JP2005271563A - Dividing processing method of hard and brittle plate and apparatus for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to simply and rapidly form a region being finely linear and easily dividable not only on a platy body of a semiconductor material, a piezoelectric ceramic material, a glass (amorphous) material or the like but even on a plate of a very hard and brittle material such as sapphire or the like. <P>SOLUTION: The linear easily dividable region connecting molten traces as mentioned later can be made when a short pulse laser beam with a wave length being optically transparent to a hard and brittle platy body as a workpiece is irradiated through a converging lens, by adjusting a focus position of the converging lens so that a converging spot of the short pulse laser beam should exist on the surface layer part of the platy body, by forming a fine molten trace being a crowd of minute cracks from the surface layer part of the platy body to the surface on every incidence of a pulse of the short pulse laser beam to the surface under moving the short pulse laser beam along a planned dividing line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for splitting a hard and brittle material plate, and more particularly, to facilitate linear separation formed by scribing a hard and brittle material plate to be split using a short pulse laser beam. The present invention relates to a method and an apparatus for dividing and processing the hard and brittle material plate through a region.

  Conventionally, when a hard and brittle material plate such as a semiconductor substrate, a piezoelectric ceramic substrate, or a glass substrate is divided and processed, along the dividing line assumed on the surface of the plate to be processed, for example, Nd: YAG Irradiation while moving a laser beam such as a laser to form a linear separation facilitating region such as a cut groove portion or a modified or altered portion including a crack or the like, after so-called scribing, A processing method for dividing or cutting the plate body by applying a strain stress to the separation facilitating region is known (see, for example, Patent Documents 1, 2, and 3).

  As described above, the conventionally known laser scribing method can be divided into the following two types with respect to the form of the linear separation facilitating region formed on the plate or substrate to be processed: Form a notch groove in the surface part of the plate (Type I), and a weakened region such as a modified or altered part containing cracks or the like inside the plate, that is, at a site deeper than the surface of the plate What is formed (type II).

  The conventionally known type I processing method is to narrow down the laser beam to be used via a condenser lens, and to focus the laser beam condensing spot from the surface of the workpiece (glass plate) (surface portion). ), And the laser beam condensing spot is moved along the assumed dividing line on the surface of the plate, and the portion (local part) that absorbs the light energy from the laser beam condensing spot Ablation is caused to evaporate the local plate material (glass material) to the outside (evaporation / spray), and as the condensed spot is separated from the transpiration local part in the moving direction, the transpiration local part is melted. The remaining portion is re-solidified to form a cut groove portion that follows the dividing line in the surface portion of the plate (see Patent Document 1). Further, the conventionally known type II processing method uses a so-called short pulse laser beam having a small pulse width as the laser beam to be used, and the short pulse laser beam to be used is the condenser lens as in the above type I. And the condensing spot corresponding to each pulse of the short pulse laser light is set to be located inside the plate to be processed, and the condensing spot is set along the predetermined dividing line. Each time the pulse of the short pulse laser beam is incident on the local area corresponding to the condensing spot inside the plate body, the multi-photon absorption is performed at the pulse (laser light) irradiation local area. The ablation is caused to cause modification or alteration of the local portion, and a line-like modification or alteration portion is formed inside the plate material as the focused spot is separated (patent text). See 2, 3).

  However, in the above-mentioned conventionally known scribe processing method, the scribe target is glass plate, semiconductor substrate, piezoelectric ceramic substrate, harder to several steps than a plate such as a composite substrate obtained by bonding a metal layer to a semiconductor substrate, For example, in the case of a hard and brittle material plate such as sapphire, the surface portion of the sapphire plate in order to not remarkably increase the total energy input of the laser beam used for the processing in the type I It is impossible to form a cut groove by causing ablation. However, when the power density of the converging spot is increased, the groove width of the cut groove to be formed is increased, the roughness of the cross section of the plate divided through the cut groove is increased, and the processing accuracy is reduced. , Trouble occurs. In addition, the bottom of the cut groove formed on the surface portion of the sapphire plate body is covered with a re-solidified sapphire layer or film, and the bottom of the cut groove is less likely to have an acute-angled shape. It is hard to get.

  Moreover, in the above-mentioned type II, a modified portion or a modified portion is formed inside the hard and brittle material plate such as sapphire, and the surface portion is substantially unprocessed (unmodified). Since it is in a state, that is, a state covered with a sapphire layer or a film, it is difficult to obtain an effective effect of facilitating division or cutting as in the above type I. In addition, although the substrate can be divided by strengthening the strain stress acting on the modified or altered portion formed inside the sapphire substrate, the surface roughness of the divided cross section becomes rough, and this method is For example, it is difficult to put the microelectronic device formed on one surface of the sapphire substrate into a chip-like (dicing) process for separating each device.

Japanese Patent Laid-Open No. 05-32428 Japanese Patent Laid-Open No. 10-22237 JP 2000-192370 A

  The problem or purpose to be solved is that the surface of the hard and brittle material plate to be divided using a laser beam is formed into a linear division facilitating area following the division line assumed on the surface of the plate. In the so-called laser scribing process for forming sapphire, for example, not only plates such as semiconductor materials, piezoelectric ceramic materials, glass (amorphous) materials, but also hard and brittle material plates such as sapphire, which are much harder than those. It is also possible to easily and quickly form a fine linear divisional easy region on the body.

