KR20190103821A - Beam driller using multiplefocusing controller and Beam drilling method - Google Patents

Abstract

Provided are a beam drilling device and a beam drilling method. The disclosed beam drilling device comprises: a light source; a light modulator which changes a light path; a multi-focus adjustment part for changing a focal length of a light transmitted from the light modulator; an XY stage supporting an object of a multi-layer structure; and a control part wherein a first layer of the multi-layer structure is processed by a first focal length light, and a second layer is processed by a second focal length light. The beam drilling device according to the present disclosure is a combination of the multi-focus adjustment part and the light modulator, does not change a focal length in a Z-axis direction in a via hole processing of a PCB and the like, and shortens a processing time by changing the focal length without delay for improving a processing quality.

Description

Beam driller using multiple focusing controller and beam drilling method

The present disclosure relates to a beam drilling apparatus and a drilling method using a multi-focus control unit capable of minimizing a time required for changing a focal length in laser processing of a wiring circuit board.

Recently, processing technology for cutting, drilling, and patterning objects has been developed in various industries. This processing technique generally scans the surface of the workpiece with a laser beam to process the shape or physical properties of the surface of the workpiece. There may be various examples of the object to be processed, and for example, include a two-dimensional planar object such as a silicon wafer. The technology for fast processing of the object to be processed can improve the fairness and bring a lot of cost in terms of technology development continues.

In general, processing equipment of a printed circuit board (PCB) is divided into two stages of processing a copper foil in the upper part and a polyimide in the middle part in the processing of a blind via hole (BVH). do. At this time, since the movement of the z-axis motor is required during the two-stage processing of copper foil and polyimide, the processing time is long, and the quality of processing is deteriorated.

The present disclosure is to provide a beam drilling apparatus and a drilling method using a multi-focus control unit that can minimize the time required to change the focal length in the laser processing of the wiring circuit board.

Beam drilling apparatus according to one disclosure, the light source; An optical modulator for changing a path of light transmitted from the light source; A multi focus control unit for changing a focal length of light transmitted from the light modulator; A scanner unit for moving the light transmitted from the multi-focus control unit to an object; An XY stage for supporting an object having a multi-layer structure including a first layer and a second layer positioned below the first layer; And controlling the light source, the light modulator, the scanner unit, and the XY stage so that the first layer of the object is processed into first focal length light, and the second layer of the object is processed into second focal length light. It includes a control unit.

The first layer is formed of a material having a higher hardness than the second layer, and the controller is configured to control the light modulator to process the first layer into forward focus light and to process the second layer into out focus light. Can be.

The object of the multilayer structure may be a printed circuit board.

The first layer may be formed of a copper film, and the second layer may be formed of polyimide.

The multi focus controller may include a first beam expander for focusing the beam at a first focal length and a second beam expander for focusing the beam at a second focal length.

The optical modulator may be an optical optical modulator.

The controller may control at least one of the XY stage and the scanner unit to process the first layer in the form of a closed loop and to remove the first layer.

According to one disclosure, a beam drilling method for processing an object including a multilayer having different hardness, comprising: machining a first layer with a first beam expander having a first focal length; And processing the second layer by switching the beam with a light modulator to a second beam expander having a second focal length.

The hardness of the first layer is lower than the hardness of the second layer, the step of processing the first layer is a step of processing in the forward focus, the step of processing the second layer may be a step of processing out of focus have.

The step of processing the first layer may be a step of processing and providing at least one of the XY stage and the scanner unit while moving in the XY plane.

The step of processing the second layer may be a step of providing at least one of the XY stage and the scanner unit by processing the second layer while moving in the XY plane.

The processing of the second layer may be processing using an optoacoustic modulator.

A beam drilling method for processing an object including multilayers having different hardness according to another disclosure, the method comprising: determining an appropriate focal length based on a location and a material of an object; Switching to and selecting a beam expander that satisfies the determined appropriate focal length of the multi focus controller by an optical modulator; And processing the object to the appropriate focal length.

The optical modulator may be an optoacoustic modulator.

