Many aspects of the present method for processing a brittle substrate can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present method.
Corresponding reference characters indicate corresponding parts throughout the drawings. The exemplifications set out herein illustrate at least one preferred embodiment of the present method, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Reference will now be made to the drawings to describe preferred embodiments of the present method for cutting a brittle substrate in detail.
Referring to
Step 1: providing a brittle substrate 20 having a substrate surface 201. The brittle substrate 20 is placed on a holding plate (not shown). The brittle substrate 20 is comprised of a material, which can include, for example, glass, ceramic, quartz, and semi-conductor material.
Step 2: applying a first laser beam 240 onto the brittle substrate surface 201 to form a pre-cut groove 23 in the brittle substrate 20, the first laser beam 240 being generated from a solid-state laser device 210.
The first laser beam 240 is reflected by a first reflector 220 and passes through a first focusing lens 230. The first laser beam 240 is focused through the first focusing lens 230 and impinges on the brittle substrate surface 201 form a first laser spot 21. The first laser beam 240 continuously heats a zone under the first laser spot 21, vaporizing material of the brittle substrate 20 to form a pre-cut groove 23 along a direction B. In this embodiment, the solid-state laser device 210 is a high-power solid-state laser device, the solid-state laser device 210 with some parameters of a specific wavelength, frequency, energy density and beam diameter will have sufficient energy to enable its pulse to impact and vaporize material of the brittle substrate 20. The solid-state laser device 210 can have the following parameters: a wavelength in an approximate range from 200 to 1064 nm, a frequency in an approximate range from 50 to 80 KHz, a pulse duration in an approximate range from 10 to 40 nanosecond, a laser beam diameter viz. diameter of the first laser spot 21 in an approximate range from 15 to 1000 microns, an energy density in an approximate range from 120 to 250 J/cm.sup.2, a power in an approximate range from 0.5 to 1.8 w. Preferably, the wavelength should bein an approximate range from 355 to 570 nm, and the laser beam diameter should be in an approximate range from 15 to 300 microns. Because depth and width of the pre-cut groove 23 corresponds to the diameter of the first laser spot 21 and the energy density, the pre-cut groove 23 can be formed rapidly and accurately without generation of the first micro-cracks by the small diameter of the first laser spot 21 and higher energy density, at the same time, the pre-cut groove 23 formed by the first laser beam 240 should have better uniformity and be more linear.
Alternatively, the first laser beam 240 may directly impinge on the surface of the brittle substrate 20 to form the pre-cut groove 23 without using the first reflector 220 and the first focusing lens 230.
Referring to
Step 3: applying a second laser beam 280 onto the brittle substrate surface 201 along the precut groove 23 to heat the brittle substrate 20, the second laser beam 280 being generated from a gas laser device 250.
Referring to
Alternatively, the second laser beam 280 may directly impinge on the pre-cut groove 23 at relative beam energy to result in a local heat-expansion with a high stress concentration without the second reflector 260 and the second focusing lens 270.
The second laser beam 280 is selected corresponding to a characteristic of absorptive wave of the brittle substrate 20. The gas laser device 250 can be selected from a group including CO2 lasers, CO lasers, nitrogen molecular lasers and inert gas lasers to match with the material of the substrate. For example, a CO2 laser can be selected for a glass substrate; the nitrogen molecular laser should be selected for a ceramic glass substrate etc. In this embodiment, the gas laser device 250 is a CO2 laser, the second laser beam 280 is generated by a CO2 laser having a wavelength of 10.6 microns.
Referring to
Step 4: applying a coolant onto the brittle substrate 20 along the pre-cut groove 23 so as to cause a through crack in the brittle substrate 20 thus allowing the complete cutting of the brittle substrate 20.
Referring to
By heating and cooling the pre-cut groove 23, the pre-cut groove 23 is heat-expanded and contracted and thereby high thermal stress is concentrated on the pre-cut groove 23 of the brittle substrate 20.
When the thermal stress exceeds bonding force of the material molecules of the brittle substrate, material molecules bonding is broken and cracking is generated along the pre-cut groove 23.
The generated crack is propagated along the propagation direction of the second laser beam 280, that is, perpendicularly with respect to the surface of the brittle substrate 20, so the brittle substrate 20 is completely cut.
Referring to
The coolant in the coolant unit 290 may be gas, liquid or a combination thereof. The gas coolant is selected from a group consisting of air, cooling oil, helium gas, nitrogen, CO2 and any combination thereof. The liquid coolant is selected from a group consisting of pure water, alcohol, acetone, isopropanol, cooling oil, liquid nitrogen, liquid helium and any combinations thereof.
In this embodiment, the first laser beam 240 generated by the solid-state laser device 210 can form a pre-cut groove 23 having a better uniformity and linearity, so thus allowing control of generation of micro-cracks. So, the brittle substrate can be cut approximate without formation of micro-cracks.
It is to be understood that the above-described embodiment is intended to illustrate rather than limit the invention. Variations may be made to the embodiment without departing from the spirit of the invention as claimed. The above-described embodiments are intended to illustrate the scope of the invention and not restrict the scope of the invention.
Number | Date | Country | Kind |
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200610062074.3 | Aug 2006 | CN | national |