  In order to solve the above-mentioned problems or achieve the above object, the division processing method of the present invention is adapted to scribe a hard and brittle material plate to be processed by optical scribing. When a short pulse laser beam having a transparent wavelength is incident on the surface of the hard and brittle material plate through a condensing lens, the condensing spot or waist portion of the short pulse laser beam is the hard brittle material plate. The focal position of the condensing lens is adjusted so that it exists in the surface layer of the body, and the optical axis of the short pulse laser beam is moved relatively along the assumed dividing line with respect to the hard and brittle material plate. However, every time a pulse of the short pulse laser beam is incident on the surface of the hard and brittle material plate, a fine dissolution mark is formed from the surface layer portion of the hard and brittle material plate to the surface, and micro cracks are clustered. These dissolution marks are intermittent It is characterized in further comprising the step of forming a linear easily separable region where continuous to or sequentially.

  Further, the division processing method of the present invention described above applies strain stress to the linear separation facilitating region formed by the short pulse laser beam formed on one surface of the hard and brittle material plate to be divided. It includes a step of dividing the hard and brittle material plate.

  Further, the splitting apparatus capable of carrying out the split processing method of the present invention is a laser beam generating means for generating a short pulse laser beam having an optically transparent wavelength with respect to a hard and brittle material plate to be split. A first stage on which the hard and brittle material plate is placed, and the short pulse laser beam is condensed so as to be perpendicularly incident on the surface of the hard and brittle material plate placed on the first stage. The objective lens means provided on the first stage and the objective lens means are moved relative to the hard and brittle material plate placed on the first stage, and placed on the first stage. A focal position adjusting means, a laser beam generating means, a moving means, and a focal position adjusting means for adjusting a focal position of the objective lens means by adjusting a distance between the hard and brittle material plate and the objective lens means. Program control the operation of the electronic The objective lens means comprising a laser scribing mechanism section comprising control means and data input means for inputting a focus position correction amount to the electronic control means in accordance with processing conditions for the hard and brittle material plate. The focus position is adjusted to the surface of the hard and brittle material plate using visible light from an illumination light source, and then the focus position adjustment means is adjusted based on the focus position correction amount data, thereby the objective lens. The means is shifted so that the focal position correction amount is shifted to the hard and brittle material plate side so that the condensing spot or waist portion of the short pulse laser beam is present on the surface layer portion of the hard and brittle material plate, By moving the focused spot or waist of the short pulse laser light by the moving means relative to the division line assumed on the surface of the hard and brittle material plate, Each time a pulse of pulsed laser light is incident on the surface of the hard and brittle material plate, fine melt marks are formed from the surface layer portion of the hard and brittle material plate to the surface, and these melts are dissolved. A linear separation facilitating region in which the traces are intermittently or continuously connected is formed.

  Another division processing apparatus according to the present invention is a scribing process in which a linear separation facilitating region is formed by fine dissolution traces from a surface layer portion of a hard and brittle material plate to be processed to a surface thereof to form a microcrack. A second stage on which the hard and brittle material plate is placed, which is movable in the XY-θ axis direction, and a pair of fixing means for fixing the hard and brittle material plate mounted on the second stage; A break blade member disposed at an interval facing the fixing means for the hard and brittle material plate, and a linear shape formed on the hard and brittle material plate placed on the second stage. Both the side portions of the separation facilitating region are fixed by the pair of fixing means, and the portion corresponding to the separation facilitating region on the other surface of the hard and brittle material plate is pressed by the break blade member. Bending stress is applied to the easy area Characterized by being configured to fracture.

  According to the present invention, by adjusting the setting position of the focused spot or waist of the short pulse laser beam for scribe processing in the layer region (surface layer portion) near the surface of the hard and brittle material plate to be divided, The laser beam incident local part corresponding to each pulse of the short pulse laser beam in the surface layer part of the plate body does not include a denatured part such as a melted part or a sintered part, which prevents separation or cleaving. Fine dissolution marks in which cracks are clustered, and therefore, an effective weakened linear separation facilitating region in which these dissolution marks are continuously or intermittently connected can be formed. In addition to this, by making it possible to adjust the relative movement speed of the optical axis of the short pulse laser beam with respect to the hard and brittle material plate, the interval between the incident local portions of each pulse of the short pulse laser beam is adjusted. By changing D, and appropriately adjusting the heat transfer action (heat transfer coefficient) generated between the incident local part of the current pulse and the incident local part of the previous pulse, the size of each dissolution mark and the dissolution mark region The mechanical strength (fragility) of the material, and therefore the width (line width) and mechanical strength (fragility) of the linear separation facilitating region formed by these dissolution marks can be adjusted, and the work of the division processing Efficiency and division processing accuracy can be increased effectively.

