JP2004230750A - Mold cleaning method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently remove a residue adhering to a mold without damaging the mold. <P>SOLUTION: The mold 13 with the residue 14 adhering thereon is prepared. By making pulse laser beam, which has a property to penetrate the residue and reflect at an interface between the residue and the mold and consequently separate the residue at the reflected position from the mold, incident from the surface of the residue onto the mold, some part of the residue at the incident position is separated from the mold. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mold cleaning method and apparatus suitable for cleaning a semiconductor manufacturing mold for encapsulating a semiconductor chip with a resin material.
[0002]
[Prior art]
In an LSI sealing process using a semiconductor manufacturing sealing mold, the mold is filled with, for example, an epoxy resin and cured to perform processing. Each time, the epoxy resin gradually adheres to the mold surface as a residue. When the thickness of the attached residue increases, the pattern of the residue is transferred to the outer surface of the sealed LSI product. Therefore, the sealed LSI product may be determined to be defective even if there is no problem in performance. . In addition, the thickened residue makes it difficult for the product after sealing to peel off from the mold. For this reason, it is necessary to periodically clean the semiconductor manufacturing sealing mold.
[0003]
There is known a mold cleaning method in which the same process as sealing is performed a plurality of times with a melanin resin instead of an epoxy resin, so that the epoxy resin is gradually adsorbed on the melanin resin. In this cleaning method, the sealing mold may be disassembled, the residual film of the epoxy resin may be peeled off, and then the mold may be assembled again. However, since the adhesion of the residual film to the mold is high, this cleaning method requires time and effort. Usually, cleaning is performed once a week with a cleaning time of about 5 hours or less at a time. In recent years, with the specialization of additives used for semiconductor encapsulation, the number of times of cleaning tends to increase to about once every few days.
[0004]
A method of using a laser beam for cleaning a mold for semiconductor manufacturing sealing has also been proposed.
[0005]
For example, there is a method in which a mold is irradiated with an impulse laser beam, and the adhered substance is broken by ultrasonic vibration to be separated. (For example, see Patent Document 1)
In addition, a laser beam is radiated to a severely dirty part of the mold, and the resin adhering to the mold is burned and carbonized or peeled off by the energy of the beam, and then the simulation frame is fixed to the mold. There is also a method in which a dummy shot in which a synthetic resin is appropriately injected into a mold is repeated a plurality of times, and carbonized or incompletely peeled ones are removed together with the synthetic resin of the dummy shot. (For example, see Patent Document 2)
Further, there is a method of irradiating a laser beam to a residue attached to a mold and efficiently decomposing and removing mold contaminants adhered and accumulated on the mold surface by intermittent thermal shock waves and microresonance of the beam. Has been devised. (For example, see Patent Document 3)
Recently, a laser processing method different from the conventional ablation processing has been invented and published by the present inventors. For example, one shot of a pulsed laser beam, for example, a fundamental wave (wavelength: 1047 nm) of a Nd: YLF laser is incident on a resin coating layer laminated on a metal layer. The resin coating layer is formed of a resin material that is substantially transparent to the fundamental wave of the Nd: YLF laser, and the metal layer is formed of a metal material that reflects most of the fundamental wave of the Nd: YLF laser. Most of the laser beam passes through the resin coating layer and is reflected at the interface between the resin coating layer and the metal layer. A portion of the resin coating layer where the laser beam is incident is separated from the metal layer, and a hole is opened in the resin coating layer.
[0006]
Holes formed in the resin coating layer by a one-shot pulsed laser beam by this laser processing method can be perforated in the resin coating layer with almost no damage to the metal layer as compared with conventional ablation processing. it can. (For example, see Patent Document 4.)
In the laser processing method described in Patent Document 4, peeling of the resin coating layer from the metal layer is caused by a laser beam that causes thermal decomposition of the resin at the interface between the resin coating layer and the metal layer, and the pressure of the resin coating layer causes the resin coating layer to be decomposed. It is considered that the film was formed as a result of inducing peeling. The phenomenon in which the interface between the resin coating layer and the metal layer is in a high pressure state and a part of the upper resin coating layer peels off due to this pressure is referred to as “lifting phenomenon”. Processing using the “lifting phenomenon” is referred to as “lifting processing”.
