JP2010090471A - Apparatus and method for laser beam machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for laser beam machining, capable of reducing machining time while maintaining quality of machining by a laser CVD method. <P>SOLUTION: A plurality of slits of various forms corresponding to various shapes of defects is previously prepared, and irradiation of laser beams of these shapes is collectively performed to form a conductive film. A process for correcting a disconnected part comprises a step carried out under first conditions regarding laser output and machining time and a step carried out under second conditions regarding laser output and machining time, wherein the second laser output condition is lower than the first laser output condition and the second machining time condition is longer than the first machining time condition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and method suitable for applications such as laser repair of circuit boards.

  As a method of correcting a so-called wiring defect such as a disconnection portion of a wiring formed on a substrate, a processing method by a laser CVD (Chemical Vapor Deposition) method is known (for example, Patent Document 1). reference). This is a method of electrically connecting the disconnection portion of the wiring by depositing a conductive film on the disconnection portion or a bypass path that bypasses the disconnection portion using a laser CVD method.

  6A and 6B show the configuration of a related laser processing apparatus. In the laser processing apparatus shown in FIG. 6A, along the optical path of the laser light 8, the slit 9, the relay lens 11, the objective lens 12, the gas window 14, and the substrate 15 that is a workpiece are arranged in this order. .

  Next, a method for correcting a wiring defect by the laser processing apparatus of FIG. A laser beam 8 spread by an expander (not shown) is cut out as a rectangular laser beam 10 by a slit 9 having a rectangular opening 9a. As shown in FIG. 6B, the slit 9 has teeth 27a and 27b movable in the X direction in the figure and teeth 28a and 28b movable in the Y direction in the figure. In addition, in FIG.6 (b), illustration is abbreviate | omitted about the structure of the slit 9 other than the above.

  The cut laser beam 10 is formed as a rectangular image 13 having a predetermined size by the relay lens 11 and the objective lens 12. Further, a source gas of a laser CVD method is supplied toward the substrate 15 from a gas window 14 provided below the objective lens 12. Thereby, a conductive film is formed on the exposed surface in accordance with the shape of the image 13, thereby correcting the wiring defect. In the example of FIG. 6A, the substrate 15 is placed on an XY stage (not shown), and the wiring defect can be corrected while moving in the XY direction according to the shape of the defective portion.

The corrected shape of the wiring defect is, for example, a shape like the straight wiring 17 shown in FIG. 7A and the bypass wiring 19 shown in FIG. The correction process for such a shape is performed, for example, by the following procedure. First, the laser beam 10 cut out by the slit 9 shown in FIG. 6A forms a rectangular image 13 shown in FIG. 7A at the processing start point. Thereby, the conductive film is deposited in a rectangular shape on the surface of the substrate 15. Thereafter, the linear wiring 17 is obtained by moving the image 13 relative to the scanning direction 16 on the substrate 15 by the operation of the XY stage. Similarly, the bypass wiring 19 shown in FIG. 7B is obtained by moving the rectangular image 13 on the substrate 15 in the same manner.
JP 2004-61689 A

  However, the method shown in FIGS. 6 and 7 has a problem that the processing time is long. In the above method, the processing speed is about 4 μm / s. Since correction of wiring defects usually involves reciprocation (two scans), if the length of the corrected portion is 50 μm, it takes about 26 seconds.

  Therefore, it is conceivable to prepare a plurality of slit shapes according to various defect shapes in advance and irradiate laser light in that shape all at once to form a conductive film, but if the intensity of the laser light is too strong The formed film is damaged and peeled off, and if it is too weak, there is a problem that it takes time similar to the above method to form the film.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a laser processing method and apparatus capable of shortening the processing time while maintaining the processing quality by the laser CVD method. It is in.

A laser processing apparatus according to the present invention includes a mask having a slit that defines a shape of a laser beam irradiated toward a substrate, an optical system that forms an image of the laser beam having the defined shape on the substrate, A source gas supply means for supplying a source gas necessary for the laser chemical vapor deposition method toward the substrate, a condition relating to a combination of the laser output and the processing time, a predetermined first condition and a predetermined second condition, And a condition switching means for switching to
The slit has a predetermined slit shape so as to connect a disconnected portion of the wiring formed on the substrate, and the laser output in the second condition is lower than the laser output in the first condition, The processing time under the second condition is longer than the processing time under the first condition.

