a desired pattern is drawn on a medium. The heat treatment for evaporating the organic solvent can be performed at this stage after patterning wiring, or the organic solvent is removed by performing heat treatment on the media in a drying furnace. FIG. 3 shows the case of copper particles as the surface of the patterned wiring (metal fine particle coating layer) that has been dried.
FIG. 4 is a scanning electron micrograph. The magnification of the photo is 100,000 times, and the scanning electron microscope is also called SEM.

  Although the present invention can be applied even in the state of FIG. 3, the kinetic energy of the charged particle beam to be irradiated is effectively used and scattering is reduced. It is necessary to increase the adhesion between the medium and the patterning wiring formed by the metal fine particle coating layer. For this reason, it is desirable to apply pressure to the patterning surface of FIG. 3 using a surface pressing jig or the like with the weight of the plate 103 as a preferable one, and to generate the surface state shown in FIG.

FIG. 5 is an external perspective view of the surface pressing jig.
The surface pressing jig has four parallel guide rods 102a to 102d arranged at the four corners of the table 101. The guide rods 102a to 102d penetrate the table 101 and face the table 101 so as to be separated from the table 101. The jig is made of a plate 103 provided and applies a pressing load to the medium 14 in a plane.
Here, the reason why the pressing load is applied to the medium 14 will be described.

This has two effects.
1． To eliminate the space in the applied layer, that is, the gap.
2． To make the height of the surface substantially uniform. For example, when a charged particle beam such as an electron beam hits an object, it is scattered backward and forward while changing its kinetic energy into heat. When there is a gap, the backward scattering becomes non-uniform. Also, if there are large irregularities on the surface, the convex portions will melt first, and the portions will fall off. In order to prevent this, it is leveled with a surface pressing jig or the like.

First, a linked sintering method as a method for forming a thin film conductor layer according to the present invention will be described with reference to a sintering model diagram of FIGS. 1A to 1C and FIG. 2 illustrating a charged particle beam irradiation procedure. To do.
1A is an example of the wiring pattern 100, FIG. 1B shows an enlarged view of the square region 101 of the wiring pattern 100 shown in FIG. 1A, and FIG. The enlarged view of FIG.1 (b) is shown. FIG. 2 is a diagram illustrating an example of scanning with a charged particle beam.

  In the coupled sintering method of the present invention, the charged particle beam is applied to the regions Sx and Sy in FIGS. 1B and 1C, and the charged particle beam is applied to the procedure A → B → C →. → Sequential scan irradiation as in K is performed to locally melt the metal fine particles in the irradiation region. The Sx and Sy regions are preferably a small partial region of several hundreds of nm, and Sx = Sy. Metal particles having a diameter Sx (= Sy, 200 nm to 1 μm particle size) are newly generated and sequentially melt-connected to form a chain-like connection structure as shown in FIG.

Hereinafter, an embodiment of a firing process suitable for the present invention will be described in detail with reference to FIGS.
6 is an example of a hardware block diagram of a thin film conductor layer sintering apparatus using, for example, an electron beam as a charged particle beam, and FIG. 7 is a functional block diagram of the sintering apparatus shown in FIG. It is an example.
6 mainly includes a host controller 60, a blanking controller 32, a first deflection controller 30, a second deflection controller 28, a position controller 26, a rotation controller 25, and a firing signal generator 31. , A rotation signal processing device 24, an electro-optical column 1, and a sample chamber 10.

  The electron optical column 1 includes an electron gun 2, a blanker 4, an electron lens 5, an aperture 6, circumferential deflectors 8 and 29, radial deflectors 7 and 27, and an electromagnetic lens 9.

In the sample chamber 10, a turntable 13, a stage 12, an air spindle 61, a rotation angle detection device 17, a position detection device 15, a vibration isolation table 18, and a valve 20 are arranged.
The turntable 13 is a mounting table on which the medium 14 is rotatably mounted. The stage 12 is movable in the X direction by a feed screw fixed to the output shaft of the drive motor 11.

  The top plate of the sample chamber 10 is provided with a chamber composed of another partition 10a that can be isolated from the space configured in the sample chamber 10, and both spaces communicate with each other by opening and closing the partition valve 82. An ink jet head (IJ) 80 as an application means is suspended, and ink from the ink tank 81 can be applied onto the medium 14 by a signal from the host control device 60, for example. At the time of ink application, it is performed at atmospheric pressure.

