JPH09248692A - Laser marking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable marking of clear characters or the like by injecting gas and removing smoke generating from a marking area. SOLUTION: A clean gas 47 (air) is injected from a gas ejecting nozzle 45 to a marking area, thereby instantly removing from the marking area the smoke or soot, etc., (50) generated from the surface of a resin package, an object 3 to be marked by laser marking. Consequently, in printing the next character, interposition is eliminated such as smoke 50 obstructing a laser beam 34, thereby enabling marking by the laser beam 34 with a prescribed light intensity and realizing a clear marking. In addition, the smoke 50 blown off by the gas 47 from the ejecting nozzle 45 is instantly removed from the working space by a ventilator 41; therefore, possibility is eliminated for the gas to enter the marking area again, so that a clear marking is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser mark device and, for example, to a technique effective when applied to a technique for marking characters or symbols on a resin package surface of a semiconductor device such as an IC (integrated circuit device).

[0002]

2. Description of the Related Art A laser marking method is known as one of methods for forming a mark on a resin package surface of a semiconductor device.

Regarding marking on a semiconductor package, for example, "TOSHIBA REVIEW", Vol.
No., 1989, P593 to P596. In this document, regarding the laser marking method, a mask method for marking a character or the like on the semiconductor package surface with a laser beam transmitted through a mask, a scanning method for scanning a narrowed laser beam to directly mark the semiconductor package surface, a mask It describes a method of partially raster-scanning a pattern for marking.

[0004]

The applicant of the present invention also marks the package surface of a semiconductor device with a laser mark device. In this case, the mask is relatively moved to sequentially select fonts (characters) written on the mask and irradiate with laser light to mark characters and the like on the package surface one after another.

On the other hand, for the purpose of improving the releasability at the time of transfer molding, the material forming the package of the semiconductor device has recently been changed to a new resin material. This resin is an epoxy resin as in the conventional case, but since sufficient marking cannot be performed with the irradiation energy of 600 to 800 mJ which is conventionally used, it is about 1.5 to 2 times that of the conventional irradiation energy. It was decided to perform marking with a high irradiation energy of 1200 mJ.

However, it has been found that in the method of sequentially marking characters by increasing the irradiation energy, a phenomenon in which some characters become unclear occurs.

For example, FIG. 6 shows a semiconductor device 1 in the process of manufacture. A package 3 made of resin (resin) is formed on a part of a lead frame 2 by transfer molding, and the semiconductor device part is partly formed. I am configuring. For example, when a character string "ABC ... BE" is printed on the surface of the package 3 over two lines, the first character "A" 4 is not blurred, but the characters following it are not blurred. In the case of No. 4, as shown in FIG. 6, it has been found that defective character 5 may be partially missing. In FIG. 6, the character 4 "B" and "C" following the character 4 "A" becomes the defective character 5 with the upper half missing, and the character 4 "B" before the character 4 "E" is lower. The defective character 5 is missing at the left end.

This is because when the resin (package 3) is irradiated with a laser beam having a large irradiation energy, a large amount of smoke or soot is generated due to the large irradiation energy, and the smoke or soot or the like is generated on the surface of the package 3. It was found that when the following characters were printed while drifting in the space, the smoke and soot became obstacles and the irradiation energy of the laser light with which the surface of the package 3 was irradiated was reduced. That is, the laser light in the portion hit by the smoke or soot is completely blocked by the smoke or soot, or the light intensity is lowered, so that an unprinted portion is generated or light printing is performed. Depending on the size of the spread range of smoke, soot, etc., the entire printed portion is not printed, and some characters are missing or some characters are missing.

Since the semiconductor device is manufactured in a work environment where dust is disliked, the work environment (work room) is set to a clean state. The laser mark working environment does not require a high degree of cleanliness as in the photolithography working environment because the semiconductor chip is sealed in the package, but the laser marking device is also used in a clean environment. For example,
The laser mark device is used by being installed in a clean room by downflow, as described in the above document.

As a result, smoke, soot and the like generated during laser light irradiation are sequentially exhausted by the action of the clean room.

