JPH07116884A - Laser processing apparatus, laser processing method, dam bar cutting method, and lead frame processing method - Google Patents

Abstract

(57) [Abstract] [Purpose] A laser processing apparatus and a laser processing method capable of reducing dross and spatter adhering to the vicinity of a cut portion of a work material, and a dam bar cutting method and a lead using the laser processing method. A method of processing a frame is provided. [Structure] A laser beam 52 having an elongated elliptical cross section is used, and when the dam bar 1 is cut by the laser beam 52 while ejecting an assist gas, a substantially triangular cross section is formed below the dam bar 1 and its top is The gas flow control jig 10 having the triangular dam portion 10A arranged so as to face the flow of the assist gas is arranged. At this time, the triangular weir 10
The ridgeline 10a of A and the longitudinal direction of the spot on the dam bar 1 are made to face each other. Further, the gas flow control jig 10 is cooled by the coolant 16, and the jet ports 12b, 12
A part of the coolant is ejected from c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and a laser processing method for cutting a material to be processed by a laser beam while ejecting an assist gas, and a dam bar cutting method and a lead frame using the laser processing method. Regarding processing method.

[0002]

2. Description of the Related Art As a recent processing technique for forming a predetermined pattern by appropriately notching a metal plate which is a work material,
There are etching and punching by pressing. These processing techniques are often applied to the production of lead frames used in semiconductor devices, because they can efficiently and easily obtain good processing shapes. The lead frame is a metal plate on which fine processing patterns such as inner leads and outer leads are provided.In this lead frame, after the semiconductor chip is mounted, the terminals of the semiconductor chip and the inner leads are electrically connected. Connected.

On the other hand, laser processing is a processing method in which a laser beam, which is a high-density energy heat source, is focused on the surface of a material to be processed, and the material is melted and melted locally and instantaneously. It is suitable for finely and precisely processing a plate. For example, in the method disclosed in Japanese Patent Laid-Open No. 2-301160, laser processing is used to form a predetermined cutting pattern on a lead frame or to cut a dam bar that connects outer leads of the lead frame.
Since this laser processing is processing that uses melting due to heat input, the melt generated during processing is scattered and adheres to the lead frame surface as spatter, or the melt aggregates and resolidifies to form dross. It remains on the end face of the cut part. In particular, a large amount of these dross and spatter adheres near the end surface of the cut portion on the opposite side (hereinafter referred to as the back surface side) of the work material from the side irradiated with the laser beam image. Therefore, in the general laser processing including the method described in JP-A-2-301160, the melt is blown off by the assist gas ejected coaxially with the laser beam to suppress the attachment of dross and spatter. .

Further, in the prior art disclosed in Japanese Patent Laid-Open No. 3-294081, a dust collecting duct and a vacuum suction device are arranged on the back surface of the cut portion of the workpiece to collect the assist gas and the molten material that scatters. By sucking from the duct, dross and spatter are prevented from adhering to the cutting part.Furthermore, fluid is supplied to the inner surface of the dust collection duct to prevent the spatter from adhering to the inner surface of the dust collection duct. ing.

[0005]

In recent years, in the processing technique for processing a metal plate as described above, it is required to perform finer processing. In particular, the above lead frame is required to have a narrow pitch and a large number of pins in order to cope with high-density mounting and high integration of semiconductor chips, and it is also necessary to have high processing accuracy. .
As described above, it is difficult to perform fine and highly accurate processing of a work material to form a lead frame having a large number of pins at a narrow pitch by the above-described press processing or etching processing.

On the other hand, in the prior art disclosed in Japanese Patent Application Laid-Open No. 2-301160, laser processing is used, and therefore fine and highly accurate processing which is impossible with the above-mentioned press processing or etching processing is possible. In this case, the melt produced by the laser processing is blown off by the assist gas as described above, and the adhesion of dross and spatter is suppressed, but its removal is incomplete, and the melt inevitably remains after processing. It is inevitable that dross and spatter adhere to the work material.

