KR20100118230A - Method for fabricating conductive micro-pattern - Google Patents

Abstract

PURPOSE: A method for manufacturing a fine conductive pattern is provided to improve the precision and the electric conductivity of the fine conductive pattern using a laser-induced deposition method. CONSTITUTION: A receiving substrate is located in a laser processing machine(S100). A metal thin film layer is formed on the lower side of a transparent substrate(S200). A polymer layer is formed on the surface of the metal thin film layer(S300). The transparent substrate is spaced apart from the receiving substrate such that the polymer layer is corresponded to the surface of the receiving substrate(S400). Laser is radiated to the upper side of the transparent substrate(S500).

Description

Method for manufacturing a fine conductive pattern {Method for fabricating conductive micro-pattern}

The present invention relates to a method of manufacturing a fine conductive pattern, and more specifically, it is possible to improve the precision and electrical conductivity of a fine pattern by using laser induced deposition, and to deposit a three-dimensional fine structure such as a fine pattern and a microelectrode. In addition, the present invention relates to a method of manufacturing a fine conductive pattern capable of maintaining physical properties of a deposited thin film and preventing thermal damage such as microcracks of a substrate.

Recently, technology development researches on high-performance micro components from optical digital communication technology, display technology and micro processing technology to micro chemistry, bioanalysis, and medicine are being actively conducted.

Accordingly, various processes for manufacturing microstructures having a micro-nano unit size shape have been studied. As a result, the processing technology is gradually changing to the trend of miniaturization, functionalization and diversification, and the demand for product shape precision is increasing.

Fine pattern fabrication technology is a technology that is used for the manufacturing of optical component devices and manufacturing micro components, microfabrication, printing, electronic component manufacturing, conductive circuit manufacturing.

Currently, a technique used as a fine pattern manufacturing technology is a lithography process based on a semiconductor process, but a mask manufacturing process is required, which causes problems in economical efficiency when producing small quantities of prototypes or multi-types.

Therefore, a technique of manufacturing a fine pattern on the surface of a material by using laser induced forward transfer (LIFT) without a mask has been proposed. However, until now, the pattern manufactured by the LIFT process has a low precision, thereby limiting the application field. Have.

In addition, since the deposition is induced by a laser, the physical properties of the deposited thin film are changed by the high heat energy introduced therein, or thermal damage such as microcracks of the substrate occurs.

The present invention is to solve the above problems, an object of the present invention is to improve the precision and electrical conductivity of the micropattern using the laser induced deposition method, the deposition of three-dimensional microstructures such as micropattern and microelectrode It is possible to provide a method of manufacturing a fine conductive pattern capable of maintaining the physical properties of the deposited thin film and preventing thermal damage such as microcracks of the substrate.

In order to achieve the above object of the present invention,

According to one aspect of the invention,

(a) placing the receiving substrate on the laser processor;

(b) forming a thin metal layer on the lower surface of the transparent substrate;

(c) forming a polymer layer on the surface of the metal thin film layer;

(d) positioning the transparent substrate above the receiving substrate so that the polymer layer corresponds to the surface of the receiving substrate; And

(e) there is provided a method of manufacturing a fine conductive pattern comprising the step of irradiating a laser on the upper surface of the transparent substrate.

As described above, the method of manufacturing a fine conductive pattern according to the present invention can improve the precision and electrical conductivity of the fine pattern by using a laser induced deposition method, and the deposition of three-dimensional fine structures such as fine patterns and fine electrodes It is possible to maintain the physical properties of the thin film to be deposited, and to prevent thermal damage such as microcracks of the substrate.

Hereinafter, a method of manufacturing a fine conductive pattern according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The accompanying drawings show exemplary forms of the present invention, which are provided to explain the present invention in more detail, and the technical scope of the present invention is not limited thereto.

In addition, the thickness and size of each member shown in the drawings may be exaggerated or reduced for convenience of description.