  The upper part of the sample chamber 10 communicates with the electron optical column 1 so that the medium 14 can be irradiated with the electron beam 3 from the electron gun 2.

  In the sintering apparatus shown in FIG. 6, the electron beam 3 emitted from the electron gun 2 in the electron optical column 1 passes through a blanker 4 constituted by parallel plate electrodes, for example, and is converged by an electron lens 5. The electron beam 3 is, for example, a first radial deflector 7 configured by a parallel plate electrode that deflects the electron beam 3 in the radial direction via the aperture 6 and a first circumferential direction that is deflected in the circumferential direction. The light is deflected by a first deflecting device constituted by the deflector 8. Further, a second radial deflector 27 configured by, for example, parallel plate electrodes for deflecting the electron beam 3 in the radial direction and a second circumferential deflector 29 configured to deflect in the circumferential direction are used. It is deflected by the deflection device. By converging with the electromagnetic lens 9, the medium 14 provided with the dry patterned patterning wiring is irradiated.

  Here, when a positive voltage is applied to the first and second radial deflectors 7 and 27, the electron beam 3 is deflected downward in the medium 14, and the first and second circumferential deflectors 8 are deflected. , 29 is configured to be deflected to the upper side in FIG. 6 when a positive voltage is applied. Inside the sample chamber 10 is housed a stage 12 on which a medium 14 coated with a metal fine particle coating layer such as copper particles is mounted on the upper surface. The stage 12 is driven by a position controller 26 by a drive motor 11. Is driven to rotate and can move freely in the plane. The electron optical column 1 is placed on the upper surface of the sample chamber 10.

A main body portion including the electron optical column 1 and the sample chamber 10 is installed on a vibration isolation table 18. The inside of the electron optical column 1 and the sample chamber 10 is evacuated by a pump 21 through a valve 20 and is kept at a vacuum degree of the order of 10 ⁻⁵ Pa. The stage 12 is provided with a position detection device 15 such as a laser holoscale having a resolution of 1 nm or less per pulse via a position signal processing device 34. The position controller 26 receives position command information 39 such as a pulse train from the host controller 60, and sequentially compares the current position information 42 with the position detector 15 and the position signal processor 34 to perform position servo control.

  On the upper surface of the stage 12, for example, an air spindle 61 in which hydrostatic bearings are formed in a radial direction and a thrust direction is fixed. The air spindle 61 is connected to a rotation angle detection device 17 such as a rotary encoder that sends out a pulse signal obtained by dividing a round into several thousand to several hundred thousand, for example, and an origin pulse signal once per round, via a rotation drive motor 16. The rotation signal processing device 24 is provided coaxially.

  The output information to the rotation drive motor 16 and the rotation angle information from the rotation angle detection device 17 through the rotation signal processing device 24 are input to the rotation controller 25 and the A phase signal 46 and B phase signal 45 are input to the rotation controller 25 as a whole. It is composed. The rotation device receives a rotation command pulse signal 40 such as a pulse train from the host control device 60, and sequentially compares it with the current rotation angle information 23 such as a pulse train of the rotation angle detection device 17 via the rotation signal processing device 24. Control or rotational positioning control. Thereby, it is set as the structure which can be positioned to arbitrary rotation and arbitrary rotation angle positions. In PLL (Phase Locked Loop) control, feedback control is performed based on an input periodic signal, and a signal whose phase is synchronized is output from another oscillator.

  A Z-phase signal that is output from the rotation signal processing device 24 and serves as an origin signal generated once per rotation by the rotation device is input to the firing signal generating device 31 together with the A-phase signal 46 and the B-phase signal 45. A rotation angle detection device 17 such as a rotary encoder sends a pulse signal obtained by dividing one round into several thousand to several hundred thousand, and an origin pulse signal once per round.

  The firing signal generation device 31 generates drive signals necessary for firing, which are supplied to the blanking control device 32 for turning on and off the electron beam, the first deflection control device 30, and the second deflection control device.

