JP5224139B2 - Mold removal method and mold removal apparatus - Google Patents

Description

  The present invention relates to a mold removal method and a mold removal apparatus for measuring a thickness of a mold covering a workpiece such as an IC mold to remove the mold and processing the IC to a state close to exposure.

It is possible to perform failure analysis of ICs (Integrated Circuits) created by integrating many micro devices such as transistors, diodes, resistors, capacitors, etc. on a single substrate and electrically connecting or insulating each other. Has been done. The semiconductor chip is sealed with a resin mold or the like in the IC package. Thus, when there is a malfunction in the integrated circuit formed on the semiconductor chip of the IC package, the resin sealing the semiconductor chip is removed to expose the semiconductor chip in order to analyze the cause and correct the circuit. It is demanded to make it.
For this reason, conventionally, as a method for opening the IC package, the resin is removed by spraying a working medium such as nitric acid onto a resin mold sealing the semiconductor chip of the IC package (hereinafter referred to as “Prior Art 1”). For example, see Patent Document 1.) Further, dry etching or the like is used (hereinafter referred to as “conventional technology 2”, for example, see Patent Document 2).

  However, in the chemical solution method in which the resin mold is removed by using the solution of the prior art 1 and the IC package is opened, the problem of corrosion of the IC constituent material, waste liquid treatment and equipment corrosion, and the dry etching of the prior art 2 is the processing speed. There is a problem that is slow. Further, in the prior art 1 and the prior art 2, since the position and installation state of the semiconductor chip sealed with the resin mold is not known, the semiconductor chip is damaged in the removal process and covers the semiconductor chip. There was a problem that the resin could not be removed completely cleanly.

  As a technique for solving the problems of the prior art 1 and the prior art 2, the present applicant has proposed a technique for removing a resin mold by a laser (hereinafter referred to as “prior art 3”; for example, refer to Patent Document 3). The laser processing apparatus of the prior art 3 can solve the problems of the prior art 1 and the prior art 2. However, because it is in the early stages of development, the amount of emitted laser light for measurement emitted from the laser light emitting means can be reduced. An emission light quantity measuring means for measuring, and a light quantity correction means for correcting the reflected light quantity measured by the reflected light quantity measurement means based on the emitted light quantity measured by the emitted light quantity measurement means; and a resin mold There is a drawback that the apparatus becomes expensive, for example, the reflected light of the reflected measurement laser beam is guided to a light receiving element via an optical system. Further, since the processing is performed under uniform conditions regardless of the residual thickness of the resin mold, there is a problem that the processing speed and precision are lacking.

JP 2000-323506 A JP 2004-179185 A JP 2008-290117 A

  The present invention has been made in view of the conventional problems, and an object of the present invention is to leave a resin of 100 microns or less from the surface of the IC chip and to provide a mold that covers the IC chip without damaging the IC chip. An object of the present invention is to provide a mold removal method and a mold removal apparatus that can be removed with high speed and precision and with simple means.

  Therefore, the present invention monitors the residual thickness of the mold and performs laser processing by selecting either primary processing or finishing processing according to the mold removal conditions, thereby minimizing the thickness without damaging the IC chip. Another object of the present invention is to provide a mold removal method and a mold removal apparatus that can remove a mold at high speed and precision with a simpler apparatus configuration.

In order to achieve the above object, the mold removing method of the present invention firstly includes a step of preparing an IC package comprising an IC chip and a secondary wiring, and a mold member covering them,
A step of setting mold removal conditions;
Installing the IC chip at a laser beam emission position;
A measuring step of performing alignment in the height position direction of the mold member, measuring a reflected / scattered light amount at a coordinate position in the X and Y directions of the mold member by emitting a measurement laser, and storing the measured value;
Determining whether the measured value satisfies the removal condition of the mold;
When the measurement value satisfies the mold removal conditions, a finishing process step of performing laser finishing under the processing conditions set according to the mold removal conditions;
When the measured value does not satisfy the mold removal condition, laser primary processing is performed under processing conditions set according to the stored measured values in the X and Y direction positions, and the measurement step is performed after the laser primary processing is completed. The primary processing step to go back to
It is characterized by having.
As the “reflected / scattered light amount”, for example, a determination result of the reflected / scattered light amount with respect to a separately set threshold value can be adopted.
According to the first feature, removal can be performed at high speed until the residual thickness of the mold member is minimized without damaging the IC chip.
Even when it is necessary to perform a chemical solution or dry etching after the removal operation of the present invention, the residual thickness of the mold member is removed to 100 microns or less, so that the treatment can be performed quickly and with a small amount of the chemical solution. It can be carried out.
Furthermore, by setting the mold removal conditions and determining whether the measured values of the thickness of the mold member in the X and Y directions satisfy the mold removal conditions, either finishing or primary processing is selected. The processing according to the residual mold thickness can be performed.

