JPH10193161A - Laser marking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a semiconductor wafer from adherence of dust generating at the time of laser marking and to ensure laser marking without lowering the yield. SOLUTION: The laser marking device 10 is provided with a transparent marking chamber 13 that is connected to a sucking device through an exhaust pipe 32. In addition, an optical system 12 is arranged in such a manner as a laser beam L is emitted from the lower part of the marking chamber 13, transmitting through the chamber to the lower face 7a of a wafer 7 placed in the chamber 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a marking device, and more particularly, to a marking device used for marking a semiconductor wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, in order to manage a semiconductor wafer, a semiconductor wafer is marked (engraved) with characters, numerals and the like by a laser. FIG. 4A is a partially broken front view of a conventional marking device, and FIG. 4B is a sectional view taken along the line [B]-[B] in FIG. 4A. is there. As shown in FIG. 4A, a laser oscillator 2 is provided above the chamber 1, and a side wall is provided with:
A shutter 5 for taking in and out the semiconductor wafer 3 is provided. The marking is performed as follows. The semiconductor wafer 3 is placed on the wafer support 4 provided in the chamber 1 and the shutter 5 of the chamber 1 is closed. Next, a laser beam L ′ is emitted from the laser oscillator 2 to the vicinity of the orientation flat 3a of the semiconductor wafer 3, that is, to the marking portion 3b.
At this time, the melted silicon is scattered by the laser beam L ', and cools to become fine particles, that is, dusts d. In the conventional technique, since the laser light L ′ is emitted from above the semiconductor wafer 3, the scattered dust d adheres to the upper surface of the semiconductor wafer 3. The dust d attached to the semiconductor wafer lowers the yield of the semiconductor device. This is due to device densification
At present, as miniaturization is progressing, this is a major problem.

Therefore, it is conceivable to perform marking by weakening the laser beam L 'to such a degree that silicon does not scatter. However, this does not allow deep marking. That is, when films such as wiring are stacked on the marked characters and numerals, these characters and numerals become invisible and the production control of the semiconductor wafer becomes impossible. When marking is performed in a state where films are stacked, that is, in a state where an oxide film or a polysilicon film is formed on a single-crystal silicon wafer, the single-crystal silicon is evaporated and
In addition to melting, the film formed on the single crystal silicon wafer also peels off, generating a large amount of dust. That is, this large amount of dust adheres to the upper surface of the semiconductor wafer 3 and further reduces the yield of semiconductor devices.

Accordingly, Japanese Patent Application Laid-Open Nos. Hei 5-23875, Hei 8-45799 and Hei 64-48685 are disclosed.
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a technique for preventing contamination of a semiconductor wafer by silicon dust generated by laser marking. In other words, Japanese Patent Application Laid-Open No. Hei 5-23875 discloses a mechanism in which a semiconductor wafer is set so that the surface of the semiconductor wafer irradiated with a laser is at 0 ° to 90 ° with respect to a horizontal plane, and silicon dust is generated. It does not adhere to a semiconductor wafer. Japanese Patent Application Laid-Open No. 8-45799 discloses that a gas capable of etching silicon is introduced into a marking chamber, and this gas and silicon dust are chemically reacted to produce a silicon compound gas. It is disclosed that dust does not adhere to the semiconductor wafer. Further, JP-A-64-48685 discloses that the angle of incidence of laser light on a semiconductor wafer is 20 ° to 40 °.
By doing so, it is disclosed that dust generated at the time of marking can be suppressed without increasing laser blur.

However, in JP-A-8-45799, it is necessary to introduce a gas containing at least one of fluorine and chlorine to cause a chemical reaction and then exhaust the gas. Further, in Japanese Patent Application Laid-Open Nos. 5-23875 and 64-48685, the generated silicon dust is scattered to the laser light optical system. In particular, in Japanese Patent Application Laid-Open No. Hei 5-23875, the laser light is irradiated from below, so that the generated dust (although it does not adhere to the semiconductor wafer), the optical system of the laser light disposed below Easy to adhere to. If dust scatters in the optical system of the laser beam, the laser beam may be adversely affected, for example, by weakening the laser beam, and the marking may not be performed reliably.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a laser marking apparatus capable of reliably marking without causing dust at the time of marking to adhere to a semiconductor wafer.