1 is a block diagram of a device used in the method of manufacturing a fine conductive pattern according to an embodiment of the present invention, Figure 2 is a transparent substrate and the receiving used in the method of manufacturing a fine conductive pattern according to an embodiment of the present invention Figure 3 is a detailed view showing a substrate, Figure 3 is a process chart showing a method of manufacturing a fine conductive pattern according to an embodiment of the present invention, Figure 4 is a laser used in the method of manufacturing a fine conductive pattern according to an embodiment of the present invention It is a conceptual diagram showing inductive deposition.

The present invention is a method of manufacturing a fine conductive pattern using a laser induced deposition method, specifically the method of manufacturing a fine conductive pattern according to an embodiment of the present invention (a) placing the receiving substrate on the laser processing machine (S100) ; (B) forming a metal thin film layer on the lower surface of the transparent substrate (S200); (c) forming a polymer layer on the surface of the metal thin film layer (S300); (d) placing the transparent substrate spaced apart above the receiving substrate so that the polymer layer corresponds to the surface of the receiving substrate (S400); And (e) includes a step of irradiating a laser on the upper surface of the transparent substrate (S500).

Referring to FIG. 4, a laser induction deposition method is described. The metal thin film layer 2 is deposited on the rear surface of the transparent substrate 1 through which a laser beam is transmitted by using an electron beam or the like, so as to face the metal thin film layer 2. The receiving substrate 3 is spaced apart from the transparent substrate 1 at predetermined intervals.

Thereafter, the laser beam is irradiated onto the entire surface of the transparent substrate 1, scanned, and the fine pattern shape 4 is deposited. Specifically, the focused laser beam passes through the transparent substrate 1 to the metal thin film layer 2. When absorbed, the metal thin film of the portion to which the laser beam is irradiated is ablated and deposited on the surface of the adjacent receiving substrate 3 to form the fine conductive pattern 4.

In this document, the front surface of the transparent substrate refers to a surface corresponding to the laser, the rear surface refers to the surface on which the metal thin film layer is formed, and the surface of the receiving substrate refers to the surface facing the metal thin film layer.

Referring to Figure 1, the apparatus used in the method for producing a fine conductive pattern according to the present invention is composed of a laser processing machine including a laser beam 31 and a laser processing machine table (30).

A motor (not shown) may be installed on the table 30 of the laser processing machine, and the laser beam 31 may be moved for scanning in the horizontal direction by the motor.

Here, the receiving substrate 20 is disposed on the laser processing machine table 30, and the transparent substrate 11 is positioned between the receiving substrate 20 and the laser beam 31 in the laser processing machine, and the transparent substrate 11 is disposed. The position can be fixed through the mounting jig or the like.

The metal thin film layer 12 is formed on the rear surface of the transparent substrate 11, and the polymer layer 13 is formed on the surface of the metal thin film layer 12.

The transparent substrate 11 may be formed of a transparent material that can transmit a laser, but is not limited thereto. For example, the transparent substrate 11 may be glass or transparent resin.

Here, the metal thin film layer 12 may be formed of various metals capable of inducing a pyrolytic deposition reaction by reacting with a laser, but is not limited thereto, and may be, for example, copper, aluminum, gold, nickel, or chromium. It may be formed by a method such as an electron beam, a thermal evaporator or a sputter.

The metal thin film layer 12 may have a thickness t1 of 300 μm to 800 μm, and when formed to a thickness lower than the numerical value, the metal thin film layer 12 is easily vulcanized even with low irradiation intensity of the irradiated laser beam. Since the deposition rate deposited on the receiving substrate 20 is lowered, there may be a problem that it cannot be used as a conductive circuit board, and when formed to a thickness larger than the above value, irradiation per unit area of the laser beam causing peeling on the transparent substrate 11 may occur. Since the strength should be increased, the physical properties of the receiving substrate may be changed due to the thermal damage to the receiving substrate 20.