[0007]
[Patent Document 1]
Registered utility model 3017755 gazette
[0008]
[Patent Document 2]
JP-A-1-122417
[0009]
[Patent Document 3]
JP-A-2000-68306
[0010]
[Patent Document 4]
JP-A-2002-044970
[0011]
[Problems to be solved by the invention]
An object of the present invention is to remove a resin residue attached to a semiconductor manufacturing sealing mold at high speed, easily, and with little damage to the mold by using the lifting phenomenon. An object of the present invention is to provide a suitable mold cleaning method and a mold cleaning apparatus.
[0012]
[Means for Solving the Problems]
According to one aspect of the present invention, a step of preparing a mold to which a residue is attached, and transmitting the residue, reflecting at an interface between the residue and the mold, and removing the residue at a reflection position from the mold. While scanning the pulse laser beam having the property of peeling so that the incident position of the pulse laser beam moves on the mold, the pulse laser beam is incident on the mold from the surface of the residue, and the residue at the incident position is And a step of peeling off a part of the mold from the mold.
[0013]
The residue adhering to the mold at the irradiation position is separated from the mold by the lifting phenomenon due to the laser beam irradiation. According to this mold cleaning method, the residue can be efficiently removed from the mold without substantially damaging the mold.
[0014]
According to another aspect of the present invention, there is provided a laser light source for emitting a pulse laser beam, a beam scanning unit for scanning the pulse laser beam emitted from the laser light source, and an incident position of the pulse laser beam on a mold. And a first control means for controlling the beam scanning means so as to move the tool.
[0015]
Further, according to another aspect of the present invention, a laser light source capable of emitting a pulse laser beam having a pulse width of 10 ns or more and 30 ns or less, and the pulse laser beam emitted from the laser light source is incident on a mold. An optical system capable of manually changing the emission direction of a pulsed laser beam emitted from the optical system, and a beam transmission means for optically connecting the laser light source and the optical system. A mold cleaning device having a beam transmission unit capable of securing optical coupling between the laser light source and the optical system even when the emission direction of the pulse laser beam emitted from the optical system changes. An apparatus is provided.
[0016]
When using these mold cleaning devices, the mold can be irradiated with a laser beam, and the residue attached to the mold can be peeled off by utilizing the lifting phenomenon.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic diagram of a mold cleaning apparatus used in a mold cleaning method according to a first embodiment of the present invention. A fundamental wave (wavelength: 1047 nm) of the Nd: YLF laser is emitted from the laser light source 1, for example, a pulsed Nd: YLF laser oscillator. The laser beam is transmitted to the housing 9 along the optical fiber 2. A beam shaping optical system 3, a mask 4 having a through hole 4a, a condenser lens 5, a lens moving mechanism 6, a mirror 7, and a mirror rotating mechanism 8 are incorporated in a housing 9, and a window 10 is provided on a side surface. .
[0018]
The laser beam transmitted to the housing 9 by the optical fiber 2 enters the beam shaping optical system 3. The beam shaping optical system 3 includes a plurality of optical components including a lens, corrects a laser beam to an appropriate beam size, and emits the laser beam as parallel light.
[0019]
The laser beam emitted from the beam shaping optical system 3 is shaped into a rectangular or hexagonal cross section by a mask 4 having a rectangular or hexagonal through hole 4a, for example.
[0020]
The laser beam emitted from the mask 4 enters the condenser lens 5. The condenser lens 5 forms an image of the through hole 4a of the mask 4 on the beam irradiation surface. The condenser lens 5 is held by a lens moving mechanism 6. The lens moving mechanism 6 can move the condenser lens 5 in the direction of the optical axis of the laser beam. The laser beam emitted from the condenser lens 5 is reflected by the mirror 7, passes through a window 10 made of, for example, a flat quartz glass, and enters a mold 13 for semiconductor manufacturing sealing.
[0021]
The mold 13 includes two upper and lower molds. The lower mold of the mold 13 is shown in the figure. A plurality of recesses are formed in the main surface of the mold 13. The mirror rotation mechanism 8 can rotate the mirror 7 and change the incident position of the laser beam incident on the mold 13. The mirror rotation mechanism 8 can make the emission direction of the laser beam emitted from the window 10 of the housing 9 perpendicular to the window 10. In addition, the emission direction of the laser beam is changed from the direction perpendicular to the window 10 to both sides along the length direction (the left-right direction in FIG. 1) and the width direction (the front-back direction of the paper surface in FIG. 1). , At least 40 ° or more. Further, the housing drive system 11 can move the housing 9 at a desired speed in a substantially in-plane direction (two-dimensional direction) of the mold 13 to change the incident position of the laser beam. The control device 12 controls the movement of the condenser lens 5 by the lens moving mechanism 6, the rotation of the mirror 7 by the mirror rotation mechanism 8, and the movement of the housing 9 by the housing drive system 11. Residues 14 of, for example, thermosetting epoxy or silicone resin adhere to the surface of the mold 13 in the form of a film, for example. The laser beam is incident on the surface of the mold 13 where the residue 14 is attached.