[0007]

The object of the present invention is to provide a laser marking apparatus (10) for marking a semiconductor wafer (7) by irradiating a laser beam (for example, L in the embodiment; hereinafter the same). The semiconductor wafer (7) is hermetically inserted into a chamber (13) having an exhaust hole (13ba), and the semiconductor wafer (7) is inserted into the chamber (13b).
The problem is solved by a laser marking device (10), wherein the semiconductor wafer (7) is irradiated with the laser light (L) while forcibly exhausting the inside of the chamber (13) through a).

That is, since the inside of the chamber is forcibly exhausted at the time of laser marking, the generated dust is forcibly exhausted from the inside of the chamber. Therefore, dust does not adhere to the semiconductor wafer in the chamber.

[0009] The above problem is a problem with laser light (for example,
In the laser marking device (10) for performing marking on the semiconductor wafer (7) by irradiating L of the embodiment (hereinafter the same), at least a part of the bottom (13c) is formed in a chamber (13) made of a transparent material. The semiconductor wafer (7) is inserted with the marking surface (7a) of the semiconductor wafer (7) facing downward, and the laser beam (L) is transmitted through the transparent body to the chamber (13). The laser marking device (10), which is irradiated from below.

That is, since laser light is irradiated from outside the chamber, dust generated at the time of marking does not scatter to the optical system of the irradiated laser light. Therefore, laser marking can be performed without adversely affecting the laser beam. In addition, since the laser is applied to the marking surface of the semiconductor wafer facing downward from below, dust generated during marking falls down due to gravity and does not adhere to the semiconductor wafer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS After a semiconductor wafer is inserted in a sealed state into a chamber having an exhaust hole, the semiconductor wafer is irradiated with laser light while forcibly exhausting the chamber through the exhaust hole. That is, dust generated at the time of marking is discharged to the outside of the chamber by the forced exhaust in the chamber. Therefore, the generated dust does not adhere to the semiconductor wafer in the chamber. Further, the dust that has been forcibly discharged out of the chamber is not scattered on the semiconductor wafer located in a place other than the chamber of the laser marking device, so that the dust does not adhere to the semiconductor wafer outside the chamber. Therefore, the yield of the semiconductor device can be improved.

Further, if the exhaust hole is provided at a position lower than the semiconductor wafer placed in the chamber,
When forced exhaust is performed, dust is scattered toward the semiconductor wafer, and the possibility that dust adheres to the semiconductor wafer can be prevented. Also, if this exhaust hole is provided near the marking portion of the semiconductor wafer,
It is possible to prevent the dust from scattering and adhering near the semiconductor wafer when forcibly exhausting. In addition, if forced exhaust is performed in a sealed state, the exhaust efficiency can be increased, so that dust is less likely to adhere to the semiconductor wafer.

At least a part of the chamber of the marking device is made of a transparent material, and if laser light is irradiated from the outside of the chamber through the transparent material, dust generated at the time of marking will generate laser light. Does not scatter to the optical system for irradiating the semiconductor wafer. Therefore, reliable marking can be performed without adversely affecting the laser beam.

In addition, a semiconductor wafer is inserted into a chamber having at least a part of the bottom part made of a transparent body, with the marking surface of the semiconductor wafer facing downward, and laser light is applied through the transparent body to the lower part of the chamber. More irradiation. That is, dust generated at the time of marking falls down due to gravity and does not adhere to the semiconductor wafer. At this time, since the laser light is irradiated from outside the chamber, dust falling downward due to gravity does not scatter to the optical system of the irradiated laser light. Therefore, laser marking can always be performed reliably without adversely affecting the laser light (for example, light weakening).

Further, in this marking apparatus, if an exhaust hole is provided in the chamber and the inside of the chamber is forcibly exhausted from the chamber at the time of marking, dust generated and dropped under the semiconductor wafer is discharged out of the chamber. The exhaust hole at this time may be provided below the position where the semiconductor wafer is placed and in the vicinity of the marking portion of the semiconductor wafer for the above-described reason.