The beam drilling apparatus according to the present disclosure is a combination of a multi-focus control unit and an optical modulator, and does not change the focal length in the Z-axis direction in via hole processing of a PCB, and changes the focal length without delay to shorten the processing time and the quality To improve.

FIG. 1 is a schematic cross-sectional view of a process object having a printed circuit board structure and a process of forming a blind via hole (BVH).
2 is a flow chart showing a beam drilling method according to the prior art.
3 is a view schematically showing a beam drilling apparatus according to one disclosure.
4 is a flow chart illustrating a beam drilling method according to one disclosure.
FIG. 5 is a view illustrating a time point of generation of an optical modulator driving signal for changing a focal length without losing time and a light source continuously driven.
6 is a view schematically showing a beam drilling apparatus according to another disclosure.
7 is a schematic cross-sectional view of a workpiece having a multilayer structure and a process of forming a blind via hole (BVH).
8 is a flowchart illustrating a beam drilling method according to another disclosure.

Hereinafter, a continuous machining apparatus and a continuous machining method according to an exemplary embodiment will be described in detail with reference to the accompanying drawings.

In the drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of description. Meanwhile, the embodiments described below are merely exemplary, and various modifications are possible from these embodiments.

Hereinafter, what is described as "upper" or "upper" may include not only directly over and in contact but also overlying.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a schematic cross-sectional view of a process object having a printed circuit board structure and a process of forming a blind via hole (BVH). Referring to FIG. 1, the object to be processed in the form of a printed circuit board includes a first layer L1, a second layer L2, and a third layer L3. In general, the second layer L2 is provided between the first layer L1 and the third layer L3 and is formed of a softer material than the first layer L1 and the third layer L3. For example, the second layer l2 may be formed of polyimide. In general, the first layer ℓ1 and the third layer ℓ3 are formed of the same material and are formed of a copper film. However, this is only an example on the premise of a processing object in the form of a printed circuit board and is not limited thereto.

In general, a printed circuit board is formed of a double-sided printed circuit board type or a multilayer printed circuit board type by coating copper foil on both sides of an epoxy-based insulating layer. By forming blind via holes in such a printed circuit board, a through hole connecting two or more conductor layers to each other can be formed. Therefore, the process of blind via holes is indispensable for the use of a printed circuit board.

Referring to FIG. 1A, a processed object having a multi-layered structure of three or more layers is provided.

Referring to FIG. 1B, a via hole may be formed in a portion of the first layer L1 positioned at the top of the multi-layer structure.

Referring to FIG. 1C, a via hole may be formed in a portion of the second layer L2 positioned at the lower end of the first layer L1 having a multi-layer structure.

In the case of a printed circuit board, since the material and the hardness of the first layer L1 and the second layer L2 are different, a processing apparatus and a processing method reflecting such a hardness difference are required for processing using a laser beam.

2 is a flow chart showing a beam drilling method according to the prior art.

Referring to FIG. 2, in the beam drilling method according to the related art, the laser beam is forward-focused (S1) by moving the Z-axis motor to process the first layer of the object.

Thereafter, the XY stage and the scanner unit are driven to move in the X-Y plane to process and remove the first layer (S2). As a result, a blind via hole is formed in the first layer.

Thereafter, the Z-axis motor is moved to out focus S3. As described above, since the position and the material of the first layer and the second layer are different, the focal lengths required for processing are different accordingly. Thus, in order to adjust the focal length, it is required to adjust the focal length of the laser beam using the Z-axis motor. For example, in the case of printed circuit board processing, since the second layer is an insulating layer, the hardness is lower than that of the first layer and the third layer, which are conductive layers. Therefore, the second layer may be processed by out-focusing the beam on the premise of using light of the same output.

Thereafter, the XY stage and the scanner unit may be driven to move in the X-Y plane to process and remove the second layer (S4).

As described above, the beam drilling method according to the related art requires an operation of changing the focal length by moving the optical module in the Z-axis direction using a Z-axis motor. In the case of such a Z-axis drive, the machining time is increased and the machining quality is degraded. In particular, in the case of laser beam processing, since the mass of the scanner unit and the motor unit is heavier than several hundred g, it takes time to accelerate and stop due to inertia during Z-axis driving, and there is a problem that vibration occurs.