  The laser processing method according to the present invention includes a step of defining a shape of a laser beam by a slit having a predetermined slit shape that connects a disconnection portion of a wiring formed on a substrate, and the laser beam is transmitted by an optical system. A step of forming an image on the substrate, and a step of correcting the disconnected portion by depositing the conductive film having the predetermined slit shape imaged on the substrate by using a laser chemical vapor deposition method. The step of correcting the disconnection portion includes a step executed under a first condition and a step executed under a second condition relating to a combination of laser output and processing time, and the laser output under the second condition is The laser output is lower than the laser output under the first condition, and the processing time under the second condition is longer than the processing time under the first condition.

  The present invention has the following features. In the laser processing apparatus of the present invention, the shape of the laser beam is defined by a slit-shaped mask provided in advance according to the wiring pattern. Then, the laser beam whose shape is defined is imaged on, for example, a disconnection portion (a wiring defect such as disconnection) in the wiring formed on the substrate, and the disconnection portion is corrected by a laser CVD method. As a result, the correction processing time can be greatly shortened as compared with a method of performing correction in a desired shape while scanning a beam formed in a rectangular shape.

  In this case, it is good also as having the slit switching means which moves a mask and switches a slit shape.

  The slit shape may include at least a linear shape and a shape that bypasses and connects the disconnected portion. The detour shape can be, for example, a U-shape.

  Further, the slit shape may include a predetermined mark shape that can be recognized on the substrate. Thereby, in addition to wiring correction, for example, marking on the substrate can be performed.

  Furthermore, the processing can be efficiently performed by performing the laser CVD method by a so-called gas curtain method in which the source gas of the laser CVD method is locally confined with a purge gas.

  According to the present invention, by using a slit having a predetermined corrected shape according to the wiring pattern of the workpiece, the conductive film is formed in a batch with the corrected shape by changing the processing conditions. As a result, it is possible to significantly reduce the time required for correcting the disconnection portion in the wiring while maintaining the processing quality.

  Next, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1A is a cross-sectional view showing a configuration of a laser processing apparatus according to the present embodiment, and FIG. 1B is a perspective view showing a slit mask used in the laser processing apparatus. Note that the present invention can be implemented by, for example, a semiconductor manufacturing process and a liquid crystal manufacturing process, but in this specification, correction of wiring defects in the liquid crystal manufacturing process will be described.

  As shown in FIG. 1A, in the laser processing apparatus of this embodiment, a slit mask 20, a relay lens 11, an objective lens 12, a gas window 14, and a substrate that is a workpiece along the optical path of the laser light 8. 15 are arranged in this order.

  As shown in FIG. 1B, the slit mask 20 is formed with slits having a pattern shape that matches the shape of the corrected portion of the wiring defect (disconnected portion). In FIG. 1B, a straight linear slit 23 and a U-shaped detour slit 24 are formed, but slits of various shapes can be formed in addition to this. The slit mask 20 can be composed of, for example, metal and glass, and may be configured to include a mirror, for example. Moreover, the slit mask 20 can be moved on the XY plane of the drawing by the switching mechanism 21. Thereby, the slit shape irradiated with the laser beam 8 can be switched.

  The relay lens 11 and the objective lens 12 together constitute an optical system for forming an image of laser light on the substrate 15. In addition to the configuration shown in FIG. 1A, for example, another lens may be added on the optical path.

  The gas window 14 is disposed such that a surface having a CVD source gas blowing port, a purge gas blowing port, and a gas suction port (all not shown) is close to the substrate 15. Thereby, as will be described later, a so-called gas curtain is formed around the correction processing portion of the substrate 15 during correction processing.

