TWI445586B - Laser processing method and cutting method,method of dividing a structured body with multiple substrates - Google Patents

Description

Laser processing method and cutting method, and division method of structure having multilayer substrate

The present invention relates to a method for efficiently and efficiently processing an object to be processed, in particular, an object having a flat shape like a substrate, using an ultrashort pulse laser having a wavelength transparent to the object.

The present invention relates to a method of dividing a structure using laser light, and the structure has a configuration in which at least two substrates are arranged in parallel with a spacer interposed therebetween and has a multilayer substrate. It is suitable for dividing a flat display panel using a glass substrate such as a liquid crystal display panel or a plasma display panel.

In the electronics industry, the miniaturization of semiconductor devices such as CPUs, DRAMs, and SRAMs has been progressing year by year, and accordingly, the internal circuits have been highly integrated. The construction of these devices is formed on a semiconductor substrate such as a germanium wafer with a highly integrated circuit pattern. In order to obtain a large number of wafers from a semiconductor wafer, it is necessary to minimize the area required to divide the wafer. For this reason, it is desirable that the scattering of the processed removal is less in the scribing step. In the cutting step of the glass substrate such as a liquid crystal display, it is expected that the division can be performed accurately with a predetermined size. In some of the division steps, it is necessary to carry out the removal processing without causing thermal damage or mechanical damage to the periphery of the processed portion, and therefore a narrow pulse wave of a nanosecond pulse wave or less is used. In the processing using ultrashort pulse laser, the conventional technique is to reduce the occurrence of the hot work metamorphic layer, or even a material transparent to this wavelength, and can be represented by a non-linear light represented by multiphoton absorption. Absorbed for processing.

The processing method of a transparent body using laser light of ultrashort pulse wave vibration is It is known in the patent document 2, and the case where the processing laser is condensed on the inner surface of the board|substrate and the processing object is processed is described in patent document 3.

Since the irradiated surface absorbs a large amount of UV laser light, plasma is generated from the irradiated surface, so that the laser light is absorbed, so that the utilization efficiency of the laser energy is lowered, and the surrounding radiation is irradiated by the secondary radiation from the plasma. When it comes to the characteristics of the surrounding components. Therefore, the semiconductor substrate, the glass substrate for a thin film transistor, and the like are divided into a scribe line step of a predetermined size, and Patent Document 3 describes that the focus is focused on the surface opposite to the surface (machined surface) that is cut into the slit. The method of processing the surface and irradiating the laser light to process the slit on the machined surface. In this method, since the laser light is condensed on the surface opposite to the incident side of the laser light and subjected to laser lift-off processing, there is a disadvantage that the depth of the processing groove cannot be sufficiently obtained. When the groove depth cannot be sufficiently obtained, in order to separate along the groove, only the bending force required for breaking is increased, and sometimes it is not divided along the cutting line. If the depth of the groove is deep enough, a small amount of stress can be divided along the cutting line.

On the other hand, in the manufacture of a liquid crystal display device, there is a step of cutting a large-sized glass substrate constituting a panel. At least two glass plates are arranged in parallel on the panel surface of the liquid crystal display device, and a color filter or a liquid crystal, a thin film transistor (TFT), a control electrode, or the like necessary for the display device is provided therebetween. In these glass sheets, a plurality of sheets of display devices are simultaneously produced by using a glass larger than the size of the final display device in the manufacturing process, whereby a plurality of sheets of display panels are simultaneously manufactured for efficiency. Therefore, it is necessary to finally cut the panel size of the product and to cut it from a large glass substrate on which a large number of sheets are formed. The cutting method of the conventional glass plate Cutting the glass surface along the required cutting line with a blade such as a diamond blade or a super-hard blade, and setting a cutting line, and then applying stress to the cutting line in a right angle direction and breaking along the cutting line a method of breaking and separating, or treating a required cutting line to scan and heat the laser light, and causing thermal stress to occur on the glass substrate, and thereby performing a method of breaking and dividing, etc., in this case, The glass plate is irradiated with a laser wavelength having a large absorption rate to locally heat, and then forced cooling is performed to divide from the irradiation position.

When a display element is inserted between two glass plates and the periphery of the glass is sealed with a sealant, and then divided into individual display panels, the two sides of the two overlapping glass plates are each scribed to a single side, and then cut. Methods. This is because the diamond blade is engraved, so after the scribing process is performed on a single surface, the two-layer glass plate is reversed and the remaining one surface is subjected to scribing, and then the two overlapping glass plates are divided together. In recent years, due to the tendency of the display panel to be enlarged in size, the size of the glass used for the panel has become larger and larger. Therefore, the handling device for manufacturing large-sized glass plates is complicated, and the scale of the reversing mechanism is changed. It is huge and has become a high-priced device. Therefore, the method of scribing from a single side without inverting the glass sheet is a practical and effective manufacturing method. Patent Document 4 discloses a proposal of irradiating an ultraviolet ray on each glass surface from a single side of two overlapping glass sheets, and performing scribing on the surfaces of both glass sheets of the two overlapping structures. In this method, when the glass is transparent to the laser light, and the laser light is irradiated from the upper glass side, it is necessary to pass the ultraviolet laser light through the upper glass to the lower glass surface. Therefore, there is a place for the lower glass When a metal film such as a metal wiring on the inner surface of the upper glass plate is irradiated with laser light, the metal film is broken or shielded by the metal film, and it is difficult to guide the laser beam to the lower glass. In the case where there is an intervening object between the two sheets of glass, it is difficult to illuminate the upper glass sheet with a laser beam from a single side and scribe the lower glass sheet.

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Patent Document 5] Japanese Patent Publication No. 8-64556

The problem to be solved is to use ultrashort pulse laser light of a wavelength transparent to a processed object, and to perform high precision processing on the opposite side (reverse side) of the processed object from the incident side, in the inside of the processed object In the direction of travel of the light, a beam of small diameter is set to cover a range longer than the depth of focus of the spot.

Further, another object of the invention is to provide a method of irradiating laser light from only one substrate surface side of a structure having a multilayer substrate and dividing the structure. Further, a division method is provided in which a metal thin film is exposed in a structure having a metal thin film between two substrates. Further, a method of dividing a structure is provided which has a sealing portion between two substrates, and when an electronic component is formed inside the sealing portion, the wiring can be led out from the electronic component to the outside of the sealing portion.

The self-bundling action occurs inside the processed object, and the processing width of the laser light is reduced, and the processing distance in the traveling direction of the laser light can be made larger than that in the normal peeling process, thereby solving the above problem.

In order to solve the above problems, the present invention is a laser processing method characterized in that an ultrashort pulse wave having a wavelength transparent to a workpiece having a first surface and a second surface is transmitted through a light collecting means. Irradiating the light to illuminate the laser beam from the side of the first surface such that the beam waist position of the laser light to be collected is formed between the first surface and the second surface of the object to be processed, a self-concentrating action caused by ultra-short pulse wave high-peak laser light propagation inside the object to be processed, forming a condensing channel in the traveling direction of the laser light, thereby forming a cavity reaching the second surface in the concentrating channel portion or reaching A hole near the second side. Thereby, the processing distance in the traveling direction of the laser light can be made larger than the normal peeling process.

Further, it is characterized in that a ridge structure in which the ridge of the vicinity of the intersection of the laser light traveling direction and the second surface is higher than the peripheral surface and has a weak mechanical strength is formed. Further, it is characterized in that the light collecting passage is formed up to the second surface, whereby the cavity is formed up to the second surface. Further, it is characterized in that the light collecting passage is formed from the first surface to the second surface, whereby the cavity is formed from the first surface to the second surface. Further, it is characterized in that the light collecting passage is formed from the first surface to the inside of the processed object, whereby the cavity is formed from the first surface to the inside of the processed object. By each, the processing distance in the direction in which the laser light travels can be made larger than the normal peeling process.