A polymer layer 13 is formed on the surface of the metal thin film layer 12, and the polymer layer 13 is not limited thereto, and after applying a polymer to the surface of the metal thin film layer 12, soft-baking. It can form by processing, The thickness t2 can be formed in 0.1-3 micrometers, It is preferable to form in about 1 micrometer. When formed to a thickness lower than the above numerical value, a layer by layer laser beam is irradiated to form a conductive layer having a desired shape by falling in shape precision and dimensional accuracy of the deposition layer of the metal thin film layer 12 of the transparent substrate 11. Problems may occur, and when formed to a thickness greater than the numerical value, the deposition structure of the deposit generated by the reaction with the laser light may not be dense, and thus may cause a problem that the adhesive strength is lowered.

The polymer layer 13 serves to improve the thickness of the deposition pattern, the adhesion to the receiving substrate 20 and the electrical properties of the conductivity in the laser flow deposition process.

In the present disclosure, unless otherwise specified, the transparent substrate 11, the metal thin film layer 12, and the polymer layer 13 may be referred to as a work piece 10.

When the fabrication of the work 10 is completed, the work 10 is disposed at a predetermined distance d above the accommodation substrate 20 such that the polymer layer 13 faces the surface of the accommodation substrate 20.

In this case, the interval d may be 50 μm to 100 μm, and when disposed at intervals lower than the numerical value, the transparent substrate may sufficiently react with the laser beam in the depth of focus area of the laser optical system in the molten state of the metal thin film layer 12. The molten residue emulsion of the polymer may be included in the deposition layer when deposited and transferred to the receiving substrate at, and may cause problems in electrical conductivity, and when disposed at intervals larger than the above value, high adhesion to the receiving substrate at the irradiation intensity of the same laser beam is achieved. Insufficient kinetic energy to allow deposition to occur due to strength may result in a weakening of the adhesive force and the bond between the deposition metals.

On the other hand, it has been described so far to position the workpiece 10 after placing the receiving substrate 20 in the laser processing machine, the present invention is not limited thereto, the arrangement of the receiving substrate 20 and the arrangement of the workpiece 10 It is also possible to reverse the order.

In addition, the apparatus used in the method for producing a fine conductive pattern according to the present invention includes a focusing lens 32 disposed between the transparent substrate 11 and the laser 31, whereby laser processing will produce a high energy intensity And focusing within a few hundreds of micrometers can form a small focal size.

When the fabrication of the workpiece 10 and the placement of the receiving substrate 20 and the workpiece 10 are completed, the laser 31 is irradiated onto the front surface of the transparent substrate 11.

The laser 31 irradiated to the metal thin film layer 12 is partially reflected according to the reflectance of the material, and the remaining energy is absorbed into the metal thin film layer 12 while the intensity of light decreases exponentially from the surface. At this time, the absorbed light energy is converted into thermal energy and the metal thin film layer 12 on the rear surface of the transparent substrate 11 causes thermal decomposition by thermal conduction. Then, the by-product 40 formed through the thermal decomposition reaction by the thermal conductivity is deposited on the surface of the receiving substrate 20, and the pulverized particles escape to the surroundings.

The laser 31 for heating the receiving substrate 20 is focused on a very small size of several tens of micrometers on the surface of the receiving substrate 20, and the polymer layer deposited on the receiving substrate absorbs the laser and heats the region of the receiving substrate. The area where deposition takes place is limited to a very small area similar to the focal size of the laser.

By forming the deposition layer 40 on the surface of the receiving substrate 20 and then performing a new deposition on the deposition layer 40 again, the thickness of the deposit can be continuously increased, and the laser is further localized. By continuously irradiating in a layer by layer order, the deposit may be deposited on the surface of the receiving substrate 20 in the height direction, thereby depositing a three-dimensional microstructure.

On the other hand, if there is no polymer layer 13 in the work piece 10, thermal decomposition may occur due to overheating of the receiving substrate because it is thermally decomposed with a laser irradiated onto the metal thin film layer 12, and the receiving wave due to thermal stress is fine cracked. Thermal damage may occur.

Since the method of manufacturing a fine conductive pattern according to an embodiment of the present invention includes the step of forming the polymer layer 13 on the workpiece 10, it is possible to prevent the physical property change of the metal thin film due to the thermal energy of the laser, By improving the absorption rate of the laser, it is possible to prevent rapid temperature rise and thermal damage on the surface of the receiving substrate, thereby improving productivity.