If these dross and spatter adhere to the surface of the material to be processed and the end faces of the leads, the processed shape deteriorates and the dimensional accuracy decreases. In particular, in the case of a lead frame, it is likely to be a main cause of performance defects such as a short circuit, and it also leads to deterioration of adhesion at the time of joining with other parts in a later process, resulting in deterioration of quality. Further, the work of removing dross and spatter after adhering thereto is inefficient, and there is a risk of the lead frame being deformed by this work, which deteriorates the performance of the semiconductor device and lowers the product yield. Therefore, the adhesion of dross and spatter should be avoided as much as possible.

Further, in the conventional technique disclosed in Japanese Patent Laid-Open No. 3-294081, the assist gas, the melt, and the like that have passed through the cutting portion are only sucked from the dust collecting duct, and dross and spatter are likely to adhere. It is not possible to positively prevent the adhesion of dross and spatter by acting near the end surface of the cut portion on the back surface side of the work material.

An object of the present invention is to provide a laser processing apparatus and a laser processing method capable of reducing dross and spatter adhering to the vicinity of a cut portion of a work material, and a dam bar cutting method and a lead using the laser processing method. It is to provide a method of processing a frame.

[0010]

In order to achieve the above object, according to the present invention, a laser oscillator, an optical means for condensing a laser beam oscillated from the laser oscillator, and coaxially with the laser beam are provided. An assist gas supply unit for ejecting an assist gas, the laser processing apparatus cutting the workpiece with the laser beam focused by the optical system while ejecting the assist gas. Provided is a laser processing apparatus characterized in that a gas flow control jig having a triangular dam having a triangular cross section and a top portion thereof facing the flow of assist gas is installed on the side. .

In the above laser processing apparatus, preferably, the laser oscillator generates a laser beam having an elongated cross-sectional shape, and the ridgeline of the gas flow control jig and the longitudinal direction of the spot on the workpiece. Face each other so that they are parallel to each other.

Preferably, the ridge of the gas flow control jig and the cutting locus of the laser beam are made to face each other in parallel.

Also, preferably, the gas flow control jig has a cooling means for containing a coolant therein.

Further, preferably, the gas flow control jig has an ejection port for ejecting the coolant from two side surfaces sandwiching a ridge.

In order to achieve the above object, according to the present invention, a laser beam oscillated from a laser oscillator is focused, and an assist gas is ejected coaxially with the laser beam while being processed by the laser beam. In a laser processing method for cutting a material, a gas flow control jig having a triangular weir portion having a substantially triangular cross-section and a top portion thereof facing the flow of assist gas below the workpiece material. Is provided, and the flow direction of the assist gas is divided into a flow along two side faces sandwiching the ridge of the gas flow control jig, and a laser processing method is provided.

In the above laser processing apparatus, preferably, a laser beam having a narrower cross-sectional shape than the laser oscillator is generated so that the ridgeline of the gas flow control jig and the longitudinal direction of the spot on the workpiece are parallel to each other. To face each other.

Preferably, the ridgeline of the gas flow control jig and the cutting locus by the laser beam are opposed to each other in parallel.

To achieve the above object, according to the present invention, the dam bar connecting the outer leads of the semiconductor device is cut by the above laser processing method, or the dam bar cutting method, or the above laser processing method. According to the present invention, there is provided a lead frame processing method characterized by cutting and processing a lead frame used in a semiconductor device.

[0019]

As described above, a large amount of dross or spatter adheres to the vicinity of the end face of the cut portion on the back surface of the work piece because the assist gas flow velocity after passing through the cut portion decreases sharply. It is considered that stagnation is formed by the flow, and thus it is impossible to sufficiently blow away the melt that becomes dross or spatter.