In addition, it is characterized by the same type or different species of the above-mentioned workpiece system The flat object of the material of the class overlaps two or more multilayer structures. Thereby, it is possible to process two or more objects at the same time.

Further, it is characterized in that another object transparent to the laser wavelength is provided on the first surface side of the object to be processed, thereby changing the length of the condensing channel caused by the self-bundling action of the object to be processed. . Thereby, the processing distance of the direction in which the laser light travels can be adjusted.

Further, it is characterized in that another object that is transparent to the laser wavelength is provided on the first surface side of the object to be processed, so that the concentrating channel caused by the self-bundling action of the object to be processed reaches the 1 side. Thereby, it can process to the front surface of a board|substrate.

Further, the ultra-short pulse laser light that is condensed by the concentrating means and condensed inside the object to be processed is relatively moved along the cutting direction at an arbitrary speed, thereby providing the space in the cavity. overlapping. Further, the ultra-short pulse laser light that is condensed by the concentrating means and condensed inside the object to be processed is relatively moved along the cutting direction at an arbitrary speed, thereby setting the cavity to be in space. Separated on. Each of the cutting lines can be formed on the object to be processed, and since the machining distance in the traveling direction of the laser light is large, the cutting can be performed with a small amount of bending stress.

Further, the object to be processed is a planar object, and the condensed laser light of the ultrashort pulse laser is inclined and incident at a constant angle from a normal direction of the first surface of the object to be processed. The condensed laser light is tilted and rotated at the aforementioned angle to perform circular scanning, and the processed surface is tilted for processing. Thereby, a circular cutting line can be produced.

Further, it is characterized in that it has an operation of performing the above-described relative movement a plurality of times and changing the height of the beam waist of the aforementioned laser light between the relative movements. Thereby, a cavity is formed in the object to be processed to reach a deep portion, so that the process from the partial cutting to the complete cutting can be performed.

On the other hand, the present invention is a method for cutting an object to be processed, characterized in that after the laser processing of the object to be processed described above, the object to be processed is cut by a small amount of stress along the processed portion. Thereby, the object to be processed can be accurately divided along the cutting line.

In addition, the liquid crystal display panel has a laminated structure of a first substrate and a second substrate, and is coated on a surface of the second substrate on the surface on the first substrate side. a cloth that adheres or adheres to a material that is opaque to the aforementioned laser wavelength, and irradiates the laser from the first substrate side so as to form a beam waist portion in the first substrate, and avoids passing the first step in the irradiation. The laser light of the substrate causes damage to the aforementioned components.

Further, in the present invention, a method of dividing the first and second substrates and a structure in which the spacers are partially interposed between the first and second substrates is provided in parallel. The method is as follows.

The ultrashort pulse laser having a pulse width of 100 ps or less having a wavelength transparent to the first and second substrates is condensed by a condensing means, and is irradiated from the outside of the first substrate to cause a beam The waist position is formed on the surface or inside of any one of the substrates, and the concentrating channel is formed in the traveling direction of the ultrashort pulse laser light due to the self-concentration caused by the ultrashort pulse laser propagation, thereby Forming a cavity in the concentrating channel portion, so that The ultrashort pulse laser light is relatively moved to form a cutting line forming step of the cutting line; and the substrate cutting step of cutting the substrate on which the cutting line is formed is cut along the cutting line. Since only one of the structures having the multilayer substrate, in particular, the two-layer substrate, is irradiated with a laser beam and processed, the simplification of the device can be achieved.

Further, the present invention is characterized in that it further has the following step A in the dicing line forming step, and has the following step C in the substrate cutting step.

Further, the present invention is characterized in that the steps of forming A and B described below in the dicing line forming step are carried out in the order of A, B or B, A, and have the following C and D in the substrate cutting step. The steps are implemented in the order of C and D. In this way, since the portion of the second substrate that does not face the first substrate can be formed, the control circuit can be formed on the inner surface of the second substrate or on the upper surface of the second substrate, and the display panel such as the liquid crystal panel can be made thin. Chemical.

Step A: concentrating the ultrashort pulse laser light so that the beam waist passes through the first substrate and reaches the second substrate, and forms a first cutting line on the second substrate, and further emits the light. The waist portion is positioned on the first substrate to condense, and the ultrashort pulse laser is relatively moved at the same plane position as the first dicing line, thereby forming a second cutting line on the first substrate.

Step B: concentrating the ultrashort pulse laser light so that the beam waist portion is located on the first substrate, and the ultrashort pulse laser light is relatively parallel with a predetermined distance from the second cutting line. The movement is performed to form a third cutting line on the first substrate.

Step C: The first and second cutting lines are pressed to cut the second and the first The substrate is used to divide the structure.

Step D: The first substrate is cut along the third cutting line, and the portion of the third cutting line is removed from the second cutting line of the first substrate.

Further, the structural system has a metal thin film on a surface of the second substrate facing the first substrate side, and the spacer is a sealing material and is surrounded by the first and second substrates and the sealing material. a space in which an electronic component is formed, the metal thin film is present across the inner side and the outer side of the space, and when the metal thin film is electrically connected to the electronic component, since the metal thin film straddles the sealing body, the metal thin film is electrically Since the electronic component is formed in the inside of the sealed body, the metal thin film can be used as a wiring, and the electronic component is wired outside the sealing portion.

Furthermore, the present invention is a laser processing apparatus characterized by comprising: an ultrashort pulse wave laser generating device; and a rotating mirror for deflecting the pulsed laser light generated from the ultrashort pulse wave laser generating device at a certain angle And rotating; the condensing lens, in such a manner that the light path and the optical axis of the pulsed laser light that is biased toward the same are synchronized with the rotating mirror, the focus is rotated to draw a circular trajectory; and the concentrating lens is made A means for moving along the optical axis direction and a processing object mounting means. According to this configuration, the cutting line can be drawn into the object to be processed in a circular manner, and further cut into a circular shape along the cutting line.

Due to the self-bundling action, in the traveling direction of the laser light, the concentrating channel is formed to cover a longer distance than the beam waist, and a cavity is formed in the concentrating channel portion, and the formation is achieved in the concentrating channel portion. 2 holes Or the cavity near the second surface is reached, so the processing distance of the laser light traveling direction is made larger than the normal peeling process.

Hereinafter, embodiments of the present invention will be described. Fig. 1 is a view showing an embodiment of a processing method of the present invention. The laser beam (beam) 2 as the ultrashort pulse wave 15 outputted from the ultrashort pulse wave laser generating device 1 is paralleled by a collimator (not shown), and is incident on the collecting lens 3 or the like. The light means is incident from the front surface 45 of the object 4 as the bundled laser beam 5. A laser with an ultrashort pulse is a laser with a pulse width of 100 ps or less. Examples of the object to be processed 4 include a dielectric material such as glass, sapphire, or diamond, or a semiconductor material such as tantalum or gallium nitride. Further, the object to be processed 4 is suitably a flat object such as a substrate. Therefore, in the following, the object to be processed 4 is sometimes referred to as a substrate. The laser is selected to be the wavelength that is transparent to the object being processed. Here, transparency is not necessarily limited to the meaning of 100% transmission of light. It also includes situations where a certain amount of laser light can pass through. For example, when the object to be processed is used as the substrate, it is only required to be an infrared region having a wavelength of 1 μm to 2 μm. Examples of the laser medium include titanium sapphire crystal (center wavelength: 780 nm), fiber added with yttrium, fiber added with yttrium, Nd:YAG crystal, Nd:YVO ₄ crystal, Nd:YLF crystal, and the like. Further, in the case where a glass substrate is used as the object to be processed, the laser medium is preferably a crystal of titanium sapphire (center wavelength: 780 nm).