The mold removal method of the present invention is secondly characterized in that, in the first feature, at least the removal area, the return light amount threshold value, the IC return light detection, the secondary wiring detection or the additional finishing are set as the setting items of the mold removal conditions. It is characterized by including any one of these.
The second feature enables more rational laser processing without waste.

Thirdly, in the mold removing method of the present invention, in the first or second feature, when the secondary wiring detection is included as the setting item of the mold removal condition, the detection of the secondary wiring leads to the IC chip. The Z-direction distance is calculated, and laser finishing is performed under the processing conditions based on the Z-direction distance.
According to the third feature, since the residual thickness of the mold member can be calculated using secondary wiring detection as a guide, setting of finishing processing conditions becomes easy.

In addition, the mold removing method of the present invention, fourthly, in any of the first to third features, the measurement laser beam is emitted to measure the amount of reflected / scattered light at the X and Y coordinate positions of the mold member. In the measurement step of storing the measurement values, the measurement laser comprising pulsed light is continuously irradiated, and the measurement position of the X and Y direction coordinates of the mold member is determined based on the laser irradiation start timing, the pulse frequency, and the scanning speed. And the amount of reflected / scattered light at the measurement position is stored.
That is, the X direction irradiation position when the Nth pulse laser is irradiated from the start of irradiation = X irradiation start X coordinate + (X direction scanning speed × N ÷ pulse frequency), and the Nth pulse laser from the start of irradiation is calculated. Y direction irradiation position when irradiated = irradiation start Y coordinate + (Y direction scanning speed × N ÷ pulse frequency).
According to the fourth feature, the measurement of the residual thickness of the mold member at the X and Y coordinate positions of the mold member can be performed continuously and at high speed.

  The mold removing apparatus of the present invention is an apparatus for laser processing an IC package comprising an IC chip, a secondary wiring, and a mold member covering them, and has a smaller output than the processing laser light and the processing laser light. One laser beam emitting unit that emits a measurement laser beam, a removal condition setting unit that sets a mold removal condition, and a laser scanning unit that irradiates a predetermined position in the X and Y directions of the IC package with a laser beam , A mounting unit that is movably provided in the Z direction, a mounting unit that mounts the IC package, a light receiving unit that measures a reflected light amount of the measurement laser light reflected by the IC package, and a mold based on the reflected light amount Measuring means for measuring the amount of reflected / scattered light at the X and Y coordinate positions of the member and storing the measured value; and A determination means for determining whether or not a condition is satisfied; and if the measured value satisfies the removal condition of the mold, laser finishing is performed under a processing condition set according to the removal condition of the mold, and the measured value is the mold When the removal condition is not satisfied, the laser primary processing is performed under the processing conditions set according to the stored measurement values in the X and Y direction positions, and after the primary processing is completed, the mold member is again in the X and Y direction coordinate positions. Control means for controlling to measure the reflected / scattered light quantity is provided.

Due to the characteristics of the mold removing apparatus described above, the removal can be performed at high speed until the residual thickness of the mold member is minimized without damaging the IC chip.
Even when it is necessary to perform a chemical solution or dry etching after the removal operation of the present invention, the residual thickness of the mold member is removed to 100 microns or less, so that the treatment can be performed quickly and with a small amount of the chemical solution. It can be carried out.
Furthermore, by setting the mold removal conditions, determining whether the measurement values at the X and Y coordinate positions of the mold member satisfy the mold removal conditions, and selecting either finishing or primary processing, Processing according to the residual mold thickness can be performed.
Furthermore, the apparatus configuration can be simplified by omitting the light amount correcting means for correcting the reflected light amount and directly measuring the reflected light without going through the optical system.