The sintering apparatus 1000 shown in FIG. 7 includes operation display means 71, rotation means 72, application means 73, control means 74, moving means 75, and irradiation means 76.
The operation display means 71 shown in FIG. 7 is realized by the host control device 60 shown in FIG. 7 is realized by the turntable 13, the rotation drive motor 16, the rotation angle detection device 17, the rotation signal processing device 24, the rotation controller 25, and the air spindle 61 shown in FIG. 7 is realized by the inkjet head 80, the ink tank 81, and the host controller 60 shown in FIG. The moving means 75 shown in FIG. 7 is realized by the drive motor 11, the stage 12, the position detection device 15, the position controller 26, and the position signal processing device 34 shown in FIG.

  The control means 74 is realized by the blanking control device 32, the first deflection control device 30, the second deflection control device 28, and the host control device 60 shown in FIG. The irradiation means 76 in FIG. 7 includes the electron optical barrel 1, electron gun 2, blanker 4, electron lens 5, aperture 6, first radial deflector 7, first circumferential deflector 8 in FIG. This is realized by the second radial deflector 27, the second circumferential deflector 29, and the electromagnetic lens 9.

Control devices such as the blanking control device 32, the first deflection control device 30, and the second deflection control device 28 have a driving configuration shown in FIG. 8 for driving an electrostatic lens, for example.
FIG. 8 is an example of a drive configuration diagram of the control device.
The control device includes a drive amplifier 90 composed of an operational amplifier, an output impedance 91, a load impedance 92, a blanker 4, a first radial deflector 7, and a first circumferential deflector 8. The output impedance 91 and the load impedance 92 are both inductive resistors having 50Ω.

  According to the above configuration, for the desired pattern firing, positioning is performed at a radial position or an angular position, which is the position information of the pattern, from the host control device 60, and the electron is transferred to an arbitrary position within the surface of the medium 14. It becomes possible to irradiate a line.

[Operation]
Next, driving signals supplied to the blanking control device 32, the first deflection control device 30, and the second deflection control device 28 for turning on and off the electron beam will be described with reference to FIGS.
FIG. 9 is an example of a blanking signal, a second deflection circumferential direction signal, a second deflection radial direction signal, and a first deflection circumferential signal of the sintering apparatus shown in FIG.

  Here, the blanking signal is off and the electron beam is emitted. When the blanking is turned off and the electron beam is emitted, the second circumferential deflector 29 is supplied with a triangular wave for performing the scanning shown in FIG. At the same time, a staircase wave is applied to the second radial deflector 27. The width of the staircase wave is a voltage VPr corresponding to the distance Pr.

Here, when LPr = n × Pr is repeated n, the beam returns to the first point A.
What baked copper particle | grains by said scanning procedure is shown in the scanning electron micrograph of FIG. Although not all circular, it can be confirmed that a chain-like connecting structure is formed.
In this case, although locally, the metal particles are completely melted and connected, a wiring pattern having a low resistance characteristic similar to that of a bulk material of metal particles can be obtained.

FIG. 11 is an example of a flowchart for explaining the method for forming a thin film conductor layer of the present invention.
First, a metal fine particle dispersed coating film layer is formed on the medium 14 as a substrate (S1).
The organic solvent is evaporated to form a dried metal fine particle coating layer (S2).
A pressing load is applied to the dried metal fine particle coating layer using the surface pressing jig shown in FIG. 5 (S3).
The dried metal fine particle coating layer is irradiated with a charged particle beam using the sintering apparatus shown in FIG. 6 to form a chain connection structure. As a result, the metal fine particles contained in the metal fine particle coating layer are sintered together, and a metal fine particle sintered body type thin film conductor layer is formed (S4).

[Effect]
According to this embodiment, using a metal fine particle dispersion liquid dispersed in a liquid phase dispersion medium containing an organic solvent, the metal fine particle dispersion liquid is applied to a predetermined position on the substrate with a predetermined film thickness, and the metal fine particle dispersion is applied. A liquid coating film layer is formed. The organic solvent contained in the metal fine particle dispersion coating film layer is evaporated to obtain a dried metal fine particle coating layer. A predetermined pressing load is applied to the dried metal fine particle coating layer from the surface of the coating layer. A predetermined focused charged particle beam is sequentially applied to a small square area of several hundreds of nanometers on the metal fine particle coating layer that has been subjected to pressure load treatment, and the metal fine particles in the square area, which is the irradiation area, are locally melted to 200 nm. Forms a square region of chain-linked structure with a particle size of ˜1 μm.