[0022]
The area of the image of the square or hexagonal through hole 4a formed on the residue 14 is, for example, 5 mm. ² It is. When a laser beam, for example, a fundamental wave of an Nd: YLF laser is incident on the residue 14, the residue 14 transmits most of the fundamental wave of the Nd: YLF laser, and the mold 13 reflects most of the fundamental wave. Due to the lifting phenomenon, the residue 14 at the position where the laser beam is incident is separated and separated from the mold 13, and a removed portion 14 a is formed in the residue 14. The removed portion 14a is formed as a result of removing the residue 14 having substantially the same area as the laser beam imaging area from the mold 13.
[0023]
When the pulsed laser beam is scanned so that the beam incident position moves on the mold 13, the removed portions 14 a are sequentially formed at different positions on the mold 13. Adjustment of the beam incident position is performed by moving the housing 9 by the housing drive system 11 and rotating the mirror 7 by the mirror rotating mechanism 8.
[0024]
When the irradiation position of the laser beam changes, the optical path length of the laser beam from the condenser lens 5 to the irradiation position of the mold 13 also changes, and the through hole 4a does not form an image on the beam irradiation surface. The lens moving mechanism 6 moves the condenser lens 5 in the direction of the optical axis of the laser beam so that the optical path length from the condenser lens 5 to the beam irradiation position is constant, and the through hole 4a is always located at the beam incident position. Make an image.
[0025]
The side surface of the concave portion of the mold surface of the mold 13 has a taper of, for example, about 6 to 15 degrees with respect to a direction perpendicular to the in-plane direction of the mold 13. When removing the residue 14 in the tapered portion, the mirror 7 is rotated by the mirror rotating mechanism 8 so that the fluctuation of the incident angle with respect to the incident angle of the laser beam incident on the other part of the mold 13 is as small as possible. The laser beam is incident on the tapered portion so that the laser beam is incident. This is because as the incident angle of the laser beam incident on the mold 13 increases, the beam spot on the beam irradiation surface increases, and as a result, the fluence of the incident beam decreases, and the separation and separation of the residue 14 can be performed sufficiently. This is because it may not be possible. Further, when the laser beam is scanned on the mold 13 and the incident position of the beam is changed, the housing 9 is moved by the housing driving system 11 while the lens 5 is moved by the lens moving mechanism 6, and the mirror is moved. The mirror 7 is rotated by the rotation mechanism 8.
[0026]
The movement of the housing 9 by the housing drive system 11, the rotation of the mirror 7 by the mirror rotating mechanism 8, and the movement of the condenser lens 5 by the lens moving mechanism 6 are all controlled by the control device 12. The structure of the mold 13 is input to the control device 12 in advance, and the control unit 12 controls them so that the through-hole 4a forms an image on the mold 13 according to the position where the beam is incident.
[0027]
When the laser beam is irradiated and the residue 14 is separated and removed from the mold 13 by using the lifting phenomenon, there is almost no damage to the mold 13. Therefore, it is possible to perform a laser beam overlapping shot (a plurality of shots of a pulse laser beam are incident on the same position). Even when the residue 14 cannot be separated by one shot, the residue 14 can be separated and removed by performing the overlapping shot. Further, by performing the superimposition shooting while scanning the laser beam, all the residues 14 can be easily removed at high speed.
[0028]
The use of the mask 4 having the square or hexagonal through-holes 4a to form the beam spot (image of the through-holes 4a) of the laser beam incident on the mold 13 into a square or hexagon is performed by the mold 13; This is because many are rectangular and have a large area, and thus are suitable for completely and efficiently removing the residue 14 over a large area by performing a laser beam overlapping shot.
[0029]
Further, the housing 9 is provided with one window 10 on each of one surface and a surface facing the window. A mold cleaning device is installed such that they face the concave portions of the upper mold and the lower mold of the mold 13, respectively. This is because the mold cleaning device shown in FIG. 1 is inserted between the upper mold and the lower mold of the mold 13 to efficiently clean both the upper and lower molds.
