JPS6040681A - Laser processing device - Google Patents

Abstract

PURPOSE:To eliminate under- and over-cutting and to perform working with hith accuracy to improve yield by providing inspecting mechanisms which inspect a material to be processed and enabling selection of the optimum conditions for irradiating a laser for the purpose of the working process. CONSTITUTION:A laser processing device consists of inspecting mechanisms 2, 5 which inspect the desired characteristic of a material 1 to be processed, a laser control mechanism 9 which controls a laser processing function according to the information on the result of the inspection emitted from the mechanisms 2, 5 and a laser generating mechanism 4. Said mechanism 4 irradiates laser light 3 controlled by the mechanism 9 to at least a part of the material 1. Under- and over-cutting is eliminated and working with high accuracy is accomplished by the above-mentioned device, by which the yield is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a laser processing device, such as a trimming device.

[Background technology]

BACKGROUND ART With the advancement of IC and LSI technology, the miniaturization of electronic devices is progressing by using hybrid ICs as subsystem circuits that are compactly configured by mounting semiconductor ICvs. Although the number of such high-voltage ICs equipped with chip resistors is increasing, film resistors are generally formed on the substrate. As one step in the manufacturing process of this film resistor, there is a trimming process to adjust the resistance value.Trimming methods can be broadly divided into element trimming, which trims while measuring the resistance value, and element trimming, which trims while measuring the resistance value, and element trimming, which corrects the circuit constants after assembly. There is a function trimming (functional trimming).

The film resistor is made by screen printing a ruthenium oxide-based glaze resistance paste on an alumina substrate and baking it at a high temperature.A thin film is formed by vapor depositing or sputtering tantalum or the like on the alumina substrate and etching it to form a pattern. The main body is the resistor.

The need for resistor trimming can be achieved by printing, vapor deposition, metallization, etc.

This is because when a resistor is formed using a method such as 1, it is extremely difficult to keep the resistance value within a desired range.

The laser trimming method uses a laser light source with good convergence to cut the film resistor with a laser beam to adjust the resistance value. Conventional laser trimming equipment was developed by Semiconductor World, 1983.

It is described in the January issue, page 90. In conventional laser trimming equipment, the laser power is set by an initial value entered into a computer. Defects occur because physical changes in the object to be processed, such as changes in the film thickness or material changes of a film resistor, are processed using a laser power set and fixed at an initial value.

For example, if the film resistor is formed thick in some parts, the thick part of the film cannot be cut sufficiently with the set laser power, resulting in poor cutting.
When non-volatile components that remain unburned in the kalito part absorb moisture or are subjected to heat stress, the resistance changes.

On the other hand, when the film resistor is formed to have a thin film thickness, the set laser power is too powerful to cut the film, resulting in excessive cutting. And - cut not only the film itself but also the substrate, providing an enclosure to the substrate as well. In addition, because the laser power is strong, the thermal stress applied to the vicinity of the cut end of the film resistor is large, and microcracks are generated on the film resistor, and the microcracks spread due to aging or thermal stress added during post-processing, resulting in the desired result. Resistance value cannot be obtained. As a result of the above, the applicant has discovered that a problem arises in that a decrease in product yield and a decrease in reliability due to changes in product characteristics over time occur due to variations in film resistor film thickness and fixed laser power. Akira was criticized.

[Purpose of the invention]

An object of the present invention is to provide a Bl technique for a sensor processing device that enables high 46S degree processing and highly reliable processing of the electronic part #+.

The above and other objects and novel features of the present invention are as follows:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief summary of typical inventions disclosed in this application is as follows.

In other words, an inspection mechanism is installed in the laser processing equipment to perform a desired characteristic inspection or (external shape inspection) of the workpiece, and based on the inspection results, the optimal laser irradiation conditions for processing the workpiece are selected. By doing so, the above objective will be achieved.

〔Example〕

FIG. 1 is a block diagram showing an overview of the laser processing apparatus of the present invention, FIG. 2 is a schematic diagram showing the overall configuration, and FIG. 3 is a flow chart showing the processing method.

The laser processing apparatus of this embodiment is roughly divided into two parts, as shown in FIG. A laser mechanism 4 that irradiates the surface of the film resistor 1 to be treated with laser light 3; and an inspection mechanism 5 that inspects whether the film resistor 1 has desired electrical characteristics while the film resistor 1 is being laser-treated. It consists of a parts handler 7 that carries in and out a wiring board 6 on which a film resistor l is formed.

FIG. 1 shows the laser processing apparatus of the present invention below.