  Wiring for the liquid crystal device is formed on the substrate 15, and defects such as disconnection in the wiring are corrected by the laser CVD method using the laser processing apparatus of the present invention. In order to align the position of the correction processing portion with the optical path of the laser beam 8, the substrate 15 is placed on an XY stage (not shown) so as to be parallel to the XY plane of the drawing. Can be moved in the X or Y direction. In addition, by moving the laser irradiation system (laser beam 8, slit mask 20, laser beam 10, relay lens 11, objective lens 12, gas window 14), the optical path of the laser beam 8 is moved to the correction processing portion on the substrate 15. It may be combined.

  Next, the operation of this embodiment will be described. First, the correction processing portion on the substrate 15 is moved on the optical path of the laser beam 8 by operating the XY stage. Then, an appropriate pattern is selected from the slit-shaped patterns of the slit mask 20 in accordance with the shape of the correction processing portion, and moved so that the pattern selected by the switching mechanism 21 is on the optical path of the laser light 8. Let

  Next, a so-called gas curtain is formed around the correction processing portion. A method for forming a gas curtain is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-347242. In the present embodiment, a CVD source gas is supplied from a source gas outlet provided on the surface of the gas window 14 on the substrate 15 side so as to cover the correction processing portion. A purge gas is then supplied from the purge gas outlet to confine the CVD source gas. For example, nitrogen gas is used as the purge gas. Further, the CVD source gas and the purge gas are sucked from the gas suction port provided at the position of the outer ring (purge gas side) of the CVD source gas confined by the purge gas. As a result, the CVD source gas covering the correction processing portion is confined in a space constituted by the gas window 14, the substrate 15, and the purge gas (gas curtain). The gas curtain may be formed before the movement of the substrate 15 and the slit mask 20.

  After forming the gas curtain, a laser beam 8 spread by an expander (not shown) is irradiated to deposit a conductive film on the correction processing portion by the laser CVD method. At this time, the optical system of the relay lens 11 and the objective lens 12 forms the laser beam 8 that has passed through the slit portion of the slit mask 20 as an image 13 having a predetermined size on the substrate 15. The shape of the image 13 is similar to the slit shape of the slit mask 20 selected in advance. The correction processing portion formed by forming the image 13 is, for example, in the shape of the straight linear wiring 6 shown in FIG. 2A or the U-shaped detour wiring 7 shown in FIG. Can do. In FIGS. 2 (a) and 2 (b), the display of wirings and the like other than the correction processing portion is omitted for simplification of illustration.

The modified wiring having the shape as shown in FIGS. 2A and 2B is formed on the wiring shown in FIG. 3A, for example. FIG. 3A is a plan view showing a wiring structure in which a data line 1, a gate line 2, and a transistor 3 which is a TFT (Thin Film Transistor) are formed on a substrate. As shown in FIG. 3A, data lines 1 and gate lines 2 constituting a liquid crystal wiring pattern are arranged on a substrate 15 in a lattice pattern. A plurality of transistors 3 are formed on the gate line 2. In FIG. 3A, wiring defects such as the disconnection defect 4 generated in the wiring formation process and the pattern shape defect 5 which is a disconnection part generated by etching or the like in the formation process of the transistor 3 remain. In the case of correcting these wiring defects, as shown in FIG. 3B, the straight wiring 6 is formed at the position of the disconnection defect 4 in FIG. Further, the bypass wiring 7 is formed at the position of the pattern shape defect 5 in FIG.

  4A is a sectional view taken along line AA shown in FIG. 3B, FIG. 4B is a sectional view taken along line BB shown in FIG. 3B, and FIG. 4C is a sectional view taken along line C in FIG. It is sectional drawing by -C line | wire. In the present embodiment, as shown in FIG. 4A, the first straight wiring 6a and the second linear wiring 6a are sequentially connected from the substrate 15 side so as to connect the disconnected portion of the data line 1 formed on the substrate 15. A straight line 6b is formed. The first straight line 6a and the second straight line 6b are both conductive films. Further, as shown in FIGS. 4B and 4C, the first bypass wiring 7a and the second bypass wiring are sequentially connected from the substrate 15 side so as to connect the pattern shape defect (disconnection portion) of the data line 1. 7b is formed. Both the first bypass wiring 7a and the second bypass wiring 7b are also conductive films. As shown in FIG. 4C, an insulating film 25 is formed on the gate line 2 before the formation of the first detour wiring 7a at a location straddling the gate line 2. By forming the corrected wiring as described above, wiring defects such as the disconnection defect 4 and the pattern shape defect 5 are corrected. The reason why the modified wiring having the two-layer structure as described above is formed will be described later.