  The coated fine particle layer is irradiated with a focused charged particle beam, and the dispersing agent covering the surface of the fine metal particle is directly brought into an “activated” state in which vibration excitation is performed. At the same time, the metal particles (atoms) in the irradiation region are locally melted by the kinetic energy of the charged particle beam and connected in a chain form to produce a metal fine particle sintered body. A thin film conductor layer having low resistance characteristics can be generated.

  Here, “transpiration” means drying the organic solvent by heating with an oven, for example. Generally, a dispersion solvent of metal fine particles having a high boiling point is used. For example, tetradecane is used for Ag ink and the like, and has a purity of 100% and a boiling point of 253 ° C. That is, the transpiration here means that the temperature is not raised to the boiling point, but left for several tens of minutes at a temperature of less than 100 ° C.

  According to the present embodiment, the focused charged particle beam is applied to the electron column that irradiates the charged particle beam within the plane of the metal fine particle coating layer, and the square region of 1 to 5 μm can be moved in the orthogonal biaxial direction. One deflection means is provided. A second deflecting means is provided which can move a charged particle beam in a rectangular region of 100 to 500 nm in the orthogonal biaxial direction in the plane of the metal fine particle coating layer. The operation of scanning the charged particle beam from the upper left apex to the upper right apex of the square region, which is the beam movable range of the second deflecting means, is directed to the lower right of the square region at a pitch corresponding to the beam diameter of the charged particle beam. Are sequentially scanned a predetermined number of times.

  Synchronously when the charged particle beam is located at the top left corner of the square area of the second deflection means, the first deflection means is stepped at a pitch corresponding to the square area size of the second deflection means. A chain connection structure is formed by sequentially moving the charged particle beam. As a result, the irradiation control of the charged particle beam becomes easy, the irradiation reproducibility and stability are excellent, and the apparatus cost can be reduced.

  According to this embodiment, a predetermined focused charged particle beam is sequentially irradiated onto a minute partial region of several hundred nm, and the irradiation region is locally melted to form a chain connection structure having a particle diameter of 200 nm to 1 μm. A secondary electron detector is provided in the vicinity of the charged particle irradiation point in order to detect secondary electrons emitted from the dried metal fine particle coating layer surface when irradiated with the charged particle beam. A two-dimensional image at the time of beam scanning of the second deflecting means capable of moving in a quadrangular region of 100 to 500 nm in two orthogonal axes is acquired, and the local melting state can be detected from the contrast strength.

  As described above, a chain connection structure can be formed by adjusting the local melting state of the metal particles while monitoring. Thereby, it is possible to sinter metal fine particles having excellent reproducibility and stability of charged particle beam irradiation, and it is possible to generate a thin-film conductor layer having good current-carrying characteristics or low-resistance characteristics equivalent to a bulk material.

<Embodiment 2>
Hereinafter, the second embodiment will be described in detail.
[Difference]
The difference between the second embodiment and the first embodiment is that the charged particle beam convergence position is shifted in the direction away from the melting surface and connected to the outer edge position where the square regions of the chain connection structure are adjacent to each other. Thus, the metal fine particles contained in the metal fine particle coating layer are sintered to form a metal fine particle sintered body type thin film conductor layer.

[Constitution]
An example of a baking process using an electron beam as a charged particle beam will be described with reference to FIG.
The electron beam 3 emitted from the electron gun 2 in the electron optical column 1 shown in FIG. 12 passes through a blanker 4 constituted by, for example, parallel plate electrodes, is converged by an electron lens 5, and passes through an aperture 6 to form an electron. The beam 3 is deflected in the radial direction.
The electron beam 3 is, for example, by a first deflecting means constituted by a first radial deflector 7 constituted by parallel plate electrodes and a first circumferential deflector 8 deflected in the circumferential direction. Deflected.
The electron beam 3 includes a second radial deflector 27 configured by, for example, parallel plate electrodes that deflect the electron beam 3 in the radial direction and a second circumferential deflector 29 configured to deflect in the circumferential direction. It is deflected by the second deflecting means.
The electron beam 3 is converged by the electromagnetic lens 9, and by a focus control means 101 that makes the convergence position of the charged particle beam variable by an electrostatic lens 100 such as a central electrode 100a and an external electrode 100b as shown in FIG. An optimum convergence diameter is set. The electron beam 3 having an optimum convergence diameter is irradiated onto the medium 14 provided with the patterning wiring subjected to the drying process.
102i is a laser lamp, and the light receiver 102j has a function of detecting the reflected light of the medium 14.