[0030]
Since the residue 14 can be removed more favorably as the intensity distribution in the beam spot of the laser beam on the surface of the mold 13 is closer to uniform, a homogenizer that makes the beam intensity closer to uniform on the beam irradiation surface is provided by a beam shaping optics. You can also join system 3.
[0031]
The use of the optical fiber 2 to transmit the beam from the laser light source 1 to the housing 9 is suitable for introducing the beam into the housing 9 that is displaced in a two-dimensional direction by the housing drive system 11. Because. The optical fiber 2 can ensure optical coupling between the laser light source 1 and the housing 9 even when the housing 9 moves.
[0032]
Further, instead of separately providing the laser light source 1 and the optical fiber 2, a fiber laser having both functions can be used.
[0033]
If the interference of the laser beam after passing through the mask 4 can be neglected, even if the condenser lens 5 and the lens moving mechanism 6 are removed from the mold cleaning apparatus shown in FIG. Can be.
[0034]
FIG. 2A is a schematic diagram of a mold cleaning device according to a second embodiment. In the mold cleaning apparatus shown in FIG. 1, a case swinging system 15 is newly added except for the condenser lens 5, the lens moving mechanism 6, the mirror 7, and the mirror rotating mechanism 8. The housing swing system 15 swings the housing 9 so as to change the emission direction of the laser beam in a two-dimensional direction. In the mold cleaning device shown in FIG. 2A, only one window 10 is provided on one surface of the housing 9 facing the housing swinging system 15. The mold cleaning device is installed such that the window 10 faces the concave portion of the mold 13 from which the residue 14 is to be removed. The control device 12 controls the displacement of the housing 9 in the two-dimensional direction by the housing drive system 11 and the swing of the housing 9 by the housing swing system 15. Since the mold cleaning apparatus shown in FIG. 2A does not include the condenser lens 5 and the lens displacement mechanism 6, it is desirable to use the mold cleaning apparatus when the interference of the laser beam after passing through the mask 4 can be ignored.
[0035]
A condenser lens 5 for forming an image of the through hole 4a on the mold 13 and a lens displacement mechanism 6 for displacing the condenser lens 5 in the optical axis direction of the laser beam are added between the mask 4 and the window 10. May be. In this case, in addition to the above control, the control device 12 controls the condensing lens by the lens displacement mechanism 6 so that the through hole 4a always forms an image on the mold 13 even if the incident position of the laser beam changes. 5 is controlled.
[0036]
FIG. 2B is a schematic view of the mold cleaning device shown in FIG. 2A in which the housing 9 has been swung by the housing swinging system 15. By swinging the housing 9, the beam emission direction can be changed, and the angle of incidence of the beam on the main surface of the mold 13 can be changed. For example, when a laser beam is emitted toward a tapered portion on the side surface of a concave portion of a mold 13 for semiconductor manufacturing sealing, the housing 9 is swung to change the beam emission direction, and the beam enters the mold 13. The pulse laser beam is scanned so that the position moves. The laser beam is made incident on the tapered portion so that the variation of the incident angle with respect to the incident angle of the laser beam incident on the other part of the mold 13 is as small as possible.
[0037]
Note that a mirror 7 and a mirror rotating mechanism 8 may be further provided between the mask 4 and the window 10. In this case, it is possible to scan the mold 13 by changing the beam emission direction without swinging the housing 9.
[0038]
Next, suitable conditions for the pulsed laser beam to be irradiated will be described. The surface of a mold for semiconductor manufacturing sealing is mainly plated with a metal such as chromium. The thickness of the plating is, for example, about 2 μm.
[0039]
FIG. 3 is a graph (simulation) showing the relationship between the depth from the metal layer surface and the temperature rise immediately after the end of the pulse of the pulse laser beam (Nd: the fundamental wave of the YLF laser) applied to the metal layer formed of chromium. Result). The horizontal axis represents the depth from the surface of the metal layer in units of "m", and the vertical axis represents the temperature rise in units of "K". The curves a, b, c, d, and e in the figure show the temperature rise when the pulse laser beams having the pulse widths of 1 ns, 10 ns, 20 ns, 50 ns, and 100 ns are incident, respectively. The calculation was performed on the assumption that the beam reflectance of chromium was 80%. The fluence of the laser beam to be irradiated was adjusted so that the temperature on the surface of the metal layer was 1800 ° C., which was lower than the melting point of chromium of 1900 ° C. When the pulse width is 1 ns, 10 ns, 20 ns, 50 ns, and 100 ns, the fluence of the laser beam on the metal layer surface is 0.27 J / cm, respectively. ² , 0.85 J / cm ² , 1.2J / cm ² 1.9 J / cm ² , And 2.7 J / cm ² Met.