In the present invention constructed as described above,
Passing the cutting part by arranging a gas flow control jig with a triangular weir in which the cross-sectional shape is almost triangular and the top part is opposed to the flow of assist gas under the work material. The assist gas hits the top of the gas flow control jig, that is, the ridge line, is divided into flows along two side faces sandwiching the ridge line of the jig, and the flow direction is bent from the center to the left and right. As a result, the assist gas divided into two flows flows in such a direction that the vicinity of the end surface of the cut portion on the back surface side of the workpiece is smashed. Moreover, since the cross-sectional area of the assist gas flow is reduced by the gas flow control jig, the flow velocity of the assist gas at this portion does not suddenly decrease, and stagnation is not formed by the flow. As a result of the above, the melt that tends to adhere near the end face of the cut part on the back side of the work piece is actively and forcibly blown off by the flow of assist gas, and dross and spatter that adhere to the cut part of the work piece are prevented. It can be reduced.

Further, when a laser oscillator for generating a laser beam having an elongated cross section is used, the ridgeline of the gas flow control jig and the longitudinal direction of the spot on the workpiece are opposed to each other. By doing so, the ridgeline of the gas flow control jig can always be positioned below the cutting portion of the work piece over the entire length of the spot on the work piece in the longitudinal direction, and the above-described action can always be obtained. become.

Further, by making the ridge of the gas flow control jig and the locus of cutting by the laser beam parallel so as to face each other, even if the laser processing portion, that is, the ejection position of the assist gas moves as the cutting progresses, Since the ridgeline of the gas flow control jig is always located below the cut portion of the workpiece, the above-described action is always obtained.

Further, by storing a coolant in the cooling means inside the gas flow control jig, the jig is cooled and the melted material or the like blown off by the assist gas to reach the jig is the surface of the jig. Is quenched in. This rapidly cooled melt is easily peeled off from the surface of the jig, so that it is prevented from adhering to the surface of the jig. Further, by cooling the gas flow control jig, it is possible to avoid melting and damage of the gas flow control jig by the laser beam that has passed through the workpiece.

Further, by ejecting the coolant from the ejection ports on the two side surfaces sandwiching the ridge of the gas flow control jig,
The melt that has been rapidly cooled as described above is washed away, and dust, gas generated during laser processing, and the like are also absorbed and removed.
Furthermore, by supplying the coolant to the back surface of the material to be processed from the ejection port until just before the cut portion is formed to penetrate,
When the cut portion penetrates, the melt generated by laser processing is rapidly cooled and easily peels off from the workpiece. Therefore, dross and spatter are prevented from adhering to the vicinity of the end face of the cut portion.

Further, according to the present invention, fine and highly accurate processing can be performed, and dross and spatter attached to the vicinity of the cut portion of the workpiece can be reduced, so that the outer leads of the semiconductor device are connected. It is useful to use the present invention to cut a dam bar. Further, it is also effective when used for cutting a lead frame used for a semiconductor device.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment in which a dam bar that connects outer leads of a semiconductor device is cut by using a laser beam having an elongated cross-sectional shape.

First, the structure of the laser oscillator, the processing head, and the optical system inside the nozzle in the laser processing apparatus of this embodiment will be described with reference to FIG. In FIG. 2, the laser oscillator 21 is provided with a laser resonator 31 and a beam diameter conversion unit 32, the processing head 24 is provided with a bending mirror 24a, and the nozzle 25 is provided with a condenser lens 26 and an assist gas supply port 25a. It is equipped. Also,
The beam diameter conversion unit 32 includes a convex cylindrical lens (cylindrical surface lens) 33 and a concave cylindrical lens 3.
4 (cylindrical lens), beam diameter conversion unit 32
The laser beam 50 is entirely driven by a drive motor (not shown).
It can be rotated about the optical axis by a predetermined angle. Further, a gas flow control jig 10 described later is arranged below the dam bar 1 (see FIGS. 3 and 4). However,
The processing head 24, the bending mirror 24a, the nozzle 25, and the condenser lens 26 constitute optical means for condensing the laser beam emitted from the laser oscillator 21.