  Here, the electron beam 3 is deflected downward in the medium 14 when a positive (+) voltage is applied to the first and second radial deflectors 7 and 27. The electron beam 3 is deflected upward in FIG. 12 when a positive (+) voltage is applied to the first and second circumferential deflectors 8 and 29.

  Inside the sample chamber 10, a stage 12 on which a medium 14 coated with a metal fine particle coating layer, such as copper particles, is mounted on the upper surface. The stage 12 is driven by rotating the drive motor 11 by the position controller 26. The electron optical column 1 is placed on the upper surface of the sample chamber 10.

Further, the main body having the electron optical column 1 and the sample chamber 10 is installed on the vibration isolation table 18. The inside of the electron optical column 1 and the sample chamber 10 is evacuated by a pump 21 through a valve 20 and maintained at a vacuum degree of the order of 10 ⁻⁵ Pa. The stage 12 is provided with a position detection means 15 such as a laser holoscale having a resolution of 1 nm or less per pulse through the signal processing means 34, for example. The position controller 26 receives position command information 39 such as a pulse train from the host controller 60, and performs position servo control by sequentially comparing it with the current position information 42 of the position detectors 15 and 34.

  Further, on the upper surface of the stage 12, for example, an air spindle 61 in which a hydrostatic bearing is formed in the radial and thrust directions is fixed. The air spindle 61 is coaxially connected with a rotation angle detection means 17 such as a rotary encoder that sends a pulse signal obtained by dividing a circle into several thousand to several hundreds of thousands equally and an origin pulse signal once in a circle via a rotation drive motor 16. It is provided in the shape. The air spindle 61 is provided together with the rotation signal processing means 24.

  The output information to the rotation drive motor 16 and the rotation angle information 45, 46 from the rotation angle detection means 17 via the rotation signal processing means 24 are input to the rotation controller 25 and constitute the rotation means as a whole. For example, a rotation command pulse signal 40 such as a pulse train is input from the host controller 60 to the rotation controller 25, and the PLF is sequentially compared with the current rotation angle information 23 such as the pulse train of the rotation angle detection means 17 via the rotation signal processing means 24. Control (continuous rotation) or rotational positioning control is performed. By this control, it can be positioned at any rotation and any rotation angle position.

The Z-phase signal 41 is output from the rotation signal processing means 24 and becomes an origin signal that is generated once by the rotation means. The Z-phase signal 41 is a rotation signal obtained by rotating the current rotation angle information 23 from the rotation angle detecting means 17 such as a rotary encoder that sends a pulse signal obtained by dividing a circle into several thousand to several hundred thousand and one origin pulse signal per circle. Processed by the processing means 24.
The A-phase signal 46, the B-phase signal 45, and the Z-phase signal 41 are input to the firing signal generating means 31 together with pattern input information (position information) 37 from the host control device 60.

  The firing signal generation means 31 generates a drive signal to be supplied to the blanking control means 32, the first deflection control means 30, and the second deflection control means 28 for turning on / off the electron beam necessary for firing. Note that the control means of the blanking control means 32, the first deflection control means 30, and the second deflection control means 28 has a driving configuration shown in FIG.

  According to the above configuration, for the desired pattern firing, the position information (radius position, angular position) of the pattern from the host control device 60 is positioned, and the electron beam is moved to an arbitrary position within the surface of the medium 14 Can be irradiated.

[Operation]
Next, driving signals supplied to the blanking control means 32 for turning on / off the electron beam, the first deflection control means 30, and the second deflection control means 28 will be described with reference to FIGS.
Here, the blanking signal is off and an electron beam is emitted. When the blanking signal is turned off and the electron beam is emitted, the second circumferential deflection means 29 is supplied with a triangular wave for performing the scanning shown in FIG. At the same time, a step wave (the width is a voltage VPr corresponding to the distance Pr) is applied to the second radial deflection means 27.
Here, when the number of repetitions of LPr = n × Pr is n, the beam returns to the first point A.