The present invention has the following excellent effects.
(1) Removal can be performed at high speed until the residual thickness of the mold member is minimized without damaging the IC chip.
Even when it is necessary to perform a chemical solution or dry etching after the removal operation of the present invention, the residual thickness of the mold member is removed to 100 microns or less, so that the treatment can be performed quickly and with a small amount of the chemical solution. It can be carried out.
(2) By setting the mold removal condition, and determining whether the measured values of the coordinate position in the X and Y directions of the mold member satisfy the mold removal condition, and selecting either finishing or primary processing The processing according to the residual mold thickness can be performed.
(3) By including at least one of removal area, return light amount threshold value, IC return light detection, secondary wiring detection, or additional finishing as setting items for mold removal conditions, it is more rational without waste Laser processing can be performed.
(4) Since the residual thickness of the mold member can be calculated using secondary wiring detection as a guide, setting of finishing processing conditions becomes easy.

(5) By calculating the measurement position of the mold member in the X and Y directions based on the laser irradiation start timing, the pulse frequency, and the scanning speed, the reflected / scattered light quantity at the measurement position is stored, so that X and Y of the mold member are stored. The measurement of the residual thickness of the mold member at the direction coordinate position can be performed continuously and at high speed.
(6) The apparatus configuration can be simplified by omitting the light amount correcting means for correcting the reflected light amount and directly measuring the reflected light without using the optical system.

It is a figure which shows the state which connected the personal computer to the laser processing apparatus of embodiment of this invention. It is a figure which shows typically schematic structure of the laser processing apparatus of embodiment of this invention. It is a figure which shows typically schematic structure of another laser processing apparatus. An IC is shown as a workpiece to be processed. (A) shows a cross-sectional state of the workpiece before laser processing, (B) shows a cross-sectional state of the workpiece during laser processing, and (C) shows The cross-sectional state of the workpiece | work in which the plastic mold was opened by laser processing is shown. It is a top view which shows the state which memorize | stores thickness, irradiating the measurement laser which consists of pulsed light continuously to the workpiece | work which is a workpiece, and calculating the measurement position of the X and Y direction of a plastic mold. It is a top view which shows the state which laser-processes, referring the thickness in the measurement position of the X and Y direction of a plastic mold. It is a figure which shows the reflectance of copper and aluminum with respect to a YAG laser and a CO2 laser. FIG. 5 shows the amount of reflected laser light for measurement in each of the states of (A), (B), and (C) of FIG. It is a flowchart explaining the process of removing a mold using a laser processing apparatus.

  Embodiments for carrying out a mold removal method and a mold removal apparatus according to the present invention will be described in detail with reference to the drawings. However, the present invention is not construed as being limited thereto, and departs from the scope of the present invention. Insofar as various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art.

FIG. 1 is a diagram showing a state in which a personal computer 2 is connected to a laser processing apparatus 1 according to an embodiment of the present invention.
The laser processing apparatus 1 has a width, height, and depth of about several tens of centimeters, and has a compact design that can be installed on a desk. Also, all the controls such as the processing range, processing start / stop, etc. can be processed from the screen of the personal computer 2. The plastic mold can be removed from the surface of the IC chip to a remaining thickness of 100 microns or less. For example, the processing time for an area of 10 mm × 10 mm is about 2 minutes.

(Schematic configuration of laser processing equipment)
FIG. 2 is a diagram schematically showing a schematic configuration of a first example of the laser processing apparatus 1 used for removing a mold such as a resin.
The laser processing apparatus 1 aligns the processing laser beam for processing a predetermined processing object 10 (hereinafter, also referred to as “work”), the focus of the processing laser beam and the workpiece 10, and the mold. A laser light source 11 as a laser light emitting means for emitting a measurement laser light for measuring the residual thickness, and a galvano capable of irradiating a predetermined position in the X and Y directions of the workpiece 10 with the laser light emitted from the laser light source 11 A laser scanning device 12 including a scanner, a light receiving element 13 as a reflected light amount measuring unit for measuring a reflected light amount of the measurement laser light reflected by the workpiece 10, an imaging element 14 capable of photographing the workpiece 10, And an optical system 15 for forming an optical path of the processing laser light and the measurement laser light emitted from the laser scanning device 12.
Further, the laser processing apparatus 1 includes a moving stage 16 that holds the workpiece 10 so as to be movable in the Z direction, and a control unit 17 that performs various controls of the laser processing apparatus 1.