  The division processing method of the present invention is not limited to a microelectronic device manufacturing material, typically a semiconductor substrate, a ceramic substrate, a glass (amorphous) substrate, a composite composite substrate, or the like. Remarkably hard, for example, it can be applied to a hard and brittle material plate such as sapphire, and has a transparent wavelength and a very short pulse width for a hard and brittle material substrate or plate to be divided, A so-called laser scribing process in which a linear separation facilitating region is formed on the surface of a plate to be processed using a short pulse laser beam (beam) will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the brittle material plate to be divided, for example, transparent to the sapphire substrate 1, that is, having a wavelength that does not cause linear absorption by the sapphire substrate 1, for example, For example, a short pulse laser beam 5 having a pulse width of 15 psec generated from an Nd: YAG mode-locked laser excited by a semiconductor laser is used. The short pulse laser beam 5 is incident on the short pulse laser beam 5 by being focused by the condenser lens 6 perpendicularly to the surface 2 of the sapphire substrate 1 to be processed. In this case, before starting the scribe processing, the surface 2 of the sapphire substrate 1 to be processed, the objective lens 6, and the like using the autofocus unit 38 of the processing apparatus (FIG. 10) of the present invention described later in detail. By adjusting the interval distance, the condensing spot or waist 7 of the short pulse laser beam 5 is shallow in the depth direction from the surface 2 of the plate 1 to be processed or the layer 4 (indicated by hatching in FIG. 2). It is set so as to exist in the surface layer portion).

  Setting of the focused spot of the short pulse laser beam 5 collected by the objective lens (collecting lens) 6 or the surface 7 of the plate 1 to be processed of the waist 7, that is, the surface 2 of the plate 1 In the position setting in the direction perpendicular to the depth direction (depth direction), first, the focus of the objective lens 6 is set to the surface 2 position (reference position) of the plate 1 to be processed using an illumination (visible light) light source, Next, the objective lens 6 is shifted by a so-called offset that shifts a predetermined distance (referred to as a focal position correction amount in this specification) from the reference position to the plate 1 side. The focal position correction amount is based on the refractive index of the hard and brittle material plate 1 to be divided, the wavelength of the short pulse laser light 5, and the optical characteristics (numerical aperture) of the condensing lens 6 to collect the laser light. Preliminary experiments were performed using the calculated values based on the theoretical calculation formula for the spot or waist position, the material and thickness of the hard and brittle material plate 1 to be processed, the peak power and pulse width of the short pulse laser beam 5 as parameters, The sum is a sum of fine adjustment values determined in accordance with the scribing result.

  Next, the optical axis of the short pulse laser beam 5 is indicated by an arrow with a predetermined processing speed Vs along a dividing line 8 (indicated by a two-dot chain line in FIG. 1) assumed on the surface 2 of the sapphire substrate 1. Is moved relative to the surface 2 of the substrate 1 in the horizontal direction B (in FIG. 2, the direction perpendicular to the paper surface). At this time, each pulse of the short pulse laser beam 5 is shown on the surface 2 of the substrate 1 with an X mark in FIG. 1, and the pulse repetition rate Vp (laser oscillation repetition period) of the short pulse laser beam 5 is shown. ) And the pulse moving speed Vs, the laser beam is incident on the laser light irradiation region 9 (denoted by reference numeral S in FIG. 3) with an interval D that is uniquely determined. The irradiation region 9 corresponding to each pulse of the short pulse laser beam 5 on the surface 2 of the substrate 1 to be processed has a size substantially corresponding to the cross-sectional area of the focused spot of the laser beam 5 or the waist 7.

Now, as shown in FIG. 3, it is assumed that one pulse of the short pulse laser beam 5 narrowed down through a condenser lens (objective lens) (not shown) is incident on the surface 2 of the sapphire substrate 1 to be processed. In the irradiation region S of the laser beam in the surface layer portion 4 of the sapphire substrate 1, that is, the substrate material (sapphire) portion or the local portion 9 corresponding to the focused spot 7 of the short pulse laser beam 5, for example, terawatt order (TW / Multi-photon absorption is induced by injection of laser power energy with a high power density of cm ² ), and so-called ablation occurs in which the local portion 9 is melted and sublimated (evaporated) in an instant. As the vapor pressure in the substrate rapidly increases, the boundary layer portion of the surface layer portion of the substrate 1 with the substrate surface 2 is also melted and sublimated by the high-temperature steam below the substrate 1, and due to the impact pressure of the vapor in the local portion 9. When a crack occurs, the vapor is sprayed to the outside of the substrate 1 while generating more cracks 10 at the boundary with the surface 2 of the local portion 9 starting from the crack. Or it is thought to be able to dissipate. When the high-pressure steam is ejected or diffused, as the short pulse laser beam 5 moves along the dividing line 8 in the lateral direction (perpendicular to the paper surface of FIG. 3), the melting / evaporation in the local portion 9 is calmed down. It is considered that microcracks are clustered in the peripheral part of the local part 9 from the local part to the substrate surface 2 in the peripheral part of the local part 9 due to the shrinkage. As a result, the region surrounding the melting / evaporating local portion 9 is modified or altered by high-temperature heat action based on multiphoton absorption, and a microcrack 10 extends from the surface layer portion 4 of the substrate 1 to the surface 2 thereof. Clustered dissolution marks will be generated. The dissolution mark region is effectively weakened by countless minute cracks that have occurred inside.

  In FIG. 3, when the pulse of the short pulse laser beam 5 that induces melting / evaporation of the local portion 9 completely disappears and a subsequent pulse (next pulse) is incident on the surface layer portion 4 of the substrate 2, In the region where the distance D is moved in the lateral direction (perpendicular to the paper surface in FIG. 3) from the irradiation region in the surface layer portion 4 of the substrate 2 by the pulse, that is, the irradiation region S of the previous pulse in FIG. In the same manner as in the irradiation region S, ablation occurs in the irradiation local area due to multiphoton absorption based on the incident light of the next pulse, and as described above, in the region surrounding the irradiation local area, Dissolution marks in which microcracks are clustered will be generated. Thereafter, in the same manner, every time each pulse of the short pulse laser beam 5 is incident on the surface layer portion 4 of the sapphire substrate 1 one after another, the respective irradiation regions are dissolved so as to include the microcracks as described above. Traces are generated. These dissolution marks are arranged in a cascaded manner following the dividing line 8, and a perforated separation facilitating region is formed on the surface 2 of the sapphire substrate 1.