In addition, by forming the metal thin film layer 12 on the rear surface of the transparent substrate 11, it is possible to prevent the plasma energy is formed to block the laser energy during processing.

5 to 10 are views showing examples and comparative examples according to the present invention.

FIG. 5 is a photograph of etching the cross-section deposited using a focused ion beam (FIB) device in order to investigate the effect of the induction deposition experiment using the polymer coating layer on the deposition cross section.

In the deposition experiment, the process using the laser induced deposition without forming the polymer layer on the workpiece was compared with the process using the laser induced deposition with the polymer layer formed on the surface of the metal thin film layer proposed in the present invention.

The deposition structure was deposited using chromium (Cr) on the silicon, the laser focus is fixed and then multi-scan the beam in the height direction. Figure 5 (a) is a cross-sectional photograph of a structure deposited using a laser induction deposition process without a polymer coating, (b) is a result of performing a laser induction deposition process after forming a polymer layer on the surface of the metal thin film layer. .

The number of scans of the laser beam is a result of analyzing a surface of a deposition structure deposited 20 times in a fixed focus method of scanning a beam after fixing the focus of the laser beam. In the deposition process without using the polymer layer, a deposition structure having a height of about 8 μm was deposited in 20 beam scans, and in the deposition process using the polymer layer, the deposition rate was increased by about 15 μm, thereby increasing the deposition rate by more than twice. I could confirm that In addition, as a result of the cross-sectional analysis of the focused ion beam device, it can be seen that the structure of the deposition layer using the polymer layer is more uniform and dense than the structure of the deposition layer when the polymer layer is not formed. This improved the absorption rate of the laser beam, thereby reducing the amount of evaporation due to thermal energy and improving the deposition rate on the receiving substrate. There was little change in the physical properties of the metal thin film due to the improved absorption rate of the beam. In addition, the laser beam is scanned again on the surface already deposited through the multi-beam scanning method of further irradiation, and thus the deposition structure becomes dense and the compression sintering effect of the molten metal particles can be obtained by the impact wave generated by the laser beam.

6 is a photograph of the deposition surface of the focused ion beam observed to analyze the effect of the polymer coating effect on the deposition surface shape. (a) is a surface shape photograph deposited using a deposition process without a coating layer, and (b) is a deposition surface shape using a polymer coating. The deposited metal thin film material is chromium (Cr) and the surface shape of the deposition surface can be observed that the deposition surface structure using the polymer coating is uniformly and precisely deposited.

The uniform deposition surface is due to the laser beam irradiation by the multi-scan method. The thin metal layer is peeled off through the pyrolysis reaction on the transparent substrate and the polymer is removed together when the induction deposition occurs on the receiving substrate. This is because the structure of the deposition surface is improved by the sintering effect. In (b), the surface of the deposition surface using the polymer coating has a sponge-like structure, and the size of the molten metal deposited on the surface is uniform to the receiving substrate with a size of 5 to 25 μm as observed through a focused ion beam image. It has a dense deposition surface shape.

FIG. 7 is an electron micrograph showing the surface shape of a metal thin film deposited on a receiving substrate before and after performing a polymer coating laser induced deposition process.

(a) and (b) are 400 nm thick chromium thin films deposited on a Pyrex glass substrate used as a transparent substrate in a laser induced deposition process, and then coated with a 1 micrometer thick polymer using a spin coater and soft baked. Electron micrographs of the surface of polymer metal-coated thin films and EDX spectra for component analysis of metal-coated thin films are shown.

As a result of the component analysis, the metal-coated thin film was found to have 76.22% (wt%) of oxygen and 23.24% of oxygen, which is a polymer organic material, in the measurement region. It was found that the chromium thin film under the polymer coating was measured at 0.54%.