[0040]
It can be seen that the fluence required to raise the temperature of the metal layer surface to 1800 ° C. increases as the pulse width increases. Irradiating a laser beam with a short pulse width shortens the time required for heat to diffuse into the metal layer, so that the temperature can be increased with a low fluence.
[0041]
However, when a laser beam is applied to the chromium-plated mold 13 to which the residue is attached and the residue is removed, a short pulse width, low fluence beam is used to give sufficient heat to the mold. It is considered difficult, and since the laser beam is focused on a narrow area, the surface of the mold 13 is ablated, and the mold 13 may be damaged. Therefore, it is considered preferable to irradiate a laser beam having a pulse width of 10 ns or more.
[0042]
Further, the plating of the mold 13 may be made of a metal other than chromium. If the pulse width is too long, heat is diffused into the mold 13 before the metal film (plating) is sufficiently heated. Also, the interface between the metal film (plating) and the base material of the mold 13 is heated, and the two may be separated due to a difference in thermal expansion. From FIG. 3, it can be seen that at a pulse width of 100 ns, heating is performed at several tens of degrees Celsius or more at a depth of 10 μm. In addition, as the pulse width becomes longer, the temperature inside becomes higher. Since a metal film (plating) is generally 10 μm or less, a pulse width longer than 100 ns increases the possibility of inducing peeling. Therefore, it is preferable that the pulse width of the irradiated laser beam be 100 ns or less.
[0043]
FIG. 4 is an SEM image of the surface of the mold 13 in which a fundamental wave of an Nd: YLF laser is incident on the mold 13 having a thickness of about 2 μm and on which chrome plating is applied, and the residue 14 is cleaned. The pulse width of the laser beam is 20 ns, and the fluence on the surface of the mold 13 is 1.4 J / cm. ² Met. Residue of the thermosetting epoxy adhered to the mold 13.
[0044]
From FIG. 4, it can be seen that the residue of the thermosetting epoxy is peeled off (peeled off and separated from the mold 13), and the clean mold 13 surface (chrome surface) is exposed. The reason for irradiating a beam with a fluence larger than the fluence used in the simulation shown in FIG. 3 is that the reflectance of chromium was larger than the value used in the simulation and that the chromium was included in the residue of the thermosetting epoxy. This is because the silica filler scattered the laser beam, resulting in a large energy loss. However, the temperature distribution in the depth direction of the metal layer as shown in FIG. 3 depends on the pulse width of the pulsed laser beam to be irradiated. For this reason, it is considered that the temperature distribution in the chrome plating of the mold 13 is not much different from the simulation result (graph c) in the case where the pulse width is 20 ns shown in FIG. Using a laser beam having a pulse width of 10 to 30 ns, the fluence of the beam on the mold 13 is set to 1.5 J / cm. ² By adjusting below, the residue can be effectively removed from the mold 13.
[0045]
Next, a method of cleaning a mold for sealing semiconductor production according to a third embodiment will be described. The mold cleaning device used is the same as that shown in FIG. 1 or FIG. In the mold cleaning method according to the first embodiment, a thermosetting epoxy or silicon resin adhered to the mold 13 is irradiated with a laser beam at a fluence of a size such that a residue is separated and separated from the mold 13 by a lifting phenomenon. The residue 14 formed by, for example, was removed from the mold 13. In the third embodiment, the residue 14 at the position where the laser beam is incident is separated from the surface of the mold 13 due to the lifting phenomenon, but the laser beam is applied to the mold 13 with a fluence of a size that does not separate from the mold 13. Make it incident.
[0046]
Similarly to the mold cleaning method according to the first embodiment, the movement of the housing 9 by the housing drive system 11 and the rotation of the mirror 7 by the mirror rotation mechanism 8 are controlled to remove the residue 14 at the laser beam incident position from the mold. The laser beam is incident on the mold 13 while scanning, with a fluence of a size that separates from the surface of the 13 but does not separate from the mold 13 (a hole is not formed in the residue 14 at the incident position). In scanning, the condenser lens 5 is moved by the lens moving mechanism 6 in the optical axis direction of the laser beam so that the through-hole 4a is always formed on the surface of the mold 13. Similar to the mold cleaning method according to the first embodiment, it is desirable to use a mask 4 having a square or hexagonal through hole 4a.