However, in the case of laser marking in which irradiation energy is increased and characters are printed one after another, in a conventional clean room, movement of smoke, soot, etc. is slow, and smoke and soot from the marking area before the next character is printed. Soot and the like cannot be completely eliminated, and the above-mentioned defective characters occur.

It is an object of the present invention to provide a laser mark device capable of sequentially marking clear characters and the like even when a large amount of smoke or soot is generated during laser light irradiation.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0014]

The following is a brief description of an outline of typical inventions disclosed in the present application.

(1) A mounting table on which an object to be marked is mounted, and a laser mark device for selectively irradiating the object to be marked on the mounting table with laser light to mark the surface of the object to be marked, A gas jet nozzle for jetting a gas against smoke, soot, etc. generated from an object to be marked on the mounting table to eliminate smoke, soot, etc. from at least the marking area, and smoke, soot blown off by the gas jet nozzle It has an exhaust device for sucking the like. The laser mark device is configured to sequentially select a font of a mask and sequentially mark the surface of the object to be marked. Clean gas is jetted from the gas jet nozzle. The object to be marked is, for example, a semiconductor device and is marked on the surface of a package made of resin.

(2) In the configuration of the above-mentioned means (1), the laser mark device is configured to scan a laser beam to directly mark a predetermined character or the like on the surface of the object to be marked.

According to the above-mentioned means (1), since clean gas is jetted from the gas jet nozzle toward the marking area, smoke, soot and the like generated from the surface of the resin package by laser marking are instantaneously emitted from the marking area. Will be eliminated. Therefore, at the time of printing the next character, the smoke and soot that interfere with the laser beam do not intervene, and it is possible to perform marking with the laser beam having a predetermined light intensity.
Vivid marking is achieved. In addition, smoke and soot blown off by the gas ejected from the gas ejection nozzle are instantly exhausted from the work space by the exhaust device,
Vivid marking is achieved without entering the marking area again.

According to the above-mentioned means (2), even when a predetermined character or the like is directly marked on the surface of the resin package by the scanning method (one-stroke writing), smoke, soot, etc. generated from the laser light irradiation portion are gas. Since the gas ejected from the ejection nozzle instantly removes it from the scan portion and the exhaust device removes it from the working space, clear characters can be marked.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

1 to 3 are views relating to a laser mark device according to an embodiment of the present invention, FIG. 1 is a schematic sectional view showing a marking device portion, and FIG. 2 is a perspective view showing the appearance of the laser mark device. 3 is a schematic diagram showing an optical system of a marking device unit, and FIG. 4 is a schematic plan view showing a semiconductor device supported by a lead frame marked by the laser mark device of the present embodiment.

As shown in the external view of FIG. 2, the laser mark device of this embodiment has a loader device 11 arranged at one end (left end) of a machine base 10 and an unloader device 1 at the other end (right end).
2 are arranged. A guide rail 13 extending from the loader device 11 to the unloader device 12 is arranged on the machine base 10. The guide rail 13 forms a guide and a mounting table for transferring or fixing an object to be marked.

The object to be marked is the semiconductor device 1 in the process of manufacture. As shown in FIGS. 1 and 4, the strip-shaped thin lead frame 2 and the package 3 for sealing a predetermined portion of the lead frame 2 are used. Has become. A semiconductor chip is fixed in the package 3, and the electrodes of the semiconductor chip and the leads 6 are connected by a conductive wire (not shown). As shown in FIG. 1, the lead frame 2 is supported on both sides by the support bases 19 of the guide rails 13.

In the present embodiment, a predetermined character string is marked on the surface of the package 3 of the semiconductor device 1 by laser marking.

The loader device 11 holds a magazine for accommodating the strip-shaped lead frame 2, and holds a frame elevator section 14 for raising and lowering the magazine and an uppermost unloader device 12 in the magazine for holding the magazine. It is composed of a frame transfer section 15 for transferring the guide rail 13.

The unloader device 12 holds a magazine for accommodating the strip-shaped lead frame 2, and also holds a frame elevator section 17 for raising and lowering the magazine and the lead frame 2 on the guide rail 13, and the frame. It is composed of a frame transfer section 16 for sequentially transferring into the magazine of the elevator section 17.