In addition, the front side is the side on which the laser light is incident, and the side opposite to the side is called the reverse side. Cluster laser beam 5 in the object 4 being processed The beam waist 6 as a condensing point is formed inside. The bundled laser beam 5 is irradiated onto the object 4 to be processed, and the beam waist 6 is aligned with an appropriate position inside the object to be processed from the front surface 45 to the back surface 44 to illuminate the beam.

Adjusting the energy, the wavelength, and the pulse width of the concentrated laser beam 5 and the focal length or condensing position of the condensing lens 3, and collecting the ultrashort pulse at a high power density inside the object 4, from The beam waist 6 is self-concentrating according to the Kerr effect in the direction of travel, forming a propagation path 8 of the beam of fine beams having a diameter of the beam waist 6 . In the first drawing, when the irradiation condition is set so that the laser beam waist portion 6 is formed from the reverse surface 44 to the front side in the thickness 7 of the workpiece 4, the incident concentrated laser beam 5 is received. The beam waist 6 is propagated as a divergent beam 10 in a region where the power density is weak and the self-assembly due to the Kerr effect does not occur, but after the light is concentrated by the beam waist, the Kerr effect occurs. When a very high power density spot is formed at the beam waist, the thin-line channel 8 propagates along the channel 8 formed to cover the distance 13 and the inside of the object, while consuming the laser beam energy When the reverse side 44 advances and the energy of the Kerr effect can be maintained on the reverse side 44, part of the object to be processed located in the channel 8 is compressed by the surrounding wave, and as a result, a fine void is formed, and the remaining portion is from the reverse side. When it is discharged to the outside or when it is not discharged, a bulge is formed on the reverse side 44, and an elongated cavity is formed along the passage 8 to cover a distance 14 from the beam waist 6 to the reverse side 44. The beam that has reached the reverse side 44 and has not been absorbed by the object to be processed is released as a divergent beam 11 because it is no longer closed by the self-concentration action.

As a condition for making the condensing effect of the beam caused by the self-bundling action in the object to be processed, there will be a condition according to the literature JH Marburger, Prog. Quantum Electron., Vo1.4, p. 35 (1975). 'An index expressed by Equation 1 which is called the critical threshold power P _cr of the self-assembly.

In Equation 1, λ is the laser wavelength, no is the refractive index of the object, and n ₂ is the nonlinear refractive index of the object.

According to Equation 1, for example, the critical threshold power of the self-assembly of quartz glass is 2.3 MW, and the peak output of the laser pulse incident on the object to be processed (the value obtained by dividing the laser pulse energy by the laser pulse width) When it becomes larger than this value, it will obviously cause self-bundling.

The generation of the self-concentration action can be changed by adjusting the energy, the wavelength, the pulse width of the ultrashort pulse laser, and the adjustment of the focal length and the condensing position of the condensing lens. Thereby, a cavity that reaches the opposite side or a hole that reaches the vicinity of the opposite side is formed. Here, the vicinity of the surface is a distance including about 1/10 of the thickness of the object to be processed from the surface toward the inside direction. The void formation state can be set as follows.

(1) Since the cavity does not reach the reverse side, a ridge structure in which the reverse surface ridge is higher than the peripheral surface and the mechanical strength is weak is formed.

(2) Forming the aforementioned concentrating channel up to the reverse side, thereby forming a cavity to the reverse side.

(3) The aforementioned concentrating channel is formed from the front surface to the reverse side, thereby forming a cavity from the front surface to the reverse side.

(4) The concentrating passage is formed from the front surface only to the inside of the processed object, thereby forming a void from the front surface only to the inside of the processed object.

According to the present invention, the ultra-short pulse laser light having a wavelength transparent to the object to be processed is condensed into a very small laser light cross-sectional area in the substrate by the concentrating optical system, thereby realizing at the condensing point. a high-power-density condensing point, whereby when the laser light propagating in the substrate is condensed, self-collection caused by the Kerr effect occurs, and on the other hand, the scattering caused by the plasma occurs at the condensing point. By the action of the two kinds of effects, the propagation of the laser pulse wave will form a self-collecting trap. (self-trapped) thin line. The range of the trap can be self-bundled by a value that is several times larger than the depth of focus of the beam waist formed near the focus under the condition of the normal power level without self-bundling. The action of the laser light propagation channel. The length of the channel will vary due to material characteristics, power density of the laser beam, energy, and the like. Since the end of the laser light propagation direction of the channel reaches the reverse side, and then the local high temperature and high pressure state is caused by the energy accumulated in the channel, and the force from the inside to the outside acts, the above-mentioned self-concentrating concentrating channel A void is formed and remains in the trajectory.

As shown in Fig. 2, a cavity of a long cylindrical passage caused by self-bundling is formed along the scanning line 48, and the self-bundling action is an ultrashort pulse from the condensed point of the laser light in the object 4 to be processed. The laser light 2 is formed in a long shape in the traveling direction 16. In addition, after formation, the scan line 48 is at a right angle. When the bending stress 49 is applied to perform the cutting, since a very deep hole is formed as compared with the hole diameter, the line along the groove (cutting line) acts as the starting point of the cutting, along the cutting line. It can cut even with weak stress. Since a continuous shallow groove or a structurally weak ridge structure is formed on the reverse side of the substrate, the cutting direction is only along the scanning line 48, that is, the cutting line can be surely produced. There may be a case where a hole is vacated on the surface near the reverse side, or a structure in which the ridge of the exit portion of the passage is higher than the surrounding surface and the mechanical strength is weak, but in either case, the laser light is cut on the substrate. Scanning in the direction of the break, thereby forming a machined shape from the deep inside of the substrate to the reverse side along the scan line 48, that is, the cut line. Since the depth of the processing groove can be sufficiently obtained, the substrate can be cut along the scanning line 48 with a small amount of bending stress 49 in the past. The formation of the cutting line may be performed not by the movement of the laser light but by the movement of the object 4 to be processed. Any kind of movement is called a relative scan. Further, in the case of scanning the laser light in the direction to be broken, by adjusting the scanning speed, the cutting line can be continuously provided on the broken section, or the cutting line can be discretely provided with the interval, in either case. The substrate can be cut along the cutting line by a small amount of bending stress.

Fig. 3 is a view showing a method of concentrating the laser beam at a certain height of the object to be processed and scanning the object to be processed once, and then changing the condensing position of the laser light condensing point, and processing again. First, as shown in Fig. 3(a), the beam waist of the laser beam is focused on the cavity forming distance 57 (about 135 μm) from the opposite surface 44 of the workpiece 4 toward the inside, and is formed by Channel 8 caused by clustering, along the scanning direction 47 and straight Scan once. Thereby, a hole column is formed linearly. Next, as shown in the third figure (b), the condensing lens 3 is moved in the optical axis direction, and the height of the beam waist is shifted toward the front side only by the cavity forming distance of about 58 to form the channel 8 and again. scanning. At this time, since the scanning is performed on the processing line 35 caused by the initial scanning, the void array is formed to be substantially continuous with the hollow row formed by the initial scanning. Further, if necessary, as shown in Fig. 3(c), the height movement of the beam waist and the scanning for forming the hole row are performed. The height movement and scanning system is only repeated as many times as necessary. By repeating this operation, a linear cavity wall surface that fits inside the workpiece 4 is formed. Finally, the workpiece 4 is subjected to bending stress and cut along the cavity wall. In the initial scan, the hole does not have to reach the opposite side. In addition, the height movement and scanning can be repeated until the beam waist reaches the front. According to this method, since the cavity is formed in the deep portion in the object to be processed, the machining from the partial cutting to the complete cutting can be performed.