The laser beam 50 generated by the laser resonator 31 is first reduced by the convex cylindrical lens 33 of the beam diameter conversion unit 32 in only one axial direction of the beam cross section, and then corrected by the concave cylindrical lens 34 into parallel light. . The laser beam 51 emitted from the concave cylindrical lens 34 enters the processing head 24, is changed in direction by the bending mirror 24 a, and enters the condenser lens 26 in the nozzle 25. The condensing lens 26 condenses the laser beam so as to have the above-mentioned predetermined energy density and irradiates the surface of the dam bar 1. The cross-sectional shape of the laser beam 52 with which the dam bar 1 is irradiated becomes an elongated elliptical shape in which only the uniaxial direction is reduced by the action of the cylindrical lenses 33 and 34, and the entire beam diameter conversion unit 32 is rotated by a predetermined angle. , An elliptical laser beam rotates about its optical axis. Further, the assist gas is ejected from the assist gas supply port 25a near the tip of the nozzle 25 coaxially with the laser beam. Instead of using the above optical system, the laser resonator may be provided with a slab type laser activator, and a slab laser having a rectangular cross section generated from this laser resonator may be used.

Next, the structure of the gas flow control jig 10 disposed below the dam bar (workpiece) 1 will be described with reference to FIGS. 1 and 3. However, FIG. 3 is a sectional view taken along the line III-III in FIG. 1, and the inside of the resin mold of the semiconductor device is omitted. As shown in FIGS. 1 and 3, the gas flow control jig 1
Reference numeral 0 has a triangular dam portion 10A having a substantially triangular cross section, and a lower base portion 10B of the triangular dam portion 10A. The top of the triangular weir 10A, that is, the ridgeline 10a is arranged so as to face the flow of the assist gas, and is arranged so that the longitudinal direction of the elliptical spot on the dam bar 1 is parallel.

A coolant reservoir 11 as a cooling means is provided inside the gas flow control jig 10, and two side faces 10b, 10 sandwiching a ridge line 10a of the triangular dam portion 10A.
Spout ports (spout ports) 12b and 12c for spouting a part of the coolant from the coolant reservoir 11 are opened in c. Further, the coolant reservoir 11 has a pipe joint 13
The pipe 14 is connected via the pipe 14, and the coolant 16 in the coolant tank 15 is supplied from the pipe 14 to the coolant reservoir 11 by the feed pump 17. Further, the valve 18 is connected to the pipeline 14.
It is attached to open and close.

Further, a part of the coolant 16 in the coolant reservoir 11 extends from the jet ports 12a and 12b to the side surface 10 of the triangular dam portion 10A as shown by arrows 19b and 19c in the figure.
The coolant is directly supplied to the back surface of the dam bar 1 just before the cutting portion 1a of the dam bar 1 penetrates while being jetted to the front surfaces of the b and 10c. Although it is desirable to use water as the coolant 16, a spatter preventive agent or the like may be used.

FIG. 4 shows a situation in which the dam bar is cut according to this embodiment. In FIG. 4, when forming the resin mold 2 that integrally seals the lead frame 5 and the semiconductor chip (not shown), the dam bar 1 prevents the mold resin from flowing out from the gap of the outer lead 3 and This is for connecting the leads of the outer lead 3 so that the outer leads 3 are not displaced from each other.

In the present embodiment, as shown in FIG. 4, the dam bar 1 is irradiated by irradiating the laser beam 52 having an elongated elliptical cross-sectional shape at a position indicated by a chain double-dashed line in the figure for one pulse or several pulses. Cut off in order. As described above, by using the laser beam 52 having an elongated elliptical cross section, the dam bar 1 can be efficiently cut. Further, by using the laser beam, fine processing becomes possible, and the lead frame 5 is processed during processing.
Almost no unnecessary deformation or distortion is given to the machine and the processing accuracy is not impaired.