  The shape and size of the dissolution mark is similar to the focused spot of the short pulse laser beam 5 or the cross-sectional shape (small circle) of the waist 7, and the depth (circular hole) of the dissolution mark is short. The pulse laser light 5 has a pulse peak power (light output power peak value) and a numerical aperture of the objective lens. Further, the distance D between the irradiation regions (local parts) of each pulse of the short pulse laser beam 5, particularly the heat transfer action between the irradiation region (local part) by the current pulse and the irradiation region (local part) by the previous pulse. Since it is presumed that the melting / evaporation at the time of generating the dissolution mark and hence the generation of the microcrack 10 is affected, the distance D, and hence the moving speed of the short pulse laser beam 5 relative to the substrate 1 or By adjusting the processing speed Vs, innumerable microcracks are generated from the laser light irradiation site of the surface layer portion 4 of the substrate 1 to the surface 2 inside each dissolution mark, and these dissolution marks are formed in a row. It is possible to effectively weaken the linear separation facilitating region (scribing portion).

  Next, it is divided or cleaved (breaked) through a linear separation facilitating region 12 formed on one surface (surface) 2 of the sapphire substrate 1 to be divided by scribing with the short pulse laser beam 5. The method will be described with reference to FIG. First, as shown in FIG. 4, while holding or fixing both side portions (portions indicated by white arrows 15 in FIG. 4) of the separation facilitating region 12 on the one surface 2 of the above-mentioned sapphire sapphire substrate 1, By applying a cutting edge such as a break blade (not shown) to the portion (the portion indicated by the white arrow 16 in FIG. 4) corresponding to the separation facilitating region 12 on the other surface (back surface) 3 of the substrate 1 and pressing it. By applying a strain stress to the separation facilitating region 12, the sapphire substrate 1 can be divided or cleaved easily and quickly.

  Next, an embodiment in which a linear separation facilitating region is formed on a hard or brittle material substrate or plate body to be subjected to various division processing using the division processing method of the present invention, that is, a scribing process using a short pulse laser beam is performed. A description will be given with a photomicrograph of the scribing section.

FIG. 5 (photograph) shows the results of confirming the change in the scribe-processed dissolution mark with respect to the change in the focal position of the condenser lens on the sapphire substrate to be processed under the following processing conditions.
Processing conditions Processing object: Sapphire substrate (thickness t = 120 μm)
Laser generator: Semiconductor laser pumped Nd: YAG laser Wavelength: 1064 nm
Pulse width: 15 psec
Pulse repetition frequency: 1 KHz
Power density: 2TW / cm ²
Numerical aperture (NA) of objective (condensing) lens: 0.4
Focal position correction amount: 3μm
Movement speed (processing speed): 20mm / sec

  Under the above processing conditions, the amount by which the focused spot 7 of the laser beam 5 is shifted in the depth direction from the surface of the sapphire substrate, that is, the shift distance ( While changing the offset value), the result (micrograph) of examining the state of occurrence of the microcracks 10 in the dissolution mark 11, that is, the form of the linear separation facilitating region 12 formed continuously by the dissolution mark 11, It shows to Fig.5 (a)-(g).

  In the processing example (g) shown in the lowermost part in FIG. 5, the focused spot 7 of the short pulse laser beam 5 is set on the surface of the sapphire substrate to be processed, and the short pulse laser is gradually moved upward. The light condensing spot was set at a deeper position in the surface layer portion of the sapphire substrate, that is, the offset values were sequentially set larger. In the uppermost processing example (a), the offset value from the surface was set to 5 μm. As can be seen from the micrograph of FIG. 5, the most cracks are generated in the dissolution mark 11 by each pulse in the separation easy region 12 at the uppermost stage (offset value of 5 μm). At the time of condensing the surface in the lowermost processing example, the length of the fine crack caused by each pulse is about 1 μm. This is considered to be due to the fact that most of the ablation transpiration pressure is evaporated in the atmosphere when a condensing spot is set on the surface of the sapphire substrate. Increasing the offset value, i.e., setting a focused spot of the laser beam at a deeper portion of the surface layer of the sapphire substrate, the vapor that has sublimated or evaporated in the local area surrounding the focused spot effectively It is thought that it evaporated to the outside of the substrate through the melting hole.

FIG. 6 shows the result of the scribe processing of the synthetic quartz substrate.
Processing conditions Processing object: Synthetic quartz substrate (thickness t = 500 μm)
Laser generator: Semiconductor laser pumped Nd: YAG laser Wavelength: 1064 nm
Pulse width: 20 psec
Pulse repetition frequency: 5KHz
Power density: 1TW / cm ²
Numerical aperture (NA) of objective (condensing) lens: 0.5
Focal position correction amount: 3μm
Movement speed (processing speed): 15mm / sec

  Even for an amorphous material plate or substrate having no crystallinity, innumerable microcracks are clustered in each dissolution mark 11 of the substrate, and such dissolution marks 11 are formed in a row. It has been confirmed that the separation facilitating region 12 can be an effective fracture base point for dividing or cleaving the amorphous substrate.