The substrate as the object to be processed is not limited to one sheet. Even in a multilayer structure in which two or more substrates of the same type or different types of materials are stacked, all the substrates can be processed. In the case of a multilayer structure, the substrates may be attached to each other or may be separated. In the case of separation, the voids may be organic materials or transparent electrode layers in addition to air. In the case of two sheets as the substrate, as shown in Fig. 4, there are cases in which the upper surface substrate 81 placed on the laser incident light side and the lower surface substrate 82 are placed on the opposite side, and the space 83 is included. In this way, the method of the present invention can be applied even to a glass composed of a plurality of layers.

As shown in Fig. 4, in the case of two substrates, the lower substrate 82 will advance. The processing is longer than the laser transmission direction. This is because the self-concentration will increase depending on the transmission distance in the object being processed. Further, when a condensing path due to self-concentration is formed, a laser having a distance of about 10 to 200 μm must propagate in the object to be processed. The longer this distance, the longer the hole will be formed even with the same energy. By using this feature, other substrates composed of different materials which are the same kind or transparent to the laser light are placed on the front side of the substrate, thereby effectively enhancing the self-bundling effect, thereby increasing the cavity formation distance and performing deeper processing. . In particular, the formation of a collecting channel on the object to be processed from the front to the back can also form a cavity to cover from the front to the back. In other substrates of non-processed objects, sometimes voids are not formed, and sometimes voids are formed.

This method can be applied to cutting a glass substrate of a liquid crystal display panel. The structure of the glass substrate of the liquid crystal display panel is constituted by an upper substrate placed on the side of the laser incident light with the gap interposed therebetween and a lower substrate placed on the opposite side.

On the upper glass substrate, an ultrashort pulse laser is irradiated from the upper side such that when the waist of the laser beam comes to a suitable position on the surface or inside of the substrate, a void is formed in the upper glass substrate. A cut surface (cut line) is formed on the upper glass substrate by relatively moving the laser light.

The ultrashort pulse laser is irradiated from the upper surface side of the upper glass substrate from the lower glass substrate in the same manner to form a cut surface. Irradiation is performed in such a manner that the laser beam waist comes to a suitable position on the surface or inside of the substrate. The ultra-short pulse laser can penetrate without causing damage to the upper glass substrate, and can form a void in the lower glass substrate. A cut surface (cut line) is formed on the lower glass substrate by scanning the ultrashort pulse laser.

Fig. 5(a) is a cross-sectional view showing the liquid crystal display panel. The liquid crystal display panel 90 is composed of a laminated structure composed of two sheets of a glass substrate. A component 95 such as a transparent electrode, a color filter, or a thin film transistor is formed on the inner surface of the upper glass substrate 91, and a component 96 such as an electrode is formed on the inner surface of the lower glass substrate 92. Further, a liquid crystal 93 is filled between two glass substrates. The liquid crystal system is sealed in the hermetic sealing material 94. In the cutting step, the upper glass substrate and the second glass substrate may be cut by the same cutting line, or the cutting step may be performed by other cutting lines that are slightly deviated. In the case of cutting along the same cutting line, the two or more substrates may be stacked and processed on all the substrates as shown in FIG. 4 described above.

Fig. 5(a) further shows that the cutting step is performed with other cutting lines that are offset. In this step, the cutting 97 of the upper glass substrate and the cutting 98 of the lower glass substrate are performed. When the concentrated laser beam 5 is irradiated from the front surface of the upper glass substrate 91 so that the laser beam waist comes to an appropriate position inside the substrate, a cavity 61 is formed in the vicinity of the reverse side of the upper glass substrate 91. A cut surface is formed on the upper glass substrate 91 by scanning the bundled laser beam 5. At this time, since the laser beam that is not consumed in the processing of the upper glass substrate 91 passes through the upper glass substrate 91 and is irradiated to the component 96 such as an electrode formed on the lower glass substrate 92, the component 96 such as the counter electrode is used. Damage is caused, and eventually it will adversely affect the operation as a liquid crystal display device. In order to prevent such an adverse effect, as shown in Fig. 5(b), the protective coating layer 99 is formed in advance by applying, adhering or adhering to the portion of the electrode 96 such as the electrode which is irradiated with the laser beam. . The protective coating layer 99 is for the bundled laser beam It is opaque in terms of wavelength. Here, the term "opaque" includes not only the case where the laser light is not transmitted at all, but also the ability to transmit a small amount of light without causing damage to the component 96 such as the electrode under the protective coating layer 99.

The processing of the lower glass substrate 92 is performed separately from the processing of the upper glass substrate 91. Similarly, the concentrated laser beam 5 is irradiated from the front surface of the upper glass substrate 91, but the laser beam waist is irradiated to an appropriate position inside the lower glass substrate 92. The clustered laser beam 5 passes through the upper glass substrate 91, and a cavity 61 is formed in the vicinity of the reverse side of the lower glass substrate 92. The bundled laser beam 5 is scanned to form a cut surface on the lower glass substrate 92. After the glass substrate is subjected to stress and the glass substrate is cut, the liquid crystal display panel is assembled to another component to manufacture a liquid crystal display device. Therefore, the method can be used to manufacture a liquid crystal display panel and a liquid crystal display device.

Another embodiment is shown when it is a plurality of substrates. In the present embodiment, a method of dividing a structure composed of two substrates is shown. Fig. 6 is a schematic cross-sectional view for explaining this embodiment.

The structure 70 has a structure in which the upper glass substrate 91 and the lower glass substrate 92 are arranged in parallel. In the case of being used as a liquid crystal display panel, the structure 70 is partially inserted into a spacer between two glass substrates. A spacer is required in order to provide a gap between two glass substrates. For example, in a liquid crystal display panel, a plurality of spherical vermiculite or an object such as a polystyrene and a cylindrical photoresist is disposed. In the present embodiment, the gas sealing material 94 is inserted between the two glass substrates, and the original purpose is In the glass substrate and the hermetic sealing material 94, a closed space is formed, but in the case where an object is not additionally inserted, it also functions as a spacer. In the case where the hermetic sealing material 94 is not inserted, a spacer is additionally inserted. On the upper surface of the lower glass substrate 92, the metal thin film wiring 89 is provided in a certain range. In the case of the gas-shielding material, the electronic component (not shown) is disposed on the glass substrate 92 on the lower portion of the closed space, and the metal film wiring 89 is preferably electrically connected to the electronic component. The gas seal stop material 94 is spanned. If the structure is a liquid crystal display panel, a display device element is formed in the closed space.

Here, the structure 70 is separated in order to be able to approach the metal thin film wiring 89 on the lower glass substrate 92 from the outside. First, the ultrashort pulse laser beam 2 is condensed from the upper surface side of the upper glass substrate 91 by the condensing lens 3, and reaches the upper surface of the lower glass plate 92 with the laser beam waist (on the incident side of the laser light) The surface or the appropriate position inside (in the figure, the laser beam waist is located above, but not limited thereto, the following is also the case) to illuminate. However, among the lower glass sheets, there is no metal film wiring 89. The laser beam 2 passes through the upper glass substrate 91, and a cavity 64 caused by self-concentration is formed in the lower glass substrate 92. The first cutting line 88 is formed on the lower glass substrate 92 by relatively continuously or discretely forming a cavity by relatively moving the laser beam 2.