  Next, in the case of sintering fine metal particles using the energy of a focused laser beam or focused charged particle beam, small square areas of several hundred nm to several tens of micrometers are connected vertically and horizontally on a plane to sinter a wide square area. It is necessary to conclude. However, the ratio of the metal in the metal fine particle dispersion liquid dispersed in the liquid phase dispersion medium containing the organic solvent is approximately 20 to 70% by weight depending on the type of the metal fine particles. Sintering reduces the pattern volume.

  Therefore, as shown in the scanning electron micrograph of FIG. 13, the adjacent portion of the region A where the sintering was performed first and the region B where the sintering was performed next was irradiated twice, causing a large volume shrinkage, Therefore, as shown in an enlarged view in FIG. 14, there is a possibility that a crack is generated and the pattern is disconnected.

A method for preventing cracks during sintering will be described with reference to the signal diagram of FIG. The overlapping portions described in FIG. 9 are omitted. FIG. 15 is another example of a drive configuration diagram of the control device.
FIG. 16 is an example of a signal diagram of the control device shown in FIG.

As shown in FIG. 16, a step signal is applied to the focus control means 101 at the time of firing on the BJ line in FIG. 2, and the focused position of the focused charged particle beam is shifted upward from the sintered surface. . By this shift, it is preferable to increase the beam diameter of the charged particle beam so that the number of collision electrons per unit area is approximately half.
Note that FIG. 2 illustrates the BJ line as an example, but the present invention is not limited to this, and is located on the AB line, the AI line, the IJ line, and the KL line. It is preferable to perform the same process when forming a boundary line between adjacent metal particle rows.
Since the metal particles are completely melted and connected to expand the range of sintering, a crack-free wiring pattern having low resistance characteristics comparable to that of a bulk material of metal particles can be obtained.

  According to the present embodiment, a “charged” state in which a dispersed charged particle beam is directly irradiated to a layer of applied metal fine particles and a vibration coating is directly applied to the dispersant covering the surface of the metal fine particles. And At the same time, the metal particles (atoms) in the irradiation region are locally melted by the kinetic energy of the charged particle beam and connected in a chain form to generate a metal fine particle sintered body. In addition, the charged particle beam is converged by shifting the convergence position of the charged particle beam away from the melting surface with respect to the outer edge position where the square regions of the chain connection structure are adjacent to each other. In other words, since it can be defocused and sintered to the adjacent outer edge of the square region that is sintered first and the square region that is sintered next, a crack-free sintered pattern can be obtained over a wide range, which is equivalent to the bulk material. A thin-film conductor layer having good current-carrying characteristics (low resistance characteristics) can be generated.

  In addition, according to the present embodiment, the first deflection unit is set to the square region size of the second deflection unit synchronously when the charged particle beam is positioned at the upper left top of the square region of the second deflection unit. The charged particle beam is sequentially moved stepwise at a pitch equivalent to a structure that forms a chain-like connection structure, which makes it easy to control the irradiation of the charged particle beam, provides excellent irradiation reproducibility and stability, and reduces the equipment cost. Can be made inexpensively.

  Further, according to the present embodiment, it is possible to form a chain connection structure while monitoring the local melting state of metal particles, and similarly, it is possible to sinter metal fine particles with excellent charged particle beam irradiation reproducibility and stability. A thin-film conductor layer having good current-carrying characteristics (low resistance characteristics) equivalent to the bulk material can be generated.

  The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. is there.

DESCRIPTION OF SYMBOLS 1 Electron optical column 2 Electron gun 3 Electron beam 4 Blanker 5 Electron lens 6 Aperture 7, 27 1st radial direction deflector 8, 29 1st circumferential direction deflector 9 Electromagnetic lens 10 Sample chamber 11 Drive motor 12 Stage DESCRIPTION OF SYMBOLS 13 Turntable 14 Media 15 Position detection device 16 Rotation drive motor 17 Rotation angle detection device 18 Vibration isolation table 20 Valve 24 Rotation signal processing device 25 Rotation controller 26 Position controller 28 Second deflection control device 30 First deflection control device 31 Firing signal Generation device 32 Blanking control device 60 Host control device 80 Inkjet head 100 Wiring pattern 102i Laser projector 102j Light receiver 1000 Sintering device

JP 2007-314866 A JP 2006-210872 A JP 2006-26602 A JP 2006-38999 A

Claims (9)