Further, the lead frame 2 attached to the guide rail 13 is intermittently transferred by a frame feeding unit (not shown) and accurately positioned at each work station by a positioning mechanism provided at each unit. Has become.

A dust removing station, a marking station, a soot removing station, and a mark inspection station are provided along the guide rail 13 from the loader device 11 side to the unloader device 12 side, and the dust removing device 20 is provided at each station. A marking device 21, a soot removing device 22, and a mark inspection device 23 are provided.
Further, inside the machine base 10, a control unit such as a central processing unit (CPU) for controlling each of the above-mentioned devices is arranged.

The dust removing device 20 cleans the surface of the package 3 to be marked. That is, the resin brush is rotated to rub the surface of the package 3 to remove dust on the surface of the package 3. The friction between the brush and the package creates static electricity, which may cause product damage.
It is designed to be discharged with a static elimination blower. Further, dust is removed by the vacuum exhaust mechanism.

As will be described later, the marking device 21 uses a mask method to perform marking on the surface of the package 3 character by character with a laser.

The laser marking is performed by burning the resin (black) on the surface of the package 3 with the energy of the laser light to form dents, and by roughening the surface to make it grayish white. As a result, soot is generated by the laser light irradiation. This soot not only adversely affects the human body, but also causes malfunctions of devices such as sensors, so it is necessary to remove it.

The soot removing device 22 is the dust removing device 20.
With the same structure as described above, the surface of the package 3 is rubbed with a brush while removing static electricity, and soot attached to the surface of the package 3 is removed. Soot is removed by the vacuum pumping mechanism.

The mark inspection device 23 is composed of an image processing device using a CCD (charge couple device) camera, and detects a marked character string (mark). Based on the inspection information from the mark inspection device 23, the control section determines whether the mark is good or bad, and if a defect occurs, the marking operation is stopped.

The optical system of the marking device 21 is shown in FIG.
It has a structure like. This optical system has a conceptual configuration and includes a laser oscillator 30, a reflecting mirror 31, a mask 32,
It is composed of an imaging lens 33. The laser beam 34 emitted from the laser oscillator 30 is reflected by the reflecting mirror 31, passes through the mask 32 and the imaging lens 33, and forms an image on the surface of the package 3. Therefore, a character corresponding to the font of the mask 32 can be printed on the surface of the package 3 by the predetermined pulse oscillation.

The mask 32 is a glass mask,
Fonts (characters) such as predetermined characters and symbols are arranged. The mask 32 is supported by the position control mechanism 35 so that a desired font can be selected at the time of marking. Then, by switching the font, characters are sequentially printed on the surface of the package 3.

On the other hand, this is one of the features of the present invention. As shown in FIG.
A gas ejection nozzle 40 and an exhaust device 41 are provided. That is, the column 42 is fixed to the machine base 10 portion on one side of the guide rail 13. The gas ejection nozzle 40 is fixed to one side surface of the column 42 by a clip band 43. Both ends of the clip band 43 are fixed to the column 42 by screws 44. When fixing the screw 44, the gas ejection nozzle 40 is clamped and fixed to the column 42 with the clip band 43. Further, when fixed, the direction of the nozzle 45 of the gas ejection nozzle 40 can be set. By this setting, gas is jetted to the marking area.

A supply pipe 46 connected to a compression pump (not shown) is connected to the rear end of the gas ejection nozzle 40.
Air 47 is jetted from the nozzle 45. In addition, by arranging a filter at a predetermined location in the transportation system,
Always blow clean air. The air 47 ejected from the nozzle 45 is ejected toward the marking area.
As a result, as shown in FIG. 1, the smoke, soot, etc. 50 generated from the surface of the package 3 at the time of marking with the laser beam 34 is instantaneously removed from the marking area by the jetted air 47.

On the other hand, on the other side of the guide rail 13, that is, on the side where the injected air 47 flows, an exhaust duct 48 of the exhaust device 41 is arranged. Although not shown, an exhaust pump is connected to the exhaust duct 48, and a soot processing device or the like is attached to the exhaust duct 48 so that the purified air is discharged into the atmosphere. Smoke, soot, etc. 50 scattered by the air 47 sprayed from the gas spray nozzle 40 is collected by the exhaust device 41 located in the scattering direction.