Next, the condensing lens 3 is moved upward, and irradiation is performed such that the laser beam waist reaches the upper surface of the upper glass plate 91 (the surface on the laser light incident side) or at an appropriate position inside. A cavity 63 caused by self-concentration is formed in the upper glass plate 91. By moving the laser beam 2 relatively A void is formed continuously or discretely, and a second cutting line 87 is formed on the upper glass substrate 91. The second cutting line 87 is formed directly above the first cutting line 88. Next, before the first and second cutting lines 88 and 87 are formed, the third cutting line 86 is formed on the upper glass plate 91 by the same method as the second cutting line 87. A void 62 is formed during this process. The third cutting line 86 is preferably provided at a position close to the hermetic sealing material or the spacer 94 between the upper and lower glass substrates 91 and 92, and is generally formed so as to straddle the metal thin film wiring 89 on the upper surface of the lower glass substrate 92. Further, the third cutting line 86 is formed to be parallel to the second cutting line 87 by a distance 77 (ΔY).

In the case of having a hermetic sealing material, in the case where an electronic component is disposed inside the enclosed space formed by the hermetic sealing material and the two substrates, the third cutting line is preferably disposed outside the closed space to approach the hermetic sealing material 94. s position.

At this time, the laser beam 2 that is not consumed when the third cutting line 86 of the upper glass substrate 91 is formed passes through the upper glass substrate 91 and is irradiated onto the metal thin film wiring 89, which may cause damage thereto. However, the intensity of the laser beam 2 transmitted through the upper glass substrate 91 is generally not strong enough to cause damage thereto. Further, in order to prevent damage, the protective coating layer may be formed by applying, adhering or adhering to the position where the metal thin film wiring 89 is irradiated with the laser beam. The protective coating layer is removed as it will be cut along the third cutting line and can be accessed from the outside as will be described later. In addition, the protective coating layer is opaque to the wavelength of the laser beam, and the so-called opacity is not only completely refracted by the laser light, but also includes the purpose of not causing damage to the part. A trace of light.

As described above, after the first to third cutting lines are formed, when the bending force is applied to the structure 70 along the first cutting line 88 and the second cutting line 87 directly above, both the lower portion and the upper glass substrate are formed. The portions where the first and second cutting lines are respectively provided are broken, whereby the structure 70 is divided along the first and second cutting lines. Next, when a bending stress is applied to the upper glass substrate 91 along the third cutting line, the distance ΔY portion of the second and third cutting lines in the upper glass substrate 91 is separated. The structure 70 is cut in the above order.

In Fig. 7, a two-layer structure cut in this manner is shown. The lower glass substrate 92 has only a ΔY corresponding to the second and third dicing line intervals 11 and a stepped structure having no upper glass substrate 91 at the upper portion. It becomes possible to approach the enlarged portion of the lower glass substrate 92 from the outside. Therefore, the electronic parts and the metal thin film wiring of the control circuit and the like can be reformed. Further, when the metal film wiring which is led out from the inside of the hermetic sealing portion to the outside is provided on the lower glass substrate, the wiring which is led to the outside can be connected.

In Fig. 7, each of the cross sections 66 and 65 of the lower glass substrate 92 and the upper glass substrate 91 has a cross section in which the first cutting line 88 and the third cutting line 86 are taken as starting points. Similarly to the formation methods of the first and second cutting lines 88 and 87, the ultrashort laser pulse waves are collected from the upper portion, and the cutting lines are formed on the lower and upper glass substrates, respectively, and then the side faces of the glass sheets are divided and formed. 67.

According to the present embodiment, since the laser beam is irradiated only from the one surface side of the glass structure, the processing can be simplified. In addition, since the lower substrate portion having no upper substrate at the upper portion can be formed, From the outside, an electronic component such as a control circuit or a metal thin film wiring can be provided from the upper substrate or on the substrate. Therefore, it is possible to reduce the thickness of the display panel. Further, it can be connected to another metal thin film wiring portion that is led out from the inside of the hermetic seal to the outside.

Fig. 8 is a view showing an example in which the present embodiment is applied to manufacture of a liquid crystal panel. In the step of manufacturing the liquid crystal panel from the large-sized structure 70 having the two large-sized glass substrates 91 and 92 on the upper and lower sides of the liquid crystal panel, the liquid crystal panel is divided into individual panels 80, and this embodiment is carried out. In the space surrounded by the glass substrates 91 and 92 and the hermetic sealing material 94 interposed therebetween, a color filter, a liquid crystal 93, a driving transistor, a wiring, a spacer, and the like necessary for the liquid crystal display panel are built in (other than the liquid crystal) Not shown). (a) is a top view and a cross-sectional view, and (b) is an enlarged cross-sectional view cut along the Y direction. The Z direction is a direction perpendicular to the paper surface.

The cutting lines 74-1 to 74-m along the X direction are formed as follows. The lower cut glass 88 is formed on the lower glass substrate 92, and the metal thin film wiring 89 is not provided in the lower glass plate. Further, in the upper glass substrate 91, a second cutting line 87 is formed on the first dicing line 88. Further, in the upper glass substrate, it is preferable to provide the third cutting line at a position close to the gas seal stopper 94. The third cutting line 86 is parallel to the second cutting line 87 by a distance 77 (ΔY). The third cutting line 86 is usually formed to straddle the metal thin film wiring 89.

The cutting lines 73-1 to 73-n along the Y direction may be provided with one cutting line one by one at intervals of the panel width 76. It can be set in the same manner as the method of forming the first and second cutting lines.

Since the cutting line can be divided along the dicing lines formed on the upper and lower glass substrates and divided in the X and Y directions in this manner, a plurality of liquid crystal displays can be produced from the large two-layer structure 70. Panel 80. In this case, particularly on at least one side surface of the liquid crystal display panel 80, on the lower glass substrate 92, the metal thin film wiring 89 is pulled out from the inside of the hermetic sealing material 94 toward the outside, and can be easily accessed from the outside. Therefore, various configurations that can be electrically connected can be realized.

In the case where the plurality of large-sized two-layer structures are individually divided into a plurality of display panels, the processing of the present embodiment can be performed by irradiating the laser beam from only one side and processing the two glass substrates to form a cutting line. Need to reverse the handling of large glass. Further, the metal film or the like of the electric wiring or the like from the internal structure of the display panel to the outside is not damaged by the laser beam, and can be easily accessed from the outside on one of the substrates, and is widened by the width of ΔY. The two glass plates form a step structure. The end of the upper glass substrate is removed as a portion between the second and third cutting lines in the vicinity of the cutting line on the surface of the lower glass substrate and facing the metal film or electronic component provided on the surface of the upper glass plate. It is easy to get close to the outside. Further, the metal thin film wiring which is led out from the inside of the display panel across the sealing portion on the lower glass substrate is feasible. Therefore, it becomes possible to perform wiring from the outside of the sealing portion.

This method is applicable not only to a liquid crystal display panel but also to other flat panel display panels such as a plasma display panel. In addition, the method can be applied to the process of these flat panel display panels.

The substrate constituting the structure is glass, but the material to be invented Not limited to this. Further, although the substrate has two layers, it is apparent that it can be applied to a substrate having three or more layers.