If the chamber of the laser marking device is made removable, the chamber can be removed and cleaned to remove the remaining dust in the chamber. Therefore, it is possible to prevent the dust remaining in the chamber from contaminating the semiconductor wafer and lowering the yield of the semiconductor device.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of the laser marking apparatus of the present invention, and FIG. 2 is [2]-in FIG.
[2] A cross-sectional view in the line direction is shown, which is indicated as a whole by 10. Laser marking device 10
Has a laser oscillator 11, an optical system 12 that scans a laser beam L oscillated from the laser oscillator 11, a marking chamber 13, and a transport unit 15 that transports the wafer 7.

The transport section 15 includes a transport robot 16, a position adjusting section 17, and elevator units 21 and 21 '. The transfer robot 16 is located at the center of the laser marking device 10 and performs a rotation and a reciprocating motion as known in the art, so that the position adjustment unit 17 and the elevator unit 2
1, 21 'and the wafer 7 to the marking chamber 13. In addition, the position adjusting unit 17 includes the turntable 1.
7a and a sensor 17b for rotating the wafer 7 to align the orientation flat 7f of the wafer 7. In addition, the ereverta units 21 and 2
Carriers 22, 22 'in which a plurality of (for example, 25) wafers 7 are arranged are placed on 1', and the elevator units 21, 21 'are moved up and down to mark from the carriers 22, 22'. The previous wafer 7 is taken out and, at the same time, the wafer 7 after the marking is accommodated.

The marking chamber 13 according to the present invention is made of a transparent material, for example, high-purity quartz glass. This is shown in FIG.
As shown in FIG.
It is supported by a marking chamber support 31 having 1a, and is disposed above the optical system 12. Further, an insertion opening 13a for inserting and removing the wafer 7 is formed in the marking chamber 13, and a shutter 35 having a seal 35a is provided in the insertion opening 13a so as to be openable and closable. Further, as shown in FIG. 1, a projection 13b is formed in the marking chamber 13 on the optical system 12 side, that is, in the vicinity of the marking portion 7m of the wafer 7 at the time of marking. An exhaust hole 13ba is formed inside the protrusion 13b. The exhaust hole 13ba is connected to an exhaust pipe 32 connected to a suction device 33 via a connector 36.
If the connection with the exhaust pipe 32 is released, the marking chamber 13 of this embodiment is simply placed on the marking chamber support 31, so that the marking chamber 13 can be easily removed from the laser marking device 10. Further, inside the marking chamber 13, a wafer support table 34 on which the wafer 7 is placed is disposed on the bottom surface.

The laser marking device 10 of the present invention comprises:
The configuration is as described above. Next, the operation will be described.

From the carrier 22 of the elevator unit 21 (or from the carrier 22 ′ of the elevator unit 21 ′), the unmarked wafer 7 is taken out by the transfer robot 16 and transferred to the position adjustment unit 17. Here, the orientation of the orientation flat 7f of the wafer 7 is adjusted so that the wafer 7 placed on the turntable 17a is rotated and marking is performed near the orientation flat 7f when the wafer 7 is inserted into the marking chamber 13. Next, the wafer 7 whose orientation of the orientation flat 7f is adjusted is transferred to the marking chamber 13 by the transfer robot 16.

That is, the wafer 7 is placed in the marking chamber 13
, The transfer robot 16 descends, and places the wafer 7 on the wafer support table 34. When the transfer robot 16 leaves the marking chamber 13, the shutter 3
5 is closed, and the marking chamber 13 becomes a closed space. In this state, the suction device 33 and the laser oscillator 11 operate. The laser light L oscillated from the laser oscillator 11
After passing through the optical system 12 (reflected by the reflecting mirrors 12a and 12b shown in FIG. 2), the light passes through the through hole 31a of the marking chamber support 31 and the bottom 13c of the marking chamber 13. Then, the marking reaches the marking portion 7m on the lower surface 7a of the wafer 7 to perform marking. At this time, the inside of the marking chamber 13 is forcibly exhausted through the exhaust hole 13ba and the exhaust pipe 32.