The results of the scribe processing of the quartz substrate are shown in FIGS. 7A and 7B.
Processing conditions Processing object: Quartz substrate (thickness t = 150μm)
Laser generator: Semiconductor laser pumped Nd: YAG laser Wavelength: 1064 nm
Pulse width: 20 psec
Pulse repetition frequency: 5KHz
Power density: 0.6 TW / cm ²
Numerical aperture (NA) of objective (condensing) lens: 0.5
Focal position correction amount: 3μm
Movement speed (processing speed): 22mm / sec

  Due to the mechanical strength characteristics of the quartz substrate, the surface layer portion is blown away simultaneously with the generation of fine cracks. However, a fine crack caused by a single pulse of a short pulse laser beam surely serves as a destruction base point for substrate division.

The scribing process result with the short pulse laser beam in the ultraviolet region is shown in FIGS. 8A and 8B.
Processing conditions Processing object: Sapphire substrate (thickness t = 70 μm)
Laser generator: Semiconductor laser excitation Nd: YAG laser Wavelength: 355 nm
Pulse width: 4.5nsec
Pulse repetition frequency: 1 KHz
Power density: 20 GW / cm ²
Numerical aperture (NA) of objective (condensing) lens: 0.5
Focal position correction amount: 3μm
Movement speed (processing speed): 7mm / sec

  According to this example, it was confirmed that a sapphire substrate having high mechanical strength can be easily divided. In addition, it was confirmed that even in a site where cracks in the surface layer portion cluster, compared to the above-described conventionally known laser scribing method (type I), there are few material alterations and melting points.

The scribing process result with the short pulse laser beam in the infrared region is shown in FIGS. 9A and 9B.
Processing conditions Processing object: Sapphire substrate (thickness t = 90 μm)
Laser generator: Semiconductor laser pumped Nd: YAG laser Wavelength: 1064 nm
Pulse width: 20 psec
Pulse repetition frequency: 5KHz
Power density: 1TW / cm ²
Numerical aperture (NA) of objective (condensing) lens: 0.5
Focal position correction amount: 3μm
Movement speed (processing speed): 10mm / sec

  By optimizing the oscillator, optical system, and various processing conditions, we have succeeded in generating finer cracks with a width of 1 μm or less. Also in this example, it was confirmed that the separation facilitating region 12 formed on the very hard sapphire substrate by the laser scribe processing method according to the present invention becomes an accurate destruction base point.

  Next, an embodiment of an apparatus for carrying out the division processing method of the present invention will be described in detail with reference to FIGS. The apparatus of the above embodiment includes a laser scribe mechanism 20 (FIG. 10) for laser-scribing a linear separation facilitating region on a hard and brittle material plate or substrate to be divided, and the laser scribe mechanism. The dividing or cleaving mechanism 50 (FIG. 11) is configured to divide or cleave the plate body or the substrate by applying a strain stress to the separation facilitating region formed by the above.

  As shown in FIG. 10, the laser scribing mechanism unit 20 of the division processing apparatus of the present invention roughly includes a laser generator 21, a main controller 31, and an objective lens that condenses the short pulse laser light 5 from the generator 21. (Condensing lens) 35, a focal position adjustment mechanism unit 40, and an XY-θ stage 41.

  The laser generator 21 basically includes, for example, a solid-state laser oscillator 22 such as Nd: YAG, a laser controller 25, an attenuator 26, and a beam expander 29. The laser resonator 22 is excited by, for example, a multimode lock method, has a wavelength that is optically transparent to the hard brittle material plate 1 to be processed, and has a very short pulse width and high power density. A short pulse laser beam (beam) is emitted. The short pulse laser beam output from the laser resonator 22 is input to the attenuator 26, and part of the output light of the attenuator 26 is input to the photodetector 28 via the beam splitter 27. Based on the detected signal, constant output control is performed by a compensation circuit (not shown) included in the attenuator 26 so that the output of the attenuator 26 has a predetermined power. The constant pulse controlled short pulse laser beam is input to a beam expander 29. The beam expander 29 expands the short pulse laser beam 5 so that the diameter of the short pulse laser beam 5 matches the diameter of the objective lens 35. The power density of the short pulse laser beam can be effectively increased. In this way, the laser generator 21 is transparent to the plate or substrate to be scribed, that is, the short pulse laser beam 5 collected by the objective lens 35 is incident on the plate 1. A short pulse having a wavelength such that linear absorption does not occur in a portion other than a condensing spot or a waist portion of the short pulse laser beam, and preferably having a short pulse width on the order of psec (picosecond). Laser light 5 is emitted.

  The short pulse laser beam 5 outputted from the beam expander 29 of the laser generator 21 is introduced into the objective lens (condensing lens) 35 through an optical system 32 including a mirror 33 for changing the optical path and a shutter 34 ( The short pulse laser beam 5 is narrowed down according to the optical characteristics of the objective lens 35 and the substrate or plate 1 to be processed placed on the XY-θ stage (first stage) 41. Incident perpendicular to the surface 2. The objective lens 35 is not shown above the XY-θ stage 41 in a direction perpendicular to the surface 2 of the workpiece (plate or substrate) 1 placed on the stage 41 (Z-axis). It is mounted on a first Z-axis stage 42 that can move up and down via a ball screw (not shown) driven by a pulse motor. The pulse motor mounted on the first Z-axis stage 42 is driven by a control signal from a stage controller 47, which will be described in detail later, and the position of the objective lens 35 mounted on the first Z-axis stage 42 in the Z-axis direction, that is, The focal position of the objective lens 35 is roughly adjusted.