Fig. 9 is a view showing an embodiment of a method of processing a bevel (inclined surface). Using the rotating mirror 51, the ultrashort pulse laser beam 2 from the ultrashort pulse laser generating device 1 is deflected and rotated 52 by a certain angle θ about the rotating shaft 55. The light paths of the rotating laser beams 53 and 54 coincide with the optical axis and use a collecting lens 3 that rotates with the rotating mirror 51, and the focus of the collecting lens 3 draws a circular trajectory. The substrate-shaped workpiece 4 is placed in advance on a workpiece mounting means (not shown) such as a pedestal. The circular trajectory and the mounting surface of the processed object mounting means are parallel, and the substrate-shaped workpiece 4 is placed in parallel with the rotation axis 55 with respect to the normal line on the front surface thereof, so that it can be placed on the workpiece 4 The laser light irradiation position is rotated and scanned, and a circular trajectory is irradiated. In this case, the workpiece 4 is inclined by the angle θ from the rotating shaft 55. First, the beam waist is focused on the cavity forming distance 57 (about 135 μm) from the opposite surface 56 of the workpiece 4 toward the inside, and is scanned in a circle, thereby shifting the angle θ from the normal. In the direction of the circle, a hollow column on the thin line is formed in a circular shape. In addition, the condensing lens 3 is moved in the direction of the rotating mirror 51 along the optical axis direction, thereby sequentially moving the cavity to form a distance of about 58, 59, and each time the movement is formed, a hole column is formed and the scanning is repeated to form a slave. The circular hollow wall surface from the front to the back of the object 4. Thereafter, it is separated by bending, and the periphery is processed by the inclined surface, and cut into a circular shape. In this way, the present invention is not only in the vicinity of the surface of the object to be processed, but also in the interior, and the formation of the cavity is repeated, and the process from the partial cutting to the complete cutting can be performed.

In the above laser processing, the pulse wave energy is preferably 1 mJ or less, and more preferably 10 μJ or less. In the case of 10 μJ or less, a slumped and smooth cut surface can be obtained, and cracks rarely occur and the breaking strength is high. When cracks or the like are present, the strength of the object to be processed such as glass is weakened, so that there is a poor condition. When the pulse wave energy is large, when the vicinity of the front surface is to be processed, the free electron plasma caused by the tip end portion of the pulse wave is reflected or scattered and absorbed at the center portion to the rear end portion of the pulse wave. Sometimes it is difficult to form a void inside the glass. When the pulse wave energy is small, since the density of the free electron plasma generated in the vicinity of the front surface becomes low, the transmission pulse wave is not greatly hindered, so that a cavity passage can be easily formed inside the glass.

Further, the ultrashort pulse laser is a laser having a pulse width of 100 ps or less, and preferably has a pulse width of 500 fs to 10 ps, and further preferably at about 2 ps. This is because the stress required for cutting the glass substrate is lowered after the fracture surface is continuously formed, and the quality of the fracture surface is good.

Further, when a glass substrate is used as the object to be processed, the pulse wave width is preferably 150 femtoseconds and the output energy is 1 μJ or more.

As shown above, the present invention provides a novel processing method capable of using a beam having a small depth of focus of a concentrated beam of ultrashort pulse waves, using a self-bundling formed in the inside of the object to be processed, The depth of use of the actual focus of the processing is increased. This method is not found in the conventional processing method and is a precision machining method that is first realized by the interaction of the laser beam and the workpiece.

[Example 1]

The laser medium is a titanium sapphire crystal (center wavelength 780 nm), a pulse width of 150 femtoseconds, and an output energy of 1 μJ or more. In addition, the object to be processed is Corning Eagle 2000 which is a glass substrate and has a thickness of 700 μm. In the case where there is no description different from the examples in the respective embodiments, these are common to all the embodiments.

In the first embodiment, when the condensing position when the object is irradiated with laser light is moved from the front side to the inside, the change in the object to be processed is observed, and the principle of the processing method is confirmed. Experimental example.

Fig. 10 and Fig. 11 are micrographs showing a cross-sectional view of the change occurring in the object to be processed. Fig. 10 shows the front surface 45 of the substrate as the object to be processed, and Fig. 11 shows the vicinity of the reverse surface 44. In the configuration of Fig. 1, an aspherical lens having an incident beam diameter of 6 mm and a focal length f of the condenser lens 3 of about 3.1 mm is used. When the transverse mode of the laser beam is used as a beam of Gaussian distribution, the beam diameter of the condensed spot is calculated to be about 1 μm, and the depth of focus including the range of 90% of the energy of the beam waist is 1 μm or less. . As such, in the case where the ultrashort pulse laser beam having the small focus depth value is irradiated onto the object 4 to be processed, the beam is bundled and irradiated in such a manner that the front surface 45 is placed at the position of the beam waist. In the case of Fig. 10, the shallow portion 21 indicated by the depth 23 from the front surface 45 is removed from the front surface 45, and when the beam waist is moved inside, the amount of surface removal is reduced, and the beam is moved inside. At the position of the waist, the ranges 24, 25, etc., in which the optical distortion occurs inside the workpiece 4 occur in the peripheral portion depending on the position in the depth direction in which the beam waist is placed. Put the beam waist inside, reduce the removal of the surface Instead, the internal optical distortion occurs, appearing in the range of 24, 25.

Fig. 11 is a cross-sectional observation photograph when the beam waist is further moved inside the substrate. The portions 31, 32 where optical changes occur in the waist portion of the beam are observed without change on the front surface 45. Further, a portion 33 which causes an optical change in the range of several hundred μm from the inside to the reverse side as it approaches the opposite surface 44 of the object to be processed is observed. Further, when the beam waist is close to about 135 μm from the back surface 44, the cavity 34 is formed linearly from the inside to the reverse side in a thin line shape. Further, when the laser beam waist is focused on the reverse side 44, only the vicinity of the reverse side is removed. From such a processing result, even if the focal depth 37 of the laser beam is about 1 μm as described above, a hole is formed as a diameter of the beam waist by forming a distance (about 135 μm) in the direction of travel of the beam. The thin-lined cavity 34, which is not found to be self-bundling, can be processed in a range of only about 2 digits of the focal depth (1 μm) of the beam. Shaped hollow processing.

[Embodiment 2]

This embodiment is a case where a cavity channel is formed in the vicinity of the reverse side and the laser light is scanned to form a cut surface of the cavity channel.

In the case of forming a fine-line void caused by the self-bundling action, as shown in the graph in Fig. 12, a funnel-shaped portion 43 may be formed on the reverse side. The funnel-shaped portions 43 are overlapped with each other by the abutting portions, and the thin-line-shaped voids are formed separately at the same place as the channels 8, and are scanned along the reverse surface 44 of the object to be processed by ultrashort laser pulses. Scanning direction to form a plurality of thin lines juxtaposed on the envelope 46 of a given processing depth Empty. Fig. 12 is a view showing a micrograph of the cut surface of the fine-line void formed in this manner. In this example, after the scanning of the laser pulse wave is performed at a scanning speed of 3 mm/s, the scanning line is bent and divided to observe the cross section. In the figure, it is shown that in the processing of the thickness 41 of the object to be processed, the envelope 46 from the reverse surface 44 to the depth 42 is covered, and a plurality of thin-line hollow passages are formed, which are divided by the starting point. The processing section of the machined object. Fig. 13 is a scanning micrograph taken of the cross section of the cavity 61, and Fig. 14 is a scanning microscope photograph in the vicinity of the reverse side. The ridge structure 71 in which the surface of the cavity 61 is formed to be higher than the surrounding and has a weak mechanical strength is shown.

[Example 3]

In the configuration shown in Fig. 3, the height of the beam waist is changed, scanning is performed plural times, and processing is performed in the vicinity of the reverse side. Fig. 15 shows a cross section of the number of times of scanning 4 times, the pulse wave energy of 10 μJ, and the pulse width of 2 ps. The pulse wave energy is reduced to optimize the pulse width, thereby forming a high quality processing region 36 near the reverse side.

[Example 4]

Also in this embodiment, as shown in Fig. 3, the height of the beam waist is changed, and scanning is performed for a plurality of times. In this embodiment, the beam waist is formed in such a manner that the processing region is set in the vicinity of the front surface of the glass substrate. Fig. 16 is a cross section showing the case where the number of scanning times is 10 μ pulse energy and the pulse width is 2 ps. By optimizing the pulse energy and the pulse width, a well-processed region 36 covering the front side can be obtained.