[0047]
The beam spot is moved while the laser beam is repeatedly shot, and the residue 14 at the beam incident position is peeled off from the mold 13 one after another. After the residue 14 is peeled off by beam irradiation, for example, an adhesive tape is attached to the residue 14 on the mold 13, and the peeled residue 14 is mechanically peeled off (separated) from the mold 13. By doing so, it is also possible to peel off the film of the large area residue 14 from the mold 13 as one sheet. The residue 14 that is separated by a plurality of shots of the pulsed laser beam and mechanically peeled off (separated) from the mold 13 is irradiated with a one-shot pulsed laser beam by the mold cleaning method according to the first embodiment. It is larger than the residue 14 to be separated and separated.
[0048]
After the irradiation with the laser beam, not only the part where the residue 14 is peeled off is removed mechanically, but also a conventional chemical residue removal method can be performed. For example, the mold 13 is irradiated with a laser beam, and a film of the residue 14 is peeled off from the mold 13 but is not separated, and a part of the film of the residue 14 may be broken, or If a part of 14 is peeled off and separated from the mold 13 but a part is not separated, in order to further perform cleaning using a melamine resin or to improve mold release. Alternatively, the encapsulating step may be performed using only a resin without adding an LSI with a large amount of a release agent. The film of the residue 14 in the state of being torn or turned up is more likely to adhere to the charged resin than that of the state in which the thickness is uniform or flat, so that a high cleaning effect can be obtained.
[0049]
Depending on the shape of the mold surface of the mold 13, the type of plating applied to the mold 13, the thickness of the film of the residue 14, the fluence of the beam to be irradiated, and the like, the rotation of the mirror 7 and the movement of the housing 9 may cause a pulse. The residue 14 can be separated from the mold 13 by irradiating the laser beam from a certain direction without changing the beam incident position on the mold 13 of the laser beam. After the peeling, the residue 14 is mechanically separated from the mold 13 with, for example, an adhesive tape (peeled off) or chemically cleaned with, for example, a melamine resin to completely remove the residue 14.
[0050]
FIG. 5A is a schematic view of the mold cleaning device in which the housing drive system 11, the housing swing system 15, and the control device 20 are removed from the mold cleaning device shown in FIG. This mold cleaning device can move or tilt the housing 9 in an arbitrary direction with a human hand, change the emission direction of the laser beam, and make the beam enter a desired position of the mold 13. . Therefore, the housing drive system 11 for moving the housing 9 in the in-plane direction (two-dimensional direction) of the mold 13, the housing swinging system 15 for rotating the housing 9, and the control device 20 for controlling them are omitted. There is. The optical fiber 2 can secure optical coupling between the laser light source 1 and the housing 9 even when the housing 9 is displaced and the emission direction of the pulse laser beam emitted from the housing 9 changes.
[0051]
FIG. 5B shows a mold cleaning unit of the semiconductor manufacturing sealing apparatus in which the mold cleaning apparatus shown in FIG. 1 except for the casing drive system 11 is incorporated in a magic hand 20 of the semiconductor manufacturing sealing apparatus. FIG. The magic hand 20 is used to transport and install the LSI in the mold 13 and to take out an LSI product sealed with resin. The control device 12 controls the displacement of the condenser lens 5 by the lens moving mechanism 6 and the rotation of the mirror 7 by the mirror rotating mechanism 8 in synchronization with the movement of the magic hand 20. For example, the mold is cleaned every time the sealing operation is performed several times.
[0052]
The apparatus shown in FIGS. 5A and 5B can be used for both the mold cleaning method according to the first embodiment and the mold cleaning method according to the third embodiment.
[0053]
In the mold cleaning apparatuses according to the first and second embodiments, the Nd: YLF laser oscillator is used, but an Nd: YAG laser oscillator or the like may be used.
[0054]
In addition, using the mold cleaning method according to the first and third embodiments, the sealing operation may be temporarily interrupted (on-line) to remove the mold residue without removing the mold from the production line. Alternatively, the mold can be once removed from the production line (off-line), and the mold residue can be removed.