  In addition, an illumination (visible light) light source 36 is attached to the first Z-axis stage 42, and the visible light from the illumination light source 36 is disposed through the prism 37 disposed on the optical path in the optical system 32. The light can enter the lens 35. Furthermore, an autofocus unit 38 is mounted on the first Z-axis stage 42 and, like the prism 37, is emitted from the illumination light source 36 via a prism 39 disposed on the optical path in the optical system 32. An autofocus unit 38 that receives the return light (the focused spot image) from the focused spot 7 on the surface 2 of the plate 1 to be processed is mounted. The autofocus unit 38 is configured to finely adjust the position of the objective lens 35 on the Z axis so that the focal position of the objective lens 35 is set on the surface of the plate 1 based on the return light. Is.

  The XY-θ stage 41 has three moving bases that are movable in the three axial directions of the X axis, the Y axis, and the θ axis, and these moving bases are each driven by an electric motor (not shown). Driven. These electric motors are controlled by a stage controller 47. A fixing ring 43 is detachably attached to the mounting table of the XY-θ stage 41. First, an adhesive sheet 44 is attached to the fixing ring 43, and a plate body or substrate 1 to be processed is attached to the adhesive sheet 44, and then the fixing ring 43 is mounted on the XY stage stage 41. Further, it is fixed via a vacuum suction member (not shown). Further, a CCD camera 45 is disposed above the mounting table, the surface 2 of the workpiece 1 fixed to the mounting table is imaged by the CCD camera 45, and this imaging signal is transferred to the image processing unit 48. The image processing unit 48 performs image processing, and based on the image processing result, the stage controller 47 aligns the workpiece 1 fixed to the mounting table of the XY-θ stage 41.

  The main controller 31 is configured using, for example, a personal computer (PC), and the cooling chiller 24 of the laser generator 21 according to the scribe processing sequence program stored in the storage unit of the main controller 31. The operation of the laser controller 25, the stage controller 47, and the image processing unit 48 is controlled. A focus position correction amount setting digital switch 49 is connected to the main controller 31, and a focus position correction amount determined in accordance with the scribe processing conditions is set in the switch 49. This setting data is transferred to the stage controller 47. The stage controller 47 moves the first Z-axis stage 42 up and down based on the focal position correction amount set via the digital switch 49, and accordingly the plate or substrate 1 to be processed from the reference position of the objective lens 35. The focus position correction amount (distance) is shifted toward the center.

  In place of the digital switch 49, for example, in the storage layer (memory) of the computer, the surface layer portion of the hard and brittle material plate to be processed is uniquely selected in advance according to a combination of various parameters. A numerical value indicating the depth from the surface, that is, a depth (hereinafter, referred to as a condensing spot position of the short pulse laser beam from the focal position of the condensing lens by the illumination light (hard brittle material plate surface)) This is referred to as an offset value), and parameter data relating to the division processing of the hard and brittle material plate body is input via the keyboard of the computer, and the parameters input by the CPU (central processing unit) of the computer The offset value is uniquely calculated according to the combination of the above, and the height position of the hard and brittle material plate to be processed according to the calculated offset value That may be adjusted focused spot or waist position of incident laser light.

  The laser beam generator 21 is selected according to the material of the hard and brittle material plate or substrate to be processed. As the laser light generator 21 applicable to the present invention, in addition to the semiconductor laser excitation mode-locked Nd: YAG laser used in the first to fifth embodiments, an Nd: YAG laser oscillated by a Q switch pulse, Nd: YV04, Nd: YLF, Nd: VAN, and the like. Further, a visible light laser, an ultraviolet region laser, or a laser term generator subjected to pulse compression in which the output wavelength of these laser oscillators is converted can be used. In the short pulse laser, a femtosecond laser such as a titanium sapphire laser, a mode-locked laser such as Nd: YAG, a laser obtained by reproducing and amplifying the laser, and a microchip laser oscillator can be used.

  Next, an operation procedure of the laser scribing mechanism unit 20 having the above configuration will be described. First, when starting the operation, the power supply of the cooling chiller 24 is turned on, and temperature control of the pumping semiconductor laser of the resonator 22 of the laser light generator 21 and the resonance medium is started. Next, the laser resonator 22, the first XY-θ stage 41, the first Z-axis stage 42, and the main controller 31 are activated to emit the short pulse laser beam 5. The output control of the short pulse laser beam 5 is performed by detecting the reference beam separated by the beam splitter 27 by the photodetector 28 and operating the attenuator 26 based on the detected value to detect the short pulse laser beam 5. Control the output. The laser resonator 22 is fixed at the most stable output and repetition frequency.

  Next, the hard and brittle material plate to be processed is attached to the first XY-θ stage 41. First, the pressure-sensitive adhesive sheet 44 is attached to the fixing ring 43, and the hard and brittle material plate 1 to be processed is attached to the pressure-sensitive adhesive sheet 44 with the surface to be scribed facing upward. In this manner, the fixing ring 43 to which the hard and brittle material plate 1 to be processed is attached is placed on the placement portion of the first XY-θ stage 41, and is fixed by vacuum suction. Next, the illumination light source 36 is turned on to illuminate the surface of the hard and brittle material plate 1 of the workpiece, and the autofocus unit 38 focuses on the surface of the hard and brittle material plate 1.