That is, the laser beam L is applied to the lower surface 7a of the wafer 7, so that the silicon of the wafer 7 is melted and marked. At the same time, the melted silicon scatters and is cooled to generate fine dust d. However, since this dust d is generated from the lower surface 7a of the wafer 7, it falls below the wafer 7 by gravity. At this time, since the inside of the marking chamber 13 is forcibly exhausted by the suction device 33, the generated dust d is immediately sucked from the marking chamber 13 to the suction device 33 via the exhaust pipe 32.

When the irradiation of the laser beam L is completed, that is, when the marking is completed in the marking chamber 13,
The operation of the suction device 33 stops. Then shutter 3
5 is opened, the transfer robot 16 is inserted into the marking chamber 13, and the marked wafer 7 is transferred to the marking chamber 13.
Remove from The marked wafer 7 is returned to the position of the carrier 22 before processing via the position adjusting unit 17.

In this embodiment, since the marking chamber 13 is made of a transparent material, the laser beam L is irradiated from outside the marking chamber 13. Therefore, the silicon generated during the marking does not scatter to the optical system 12, and the laser light does not become weak or unstable. Furthermore, since the lower surface 7a, which is the marking surface of the wafer 7, is irradiated with laser from below, the generated dust d falls downward due to gravity. That is, the dust d generated during the marking does not adhere to the wafer 7.
In addition, since the inside of the marking chamber 13 is forcibly exhausted at the time of marking, the generated dust is thereby immediately exhausted from the marking chamber 13. Therefore, dust does not adhere to the wafer. Since the shutter having the seal 35a is used, the marking chamber 13
, And the forced exhaust can be efficiently performed. In the above embodiment, if the connector connecting the exhaust pipe 32 and the protruding portion 13b is provided with a sealing property, forced exhaust can be performed more efficiently.

Further, in the present embodiment, the marking chamber 13 as a chamber is easily provided with the laser marking device 10.
It can be removed from Therefore, the marking chamber 13 can be removed periodically and cleaned, for example, by washing, so that the dust remaining in the marking chamber 13 can be completely removed. Therefore, even the dust remaining in the marking chamber 13 without being exhausted even by forcible exhaustion can be periodically removed, so that there is no fear that the dust adheres to the wafer 7.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the entire marking chamber 13, which is a chamber, is made of high-purity quartz glass, which is a transparent body. However, even if the whole chamber is not made of a transparent body, laser light is applied to the semiconductor wafer from outside. What is necessary is just to be able to irradiate. Therefore, the marking chamber 1 as shown in FIG.
It may be 3 '. That is, a hole 13d 'is formed in a part of the marking chamber 13', a transparent member 40 is attached thereto via a seal 41, and a laser beam L is radiated from outside through the transparent member 40. Is also good. Further, in the above embodiment, high-purity quartz glass is used as the transparent body, but other transparent bodies may be used, such as low-expansion glass (used as a material of a mask substrate used in a photolithography process) or Sapphire or the like may be used. This transparent body is preferably a transparent body that does not generate dust from the transparent body when transmitted by a laser.

In the above embodiment, the marking chamber 13
Although the protrusion 13b provided with the exhaust hole 13ba is formed in this embodiment, other configurations may be used as long as the exhaust hole is for forcibly exhausting.
That is, as shown in FIG. 3, a screw hole 13g 'may be provided in the wall of the marking chamber 13', and an exhaust pipe 32 'connected to the suction device may be screwed into the screw hole 13g'. In addition,
A seal 36 'may be provided at this connection to increase the exhaust efficiency. Furthermore, when the effect of preventing dust from adhering to the semiconductor wafer is obtained by forcibly exhausting the gas, it is not necessary to limit the irradiation of the laser beam from outside the transparent chamber. That is, dust is discharged out of the chamber by the forced exhaust, so that even if the laser light irradiation part is provided in the chamber exposed and the laser light is irradiated, the dust may scatter in the laser light. Absent. Therefore, since the laser beam is not adversely affected, marking can be performed reliably.

Further, in the above embodiment, the marking chamber 13
The marking chamber 13 was placed on a marking chamber support 31 as shown in FIG. 1 so that the marking chamber 13 could be removed and cleaned, that is, the marking chamber 13 could be easily removed from the laser marking device 10. The shape of this marking room support need not be limited to this,
For example, as shown in FIG. 3, it may be supported by a plurality of columns 31 '. The structure and configuration of the laser marking device 10 need not be limited to the above, and the arrangement of the laser oscillator 11, the optical system 12, and the marking chamber 13 may be different. The position adjustment unit 17 and the like may have another configuration.