  As described above, by adopting the configuration of the present embodiment, conductive films are collectively formed by the laser CVD method in accordance with a predetermined shape pattern of the modified portion. As a result, the correction processing time is greatly shortened, and high speed can be realized.

  Next, the laser processing method of the present embodiment will be described in comparison with the related techniques described above (FIGS. 6A and 6B and FIGS. 7A and 7B). FIG. 5A is a flowchart showing a laser processing method according to the related art described above. As shown in FIG. 5A, when correction processing is started (step S50), a laser beam having a predetermined (medium) intensity is output (step S52), and the XY scan of the forward path is performed to perform the first correction. Processing is performed (step S54). Next, a laser having the same intensity as in the case of step S52 is output (step S56), and the XY scan of the return path is performed to perform the second correction process (step S58). Thus, the correction process is completed by performing the CVD process in two directions (step S60). In this case, the laser beam intensity is set to such an extent that the formed film cannot be damaged.

  On the other hand, the laser processing method according to the present invention is shown in the flowchart of FIG. In the present embodiment, as shown in FIG. 5B, the first step (step S12) set so that the laser intensity is relatively high and the processing time is relatively short, and the laser intensity is set to the first step. The correction wiring is formed in two stages, ie, the second step (step S14), which is set to be lower and the processing time is longer than the first step.

  First, when the correction processing is started (step S10), the first conductive film is formed in a lump in the target region by the laser CVD method with the laser output and processing time set as the first step (step S12). This first conductive film corresponds to the first straight wiring 6a and the first detour wiring 7a shown in FIGS. The laser output set in this step varies depending on processing conditions such as the workpiece, but is preferably as high as possible. This is because peeling is less likely to occur at the interface with a workpiece such as a substrate by increasing the laser output. However, when a high laser output is irradiated for a long time until a required film thickness is reached, the formed film is damaged, and the film peels off, resulting in a problem that the adhesion strength is lowered. In the present embodiment, the first layer conductive film having high adhesion at the interface with the workpiece can be formed by forming the film for a short time with a relatively high laser output. For example, as shown in FIG. 4C, an insulating film 25 is formed on the portion where the correction wiring needs to be formed across the gate line 2 before the first conductive film is formed. deep. The insulating film 25 can be formed by a known photolithography method and etching method.

  Subsequently, the second conductive film is formed in a batch on the target region by the laser CVD method with the laser output and processing time set as the second step (step S12). This second conductive film corresponds to the second straight line 6b and the second detour line 7b shown in FIGS. In the second step, the combined film thickness of the first and second conductive films can be set to a desired value by adjusting the laser output and the processing time.

  In the second step, it is preferable to set the laser output slightly lower than in the first step. This is because by setting in this way, the adhesion between the first conductive film and the second conductive film formed in this step can be increased. Here, the laser output in the second step is preferably 50 to 80% compared to the laser output in the first step. The reason is as follows. That is, if the laser output is smaller than 50% with respect to the first step, the film forming speed becomes slow, and it becomes difficult to obtain the advantage of shortening the processing time by batch film formation. Further, when the laser output is larger than 80% with respect to the first step, the processing is performed under substantially the same conditions as the first step. This is because, since the laser output is set to be as high as possible in the first step as described above, the formed film is damaged, and it is difficult to obtain preferable adhesion to the first layer. .

  By performing the two-step correction process as described above, the correction wiring is formed by the two-layer conductive film, and the correction process is completed (step S16). As shown in FIGS. 4A to 4C, the correction wiring can be collectively formed by the laser CVD method even on the stepped portion.