This will be explained in detail with reference to FIG. A wiring board 6 on which a film resistor 1, which is an object to be processed and is indicated by a dotted line in FIG. 2, is carried in by a parts handler 7. Next, the external shape inspection mechanism 2 uses an optical microscope and uses a light cutting method.
The film thickness of the film resistor 1 on the wiring board 6 is measured. After measuring the film thickness of all the film resistors 1 formed on the wiring board 6, the measurement results are sent as a signal to the control central processing unit 9 (control CPU).
sends a signal ■ to the parts handler 71C. The parts handler 7 moves and fixes the wiring board 6 to the laser irradiation area based on the signal (2). The control CPU 9 performs arithmetic processing on the measurement result signal (2), compares the result of the arithmetic processing with the optimum relationship between the film thickness and the laser irradiation conditions previously stored in the control CPU 9, and determines the optimum laser irradiation conditions. Laser irradiation conditions include not only laser power control, but also
Beam diameter control, ultrasonic Q-switch frequency control, beam-
It consists of controlling the moving speed of the positioner, etc.

Furthermore, by providing a recognition device (not shown), the optimum laser irradiation conditions can be obtained by storing the relationship between substances and laser irradiation conditions in the control CPU 9 even when the material of the object to be treated changes. . and control CPU9
From the laser power adjustment device 12. Beam diameter adjustment device 13. Ultrasonic Q-switch frequency adjustment device 14. Signals 3a and 3 are sent to the beam position moving speed adjusting device 15, respectively.
b.

3c and 3d are sent. This time, a signal ■ is sent from the control CPU 9 to the globe 10, and the probe terminal 10a-10
b indicates electrodes 11a-11b provided on both sides of the membrane resistor 10;
placed in contact with. This glove terminal ioa
- 10b is a terminal for measuring the resistance value of the membrane resistor 1, and is connected to the inspection mechanism 5, and the inspection mechanism 5 measures the resistance value between the probe terminals 10a and 10b. Next, the control CPU 9 sends a cutting information signal based on the signal (2) input from the terminal 8 to the beam positioner 12 together with the laser irradiation command signal (3). On the other hand, a measurement start signal (2) is issued to the inspection mechanism 5, and the laser beam 3 is irradiated to the membrane resistor IVc.
The resistance value of the film resistor 1 between the resistors 10b and 10b is measured. Then, the measurement result from the inspection machine @5 is sent as a signal ■ to the control CPU 9.
send to At this time, the control CPU 9 processes the measurement result signal (■) to calculate the resistance value, and calculates the resistance value and the desired resistance value of the membrane resistor 1 based on the signal (■) input from the terminal 8↓. compare. If the resistance value calculated from the measurement result signal (2) is smaller than the desired resistance value of the film resistor 1, the laser beam 3 continues to be irradiated. When the resistance value calculated from the signal (2) and the desired resistance value of the membrane resistor (1) match, the control CPU 9 immediately sends a laser irradiation stop barrel to the laser mechanism 4, and the trimming operation is completed. and,
A trimming result information signal [Inc.] is sent from the control CPU 9 to the terminal 8 and the trimming result is displayed on a display (not shown) provided in the terminal 8.

Next, each part will be explained. The laser mechanism 4 includes a laser generator 16, mirrors 18-19 provided on a beam positioner 17 for positioning the laser beam 3, and a condenser lens 20.

As the laser generator 16, for example, yttrium aluminum garnet (YttriumAnm
inum Garnet is hereinafter referred to as YAG. ) using a laser. In the YAG laser, neodymium (Nd) ions are doped into a YAG crystal, and the Nd ions are excited with a krypton lamp to generate laser light 3. This laser light 3? :Using the ultrasonic Q-switch 14, a narrow pulse oscillation of peak output + pulse rl-+ of several kilowatts is obtained. The laser beam 3 is transmitted through a beam positioner 16
is positioned on the workpiece by mirrors 17 and 18 of
Then, the laser beam 3 is moved on the object to be processed by moving the mirrors 17 and 18. The direction of movement of the mirrors 17 and 18 is determined by the information signal (2) input from the terminal 8 to the fltU patron CPU 9. The laser beam 3 reaching the condensing lens 19 is condensed and irradiated onto an object thereon.

Next, the wiring board 6y! 'Parts handler 7 for loading and unloading
has a structure as shown in FIG. That is, the carrier surface 21 becomes a horizontal portion, and the wiring board 6 is transported by the air flow 23 ejected from the air outlet 22 provided on the carrier surface 21. Film thickness measurement area 24 on the transport table surface 21. A suppression plate 25 is provided above the laser irradiation area (h not shown). Further, a stopper 26 is provided at the lower part of the suppressing plate 25 located on the unloading side, and when the wiring board 6 is transported, the transport of the wiring board 6 is stopped by this stopper 26. The wiring board 6 is fixed, and external inspection or laser irradiation begins.