3 schematically shows a beam drilling apparatus 100 according to one disclosure. The beam drilling apparatus includes a controller 110, a light source 120, an optical modulator 130, a multi focus controller 140, a scanner unit 150, and an XY stage 160.

The controller 110 controls the operation of the light source 120, the light modulator 130, the multi focus controller 140, the scanner unit 150, and the XY stage 160. The controller 110 may be configured of, for example, an electronic control device such as a processor, a memory, and the like, and is not limited to a particular embodiment. The controller 110 may include an input device (not shown) or an output device (not shown) to receive a user input and output a control state to the user. The controller 110 may include a communication unit (not shown) to transmit / receive information with an external device. For example, the information may include control data related to control of the optical modulator 130, control data related to control of the multi focus controller 140, control data related to control of the scanner unit 150, and the light source 120. It may include control data associated with the control of.

The light source 120 may irradiate light to the light modulator 130. The light source 120 may irradiate high power light for processing the object. For example, the light source 120 may be a laser light source. For example, the light source 120 may use various types of laser light sources, such as a carbon dioxide laser, a helium-neon laser, an argon-ion laser, an excimer laser, a semiconductor laser, a solid state laser, a liquid laser, and the like. It doesn't work.

The light modulator 130 may change the path of the light transmitted from the light source 120 to the first path or the second path. For example, the optical modulator 130 may be a high speed modulator having a conversion time of 1 μs or less. For example, the optical modulator 130 may change the switching of light from the first path to the second path or from the second path to the first path within 1 μs. For example, the optical modulator 130 may be an acoustic optical modulator (AOM).

The multi focus controller 140 may adjust a focal length of the light transmitted from the light modulator 130. For example, the multi focus controller 140 may include a first beam expander 141 and a second beam expander 142. The first beam expander 141 may be provided on the first path, and the second beam expander 142 may be provided on the second path. By switching the optical modulator 130, the light may pass through the first beam expander 141 to have a first focal length. Alternatively, light may have a second focal length through the second beam expander 142 by switching of the optical modulator 130. Since the switching time of the optical modulator 130 is 1 μs or less, the focal length may also be converted to 1 μs or less. This is very short compared to the beam drilling apparatus and method according to the prior art, which takes several seconds to several tens to convert the focal length, which can bring about a reduction in machining time.

Referring to FIG. 3, the first beam expander 141 and the second beam expander 142 may have a structure in which a first lens having negative refractive power and a second lens having positive refractive power are combined. When the first lens diffuses the light, the second lens may condense the light to condense the light at a specific position. The focal lengths of the first beam expander 141 and the second beam expander 142 may be adjusted by adjusting the arrangement of the refractive power of the first lens and the second lens and / or the distance between the first lens and the second lens. For example, the first beam expander 141 may form a positive focus for condensing light on the first layer l1 of the object ob. For example, the second beam expander 142 may form an out focus for collecting light at the top or the bottom of the second layer ℓ2 of the object ob instead of directly collecting the light.

The scanner unit 150 may move the light transmitted from the optical modulator 130 in two dimensions on the surface of the object ob. The scanner unit 150 may be driven in the X-Y plane under the control of the controller 110, and may form blind via holes in the first layer l1 and the second layer l2 of the object ob.

The XY stage 160 may support the object ob. The XY stage 160 may be driven in the X-Y plane under the control of the controller 110. The XY stage 160 is driven at a low speed, and the scanner unit 150 is driven at a relatively high speed, thereby enabling efficient processing of the object ob. The controller 110 selects at least one of the XY stage 160 and the scanner unit 150 according to the size and shape of the processing target region in that the driving speeds of the XY stage 160 and the scanner unit 150 are different. Alternatively, both may be driven and processed together.

The object ob may have a multi-layered structure 1, 1, 2. As described above, the object ob may be a printed circuit board, but is not limited thereto.

Although the beam drilling apparatus 100 according to the present disclosure does not drive the scanner unit 150 in the Z-axis direction, the beam modulator 130 and the multi-focus controller 140 adjust the focal length in the Z-axis direction. It can be implemented in combination. Through this, the focus conversion time can be changed within 1 μs, so that the blind via hole of the object ob can be formed at high speed, and the Z-axis driving can be removed to prevent quality degradation due to vibration.

