CALIBRATED LASER PRINTING METHOD

Abstract

The present disclosure relates to a calibrated laser printing method, which is a pre-laser machining operation of wafers and comprises steps as follows: a piece of calibration glass is carried and leveled by a leveling system; a plurality of target points are marked on the piece of calibration glass by a laser system based on data of default positions of the plurality of target points on the piece of calibration glass; true positions of the target points on the piece of calibration glass are measured by an image system; data of measured true positions is transmitted to a resetting system; the piece of calibration glass is shifted to a next location by a displacement system on which the leveling system is carried for repetitive executions of above steps in the case of measurement not completed; data between default and true positions of the target points is compared; a reflecting mirror is deflected by an angle for calibrations of laser beams projected on a wafer in the case of any offset between default and true positions of the target points out of specification.

Claims

1. A calibrated laser printing method, comprising steps as follows: (a) a piece of calibration glass is carried and leveled by a leveling system; (b) a plurality of target points are marked on the piece of calibration glass by a laser system based on data of default positions of the plurality of target points on the piece of calibration glass; (c) true positions of the target points on the piece of calibration glass are measured by an image system; (d) data of measured true positions is transmitted to a resetting system; (e) the piece of calibration glass is shifted to a next location by a displacement system on which the leveling system is carried for repetitive executions from (b) to (e); (f) data between default and true positions of the target points is compared; (g) a reflecting mirror is deflected by an angle for calibrations of laser beams projected on a wafer in the case of any offset between default and true positions of the target points out of specification.

2. The calibrated laser printing method as claimed in claim 1 wherein a piece of calibration glass is checked by the resetting system for availability and fetched from a storage box before (a).

3. The calibrated laser printing method as claimed in claim 1 wherein surface features on the piece of calibration glass are recorded in the resetting system for defining data of default positions of the target points on the piece of calibration glass after (a).

4. The calibrated laser printing method as claimed in claim 1 wherein the piece of calibration glass is exteriorly covered with a specific coated layer which can be removed by laser beams.

5. The calibrated laser printing method as claimed in claim 1 wherein the laser system casts cross-hair reticles to mark the target points on the piece of calibration glass.

6. The calibrated laser printing method as claimed in claim 3 wherein the reflecting mirror after (g) is deflected by an angle for repetitive executions from (b) to (g).

7. The calibrated laser printing method as claimed in claim 3 wherein recalibrations at (b) are enabled in a region in which some major offsets were detected.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0021] FIG. 1 is a schematic view of a calibration machine in a preferred embodiment.

[0022] FIG. 2a is a schematic view for a plurality of target points on a piece of calibration glass in a preferred embodiment.

[0023] FIG. 2b is a schematic view for regions on a piece of calibration glass in a preferred embodiment.

[0024] FIG. 2c is a schematic view for one region to be calibrated on a piece of calibration glass in a preferred embodiment.

[0025] FIG. 3 is a schematic view for a piece of calibration glass fetched from a storage box in a preferred embodiment.

[0026] FIG. 4 is a schematic view of a piece of calibration glass in a preferred embodiment.

[0027] FIG. 5 is the first flowchart of a calibrated laser printing method in a preferred embodiment.

[0028] FIG. 6 is the second flowchart of a calibrated laser printing method in a preferred embodiment.

[0029] FIG. 7 is the third flowchart of a calibrated laser printing method in a preferred embodiment.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

[0030] A calibrated laser printing method is further illustrated in a first embodiment for clear understanding of purposes, characteristics and effects of the present disclosure.

[0031] Referring to the flowchart in FIG. 5, which comprises step a (31), step b (32), step c (33), step d (34), step e (35), step f (36) and step g (37).

[0032] As shown in FIGS. 1 and 5, the step a (31) is to carry and level a piece of calibration glass (20) by means of a leveling system (10).

[0033] Specifically, the leveling system (10) is used to level a piece of calibration glass (20) carried in the leveling system (10) through vacuum absorption, jig fixing and magnetism fixing for less displacement and/or surface warping of an object carried inside and laser beam machining applied to the object later; moreover, the piece of calibration glass (20), which is a low-cost glass object applied in laser calibration before wafer production for correct positioning of laser beam machining on the piece of calibration glass (20), comprises a specific coated layer (201) exteriorly that can be erased by laser beams, as shown in FIG. 4.

[0034] Referring to FIGS. 1 and 5, the step b (32) is to mark a plurality of target points (21) on the piece of calibration glass (20) with a laser system (11) based on data for default positions of the plurality of target points (21) on the piece of calibration glass (20).

[0035] In general, some offsets of laser beam machining are clearly detected according to comparisons of data between default and true positions of the plurality of target points (21) uniformly marked on the surface of the calibration glass (20) for measurement and/or offset detection; moreover, the laser system (10), which is a LASER (Light Amplification by Stimulated Emission of Radiation) generation device generating excited light radiations and amplifying them to laser beams by excitation source, gain medium and resonant structure for applications far and wide, is applied in precision machining and semiconductor industries because of no machining stress but good accuracy and equipped with dust collectors around for collections of powders generated in a machining process.

[0036] Preferably, the laser system (11) casts cross-hair reticles to mark the target points (21) on the piece of calibration glass (20) for clear recognitions of the target points (21).

[0037] As shown in FIGS. 1 and 5, the step c (33) is to indicate an image system (12) with which the true positions of the target points (21) on the piece of calibration glass (20) are measured.

[0038] In general, the image system (12) is able to obtain true positions of the target points (21) by transferring image data to digital signals through CCD or CMOS photosensitive elements.