The external shape inspection mechanism 2 is measured by a light cutting method using an optical microscope. The principle of the optical cutting method is as follows. An image of a thin slit is projected at a 45° angle to the surface to be examined.As a result, a cross section is created that looks like the surface is cut along a plane that includes the slit and the optical axis, and the unevenness of the surface is measured. It is something.

Next, the processing procedure flowchart shown in FIG. 3 will be explained. First, a wiring board 6, which is an object to be processed, is carried into and supplied to the external shape inspection area by the parts handler 7, and set in the external form inspection area by the press plate 25. Next, an external shape inspection is performed.

When the external shape inspection is completed, the wiring board 6 is moved and fixed to the laser irradiation area by the suppression plate 25, and the control CPU 9 selects the laser irradiation conditions. A probe l is used to measure the resistance value of the film resistor l on the wiring board 6.
O is set, measurement is started, and laser irradiation is started at the same time. Next, the measured resistance value and the desired resistance value are compared and judged, and if the desired resistance value is not reached, laser irradiation is continued. - When the laser irradiation and resistance value measurement are completed, the wiring board 6 is moved from the laser irradiation area and sent to the next process.

FIG. 5 is a plan view showing the thick film wiring board 6 processed by the laser processing apparatus of this embodiment.

Film resistors R,,R,,R,,R, on the wiring board 6.

The film thickness of R5 varies depending on the characteristics of the layout, etc., and is processed with the laser irradiation conditions being optimized individually.

As explained above, in the laser processing apparatus of this embodiment, before laser processing, the film thickness of the object to be processed is measured, and the optimum laser irradiation conditions are selected from the measurement results. As seen in laser processing equipment, there is a decrease in yield due to initial failures such as insufficient force and tension due to variations in the film thickness of the processed object, or excessive force and scattering, changes over time, or heat stress in post-processing. There will be no more sexual defects for 4-year-olds.

〔effect〕

(1) According to the present invention, the outer shape of the workpiece is inspected before laser processing, and based on the result of the outer shape inspection, the optimum conditions for laser irradiation are selected and laser processing is performed. The effect is that precision machining and highly reliable machining can be achieved.

(2) From (1) above, in the resistor trimming process,
The result is that resistance value defects are eliminated and the yield is improved.

(3) From (1) above, it is possible to obtain the effect that resistor board defects are eliminated in post-processes, particularly in processes where thermal stress is applied, and the yield is improved. Although the present invention has been specifically described, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from the spirit thereof. For example, after the heel inspection is completed, the stage for inspecting the outer shape of the processed object and the laser irradiation stage are
Minking may also be performed by laser irradiation at the same location without moving the wafer. Although a light cutting method was used as the external shape inspection mechanism, a polarization analysis method, a repeating reflection interferometer, or a no-turn recognition device may also be used. In addition, the present invention not only inspects the outer shape of the stripes (film thickness, etc.), but also inspects desired characteristics such as temperature and hardness of the processed material depending on the purpose.
σ) Laser processing can also be performed according to the characteristic test results O [Field of Application] In the above explanation, the invention made by the present inventor was mainly applied to the field of application of the invention, which is the background of the invention, which is the laser trimming device technology. Although the case has been described above, the present invention is not limited thereto, and can be applied to processing equipment techniques using lasers such as a laser scriber, a laser marker, a laser mask repair, and a laser welder. The present invention can be applied at least to conditions where objects to be processed are processed with high precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of a laser processing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the overall configuration as well. FIG. 3 is a flow chart showing the same processing procedure. FIG. 4 is a sectional view showing the main parts of the parts handler. FIG. 5 is a plan view after processing of a wiring board on which a film resistor, which is an object to be processed, is formed. DESCRIPTION OF SYMBOLS 1... Film resistor, 2... External shape inspection mechanism, 3... Laser light, 4... Laser mechanism, 5... Inspection mechanism, 6
... Wiring board, 7... Parts handler, 8... Terminal, 9... Control CPU, 10... Probe, i
oa/10b...probe terminal, lla/llb...
・Wiring electrode, 12... Laser adjustment device, 13...
Beam diameter adjustment device, 14... Ultrasonic Q switch frequency adjustment device % 15... Beam positioner movement speed adjustment device, 16... Laser generator, 17... Beam positioner, 18◆19... Mirror , 20... Condensing lens, 21... Transport platform, 22... Air jet port, 2
3...Air, 24...External inspection area - area (laser irradiation area), 25...Suppression plate, 26...Stopper. Figure 3 Figure 4 Figure 5 / /

Claims (1)

[Claims] 16 An inspection mechanism that inspects desired characteristics of a processed object, a laser control tI mechanism that controls a laser processing function according to inspection result information of the desired characteristics issued from the inspection mechanism, and a laser control mechanism that controls a laser processing function under the control of the laser control mechanism. A laser processing apparatus comprising: a laser generating mechanism that irradiates at least a portion of an object to be processed with light.