[Example 5]

In the present embodiment, the object to be processed is formed by laminating two sheets of a glass substrate. As a configuration shown in Fig. 4, the condensing position of the laser is changed from the front surface of the glass upper substrate 81 to the reverse surface to be processed. Fig. 17 shows a micrograph of the processed glass substrate. Not only the upper glass 81 but also the lower glass 82 placed on the back side thereof is also processed. The upper glass 81 is involved in a maximum of 150 μm and the lower glass 82 is processed up to a maximum of 250 μm. As described above, the substrate placed in the lower portion is processed for a long time in accordance with the direction in which the laser is transmitted.

Hereinabove, the embodiments of the present invention have been described. It is obvious that changes can be made to these without departing from the inventive concept described in the claims.

[industrial use]

In the processing of an object to be processed for a display device such as a semiconductor device or a liquid crystal, the substrate is divided into a substrate, a thin film transistor, and a display device from a surface, and a high withstand voltage power semiconductor substrate is used as an active example of the present invention. In addition, it is effective in the processing in which the inside of the layer of the multilayered electronic component is finely removed and the heat influence is small. In the production of a high-integration circuit, the product yield is improved due to the miniaturization of the processing width and the reduction of the processed material, so that the manufacturing cost of the electronic component can be reduced. Further, it is also effective in hole processing of a substrate of a semiconductor device such as quartz or sapphire. It is also effective in the processing of a filter portion in which a plurality of fine holes are provided. Further, the present invention can be utilized in the manufacture of an electronic device using a multilayer glass structure such as a liquid crystal display panel or a plasma display panel.

1‧‧‧Ultra-short pulse laser generating device

2‧‧‧Laser beam

3‧‧‧ Concentrating lens

4‧‧‧Processed objects

5‧‧‧Bundle laser beam

6‧‧‧ beam waist

7‧‧‧ thickness

8‧‧‧ channel

10‧‧‧beam

11‧‧‧Divergent beam

13, 14‧‧‧ distance

15‧‧‧ Ultrashort pulse

16‧‧‧Travel directions

21‧‧‧ shallow part

23‧‧‧depth

24, 25‧‧‧Scope

31~33‧‧‧The part that causes optical changes

34‧‧‧ Thin wire cavity

35‧‧‧Processing line

36‧‧‧Processing area

37‧‧‧Depth of focus

41‧‧‧ thickness

42‧‧‧depth

43‧‧‧Funnel-shaped part

44‧‧‧n

45‧‧‧ positive

46‧‧‧Envelope

47‧‧‧Scanning direction

48‧‧‧ scan line

49‧‧‧Bending stress

50‧‧‧Laser beam

51‧‧‧Rotating mirror

52‧‧‧Rotate

53, 54‧‧ ‧ laser beam

55‧‧‧Rotary axis

56‧‧‧n

57~59‧‧‧distance

61~64‧‧‧ hollow

65, 66‧‧‧ section

67, 68‧‧‧ side

70‧‧‧structure

71‧‧‧Uplift structure

77‧‧‧distance

81‧‧‧Upper substrate

82‧‧‧lower substrate

83‧‧‧ gap

86‧‧‧3rd cutting line

87‧‧‧2nd cutting line

88‧‧‧1st cutting line

89‧‧‧Metal film wiring

90‧‧‧LCD panel

91‧‧‧Upper glass substrate

92‧‧‧Lower glass substrate

93‧‧‧LCD

94‧‧‧Air seal material

95, 96‧‧‧ parts

97, 98‧‧‧ cut off

99‧‧‧Protective coating

Figure 1 illustrates the use of the Kerr effect associated with the present invention. A composition diagram of a processing method of a workpiece to be processed by focusing.

The second (a) and (b) drawings are diagrams for scanning the laser and performing substrate processing.

The third (a) to (c) diagrams are diagrams showing a method of changing the condensing position of the laser light condensing point and scanning the processing object after scanning the object to be processed.

Fig. 4 is a view showing a configuration in which a multilayer structure composed of two substrates is processed.

The fifth (a) and (b) drawings are explanatory views when the liquid crystal panel structure and the two glass substrates are cut at other positions.

Fig. 6 is a schematic cross-sectional view for explaining a method of dividing a structure composed of two substrates.

Fig. 7 is a view showing an example of an approximate shape of a glass structure composed of two substrates.

The eighth (a) and (b) drawings are explanatory views when the large-sized glass structure is divided into individual liquid crystal display panels.

Fig. 9 is a view showing an embodiment in which the processing method of the present invention is applied to the inclined surface processing.

Fig. 10 is a view showing the result of the first embodiment, and is a micrograph of the vicinity of the front surface of the object to be processed.

Fig. 11 is a view showing the result of the first embodiment, and is a micrograph of the vicinity of the reverse side of the object to be processed.

Fig. 12 is a view showing the result of the second embodiment, and is an explanatory view of a cut surface of the hollow passage and a micrograph thereof.

Fig. 13 is a view showing the result of the second embodiment, and is a scanning type microscope photograph of a cross section of the photographing cavity 61.

Fig. 14 is a magnified photograph of a scanning microscope in the vicinity of the reverse side of the substrate in Fig. 13.

Fig. 15 is a view showing the results of the third embodiment, and is a micrograph of the cut surface.

Fig. 16 is a view showing the results of the fourth embodiment, and is a micrograph of a cut surface.

Fig. 17 is a view showing the results of the fifth embodiment, showing a micrograph after processing of two substrates.

1‧‧‧Ultra-short pulse laser generating device

2‧‧‧Laser beam

3‧‧‧ Concentrating lens

4‧‧‧Processed objects

5‧‧‧Bundle laser beam

6‧‧‧ beam waist

7‧‧‧ thickness

8‧‧‧ channel

10‧‧‧beam

11‧‧‧Divergent beam

13, 14‧‧‧ distance

15‧‧‧ Ultrashort pulse

16‧‧‧Travel directions

44‧‧‧n

45‧‧‧ positive

Claims (38)