[0032]

As described above, according to the present invention, the following effects can be obtained.

Since the chamber chamber is forcibly evacuated, dust generated at the time of marking is immediately discharged out of the chamber by the forcible evacuation. Therefore, dust generated at the time of marking does not adhere to the semiconductor wafer placed in the chamber. Furthermore, in order to deepen the marking (to prevent the marked characters from becoming invisible as the wiring is stacked), the laser power is increased, and even if the generation of dust is increased, dust is generated on the semiconductor wafer. Does not adhere.
Further, even if marking is performed in a state where a film (an oxide film or a polysilicon film) or the like is present on the single-crystal silicon, a large amount of dust is not attached to the semiconductor wafer. Since the inside of the chamber is closed except when the semiconductor wafer is loaded and unloaded, dust does not adhere to the semiconductor wafer outside the chamber.
Accordingly, dust does not adhere to the semiconductor wafer, and the yield of semiconductor devices can be improved.
In addition, since dust does not scatter to the irradiated laser beam and its optical system, marking can be performed reliably.

Further, since the laser light is irradiated from below, the generated dust falls downward due to gravity. Therefore, dust generated during marking does not adhere to the semiconductor wafer. Furthermore, in order to deepen the marking (to prevent the marked characters from becoming invisible as the wiring is stacked), the laser power is increased, and even if the generation of dust is increased, dust is generated on the semiconductor wafer. Does not adhere. Further, even if marking is performed in a state where a film (an oxide film or a polysilicon film) or the like is present on the single-crystal silicon, a large amount of dust is not attached to the semiconductor wafer. Further, at this time, marking is performed by irradiating a laser beam from outside the marking chamber. Therefore, the laser marking can be reliably performed without the dust falling downward being scattered to the optical system and without adversely affecting the laser. Therefore, dust generated at the time of marking does not adhere to the semiconductor wafer, and the yield of semiconductor devices can be improved.

Further, since the chamber can be removed from the laser marking device, the chamber can be periodically cleaned to completely remove dust remaining in the chamber. Therefore, dust is further prevented from adhering to the semiconductor wafer, and the yield of semiconductor devices can be further improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a laser marking device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line [2]-[2] in FIG.

FIG. 3 is a sectional view showing a main part of a laser marking device according to a modification of the present invention.

FIG. 4 is a view showing a laser marking device in a conventional example, wherein A is a partially broken front view, and B is a cross-sectional view taken along the line [B]-[B] in A.

[Explanation of symbols]

7: wafer, 7a: lower surface, 7f: orientation flat, 7
m: marking section, 10: laser marking device, 11: laser oscillator, 12: optical system, 13,
13 '... marking room, 13b ... projection, 13ba ...
... exhaust hole, 13c ... bottom, 13g '... screw hole, 3
2, 32 '... exhaust pipe, 33 ... suction device, 35 ... shutter, 35a ... seal, L ... laser light.

Claims (5)

[Claims] 1. A laser marking device for marking a semiconductor wafer by irradiating a laser beam, wherein the semiconductor wafer is hermetically inserted into a chamber having an exhaust hole, and the semiconductor wafer is inserted into the chamber through the exhaust hole. A laser marking apparatus characterized in that the semiconductor wafer is irradiated with the laser beam while forcibly exhausting air. 2. The laser marking according to claim 1, wherein at least a part of the chamber is made of a transparent material, and the laser light is irradiated from outside the chamber through the transparent material. apparatus. 3. A laser marking apparatus that performs marking on a semiconductor wafer by irradiating a laser beam, wherein at least a part of a bottom portion of the semiconductor wafer is placed in a transparent chamber, with the marking surface of the semiconductor wafer facing downward. The laser marking device, wherein the semiconductor wafer is inserted, and the laser light is irradiated from below the chamber through the transparent body. 4. The laser marking device according to claim 3, wherein the chamber is a chamber having an exhaust hole. 5. The laser marking device according to claim 1, wherein the chamber is removable.