7 (c) and (d) are SEM photographs and EDX analysis results of the surface deposited by a polymer coating deposition process on a silicon wafer. As a result of analysis of the deposition surface, 18.84% oxygen, 3.98% silicon (Si) and 77.18% chromium (Cr) were detected. As a result of the analysis of the deposition surface, using the polymer coating induction deposition process, the deposition surface does not contain carbon as an organic polymer component on the thin film, so that the polymer layer can be accommodated with the transparent substrate through the pyrolytic reaction by the irradiated laser beam. Surface analysis showed that only the molten metal was deposited on the receiving substrate by evaporation between the substrates.

8 is a SPM (Scanning Probe Microscope) photograph for measuring the shape of the deposition surface due to the polymer coating was measured in 20㎛. The size of the molten metal deposited particles in the measurement region reaches 5 to 10 μm. (B) and (d) of FIG. 8 measure the surface roughness of the deposition surface. When the polymer coating is not used, Ra = 200.65 nm, and when the polymer coating is used, Ra = 169.69 nm and about Ra = 30 nm. Roughness is improved. The surface deposited using the polymer coating was confirmed to be more uniform and flat deposition. It can be seen that the metal molecules are recombined in the process of recrystallization of the molten metal particles by the multi-scan method to increase the deposition density and the deposition surface shape.

FIG. 9 shows the edge quality and the deposition surface quality of the chromium (Cr) thin film by coating and induction deposition test results when the coating was not carried out as an experiment on the polymer coating effect. Experimental results When the coating is not coated (FIG. 9 (a)) and when the coating (SEM (FIG. 9)) shows the results of the deposition test using the polymer coating layer, the coating is not The edge quality is much clearer, and in the case of the shape of the deposition surface, a continuous and uniform surface can also be observed.

FIG. 10 is a SEM photograph of the microstructure of chromium (Cr) deposited on a silicon wafer by induction deposition experiment using a polymer coating. (A) and (b) of Figure 10 is a photograph of the micro pattern deposited using a conventional induction deposition process without a polymer coating, (c) and (d) is a coating of a polymer on the metal thin film proposed in the present invention This is the result of induction deposition process.

The deposited material is chromium, and when looking at the boundary of the deposition surface, it can be seen that the induction deposition process after the polymer coating clearly shows the deposition surface boundary. In addition, when the chromium layer is expanded, the surface of the deposition process applied after the polymer coating is deposited more densely. This is because the polymer coated before the deposition process is removed together when the metal thin film layer evaporates due to the irradiated laser to improve deposition on the surface.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having various ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. And additions should be considered to be within the scope of the following claims.

1 is a block diagram of a device used in the method for producing a fine conductive pattern according to an embodiment of the present invention.

Figure 2 is a detailed view showing a transparent substrate and a receiving substrate used in the method for producing a fine conductive pattern according to an embodiment of the present invention.

3 is a process chart showing a method of manufacturing a fine conductive pattern according to an embodiment of the present invention.

4 is a conceptual diagram showing laser induced deposition used in the method for producing a fine conductive pattern according to an embodiment of the present invention.

5 to 10 show examples and comparative examples according to the present invention.

Claims (6)

(a) placing the receiving substrate on the laser processor; (b) forming a thin metal layer on the lower surface of the transparent substrate; (c) forming a polymer layer on the surface of the metal thin film layer; (d) positioning the transparent substrate above the receiving substrate so that the polymer layer corresponds to the surface of the receiving substrate; And (e) manufacturing a fine conductive pattern comprising the step of irradiating a laser on the upper surface of the transparent substrate. The method of claim 1, In step (c), the polymer layer is a method of producing a fine conductive pattern, characterized in that formed by applying a polymer on the surface of the metal thin film layer, followed by exposure. The method of claim 1, And the laser is focused through the focusing lens and then irradiated onto the transparent substrate. The method of claim 1, In step (c), the polymer layer is a method of producing a fine conductive pattern, characterized in that the thickness is formed to 0.1㎛ to 3㎛. The method of claim 1, In the step (d), the transparent substrate is a method of producing a fine conductive pattern, characterized in that spaced apart so that the distance to the receiving substrate 50㎛ to 100㎛. The method of claim 1, In step (b), the metal thin film layer is a method of producing a fine conductive pattern, characterized in that the thickness is formed from 300㎛ to 800㎛.

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