4 is a flow chart illustrating a beam drilling method according to one disclosure. Referring to FIG. 4, in the beam drilling method according to the present disclosure, positive focusing may be formed by irradiating a laser beam to a first beam expander (first BET) with an optical modulator (AOM). The laser beam may be focused on the uppermost surface of the object having a multi-layer structure. When the object is a printed circuit board, the laser beam may be focused on a copper film on the top. In the case of copper foil, since the hardness is high because it is formed of a metal material, it may be advantageous to process the laser beam of high power to be focused.

Next, at least one of the XY stage and the scanner unit may be driven to move in the X-Y plane to process and remove the first layer (S102). Since the XY stage is a low speed drive and the scanner unit is a relatively high speed drive, it is possible to selectively drive one of both components or both together depending on the machining area. As a result, a blind via hole is formed in the first layer. For example, the controller may control the XY stage and the scanner unit to process the first layer in the form of a closed loop, and then remove an inner portion of the closed loop so that the first layer forms a hole (S102). have.

Next, the beam drilling method may form out-focusing by irradiating a laser beam to the second beam expander (first BET) with an optical modulator (AOM). The out-focused laser beam may process the upper surface of the exposed object in step S102. When the object is a printed circuit board, the laser beam may be focused on a second layer having an insulation function. For example, the second layer may be formed of a polyimide material. In this case, since the second layer is formed of a non-metallic material, the hardness is low, and it may be advantageous to process the laser beam of high power out of focus.

Next, the XY stage and the scanner unit may be driven to move in the X-Y plane to process and remove the second layer (S104). As a result, a blind via hole is formed in the second layer.

FIG. 5 is a view illustrating a time point of generation of an optical modulator driving signal for changing a focal length without losing time and a light source continuously driven. Referring to FIG. 5, the driving states of the optical modulator trigger signal, the pulse signal, and the laser control signal are shown in time series. The control unit continuously transmits the laser control signal to the light source, whereby the light source may continuously generate the laser pulse signal. For example, the light source can generate a laser pulse signal having a pulse width of several μs to several tens of μs.

The light source may continuously generate the laser pulse without being interrupted at the time when the light source is switched to the out of focus processing area which is the first focusing area and the second focusing area. When processing the first layer, the optical modulator delivers the beam to the first beam expander. When the processing of the first layer is completed, the controller may transmit the optical modulator trigger signal within the non-occurrence period of the laser pulse. The optical modulator may switch the optical modulator to deliver the beam to the second beam expander within 1 μs upon receiving the optical modulator trigger signal. This allows the second layer to be processed by switching to form out focusing while the light source is continuously operating.

The laser processing method according to this disclosure has an advantage of shortening the processing time.

6 is a schematic view of a beam drilling apparatus 200 according to another disclosure. 7 is a schematic cross-sectional view of a workpiece having a multilayer structure and a process of forming a blind via hole (BVH).

Referring to FIG. 6, the beam drilling apparatus includes a controller 210, a light source 220, an optical modulator 230, a multi focus controller 240, a scanner 250, and an XY stage 260.

The controller 210 may control the light modulator 230, the multi focus adjuster 240, the scanner unit 250, and the XY stage 260 by determining an appropriate focal length based on the position and material of the object ob. Can be.

The multi focus controller 240 according to the present disclosure may include a plurality of beam expanders 241, 242, 243, and 244. For example, the multi focus controller 240 may include a first expander 241 having a first focal length, a second expander 242 having a second focal length, and an n-1 having an n-1 focal length An nth expander 244 having an expander 243 to an nth focal length, where n is a natural number, for example, 4 or greater.