Returning to FIGS. 1 and 3, the operation of this embodiment will be described. The dam bar 1 is melted and cut by the heat input provided by the laser beam. Cutting part 1a of this dam bar 1
The assist gas (shown by an arrow 4a in the figure) passing through the ridge hits the ridge line 10a of the triangular weir portion 10A of the gas flow control jig 10, and two side faces 10b and 10c sandwiching the ridge line 10a as shown by arrows 4b and 4c in the figure. Divided into flows along
The flow direction can be bent from the center to the left and right. by this,
The assist gas indicated by the arrows 4b and 4c flows in a direction such that the vicinity of the end face of the cut portion 1a on the back surface side of the lead frame 5 is grazed. Further, since the cross-sectional area of the assist gas flow is reduced by the gas flow control jig 10, the flow velocity of the assist gas at this portion does not suddenly decrease, and stagnation is not formed by the flow.

As a result of the above, the melt that tends to adhere to the vicinity of the end face of the cut portion 1a on the rear surface of the lead frame 5 is positively and forcibly blown off by the flow of the assist gas and adheres to the vicinity of the rear surface of the cut portion 1a. Dross and spatter can be reduced.

Further, a coolant 16 such as water or an anti-spatter agent stored in the coolant reservoir 11 inside the gas flow control jig 10 cools the gas flow control jig 10 and is blown off by the assist gas to control the gas flow. The melt reaching the surface of the jig 10 is rapidly cooled on the surface of the gas flow control jig 10. The rapidly cooled melt is easily peeled off from the surface of the gas flow control jig 10, so that the melt is prevented from adhering to the surface. Furthermore, since the coolant cools the gas flow control jig 10, it is possible to avoid melting and damage of the gas flow control jig 10 by the laser beam 52 passing through the cutting portion 1a of the dam bar 1.

Further, since the coolant is jetted from the jet ports 12a and 12b to the side surfaces 10b and 10c of the triangular dam 10A, the melt rapidly cooled as described above is washed away, and dust or laser generated during laser processing. Gases and the like are also absorbed and removed. Further, since the coolant is directly supplied to the back surface of the dam bar 1 just before the cut portion 1a of the dam bar 1 penetrates, the melt generated by the laser processing when the cut portion 1a penetrates is rapidly cooled and peeled from the lead frame 5. It becomes easy to fall. Therefore, this also prevents dross and spatter from adhering to the vicinity of the end face of the cutting portion 1a.

By the way, as compared with the method in which a laser beam having a circular cross-sectional shape is used to sequentially shift the irradiation position little by little along a predetermined locus and the minute cut portions are connected while being overlapped with each other, By using a laser beam having an elongated cross-sectional shape as described above, a long gap can be processed by irradiating a pulsed laser beam once, and cutting can be efficiently performed at a remarkably high speed. Also,
By cutting while making the longitudinal direction of the laser beam cross section coincide with the traveling direction (cutting traveling direction), a long cutting portion can be cut at high speed.

However, in this case, since the length of the cut portion cut by one pulse becomes long, the amount of the melt also increases. Further, in the method using a laser beam having a circular cross-sectional shape, it is possible to re-dissolve dross or spatter that has once adhered and drop it from the cutting portion because the proportion of overlapping minute cutting portions is large. When a laser beam having an elongated cross-sectional shape is used, the proportion of overlapping cut portions is small, so that the attached dross or spatter is hardly dissolved again. That is, when a laser beam having an elongated cross section is used, the amount of dross or spatter attached may increase.

On the other hand, in this embodiment, since the gas flow control jig 10 is arranged below the dam bar (workpiece) 1 and the melt is positively and forcibly blown off by the flow of the assist gas, Even when using a laser beam having an elongated cross section as described above, it is possible to reduce the attached dross and spatter.