A laser processing method characterized in that an ultrashort pulse laser light having a wavelength transparent to a workpiece having a first surface and a second surface is condensed by a condensing means, and is irradiated from the first surface Irradiating the laser light to form a beam waist position of the laser beam to be collected between the first surface and the second surface of the object to be processed, and the ultrashort pulse inside the object to be processed a self-concentrating action caused by the propagation of the peak light of the wave height, forming a condensing channel in the traveling direction of the laser light, thereby forming a cavity reaching the second surface or a cavity near the second surface in the concentrating channel, On the first surface side of the object to be processed, another object that is transparent to the laser wavelength is provided, thereby changing the length of the light collecting channel caused by the self-concentration action of the object to be processed. The laser processing method according to claim 1, wherein the pulse laser light has a pulse wave width of 100 ps or less. The laser processing method of claim 2, wherein the pulsed laser light has a pulse width of 500 fs to 10 ps. The laser processing method according to any one of claims 1 to 3, wherein the ridge formed near the intersection of the traveling direction of the laser light and the second surface is higher than the peripheral surface and the mechanical strength is weak. Uplift structure. The laser processing method according to any one of claims 1 to 3, wherein the condensing passage is formed up to the second surface to form the cavity to the second surface. The laser processing method according to any one of claims 1 to 3, wherein the concentrating channel is formed from the first surface to the second surface, whereby the cavity is formed from the first surface to the second surface. The laser processing method according to any one of claims 1 to 3, wherein the concentrating channel is formed from the first surface to the inside of the object to be processed, whereby the cavity is formed from the first surface until the aforementioned Processing the inside of the object. The laser processing method according to any one of claims 1 to 3, wherein the processed material system is a dielectric material such as glass, sapphire or diamond, or a semiconductor such as germanium or gallium nitride. material. The laser processing method according to any one of claims 1 to 3, wherein the ultrashort pulse laser light has an output pulse wave having a pulse wave energy of 1 mJ or less. The laser processing method according to any one of claims 1 to 3, wherein the ultrashort pulse laser light has an output pulse wave having a pulse wave energy of 10 μJ or less. The laser processing method according to any one of claims 1 to 3, wherein the object to be processed is a flat object. The laser processing method according to any one of claims 1 to 3, wherein the workpiece system is a ruthenium substrate, and the wavelength is 1 μm to 2 μm. The laser processing method according to any one of claims 1 to 3, wherein the workpiece-like system has a multilayer structure in which two or more sheets of the same type or different types of materials are stacked. The laser processing method according to claim 13, wherein the object to be processed having the multilayer structure is in close contact with or has an air gap, an organic material or a transparent electrode layer therebetween. The laser processing method according to any one of claims 1 to 3, wherein the object on the first surface side of the object to be processed is provided with another object transparent to the laser wavelength, thereby changing The length of the aforementioned concentrating channel caused by the self-bundling action of the aforementioned object to be processed. The laser processing method according to any one of claims 1 to 3, wherein the object on the first surface side of the object to be processed is provided with another object transparent to the laser wavelength, thereby The concentrating channel caused by the self-bundling action of the object to be processed reaches the first surface. The laser processing method according to any one of claims 1 to 3, wherein the condensing means is condensed in the inside of the object to be processed along the cutting direction at an arbitrary speed The aforementioned ultrashort pulse laser light moves relative to each other to set spatial overlap of the aforementioned holes. The laser processing method according to any one of claims 1 to 3, wherein the condensing means is condensed in the inside of the object to be processed along the cutting direction at an arbitrary speed The aforementioned ultrashort pulse laser light is relatively moved, thereby arranging the aforementioned holes to be spatially separated. The laser processing method of claim 17, wherein the processed object system is formed into a planar object, so that the ultrashort pulse laser is The condensed laser light is inclined and incident at a constant angle from the normal direction of the first surface of the object to be processed, and the condensed laser light is tilted and rotated at the aforementioned angle to perform circular scanning and processing. The surface is tilted for processing. A laser processing method according to claim 17, wherein the method of performing the plurality of relative movements and changing the height of the beam waist of the laser light between the relative movements is performed. A method for cutting an object to be processed, characterized in that after the laser processing of the object to be processed by the method of claim 17 of the patent application, the object to be processed is cut by a small amount of stress along the processed portion. A method for cutting a liquid crystal display panel substrate, which is the method for cutting an object to be processed according to claim 21, wherein the object to be processed is a substrate of a liquid crystal display panel. A liquid crystal display panel substrate cutting method according to claim 22, wherein the liquid crystal display panel has a laminated structure of a first substrate and a second substrate, and the cutting method The material that is mounted on the surface of the first substrate on the first substrate side is coated, adhered, or adhered to a material that is opaque to the laser wavelength, and the laser is irradiated from the first substrate side so that the first The step of forming a beam waist in the substrate prevents damage to the aforementioned components by the laser light passing through the first substrate during the irradiation. A method of manufacturing a liquid crystal display panel, comprising the method for cutting a liquid crystal display panel substrate according to claim 22 or 23. A method of dividing a structure, the first and second substrates of the structure The spacers are arranged in parallel and partially sandwich the spacers therebetween, and the division method has a pulse wave width of 100 ps or less having a wavelength transparent to the first and second substrates by the condensing means. The pulse wave is concentrated and irradiated from the outside of the first substrate, so that the beam waist position is formed on the surface or inside of any one of the substrates, due to self-concentration caused by the ultrashort pulse laser propagation. Forming a concentrating channel in the traveling direction of the ultrashort pulse laser light, thereby forming a cavity in the concentrating channel portion, and relatively moving the ultrashort pulse laser light to form a cutting line forming step of the cutting line; and The substrate cutting step of cutting the substrate on which the cutting line is formed is cut along the cutting line, and the cutting line forming step has the following A, the substrate cutting step having the following C:A: to make the shot The bundle waist portion is condensed by the first substrate to the second substrate, and the ultrashort pulse laser is condensed, and the first dicing line is formed on the second substrate, and the beam waist is further located on the first substrate. Way to collect light, and in the first a step of relatively moving the ultrashort pulse laser at a plane position where the cutting line is the same, thereby forming a second cutting line on the first substrate; C: cutting the second and along the first and second cutting lines The first substrate is a step of dividing the structure. The method of claim 25, wherein the dicing line forming step further comprises the following B, in the order of the foregoing A, the B or the B and the A, the substrate cutting step further has the following D is implemented in the order of C and D: B: the above-mentioned beam is placed so that the beam waist is located on the first substrate a short pulse wave laser condensing light, wherein the ultrashort pulse laser light is relatively moved in parallel with a predetermined distance from the second cutting line, thereby forming a third cutting line on the first substrate; D: along The third cutting line cuts the first substrate, and the step of removing the portion of the third cutting line from the second cutting line of the first substrate. The method of claim 26, wherein the structural system has a metal thin film on a surface of the first substrate facing the second substrate side. The method of claim 27, wherein the third cutting line formed on the second substrate spatially straddles the metal thin film. The method of claim 25, wherein the spacer is a sealing material and constitutes a space surrounded by the first and second substrates and the sealing material. The method of claim 27, wherein the spacer is a sealing material and constitutes a space surrounded by the first and second substrates and the sealing material, and an electronic component is formed in the space. The metal thin film is present across the inside and outside of the space, and the metal thin film is electrically connected to the electronic component. The method of any one of the 25th to 28th, wherein the first substrate and the second substrate are both glass substrates. The method of any one of claims 25 to 28, wherein the aforementioned structure is a liquid crystal display panel or a plasma display panel. A method of manufacturing a liquid crystal display panel or a plasma display panel, comprising the method described in claim 32. A laser processing apparatus having: a mounting means for mounting an object having a first surface and a second surface; and an ultrashort pulse laser generating device for generating ultrashort pulse laser light having a wavelength transparent to the object to be processed; and The optical lens condenses the pulsed laser light generated by the ultrashort pulse laser generating device, and the ultrashort pulse laser light collected by the condensing means is irradiated from the side of the first surface, so that The beam waist position of the ultrashort pulse laser light that has been condensed is formed between the first surface and the second surface of the object to be processed, and the ultrashort pulse high peak laser light inside the object to be processed a self-concentrating action caused by the propagation, forming a concentrating channel in the traveling direction of the laser light, thereby forming a cavity reaching the second surface or a cavity near the second surface in the concentrating channel, by being processed in the foregoing On the first surface side of the object, another object that is transparent to the aforementioned laser wavelength is provided to change the length of the light collecting channel caused by the self-winding action generated in the object to be processed. The laser processing apparatus of claim 34, further comprising: a rotating mirror that deflects and rotates the ultrashort pulse laser light at a certain angle; and a concentrating lens moving means to bias the aforementioned The light path of the pulsed laser light and the optical axis are aligned, and the condensing lens is rotated in synchronization with the rotating mirror, and the focus of the condensing lens is drawn by a circular trajectory by rotation. A laser processing apparatus as claimed in claim 34 or 35, The light collecting passage is formed up to the second surface to form the cavity to the second surface. The laser processing apparatus according to claim 34 or 35, wherein the first light collecting passage is formed from the first surface to the second surface, whereby the cavity is formed from the first surface to the second surface. The laser processing apparatus according to claim 34, wherein the concentrating passage is formed from the first surface to the inside of the workpiece, whereby the cavity is formed from the first surface to the inside of the workpiece.