Since the multi focus adjuster 240 includes a plurality of beam expanders 241, 242, 243, and 244 having a plurality of focal lengths in advance, only the switching operation of the optical modulator 230 corresponds to various types of objects ob. It may be possible to irradiate light having a focal length. For example, the object ob may have four or more layer structures L1, L2, L3, L4, and L5. The control unit 210 is based on the thickness and material of the plurality of layer structures (l1, l2, l3, l4, l5) of the object ob through a separate input unit (not shown) or photographing unit (not shown). The proper focal length can be calculated. The controller 210 may control the optical modulator 230 to select an appropriate beam expander when processing each layer based on the calculated focal length result.

For example, referring to FIG. 7, for an object ob including five layers l1, l2, l3, l4, and l5, the first layer l1 includes a beam expander having a first focal length. Can be used to perform the first focusing process. The second layer ℓ2 may perform a second focusing process by using a beam expander having a second focal length. The third layer ℓ3 may perform a third focusing process by using a beam expander having a third focal length. The fourth layer L4 may perform a fourth focusing process by using a beam expander having a fourth focal length.

8 is a flowchart illustrating a beam drilling method according to another disclosure.

Referring to FIG. 8, the controller may determine an appropriate focal length based on the position and the material (hardness) of the object (S201).

Next, the optical path may be switched with a beam expander corresponding to an appropriate focal length to form a laser beam having the focal length.

For example, the optical modulator may switch the laser beam to the first expander (S202-1) and form a laser beam having a first focal length (S203-1). Alternatively, the optical modulator may switch the laser beam to the second expander (S202-2) and form a laser beam having a second focal length (S203-2). Alternatively, the optical modulator may switch the laser beam to the n-th expander (S202-3) and form a laser beam having a second focal length (S203-3) (where n is a natural number of 3 or more).

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

l1: first layer l2: second layer l3: third layer
100: beam drilling device
110: control unit 120: light source 130: light modulator 140: multi-focus control unit
150: scanner portion ob: object 160: XY stage
141: first beam expander 142: second beam expander

Claims (14)

Light source;
An optical modulator for changing a path of light transmitted from the light source;
A multi focus control unit for changing a focal length of light transmitted from the light modulator;
A scanner unit for moving the light transmitted from the multi-focus control unit to an object;
An XY stage for supporting an object having a multi-layer structure including a first layer and a second layer positioned below the first layer; And
A controller configured to control the light source, the optical modulator, the scanner unit, and the XY stage so that the first layer of the object is processed into first focal length light and the second layer of the object is processed into second focal length light Beam drilling apparatus comprising a. According to claim 1,
The first layer is formed of a material of higher hardness than the second layer,
And the controller controls the optical modulator to process the first layer into forward focus light and to process the second layer into out focus light. According to claim 1,
And a multi-layered object is a printed circuit board. According to claim 1,
The first layer is a copper film, and the second layer is formed of polyimide. According to claim 1,
The multi focus control unit includes a first beam expander for focusing the beam at a first focal length and a second beam expander for focusing the beam at a second focal length. According to claim 1,
And the optical modulator is an optical optical modulator. According to claim 1,
The control unit controls at least one of the XY stage and the scanner unit to process the first layer in the form of a closed loop (closed loop), the beam drilling apparatus for removing the first layer. In the beam drilling method for processing an object including a multilayer having a different hardness,
Processing the first layer with a first beam expander having a first focal length; And
Switching the beam to a second beam expander having a second focal length with an optical modulator to process the second layer. The method of claim 8,
The hardness of the first layer is lower than the hardness of the second layer,
The step of processing the first layer is a step of processing in the forward focus,
Processing the second layer is processing out of focus. The method of claim 8,
The step of machining the first layer, the beam drilling method is a step of providing at least one of the XY stage and the scanner unit by processing the first layer while moving in the XY plane. The method of claim 8,
The step of machining the second layer, the beam drilling method is a step of providing at least one of the XY stage and the scanner unit by processing the second layer while moving in the XY plane. The method of claim 8,
Processing the second layer is a step of processing using an optoacoustic modulator. In the beam drilling method for processing an object including a multilayer having a different hardness,
Determining an appropriate focal length based on the location and location of the object;
Switching to and selecting a beam expander that satisfies the determined appropriate focal length of the multi focus controller by an optical modulator; And
Processing an object with the appropriate focal length. The method of claim 13,
And the optical modulator is an optoacoustic modulator.

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