Of course, even when a laser beam having a circular cross-sectional shape is used, it is possible to reduce the attached dross and spatter as in this embodiment. Further, when cutting a long cut portion as in the case of processing a lead frame described below, the ridge line of the triangular dam portion and the cutting locus by the laser beam may be made to face each other. As a result, even if the laser processing portion, that is, the position where the assist gas is ejected moves as the cutting progresses, the ridgeline of the triangular dam portion 10A can always be positioned below the cutting portion of the workpiece, and the melted material Blow off by the flow of assist gas,
Adhesive dross and spatter can be reduced.

Further, in this embodiment, fine and highly accurate processing is possible, and dross and spatter attached to the vicinity of the cut portion of the workpiece can be reduced. It is effective not only for cutting but also for cutting the lead frame itself used for the semiconductor device.

FIG. 5 shows an example of the lead frame.
In addition, in FIG. 5, in consideration of generality, the lead frame and each component thereof are assigned with numbers different from the numbers of the lead frame and each component of FIGS. 1 to 4. Figure 5
In the lead frame 100, a die pad 101 on which a semiconductor chip is mounted is provided in the center portion, and a large number of inner leads 102 and outer leads 103 continuous with the inner leads 102 are arranged so as to surround the die pad 101. Has been done. Adjacent outer leads 103 are connected to each other by a dam bar 104. The area around the die pad 101 is the arm 10.
Notches 5 are provided with a notch 106, and the notch 106 causes the inner lead 102 to move to the die pad 10.
The inner leads 102 separated from each other and adjacent to each other are separated from each other by the notch 106. Further, a positioning hole 108 is provided in the outer frame portion 107 on the outer periphery of the lead frame 100 for positioning when the terminals of the semiconductor chip and the inner leads 102 are connected.

The inner lead 102 extends so as to converge toward the die pad 101, and its tip portion is used for electrical connection after mounting a semiconductor chip (not shown) on the die pad 101. It is wide enough. Therefore, the gap between the adjacent leads on the inner side of the inner lead 102 is particularly narrow and has an extremely fine structure, and the processing of this portion is the most strict in dimensional accuracy and cleanliness in the processing of the lead frame. .

For example, the outer lead pitch is 0.3.
mm, the number of pins is about 300, the plate thickness is 0.1
A thin plate of 42 alloy or copper alloy of about 0.15 mm is used. The pitch of the inner leads of the lead frame is 0.15 to 0.
The width of about 2 mm is conceivable, but for this purpose, the gap between the leads must be as narrow as about 0.05 to 0.08 mm. That is, in such a lead frame, it is necessary to perform a cutting process with a cutting width narrower than the plate thickness, and in addition, in order to accurately connect a large number of leads to the terminals of the semiconductor chip, the processing accuracy of each lead is also high. It is necessary to manage it strictly.

In the present embodiment, since the laser beam is used and the adhesion of dross and spatter can be reduced, it is possible to perform processing with a cutting width narrower than the plate thickness with high accuracy.

FIG. 6 shows an example of a semiconductor device manufactured using the above lead frame. In the semiconductor device 110 shown in FIG. 6, the semiconductor chip 111 is mounted on the die pad 101, and the inner lead 102 and the terminal of the semiconductor chip 111 are electrically wire-bonded by the wire 112, and the semiconductor chip 111 and the inner lead 102 are included. The part is sealed by the resin mold 113. Further, the dam bar 104 (see FIG. 5) is cut as described in this embodiment, and the outer lead 1
03 are individually separated, and outer lead 1
Reference numeral 03 is bent outside the resin mold 113. The bent portion of the outer lead 103 is a portion to be connected to the circuit pattern of the printed circuit board when the semiconductor device 110 is mounted on the printed circuit board later.