Hereinafter, the processing laser beam and the measurement laser beam are collectively expressed as “laser beam”. In the following description, the left-right direction in FIG. 2 is referred to as the X direction, the vertical direction on the paper is referred to as the Y direction, and the up-down direction (that is, the optical axis direction of the laser light irradiated onto the workpiece 10).
Further, in this embodiment, the optical axis direction of the laser beam irradiated to the workpiece 10 is perpendicular to the processing surface, but the present invention can be implemented even if the beam is irradiated at an angle.

  The optical system 15 condenses the laser light of the laser scanning device 12 and irradiates the workpiece 10 with the condensing lens 18, the beam splitter 19 disposed between the condensing lens 18 and the workpiece 10, the imaging device 14, and the like. A lens 20 disposed between the beam splitter 19 and the beam splitter 19;

  The beam splitter 19 transmits the laser light emitted from the laser scanning device 12 and transmitted through the condenser lens 18 toward the workpiece 10 and reflects the reflected light from the workpiece 10 toward the imaging element 14.

The laser light source 11 is, for example, a fiber laser, and outputs the processing laser light and the measurement laser light as described above. The output of the measurement laser beam is much smaller than the output of the processing laser beam.
Further, in this embodiment, the wavelength of the processing laser light and the wavelength of the measurement laser light are substantially equal, and the focal position of the processing laser light and the focal position of the measurement laser light are substantially the same.

  The light receiving element 13 as a reflected light amount measuring means for measuring the reflected light amount of the measurement laser light is composed of an element such as a photodiode or a phototransistor. The light receiving element 13 directly receives the measurement laser light reflected and scattered by the workpiece 10 and converts the received light amount into an electrical quantity.

  The image sensor 14 is an image sensor such as a CCD or a CMOS. The imaging element 14 is arranged so that the position where the reflected light of the workpiece 10 forms an image is the light receiving surface of the imaging element 14 when the workpiece 10 is at the focus F of the measurement laser beam.

  The moving stage 16 includes a holding unit 21 that holds the workpiece 10 and a drive unit 22 that drives the holding unit 21. The drive unit 22 drives the holding unit 21 in the Z direction.

  A laser light source 11, a laser scanning device 12, a light receiving element 13, and a moving stage 16 are connected to the control unit 17. The control unit 17 performs various controls of the laser processing apparatus 1. For example, the control unit 17 outputs a laser beam emission command or a stop command to the laser light source 11. Further, the control unit 17 measures and records the residual mold thickness of the workpiece 10 based on the amount of reflected light measured by the light receiving element 13, determines whether a mold removal condition described later is satisfied, and sets processing conditions. .

FIG. 3 is a diagram schematically showing a schematic configuration of a second example of the laser processing apparatus 1 used for removing a mold such as a resin.
In FIG. 3, the same reference numerals as those in FIG. 2 denote the same members, and the description of those members is omitted.
In this example, a beam splitter 23 is installed in the optical path connecting the laser light source 11 and the laser scanning device 12, and the reflected light reflected by the workpiece 10 is guided to the beam splitter 23 through the optical system 15 and the laser scanning device 12. The light reflected by the light 23 is received by the light receiving element 13.
According to this example, since measurement is possible on the same optical axis as the processing light, no measurement error due to a change in the position of the measuring element occurs even when reflected / scattered light is not output uniformly in the X and Y directions. Therefore, the measurement accuracy is improved.

(Setting of Z position of workpiece)
By measuring the distance between the laser emission surface and the moving stage 16 and trial processing, a position that is regarded as a focal point is obtained in the production inspection stage. This result is stored in the control software of the apparatus, and is set by controlling the Z direction further away by the thickness of the workpiece 10 placed on the moving stage 16 during operation.