A thin film conductor layer forming method for forming a thin metal conductor layer of a metal fine particle sintered body on a substrate,
A metal fine particle dispersion obtained by dispersing a metal fine particle having a surface coating molecular layer of a dispersant on the surface of the metal fine particle as a dispersoid and dispersed in a liquid phase dispersion medium containing an organic solvent is applied to the substrate. Forming a dispersion coating film layer;
Evaporating the organic solvent to form a dried metal fine particle coating layer;
Applying a predetermined pressing load from the coating layer surface to the dried metal fine particle coating layer,
A step of sequentially irradiating a charged particle beam to a metal fine particle coating layer that has been subjected to a pressure load treatment to form a chain-like connection structure;
A method for forming a thin film conductor layer, comprising: A step of sequentially irradiating the charged particle beam and locally melting the irradiation region to form a chain-like connection structure,
The charged particle beam is sequentially scanned at a pitch corresponding to the beam diameter of the charged particle beam from one apex of the square region, which is a movable range of the beam, to the other apex facing the charged particle beam. 2. The method of forming a thin film conductor layer according to claim 1, wherein the charged particle beam is sequentially moved stepwise to form a chain-like connection structure and sintered in synchronization with a position on the top of the thin film conductor. . The metal fine particles contained in the metal fine particle coating layer are formed by shifting the converging position of the charged particle beam in a direction away from the melting surface to the outer edge position where the square regions of the chain connection structure are adjacent to each other and melting and connecting them. A process in which mutual sintering is performed to form a metal fine particle sintered body type thin film conductor layer;
The method of forming a thin film conductor layer according to claim 2, comprising: The step of sequentially irradiating the charged particle beam to form a chain connection structure includes:
A secondary electron detector is installed in the vicinity of the charged particle irradiation point, and a two-dimensional image at the time of beam scanning of the second deflecting means capable of moving in a quadrangular region in two orthogonal axes is acquired. The method for forming a thin-film conductor layer according to any one of claims 1 to 3, wherein the state is detected. A method of forming a thin film conductor layer of a metal fine particle sintered body on a substrate,
The metal fine particles used for the production of the thin film conductor layer are metal fine particles composed of a metal material having a melting point exceeding 200 ° C. and having an average particle diameter in the range of 1 to 100 nm. A step of providing a coating molecular layer of a dispersant that prevents aggregation between fine particles and a metal fine particle dispersion liquid in which a metal fine particle having a coating molecular layer is dispersed in a liquid phase dispersion medium containing an organic solvent is used. Applying the metal fine particle dispersion to the substrate, and moving means that can move in a plane freely by placing the substrate opposite to the application means for applying the metal fine particle dispersion to the substrate. A step of applying a metal fine particle dispersion with a predetermined film thickness to a predetermined position on a substrate to form a metal fine particle dispersion coating film layer, and evaporating an organic solvent contained in the metal fine particle dispersion coating film layer. , Drying process A step of the finished metal fine particle coating layer, a method of forming a thin film conductor layer of the fine metal particles sintered body having,
Applying a predetermined pressing load from the coating layer surface to the dried metal fine particle coating layer,
Irradiate the fine particle partial area of several hundreds of nanometers in order with a focused control means that makes the charged particle beam convergence position variable to the metal particle coating layer that has been subjected to the pressure load treatment. A step of locally melting the fine metal particles to form a chain connection structure having a particle diameter of 200 nm to 1 μm;
The step of applying the pressing load and the step of forming the chain connection structure are sequentially repeated to form a square region of the chain connection structure vertically and horizontally;
By shifting the convergence position of the charged particle beam in a direction away from the melting surface and connecting to the outer edge position where the plurality of square regions are adjacent to each other, the metal fine particles contained in the metal fine particle coating layer can be connected to each other. A step of sintering and forming a metal fine particle sintered body type thin film conductor layer; and