[0055]
As described above, the present invention has been described with reference to the examples. However, the present invention is not limited to these examples. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.
[0056]
【The invention's effect】
As described above, according to the present invention, utilizing the lifting phenomenon, the residue of the resin adhered to the mold for semiconductor manufacturing sealing, high-speed, simple, also, and hardly damage the mold In addition, it is possible to provide a mold cleaning method and a mold cleaning device suitable for removal.
[Brief description of the drawings]
FIG. 1 is a schematic view of a mold cleaning device used in a mold cleaning method according to a first embodiment.
FIGS. 2A and 2B are schematic diagrams of a mold cleaning device according to a second embodiment.
FIG. 3 is a simulation result showing the relationship between the depth from the metal layer surface and the temperature rise immediately after the end of the pulse of the pulsed laser beam applied to the metal layer formed of chromium.
FIG. 4 is an SEM image of a mold surface after a laser beam has been incident on a chrome-plated mold and residues have been cleaned.
FIG. 5A is a schematic diagram of a mold cleaning device, and FIG. 5B is a schematic diagram showing a mold cleaning unit incorporated in a magic hand of a semiconductor manufacturing sealing device.
[Explanation of symbols]
1 Laser light source
2 Optical fiber
3 Beam shaping optical system
4 Mask
4a Through hole
5 Condensing lens
6. Lens moving mechanism
7 Mirror
8 Mirror rotation mechanism
9 Case
10 windows
11 Housing drive system
12 Control device
13 Mold
14 residue
14a Removal part
15 Housing swing system
20 Magic Hand

Claims (12)

A step of preparing a mold to which the residue has adhered;
A pulse laser beam having the property of transmitting the residue, reflecting at the interface between the residue and the mold and separating the residue at the reflection position from the mold, the incident position of the pulsed laser beam is A step of causing the residue to enter the mold from the surface of the residue while scanning so as to move on the mold, and removing a part of the residue at the incident position from the mold. The mold cleaning method according to claim 1, wherein the residue is formed of a thermosetting epoxy or a silicone resin. The mold cleaning method according to claim 1, further comprising, after the pulsed laser beam passes through the through-hole, incident on the mold under a condition that the through-hole forms an image on the mold. The mold cleaning method according to claim 3, wherein the shape of the image of the through-hole formed on the mold is a square or a hexagon. The mold cleaning method according to claim 1, wherein a pulse width of the pulse laser beam is 10 ns or more and 100 ns or less. The mold cleaning according to any one of claims 1 to 4, wherein a pulse width of the pulse laser beam is 10 ns or more and 30 ns or less, and a fluence of the pulse laser beam incident on the mold is 1.5 J / cm ² or less. Method. The mold cleaning method according to any one of claims 1 to 6, wherein the step of peeling a part of the residue from the mold includes a step of separating a part of the peeled residue from the mold. A laser light source for emitting a pulsed laser beam,
Beam scanning means for scanning a pulse laser beam emitted from the laser light source,
A first control unit for controlling the beam scanning unit such that an incident position of the pulse laser beam moves on the die. 9. The mold cleaning apparatus according to claim 8, further comprising a first moving unit that moves the beam scanning unit in a two-dimensional direction. Further, a mask which is provided on an optical path of a pulse laser beam emitted from the laser light source and has a through hole for shaping a beam cross-sectional shape of the pulse laser beam,
An imaging lens that forms an image of the through hole of the mask on the mold surface;
Second moving means for moving the imaging lens in the optical axis direction of the pulse laser beam;
The second moving unit so that the pulsed laser beam that scans the mold by the beam scanning unit is incident on the mold under a condition that the through hole of the mask forms an image on the mold. The mold cleaning apparatus according to claim 8, further comprising: a second control unit configured to perform control. The mold cleaning apparatus according to claim 8, further comprising an optical fiber that transmits a pulse laser beam emitted from the laser light source to the first moving unit. A laser light source capable of emitting a pulsed laser beam having a pulse width of 10 ns or more and 30 ns or less,
An optical system capable of causing a pulse laser beam emitted from the laser light source to be incident on a mold, and an optical system capable of manually changing an emission direction of the pulse laser beam emitted from the optical system,
A beam transmission unit for optically connecting the laser light source and the optical system, wherein an optical communication between the laser light source and the optical system is performed even when an emission direction of a pulse laser beam emitted from the optical system changes. And a beam transmitting means capable of ensuring a proper coupling.

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