(Resin mold removal)
Hereinafter, a resin mold removing method for exposing the semiconductor chip by removing the resin mold covering the semiconductor chip in the package using the above-described laser processing apparatus will be described.
FIG. 4 shows, for example, an IC package as a workpiece to be processed. (A) shows a cross-sectional state of the workpiece before laser processing, and (B) shows a cross-section of the workpiece during laser processing. The state (C) shows a cross-sectional state of the workpiece in which the plastic mold is almost opened by laser processing.
As shown in FIG. 4A, the IC package 30 is roughly composed of an IC chip 31 such as a transistor, a diode, a resistor, and a capacitor, a secondary wiring 32 that electrically connects the IC chips to each other, and the IC chip 31. It is comprised from the plastic mold 33 which covers.

Since YAG laser (wavelength 1064 nm) and CO2 laser (wavelength 10.64 μm) are absorbed by IC mold material and substrate resin material, they are often used for model marking.
On the other hand, when the reflectance of copper and aluminum, which are wiring materials, is shown in FIG. 7, both the copper and aluminum are 80% or more for the YAG laser, and the reflectance is 95% or more for the CO 2 laser. Further, the IC chip 31 made of silicon or the like reflects these laser beams better than the mold material. On the other hand, the IC mold material absorbs this laser beam well.
The workpiece to be processed according to the present invention is not limited to a resin mold, and can be applied to, for example, a composite material mixed with a bulk material such as ceramic.

When the IC package 30 shown in FIG. 4 (A) is opened from above the IC chip 31 for failure analysis, laser processing is performed from the upper surface 34 of the IC package 30, and FIG. 4 (B) and FIG. As shown in (C), the plastic mold 33 is gradually removed, and the coating of the plastic mold 33 becomes thin until the IC chip 31 is close to being exposed.
When the thickness of the plastic mold 33 is large, the irradiated laser beam for measurement is absorbed by the plastic mold 33 and a relatively small amount of reflected / scattered light is generated. As processing advances and the secondary wiring begins to be exposed, the amount of light received by the light receiving element 13 increases due to the large reflection of the metal wiring. When the plastic mold 33 is eliminated, only the reflected / scattered light on the surface of the chip 31 having a relatively high reflectance is measured, so that the measured light quantity takes a maximum value. By monitoring the change in the measured light quantity by the processing state detection means of the control unit 17, it is possible to grasp the processing state, that is, the residual thickness of the plastic mold 33.

When the removal of the plastic mold 33 is performed until the IC chip 31 is close to being exposed as shown in FIG. 4C, the amount of reflected light shown by C in FIG. 8 is reached, and as shown in FIG. When the plastic mold of the part is left, laser processing is performed until the amount of reflected light shown by B in FIG. The mold is not limited to resin, but may be ceramic.

In FIG. 4, focusing on the secondary wiring 32, the secondary wiring 32 is covered with the plastic mold 33 in (A), but is exposed in (B). In the case of (A), the irradiated measurement laser light is absorbed by the plastic mold 33, and a relatively small amount of reflected / scattered light is generated. As the processing progresses and the secondary wiring 32 is exposed, the measurement laser light is reflected / scattered on the surface of the secondary wiring 32, so that the amount of measurement light received by the light receiving element 13 increases, so the secondary wiring 32 is exposed. Can be detected.
When the difference in height between the secondary wiring 32 and the IC chip 31 is known in advance, the thickness of the plastic mold 33 remaining on the IC chip 31 can be known. In such a case, subsequent processing conditions can be set by detecting the secondary wiring 32.

FIG. 5 shows a state in which the IC package 30 as the object to be processed is continuously irradiated with a measurement laser made of pulsed light, and the thickness is stored while calculating the measurement positions of the plastic mold 33 in the X and Y directions. It is a top view.
Now, as shown in the figure, set the origin of the XY coordinates as the measurement start position, irradiate the laser for measurement consisting of pulsed light while moving in the X direction, return to the left end when irradiated to the right end, and return to the Y direction Measurement is performed over the entire measurement area by moving and illuminating the next column while moving in the X direction.
At this time, if the number of pulses of the measurement laser and the scanning speed are known, the XY position of the measurement point can be specified from the measurement start position and the laser irradiation start timing. From the measurement point and the amount of reflected light at this measurement point, the residual thickness of the plastic mold 33 at the XY position of the IC 30 is calculated and stored.
Note that the laser beam for measurement is not limited to pulsed light but may be continuous light.