  Material physical properties, surface roughness, physical properties such as semiconductor devices stacked on the hard and brittle material plate, wavelength of the objective lens 6 to be used, short pulse laser beam 5, output power, etc. Based on the data, the optimum machining conditions are set with respect to the sweep speed of the XY stage in the first XY-θ stage 41 and the like. Further, with respect to the focal position of the objective lens 6, the fine adjustment amount of the focal position on the surface layer portion of the hard and brittle material plate 1, the short pulse laser beam 5, and the illumination light source 36 at the time of autofocusing from the desired microcrack form. The first Z-axis stage 42 sets the optimum value in consideration of the correction amount when there is a shift in the focal position at.

  Next, the dividing line 8 marked on the surface of the hard and brittle material plate 1 to be processed is observed using the CCD camera 45, and based on the processing data by the image processing unit 48, the first XY-θ stage. 41 is operated to match the plate 1 to be processed with the dividing line 8. At this time, information such as the processing speed and the pitch of the divided lines is input to the main controller 31. When all the settings are completed, the first XY-θ stage 41 is moved to a predetermined machining start position and is set in a standby state.

  In response to a processing command from the main controller 31, the illumination light source 36 is turned off, the shutter 34 is opened, and the short pulse laser beam 5 is irradiated onto the hard and brittle material plate 1. The first XY-θ stage 41 is operated under predetermined processing conditions, and scribing is performed.

  When the scribing process is completed, the shutter 34 is closed, and the first XY-θ stage 41 returns to the standby position. Next, when a carry-out command is transferred from the main controller 31, the first XY-θ stage 41 moves to the carry-out position together with the take-out command thereafter, and the vacuum adsorption of the fixing ring 43 is performed. finish. Thus, the to-be-processed body 1 scribe-processed is taken out with the fixing ring 43, and transfers to a division | segmentation process.

  Next, FIG. 10 shows a schematic configuration of the division or cleaving mechanism unit 50 in the division processing apparatus of the present invention. The dividing or cleaving mechanism 50 is pushed to a portion corresponding to the linear separation facilitating region 12 on the surface opposite to the surface scribed on the plate 1 to be processed by the laser scribing mechanism 20 described above. A break blade 57 that exerts pressure, and a second Z-axis stage 52 that is mounted with the break blade 57 and is movable up and down are provided. As in the scribing mechanism section 20, the scribe-processed plate 1 to be divided and processed is attached to the adhesive sheet 54 attached to the fixing ring 53 with the scribe surface turned upside down. The 2X-Y-θ stage 51 is fixed on the mounting table. At this time, similarly to the first XY-θ stage 41 described above, the second XY-θ stage 51 moves the stage in the three-axis direction (XY-θ-axis direction), and the fixing ring 53 is positioned. . A CCD camera 55 is disposed below the fixing ring 53, and the scribe-processed linear separation facilitating region 12 of the plate 1 attached to the ring 53 is observed from below. The second XY-θ stage 51 and the second Z-axis stage 52 are controlled by a control panel 58.

  The plate 1 to be processed is transported to the first XY-θ stage 41 in the laser scribe processing mechanism unit 20 and the second XY-θ stage 51 in the division or cleaving mechanism unit 50. For example, a conveying means such as a belt conveyor (not shown) may be provided to operate the laser scribe processing mechanism unit 20 and the division processing mechanism unit 50 in a linked manner.

It is a schematic diagram explaining the basic composition concept of the present invention. It is a partially cutaway sectional view seen from the AA line of FIG. FIG. 3 is a schematic diagram for explaining a melting / evaporation phenomenon based on ablation occurring in a focused spot of the short pulse laser beam in FIG. 2. It is a schematic diagram explaining the principle which divides | segments the hard-brittle material board | plate to be processed through the linear separation easy area | region formed by the laser scribe processing method of this invention. A microscope in which seven scribing results are imaged on the same scale when the position of the condensed spot of the short pulse laser beam or the waist part in the surface layer portion of the sapphire substrate is variously changed using the division processing method of the present invention. It is a photograph. It is the microscope picture which image | photographed the plane (A) and the cross section (B) of the Example which carried out the laser scribing process of the synthetic quartz board | substrate using the method of this invention. It is the microscope picture which image | photographed the plane (A) and the cross section (B) of the Example which carried out the laser scribing process of the quartz substrate using the method of this invention. It is the microscope picture which image | photographed the plane (A) and the cross section (B) of the Example which carried out the laser scribe process of the sapphire board | substrate using the method of this invention. It is the microscope picture which image | photographed the plane (A) and the cross section (B) of the Example which carried out the laser scribing process of the sapphire substrate on the conditions different from the process conditions in FIG. 8 using the method of this invention. It is a block diagram which shows schematic structure of the division processing apparatus which can implement the scribing process in the division | segmentation processing method of this invention. It is a block diagram which shows schematic structure of the division | segmentation processing apparatus which can implement the division | segmentation or cleaving process in the division | segmentation processing method of this invention.