[0039] As shown in FIGS. 1 and 5, the step d (34) is to transmit data of measured true positions of the target points (21) to a resetting system (13).

[0040] Specifically, the resetting system (13) in which data related to the piece of calibration glass (20) as well as default and true positions of the target points (21) are stored has functions of data comparisons and laser parameter corrections.

[0041] As shown in FIGS. 1 and 5, the step e (35) is to shift the piece of calibration glass (20) to a next location by the displacement system (14) on which the leveling system (10) is carried for repetitive executions from step b (32) to step e (35).

[0042] In general, the displacement system (14) is an XY table with which the leveling system (10) is shifted along X and Y axes.

[0043] As shown in FIGS. 1 and 5, the step f (36) is to compare data of default and true positions of the target points (21).

[0044] In practice, the data of true positions of the target points (21) collected completely from step c (33) to step e (35) are compared with data of default positions of the target points (21).

[0045] Finally, as shown in FIGS. 1 and 5, the step g (37) is to deflect a reflecting mirror (111) by an angle and calibrate a location of laser beams projected on a wafer in the case of any offset between default and true positions of the target points (21) out of specification.

[0046] Specifically, the reflecting mirror (111) is a scanning galvo installed at the path of laser beam transmission and also a galvo-based mechanical scanner with a motor-driven physical mirror; the reflecting mirror (111) is connected with an electric motor's shaft mostly or the reflecting mirror (111) along with an electric motor is a stand-alone integrated unit in some designs probably.

[0047] FIG. 6 illustrates a calibrated laser printing method in a second embodiment in which the symbols identical to those of the first embodiment in FIGS. 1 and 5 are not explained hereinafter. The differences in the second embodiment differing from the first embodiment are more steps such as step a0 (311), step b0 (321) and step h (38) in FIG. 6, compared with FIG. 5.

[0048] Referring to FIG. 6, which illustrates a flowchart with step a0 (311), step a (31), step b0 (321), step b (32), step c (33), step d (34), step e (35), step f (36), step g (37) and step h (38).

[0049] As shown in FIGS. 1, 3 and 6, step a0 (311) is to check availability of a piece of calibration glass (20) by the resetting system (13) before the piece of calibration glass (20) is unloaded from a storage box (22).

[0050] In the second embodiment, the resetting system (13) records service conditions of a piece of calibration glass (20) and the storage box (22) accommodates five pieces of calibration glass (20), each of which can be fetched by a robot.

[0051] As shown in FIGS. 1 and 6, a piece of calibration glass (20) caught by a robot is placed on and carried and leveled at the leveling system (10) in step a (31) after step a0 (311).

[0052] As shown in FIGS. 1 and 6, step b0 (321) is to record surface features of the piece of calibration glass (20) in the resetting system (13) for defining data of default positions of the target points (21) on the piece of calibration glass (20); accordingly, the piece of calibration glass (20) will be employed repeatedly until the piece of calibration glass (20) is unqualified.

[0053] Referring the step b (32) to the step g (37) hereinbefore. As shown in FIGS. 1 and 6, the step b (32) is to mark the target points (21) on the piece of calibration glass (20) by the laser system (11) based on data of default positions of the plurality of target points (21) on the piece of calibration glass (20); the step c (33) is to measure true positions of the target points (21) on the piece of calibration glass (20) by the image system (12); the step d (34) is to transmit data of the measured positions to the resetting system (13); the step e (35) is to shift the piece of calibration glass (20) to a next location by the displacement system (14) on which the leveling system (10) is carried for repetitive executions from the step b (32) to the step e (35); the step f (36) is to compare data between default and true positions of the target points (21); the step g (37) is to deflect the reflecting mirror (111) by an angle and calibrate a location of laser beams projected on a wafer in the case of any offset between default and true positions of the target points (21) out of specification.

[0054] Finally, step h (38) is to repeat the step b (32) to the step g (37) when the reflecting mirror (111) was deflected by an angle; moreover, step h (38) is to check whether laser beams adjusted are projected to an expected target.

[0055] FIG. 7 illustrates a calibrated laser printing method in a third embodiment in which the symbols identical to those of the first and/or second embodiment in FIGS. 1, 5 and 6 are not explained hereinafter. The difference in the third embodiment differing from the first and/or second embodiment is an additional step of step b1 (322) in FIG. 7, compared with FIG. 6.

[0056] Referring to FIG. 7, which illustrates a flowchart with step a0 (311), step a (31), step b0 (321), step b1 (322), step b (32), step c (33), step d (34), step e (35), step f (36), step g (37) and step h (38).

[0057] In the third embodiment, most steps are identical to those in the second embodiment except step b1 (322). As shown in FIGS. 1 and 7, recalibrations in step b1 (322) are enabled in a region in which major offsets are detected.

[0058] In practice, as shown in FIG. 2b, there are a first region (W), a second region (X), a third region (Y) and a fourth region (Z) virtually divided within an area to be machined. Referring to FIG. 7, which illustrates step b1 (322) is added with the step b (32) in the second embodiment enabled again after completion of the step h (38) for the first time. If there are some offsets between default and true positions of the target points (21) in the second region (X) out of specification only, the laser system is activated again to mark the target points in the second region (X) on the piece of calibration glass for least calibration time.

[0059] Accordingly, a calibrated laser printing method which differs from an ordinary calibration device and is referred to as creative work in the semiconductor industry meets patentability and is applied for the patent.

[0060] It should be reiterated that the above descriptions present the preferred embodiments, and any equivalent change in specifications, claims or drawings still belongs to the technical field within the present disclosure with reference to claims hereinafter.