FIG. 6 is a plan view showing a state in which laser processing is performed with reference to thicknesses at measurement positions in the X and Y directions of the plastic mold.
In the laser processing, as shown in the figure, the origin of the XY coordinate is set as the processing start position, the processing laser is irradiated while moving in the X direction, and when it reaches the right end, it returns to the left end and moves in the Y direction. Then, irradiation is performed over the entire processing area by irradiating the next row while moving in the X direction.
At this time, since the residual thickness of the plastic mold 33 at the XY position of the IC package 30 is stored, the processing conditions are set based on this storage. Processing conditions include irradiation / non-irradiation, laser output, laser irradiation frequency, laser scanning speed, number of times of laser scanning, laser irradiation pulse, and the like.
The processing laser light is not limited to pulsed light but may be continuous light.

FIG. 9 is a flowchart showing a processing step for realizing the removal of the plastic mold.
(A) Plastic mold removal conditions are set (step 2).
The setting items include laser output conditions, removal area, return light amount threshold, IC chip return light detection, secondary wiring detection, and the number of additional finishing after detection.
(B) Operate the laser scanning device and the moving stage to place the workpiece at the laser beam irradiation position (step 3).
(C) In order to monitor the residual thickness of the plastic mold, the amount of reflected and scattered light is measured (step 4).
Measurement is performed while specifying the position of the IC in the X and Y directions.
(D) The amount of reflected laser light for measurement at the position of the IC in the X and Y directions is stored (step 5).
(E) It is determined whether the measurement of the residual thickness of the plastic mold is completed in the X and Y direction regions of the IC (step 6).
If not completed, the process returns to step 3.
If the machining system is improved according to the workpiece and the machining know-how is sufficient, it is possible to omit the repeated steps 3 to 6 several times.
(F) It is determined whether the conditions of the items set in the plastic mold removal conditions are satisfied (for example, the determination result of the amount of reflected / scattered light with respect to a separately set threshold value) (step 7).
When it is satisfied, the process proceeds to the laser finishing process, and when it is not satisfied, the process proceeds to the laser primary process.
(G) In order to perform laser finishing, the laser irradiation position is returned to the origin (step 8).
(H) A processing condition is set according to the removal condition of the plastic mold (the laser output condition is changed to the finishing processing condition) (step 9).
For example, when the secondary wiring detection is set as the plastic mold removal condition, the thickness remaining on the IC chip is calculated after the secondary wiring detection, and based on this, processing conditions, that is, irradiation / non-irradiation, Processing conditions such as laser output, laser irradiation frequency, laser scanning speed, number of times of laser scanning, and laser irradiation pulse are set.
(I) Laser processing is performed based on processing conditions (step 10).
(J) It is determined whether the set machining conditions are completed (step 11).
If not completed, the process returns to step 8. If the processing know-how is sufficient, this step can be omitted.
(K) In order to perform the primary laser processing, the laser scanning device and the moving stage are operated to place the workpiece at the irradiation position of the laser beam (step 13).
(L) The processing conditions are set according to the memory of the residual thickness of the plastic mold at the X and Y direction positions of the IC (step 14).
For example, when the secondary wiring detection is set as the plastic mold removal condition, but the secondary wiring is not detected, the processing conditions, that is, irradiation / non-irradiation, laser output, laser irradiation frequency, laser scanning speed are based on this. Then, processing conditions such as the number of times of laser scanning and a laser irradiation pulse are set.
(M) Laser processing is performed based on the processing conditions (step 15).
(N) It is determined whether or not the set machining conditions have been completed (step 16).
If not completed, the process returns to step 13. If completed, return to step 3 in the measurement loop.

  The IC generally includes an IC chip such as a transistor, a diode, a resistor, and a capacitor, a wiring member that electrically connects the IC chip to each other, and a resin mold that covers the IC chip. The workpiece to be processed according to the present invention is not limited to an IC chip, but can be applied to a composite material mixed with a bulk material such as ceramic.