Explanation of symbols

1 Hard and brittle material plate (or substrate) to be processed
2 Surface of plate to be processed 3 Back surface of plate to be processed 4 Surface layer of plate to be processed 5 Short pulse laser beam (beam)
6 Objective lens (Condenser lens)
7 Condensing spot or waist of laser beam 8 Dividing line 9 Laser light irradiation area (local part)
10 Microcracks 11 Dissolution marks 12 Easy separation region (laser scribe part)
15 White arrow (Strain stress direction)
16 Outline arrow (Strain stress direction)
DESCRIPTION OF SYMBOLS 20 Laser scribe mechanism part 21 Laser light generator 22 Laser resonator 24 Laser resonator cooling chiller 25 Laser controller 26 Attenuator 27 Beam splitter 28 Photo detector 29 Beam expander 31 Main controller 32 Optical system 33 Mirror 34 Shutter 35 Objective Lens (Condenser lens)
36 Illumination light source 37 Prism 38 Autofocus unit 39 Prism 40 Focus position adjustment mechanism 41 XY-θ stage (first stage)
42 First Z-axis stage 43 Fixing ring 44 Adhesive sheet 45 CCD camera 47 Stage controller 48 Image processing unit 49 Digital switch 50 Division or cleaving mechanism 51 XY-θ stage (second stage)
52 Second Z-axis stage 53 Fixing ring 54 Adhesive sheet 55 CCD camera 56 Receiving blade 57 Break blade 58 Control panel

Claims (6)

  When short pulse laser light having a wavelength optically transparent to the hard and brittle material plate to be divided is incident on the surface of the hard and brittle material plate through a condenser lens, the short pulse laser light The focal position of the condensing lens is adjusted so that the condensing spot or the waist part exists on the surface layer of the hard and brittle material plate, and the optical axis of the short pulse laser beam is assumed with respect to the hard and brittle material plate Each time the pulse of the short pulse laser beam is incident on the surface of the hard and brittle material plate while moving relatively along the divided line, the surface of the hard and brittle material plate reaches the surface thereof. A method of splitting a hard and brittle material plate body, comprising the steps of forming fine melt marks in which micro cracks are clustered and forming a linear separation facilitating region in which these melt marks are intermittently or continuously connected. .   2. The method according to claim 1, further comprising a step of dividing the hard and brittle material plate by applying strain stress to a linear separation facilitating region formed on one surface of the hard and brittle material plate to be divided. Split machining method. A short pulse laser beam having an optically transparent wavelength with respect to the hard and brittle material plate to be divided and having a pulse width of 2 psec to 8 nsec, and is focused on the surface layer portion of the hard and brittle material plate The division | segmentation processing method of Claim 1 or Claim ² with which the power density in the condensing spot or waist part of the short pulse laser beam narrowed down through the lens shall be 15 GW / cm < ² > -8TW / cm < ² >.   The division processing target is a sapphire substrate, and a condensing spot or waist portion of a short pulse laser beam incident on one surface of the sapphire substrate via a condensing lens is formed at a depth of 0 to 8 μm from the surface of the sapphire substrate. The division | segmentation processing method in any one of Claims 1-3 which was set to the surface layer part of the length part. Laser light generating means for generating a short pulse laser beam having an optically transparent wavelength with respect to the hard and brittle material plate to be divided, a first stage on which the hard and brittle material plate is placed, and the short The objective lens means provided so as to condense the pulsed laser light so as to be perpendicularly incident on the surface of the hard and brittle material plate placed on the first stage, and the objective lens means include the first stage. Adjusting the distance between the moving means that moves relative to the hard and brittle material plate placed on the first stage and the objective lens means by moving the hard brittle material plate placed on the first stage. Focus position adjusting means for adjusting the focal position of the objective lens means, electronic control means for controlling the operation of the laser beam generating means, the moving means and the focus position adjusting means, and processing on the hard and brittle material plate Increase the focus position correction amount according to the conditions. Input to the electronic control unit, comprises a laser scribing mechanism constituted by a data input means,
By adjusting the focal position of the objective lens means to the surface of the hard and brittle material plate using visible light from an illumination light source, and then adjusting the focal position adjustment means based on the focal position correction amount data The objective lens means is shifted to the hard and brittle material plate side so that the focal position correction amount is shifted so that the condensing spot or waist portion of the short pulse laser beam exists in the surface layer portion of the hard and brittle material plate. The short pulse laser is adjusted by moving the focusing spot or waist of the short pulse laser light relatively along the division line assumed on the surface of the hard and brittle material plate by the moving means. Each time a pulse of light is incident on the surface of the hard and brittle material plate, a fine dissolution mark is formed from the surface layer portion of the hard and brittle material plate to the surface, and these dissolution marks are formed. And configured to form a connection to or disassembly region of continuously continuous linear, of hard and brittle materials plate body cracking apparatus.   A scribe in which a linear separation facilitating region is formed by fine dissolution marks formed from a surface layer portion of a hard and brittle material plate to be processed to a surface thereof using the division processing apparatus according to claim 5. A second stage on which the processed hard and brittle material plate is placed, which is movable in the XY-θ-axis direction, and a pair of fixing means for fixing the hard and brittle material plate mounted on the second stage. And a break blade member disposed at an interval facing the fixing means for the hard and brittle material plate, and a linear shape formed on the hard and brittle material plate placed on the second stage. The both sides of the separation facilitating region are fixed by the pair of fixing means, and the break blade member is used to press the portion corresponding to the separation facilitating region on the other surface of the hard and brittle material plate. Bending stress is applied to the easy separation region It was constructed to fracture, the hard and brittle material plate of the cracking apparatus.