A method of forming a thin film conductor layer, comprising:   The step of melting and connecting the square regions by shifting the convergence position of the charged particle beam in a direction away from the melting surface includes: a magnetic lens that converges the charged particle beam on an electron column that irradiates the charged particle beam; , Focus control means provided with electrostatic lenses above and below the magnetic lens, and the converged charged particle beam can move within the plane of the metal fine particle coating layer in the square area of 1-5 μm in the orthogonal biaxial direction A first deflecting means, a second deflecting means capable of moving a charged particle beam within a plane of a metal fine particle coating layer in a rectangular region of 100 to 500 nm in two orthogonal axes, and the charged particle beam The scanning operation from the top left corner to the top right corner of the square area, which is the beam movable range of the second deflecting means, is directed to the lower right corner of the square area, and scanning is sequentially performed at a pitch corresponding to the beam diameter of the charged particle beam a predetermined number of times At the same time, the focus control means provided with an electrostatic lens only in the irradiation part adjacent to the next sintered area defocuses the convergence position stepwise in the direction away from the melting surface, and the charged particle beam is converted into the second deflection means. In synchronization with the position at the top left of the square area of the first deflection means, the charged particle beam is sequentially moved stepwise at a pitch corresponding to the square area size of the second deflection means to form a chain. 6. The method of forming a thin film conductor layer according to claim 5, wherein the connecting structure is formed to sinter the small area, and the adjacent outer edge portions of the small area are connected and sintered in a wide range.   In the step of forming the chain connection structure, secondary electrons are detected in the vicinity of the charged particle irradiation point in order to detect secondary electrons emitted from the surface of the coating layer of the dried metal fine particles when the charged particle beam is irradiated. To obtain a two-dimensional image at the time of beam scanning of the second deflecting means capable of moving in a quadrangular region of 100 to 500 nm in two orthogonal axes, and to detect the local melting state from the contrast strength The method for forming a thin film conductor layer according to claim 5 or 6, wherein the thin film conductor layer is formed. A thin-film conductor layer sintering apparatus for forming a thin-film conductor layer of a metal fine-particle sintered body on a substrate,
A metal fine particle dispersion obtained by dispersing a metal fine particle having a surface coating molecular layer of a dispersant on the surface of the metal fine particle as a dispersoid and dispersed in a liquid phase dispersion medium is applied to a substrate to form a coating film layer of the metal fine particle dispersion Coating means to form;
A moving means that is arranged to face the coating means and is movable in a plane by placing the substrate;
An irradiation means for forming a dried metal fine particle coating layer;
A pressing load means for giving a predetermined pressing load in a plane with respect to the dried metal fine particle coating layer,
A charged particle beam is sequentially irradiated onto the metal fine particle coating layer that has been subjected to the pressure load treatment by the irradiation means, and the metal fine particles in the irradiation region are locally melted to form a chain connection structure, which is included in the metal fine particle coating layer. A thin film conductor layer sintering apparatus, wherein metal fine particles are sintered with each other to form a metal fine particle sintered body type thin film conductor layer. The metal fine particles used for the production of the thin film conductor layer are composed of a metal material having a melting point of at least 200 ° C., and the metal fine particles have an average particle diameter in the range of 1 to 100 nm.
A coating molecular layer of a dispersant is provided on the surface of the metal fine particles to prevent aggregation between the metal fine particles, and the metal fine particles having the coating molecular layer are dispersed in a liquid phase dispersion medium containing an organic solvent as a dispersoid. An application means for applying the metal fine particle dispersion to the substrate using the metal fine particle dispersion;
A moving means that faces the coating means and is movable in a plane by placing a substrate;
Means for moving the metal fine particle dispersion liquid to a predetermined position on the substrate by the moving means and applying the metal fine particle dispersion liquid at a predetermined film thickness;
A thin-film conductor layer for forming a thin-film conductor layer of a metal fine-particle sintered body having means for evaporating an organic solvent contained in the metal-fine-particle-dispersed coating film layer to form a dried metal fine-particle coating layer A sintering device of
A means for applying a predetermined pressing load from the coating layer surface to the dried metal fine particle coating layer,
Means for sequentially irradiating a minute partial region of several hundred nm with a predetermined converged charged particle beam by a focus control means for changing the convergence position of the charged particle beam with respect to the metal fine particle coating layer that has been subjected to the pressure load treatment;
Means for locally melting metal fine particles in the irradiation region to form a chain-like connected structure having a particle diameter of 200 nm to 1 μm;
When the charged fine particle beam is sequentially irradiated onto the square region, which is the beam movable range, to form the quadrangular chain connection structure in a wide range, vertically and horizontally, the convergence position of the charged particle beam is shifted in a direction away from the melting surface. Means for melting and coupling,
9. The sintering of a thin film conductor layer according to claim 8, wherein the metal fine particles contained in the metal fine particle coating layer are sintered to form a thin metal conductor layer of a metal fine particle sintered body type. apparatus.