When the thickness of the resin mold is large, the irradiated laser beam for measurement is absorbed by the resin mold, and a relatively small amount of reflected / scattered light is generated. As processing advances and the secondary wiring begins to be exposed, the amount of light received by the light receiving element 13 increases due to the large reflection of the metal wiring. Then, in addition to the reflected / scattered light from the resin mold, the laser transmitted through the resin mold is reflected / scattered on the surface of the IC chip.
Thereby, the measurement light quantity received by the light receiving element increases. When the resin mold disappears, only the reflected / scattered light on the surface of the IC chip having a relatively high reflectance is measured, so the measured light quantity takes the maximum value. The machining state can be grasped by monitoring the change in the measured light quantity by the machining state detection means of the control unit 17.

  Opening the IC package to take out the failed semiconductor chip.

1 Laser processing equipment 2 Personal computer 10 Processing object (work)
DESCRIPTION OF SYMBOLS 11 Laser light source 12 Laser scanning device 13 Light receiving element 14 Image pick-up element 15 Optical system 16 Moving stage 17 Control part 18 Condensing lens 19 Beam splitter 20 Lens 21 Holding part 22 Drive part 23 Beam splitter 30 IC package 31 IC chip 32 Secondary wiring 33 Plastic mold 34 IC package top surface

Claims (4)

A step of preparing an IC package including an IC chip and a secondary wiring and a mold member covering them;
A step of setting mold removal conditions;
Installing the IC chip at a laser beam emission position;
The mold member is aligned in the height position direction, continuously irradiated with a measurement laser composed of pulsed light, and measured in the X and Y directions of the mold member based on the laser irradiation start timing, pulse frequency, and scanning speed. A measurement step of measuring the amount of reflected / scattered light at the measurement position while calculating the position, and storing the measurement value;
Determining whether the measured value satisfies the removal condition of the mold;
When the measured value satisfies the mold removal conditions, a finishing process step of performing laser finishing by irradiating a processing laser consisting of pulsed light under the processing conditions set according to the mold removal conditions;
When the measurement value does not satisfy the mold removal condition, laser processing is performed by irradiating a processing laser composed of pulsed light under the processing condition set according to the stored measurement value in the X and Y position. A primary processing step of returning to the measurement step after completion of the laser primary processing;
A mold removing method comprising:   2. The mold removal method according to claim 1, wherein the setting item of the mold removal condition includes at least one of removal area, return light amount threshold value, IC return light detection, secondary wiring detection, and additional finishing. .   When secondary wiring detection is included as a setting item for the mold removal condition, the Z-direction distance to the IC chip is calculated based on the detection of the secondary wiring, and laser finishing is performed under the processing conditions based thereon. The mold removing method according to claim 1 or 2. In an apparatus for laser processing an IC package composed of an IC chip and a secondary wiring and a mold member covering them,
And one laser beam emitting means for emitting a processing laser beam including a pulse light and the than the processing laser beam and an output of the small pulse light measurement laser beam,
Removal condition setting means for setting mold removal conditions;
Laser scanning means for continuously irradiating a measurement laser made of pulsed light to predetermined positions in the X and Y directions of the IC package;
A mounting means provided so as to be movable in the Z direction and for mounting the IC package;
A light receiving means for measuring a reflected light amount of the measurement laser light composed of the pulsed light reflected by the IC package;
Measuring means for measuring the reflected / scattered light quantity at the measurement position while calculating the measurement position in the X and Y directions of the mold member based on the laser irradiation start timing, the pulse frequency and the scanning speed, and storing the measurement value;
Determining means for determining whether the measured value satisfies the removal condition of the mold;
When the measured value satisfies the mold removal condition , laser finishing is performed with a processing laser beam composed of pulsed light under a processing condition set according to the mold removal condition, and the measured value is When the removal condition is not satisfied, the primary laser processing is performed with the processing laser beam composed of pulsed light under the processing conditions set according to the stored measurement values in the X and Y direction positions, and the mold member is again processed after the primary processing is completed. A mold removing apparatus comprising: control means for controlling to measure the amount of reflected / scattered light at the X and Y direction coordinate positions.

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