In the laser mark device of this embodiment, the lead frame 2 on which the package 3 is formed by the loader device 11 is transferred onto the guide rail 13. The lead frame 2 on the guide rail 13 is guided by the frame feed unit (frame feed mechanism) (not shown).
It is transferred intermittently over the top. Further, at each station, positioning is performed with high accuracy by a positioning mechanism (not shown).

The surface of the package 3 of the semiconductor device 1 supported by the lead frame 2 is cleaned by the dust removing device 20 at the dust removing station, and a desired mark is marked by the marking device 21 at the marking station. Then, it is cleaned by the soot removing device 22, and at the mark inspection station, the mark inspection device 23 determines the quality of the mark. When the mark inspection device 23 makes the mark defective, the marking operation is stopped.
After the repair by the worker, the marking work is continued again. Lead frame 2 advanced to the end of guide rail 13
Are sequentially stored in the unloader magazine by the unloader device 12.

The laser mark device of the present embodiment uses the package 3 at the time of marking at the marking station.
Laser marking is performed while injecting clean air 47 from the gas ejection nozzle 40 to the surface portion of, i.e., the marking area. As a result, even if smoke, soot, etc. 50 are sequentially generated by the laser marking, the smoke, soot, etc. 50 are instantaneously removed from the marking portion by the air 47 ejected from the gas ejection nozzle 40, so the mask 3
Printing (marking) that sequentially switches between 2 fonts
However, the smoke, soot, etc. 50 do not obstruct the printing, and accurate printing can be performed. FIG. 4 shows an example in which a mark (character string) 7 having no missing characters 4 and no missing characters 4 is printed on the surface of the package 3. The mark 7 is inscribed in two stages as "ABC ... BE".

Since the laser mark device of the present embodiment is provided with the exhaust device 41 for sucking and exhausting the smoke 50, the soot 50, etc. scattered on the air 47 jetted from the gas jet nozzle 40, Smoke, soot, etc. 50 will not migrate and drift again in the marking area. Therefore, marking can always be performed in a good state.

In the laser mark device of this embodiment, even if a large amount of smoke or soot is generated during laser light irradiation, it can be instantly removed from the marking area, so that the surface of the package made of resin that easily produces smoke or soot can be eliminated. Can also mark the mark accurately.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the present invention can be applied to a laser mark device of a scanning (single stroke writing) type.
FIG. 5 is a schematic view showing an optical system of the marking device 21 in the laser mark device according to another embodiment of the present invention.

The scanning type optical system shown in FIG. 5 has a conceptual configuration, and is composed of a laser oscillator 60, a reflecting mirror 61, a first scanning mirror 62, a second scanning mirror 63, and an imaging lens 64. The laser beam 65 emitted from the laser oscillator 60 is sequentially reflected by the reflecting mirror 61, the first scanning mirror 62, and the second scanning mirror 63, passes through the imaging lens 64, and is focused on the surface of the package 3. ing. The rotation of the first scanning mirror 62 is controlled by a first scanning motor 66. Further, the second scanning mirror 63 has a structure in which its rotation is controlled by a second scanning motor 67. The rotation axis of the first scanning mirror 62 and the rotation axis of the second scanning mirror 63 are orthogonal to each other, and the first scanning motor 66 and the second scanning motor 66
By controlling the scanning motor 67, the laser beam 65 focused on the surface of the package 3 can be freely moved, and characters and the like can be drawn. This allows marking.

Even in the laser marking by the scanning method, smoke, soot, etc. are generated in the irradiation portion of the laser beam 65, but the smoke, soot, etc. are instantly blown off by the air 47 jetted from the gas jet nozzle 40, Moreover, since the exhaust device 41 exhausts the air, smoke, soot, etc. do not become an obstacle to the laser beam 65, and characters are not dropped or chipped, and accurate printing is possible.