As described above, according to the present embodiment, since the gas flow control jig 10 is arranged below the dam bar (workpiece) 1, the assist gas passing through the cutting portion 1a has the ridge line 1
0a is divided into a flow along two side faces 10b and 10c, and the flow proceeds in such a direction as to graze the vicinity of the end face of the cut portion 1a on the back surface side of the lead frame 5, and the cross-sectional area of the flow of the assist gas becomes small, so that the flow velocity is Does not drop sharply. Therefore, the melt is positively and forcibly blown off by the flow of the assist gas, and dross and spatter attached to the vicinity of the back surface of the cut portion 1a can be reduced.

Further, since the ridge line 10a and the spot on the dam bar 1 are opposed to each other so as to be parallel to each other, the triangular dam portion 10A is always provided over the entire length of the spot in the longitudinal direction.
The ridgeline 10a can be positioned, and the above-described effect can always be obtained.

Further, since the gas flow control jig 10 is cooled by the coolant 16 in the coolant reservoir 11, the melt or the like blown off by the assist gas is rapidly cooled on its surface, and the gas flow control jig 10 is cooled from the surface. It is prevented from peeling off and adhering to the surface. Further, since the gas flow control jig 10 is cooled, it is possible to avoid melting and damage of the gas flow control jig 10 by the laser beam.

Further, since the coolant is jetted from the jet ports 12a, 12b to the surfaces of the side faces 10b, 10c of the triangular dam 10A, the rapidly cooled melt is washed away, and dust and gas generated during laser processing are absorbed, To be removed. further,
Dam bar 1 until just before the cut portion 1a of the dam bar 1 penetrates
Since the coolant is directly supplied to the back surface of the, the melt generated by laser processing when the cut portion 1a penetrates is rapidly cooled and easily peeled off from the lead frame 5. Therefore, this also causes dross and spatter to occur in the cutting portion 1a
Is suppressed from adhering to the vicinity of the end face.

Further, when cutting a long cutting portion, since the ridge line of the gas flow control jig and the cutting trajectory by the laser beam are opposed to each other so as to be parallel to each other, the ejection position of the assist gas moves as the cutting progresses. However, the ridge of the gas flow control jig can always be positioned below the cutting part,
The above effects are always obtained.

The present invention may be used for cutting a metal mesh sheet, a metal mask for screen printing, etc., in addition to the cutting of the dam bar and the cutting of the lead frame.

[0054]

According to the present invention, since the gas flow control jig is arranged below the work material, the assist gas passing through the cutting portion is divided into two flows, and the assist gas on the back surface side of the work material is divided. While flowing near the end face of the cut portion in a direction that makes the surface faint, the cross-sectional area of the flow of the assist gas does not decrease and the flow velocity does not suddenly decrease. Therefore, the melt is positively and forcibly blown off by the flow of the assist gas, and dross or spatter attached to the vicinity of the cut portion of the workpiece can be reduced.

When a laser beam having an elongated cross-sectional shape is used, the ridge line of the gas flow control jig and the longitudinal direction of the spot on the workpiece are made to face each other, so that the above effects are always obtained. To be

Further, when cutting a long cutting portion, since the ridge line of the gas flow control jig and the cutting locus are opposed to each other in parallel, even if the ejection position of the assist gas moves as the cutting progresses, The above effect is always obtained.

Further, since the coolant is contained in the cooling means inside the gas flow control jig, the gas flow control jig is cooled,
The melt blown off by the assist gas is prevented from peeling off from the surface and adhering to the surface. Further, it is possible to avoid melting and damage of the gas flow control jig due to the laser beam.

Further, since the coolant is jetted from the jet port of the gas flow control jig, it is possible to absorb and remove the rapidly cooled melt, dust, generated gas and the like. Further, since the coolant is supplied to the back surface of the work material until just before the cut portion penetrates, the melt is rapidly cooled when the cut portion penetrates, and is easily peeled off from the work piece.