  In the laser processing method shown in FIG. 5A, since the processing speed is about 4 μm / s and processing is performed in a reciprocating scan, it takes about 26 seconds when the length is 50 μm. On the other hand, when the laser processing method of the present invention shown in FIG. 5B is used, in the case of a wiring defect having the same length of 50 μm as the above example, the first step is about 1.5 seconds and the second step. Is executed for about 5 seconds, and the machining is completed in about 6.5 seconds in total. That is, according to the present embodiment, the processing time can be reduced to about 1/4 compared with the laser processing method shown in FIG. Further, as in this embodiment, the correction processing is performed in two steps with mutually different laser output and processing time setting conditions, thereby forming a correction wiring film having high adhesion without damaging the film. Can do.

  It should be noted that the present invention can be applied to more various wiring defects by increasing the types of slit patterns other than the linear slit 23 and the detour slit 24 shown in FIG. The slit mask 20 may be configured to be switchable with, for example, the slit 9 shown in FIGS. 6 (a) and 6 (b).

  The laser processing apparatus of the present invention may be used as an apparatus for performing laser processing other than the correction of wiring defects by the CVD method as described above. In this case, by making the slit pattern of the slit mask 20 into a mark shape, it is possible to mark a workpiece such as a substrate. The mark shape may be, for example, a number, a character, or a symbol. The marking may be performed by depositing a mark layer by a CVD method or removing the surface of the workpiece with a laser.

  The present invention can be used for, for example, laser repair of wiring in a semiconductor manufacturing process, a liquid crystal manufacturing process, and the like.

It is a schematic diagram which shows the structure of this invention apparatus. It is explanatory drawing of the mask from which a slit shape differs. It is operation | movement explanatory drawing (the 1) of the apparatus of this invention. It is operation | movement explanatory drawing (the 2) of the apparatus of this invention. It is a flowchart which compares and shows a laser output and processing time with a prior art example and this invention. It is a schematic diagram which shows the structure of the conventional apparatus. It is operation | movement explanatory drawing of a conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Data line 2 Gate line 3 Transistor 4 Disconnection defect 5 Pattern shape defect 6 Straight wiring 7 Detour wiring 8 Laser light 9 Slit 9a Aperture 10 Laser light 11 Relay lens 12 Objective lens 13 Image 14 Gas window 15 Substrate 16 Scan direction 17 Linear wiring 18 Scanning Method 19 Detour Wiring 20 Slit Mask 21 Switching Mechanism 23 Linear Slit 24 Detour Slit 27a, 27b Teeth 28a, 28b Teeth

Claims (7)

A mask having a slit for defining the shape of the laser beam irradiated toward the substrate, an optical system for imaging the laser beam with the defined shape on the substrate, and laser chemical vapor deposition toward the substrate Material gas supply means for supplying a raw material gas necessary for the method, and condition switching means for switching a condition relating to a combination of the laser output and the processing time between a predetermined first condition and a predetermined second condition ,
The slit has a predetermined slit shape so as to connect a disconnected portion of the wiring formed on the substrate, and the laser output in the second condition is lower than the laser output in the first condition, The laser processing apparatus, wherein a processing time under the second condition is longer than a processing time under the first condition.   The laser processing apparatus according to claim 1, further comprising a slit switching unit that moves the mask to switch the slit shape.   The laser processing apparatus according to claim 1, wherein the predetermined slit shape includes at least a linear shape and a shape that bypasses and connects the disconnected portion.   The laser processing apparatus according to claim 3, wherein the predetermined slit shape includes a predetermined mark shape recognizable on the substrate.   The source gas supply means includes gas curtain forming means for locally containing the source gas by a gas curtain system by supplying a purge gas around the source gas and sucking the gas. The laser processing apparatus according to any one of 1 to 4.   A step of defining the shape of the laser beam by a slit having a predetermined slit shape that connects the disconnection portion of the wiring formed on the substrate, a step of imaging the laser beam on the substrate by an optical system, Correcting the disconnection by depositing the predetermined slit-shaped conductive film imaged on the substrate using a laser chemical vapor deposition method, and correcting the disconnection Comprises a step executed under the first condition and a step executed under the second condition relating to the combination of the laser output and the processing time, and the laser output under the second condition is higher than the laser output under the first condition. The laser processing method is characterized in that the processing time under the second condition is low and longer than the processing time under the first condition.   The laser processing method according to claim 6, wherein the laser output in the second processing step is 50 to 80% of the laser output in the first processing step.

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