Further, in the above-described embodiment, an example in which the gas ejection nozzle and the exhaust device are provided has been described, but the structure may be such that only the gas ejection nozzle is provided and the exhaust device is not installed. That is, since a clean gas is constantly blown from the gas ejection nozzle to the marking area, smoke, soot, etc. generated during marking are instantaneously excluded from the marking area, and the light intensity of the laser beam for marking does not decrease. It does not occur and accurate marking is always possible. In particular, in the case of a laser mark device installed in a clean room, smoke, soot, etc. removed from the marking area are
It is quickly removed from the work space by the action of the clean room, and it does not hinder the work.

The gas jetted from the gas jet nozzle may be another gas such as nitrogen gas.

In the above description, the case where the invention made by the present inventor is mainly applied to the laser marking technology which is the field of application which is the background of the invention has been described, but the invention is not limited thereto.

The present invention can be applied to at least a laser processing technique for generating smoke, soot and the like.

[0051]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

(1) In a laser mark device that sequentially selects and sequentially marks mask fonts and a laser mark device that uses a scanning method, smoke, soot, etc. are generated from the laser light irradiation portion. As it is instantly blown off by the air jetted from the jet nozzle toward the marking area, and is sucked and exhausted by the exhaust device, the smoke and soot, etc. will not be dropped or chipped as an obstacle, so accurate Mark can be marked on. Therefore, a reduction in marking cost can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a marking device portion of a laser mark device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an appearance of a laser mark device according to the present embodiment.

FIG. 3 is a schematic diagram showing an optical system of a marking device unit in the laser mark device of the present embodiment.

FIG. 4 is a schematic plan view showing a semiconductor device supported by a lead frame marked by the laser mark device of the present embodiment.

FIG. 5 is a schematic diagram showing an optical system of a marking device unit in a laser mark device according to another embodiment of the present invention.

FIG. 6 is a schematic plan view of a semiconductor device or the like showing an example of a marking defect that has occurred in marking by a conventional laser mark device.

[Explanation of symbols]

1 ... Semiconductor device, 2 ... Lead frame, 3 ... Package, 4 ... Character, 5 ... Defective character, 6 ... Lead, 10 ... Machine stand, 11 ... Loader device, 12 ... Unloader device, 13 ...
Guide rails, 14 ... Frame elevator section, 15 ... Frame transfer section, 16 ... Frame transfer section, 17 ... Frame elevator section, 19 ... Support stand, 20 ... Dust removal device, 2
DESCRIPTION OF SYMBOLS 1 ... Marking device, 22 ... Soot removing device, 23 ... Mark inspection device, 30 ... Laser oscillator, 31 ... Reflecting mirror, 32 ...
Mask, 33 ... Imaging lens, 34 ... Laser beam, 35
... Position control mechanism, 40 ... Gas ejection nozzle, 41 ... Exhaust device, 42 ... Strut, 43 ... Clip band, 44 ... Screw,
45 ... Nozzle, 46 ... Supply pipe, 47 ... Injected air,
50 ... smoke or soot, 60 ... laser oscillator, 61 ... reflector,
62 ... 1st scanning mirror, 63 ... 2nd scanning mirror, 64 ... Imaging lens, 65 ... Laser beam, 66 ... 1st scanning motor, 67
… Second scanning motor.

Claims (4)

[Claims] 1. A mounting table for mounting an object to be marked, and a laser mark device for marking the surface of the object to be marked by selectively irradiating the object to be marked on the table with laser light. A laser mark device having a gas ejection nozzle for ejecting a gas onto smoke or the like generated from an object to be marked on a mounting table to remove the smoke or the like from at least a marking area. 2. A mounting table for mounting an object to be marked, and a laser mark device for marking the surface of the object to be marked by selectively irradiating the object to be marked on the table with laser light. A gas ejection nozzle for ejecting a gas against smoke or the like generated from an object to be marked on the mounting table to eliminate the smoke or the like from at least the marking area, and an exhaust device for sucking the smoke or the like blown off by the gas ejection nozzle. A laser mark device having. 3. The laser mark device according to claim 1, wherein a font of a mask is sequentially selected to sequentially mark the surface of the object to be marked. Laser mark device. 4. The laser mark device is configured to scan a laser beam to directly mark a predetermined character or the like on the surface of the object to be marked. Laser mark device.