Further, according to the present invention, it is possible to perform fine and highly accurate processing, and it is possible to reduce dross and spatter adhering to the vicinity of the cut portion of the workpiece, so that the dam bar and the lead frame are cut. It can be used for processing and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a gas flow control jig arranged below a workpiece in a laser processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a configuration of an optical system inside a laser oscillator, a processing head, and a nozzle in a laser processing apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a diagram showing a situation in which a dam bar is cut by the laser processing apparatus of FIGS.

FIG. 5 is a view showing an example of a lead frame processed by the laser processing apparatus of FIGS.

6 is a diagram showing an example of a semiconductor device manufactured by using the lead frame of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut part of dam bar 1a (dam bar) 2 Resin mold 3 Outer lead 5 Lead frame 10 Gas flow control jig 10A Triangular dam part 10B Base part 10a (Triangle dam part) ridge line 10b, 10c (Triangular dam part) side surface 11 Cooling Agent reservoir 12b, 12c Jet port (jet outlet) 15 Coolant tank 16 Coolant 17 Feed pump 21 Laser oscillator 24 Processing head 25 Nozzle 25a Assist gas supply port 26 Condenser lens 31 Laser resonator 32 Beam diameter conversion unit 50, 51,52 laser beam

Front page continuation (72) Inventor Shigeyuki Sakurai 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant (72) Inventor Yoshiya Nagano 650 Jincho-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Inside the factory (72) Inventor Shinya Okumura 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd.Tsuchiura factory (72) Inventor Nobuyuki Kimura 650 Shintachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Engineering Co., Ltd.

Claims (10)

[Claims] 1. A laser oscillator, an optical means for condensing a laser beam oscillated from the laser oscillator, and an assist gas supply means for ejecting an assist gas coaxially with the laser beam. In a laser processing apparatus that cuts a work piece with the laser beam focused by the optical system while ejecting, a cross section of a substantially triangular shape is formed below the work piece, and a top portion of the assist gas flows. A laser processing apparatus, wherein a gas flow control jig having a triangular dam portion arranged so as to face the laser is installed. 2. The laser processing apparatus according to claim 1, wherein the laser oscillator generates a laser beam having an elongated cross-sectional shape, and the laser oscillator generates a laser beam having a long and narrow cross-sectional shape and a spot on the workpiece. A laser processing device characterized in that they are opposed to each other in parallel with the longitudinal direction. 3. The laser processing apparatus according to claim 1, wherein a ridgeline of the gas flow control jig and a cutting locus by the laser beam are opposed to each other so as to be parallel to each other. 4. The laser processing apparatus according to claim 1, wherein the gas flow control jig is
A laser processing apparatus having a cooling means for containing a coolant therein. 5. The laser processing apparatus according to claim 4, wherein the gas flow control jig has an ejection port for ejecting the coolant from two side surfaces sandwiching a ridgeline. 6. A laser processing method in which a laser beam oscillated from a laser oscillator is focused, and a workpiece is cut by the laser beam while ejecting an assist gas coaxially with the laser beam. On the lower side, a gas flow control jig having a triangular weir in which the cross-sectional shape is substantially triangular and the top thereof is arranged so as to face the flow of assist gas is installed, and the flow direction of the assist gas is A laser processing method characterized in that the gas flow control jig is divided into a flow along two side faces sandwiching a ridgeline. 7. The laser processing method according to claim 6, wherein a laser beam having a cross-sectional shape narrower than that of the laser oscillator is generated, and a ridge line of the gas flow control jig and a longitudinal direction of a spot on the workpiece. A laser processing method characterized in that they are opposed to each other in parallel. 8. The laser processing method according to claim 6, wherein the ridgeline of the gas flow control jig and the cutting locus by the laser beam are opposed to each other so as to be parallel to each other. 9. A method for cutting a dam bar, which comprises cutting the dam bar connecting the outer leads of a semiconductor device by the laser processing method according to claim 6. 10. A method for processing a lead frame, which comprises cutting a lead frame used for a semiconductor device by the laser processing method according to claim 8.