JP2011036881A - Laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining method capable of easily identifying a child substrate occurring error, and enhancing the working efficiency. <P>SOLUTION: In the laser beam machining method for machining a hole in a workpiece 5 by applying the pulse-like laser beam 2 to the workpiece 5, the specifications of the laser beam 2 (the permissible range of the energy intensity, the permissible range of the inclination of the optical axis of the laser beam 2, or the like) are determined in advance, and if the applied laser beam 2 is deviated from the specifications, an identification mark 20 indicating that the workpiece 5 is defective is machined on the workpiece 5 by the laser beam 2. Any defective workpiece 5 can be easily identified by the identification mark 20. Further, any worker need not be intervened therebetween, the working efficiency can be enhanced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing method of a laser processing machine that processes holes in a workpiece such as a printed circuit board with pulsed laser light.

  FIG. 6 is a configuration diagram of the laser processing machine.

  The laser oscillator 1 outputs a pulsed laser beam 2. The mirror 3 (3a, 3b) in which the rotation axis is arranged at a twisted position is rotatable around the rotation axis as indicated by an arrow in the figure, and the reflecting surface can be positioned at an arbitrary angle. The condenser lens (fθ lens) 4 is held by a processing head (not shown). The work 5 is fixed to an XY table 6. The scan region 7 of the laser beam 2 is determined by the diameter D of the condenser lens 4 and is usually D / √2 or less (that is, the size of a square inscribed in a circle having the diameter D). In general, since the size of the workpiece 5 is larger than that of the scan region 7, the processing region of the workpiece 5 is divided in advance by the size of the scan region 7, and laser processing is performed for each scan region 7. The mirror 3 a positions the laser beam 2 in the X direction in the scan region 7, and the mirror 3 b positions the laser beam 2 in the Y direction in the scan region 7. Further, the rotation range of the mirrors 3a and 3b is set to a range in which the laser beam 2 can be scanned in the scan region 7.

  Next, the operation of the conventional laser beam machine will be described.

  When machining the hole, the mirrors 3a and 3b are positioned so that the optical axis of the laser beam 2 is coaxial with the axis of the hole to be machined, and then the pulsed laser beam 2 is output from the laser oscillator 1. The pulsed laser beam 2 oscillated from the laser oscillator 1 has its optical path defined by the mirrors 3a and 3b, is collected by the condenser lens 4, and is substantially applied to the printed circuit board 5 regardless of the rotation angle of the mirrors 3a and 3b. Incident perpendicularly, holes in the scan area 7 are processed. When the processing of the hole in the scan area 7 is completed, the XY table 6 is moved to process the hole in the next scan area.

  One characteristic of the laser source is that the actual emission angle changes even if the emission angle of the laser beam 2 is fixed. In the case of processing by shaping the outer shape of the laser beam 2 with the aperture provided in the mask, when the emission angle changes, not only the amount of light that passes through the aperture but also the intensity distribution of the laser beam 2 changes, so that the processing quality deteriorates. Therefore, the emission angle of the laser beam 2 output from the laser oscillator 1 is monitored, and when the emission angle changes, the laser is processed in accordance with the optical axis before the change of the optical axis of the laser beam 2. There exists a processing method (patent document 1). According to this method, since the optical axis of the laser beam 2 emitted from the laser oscillator 1 is always kept coaxial, the energy supplied to the processing portion does not change, and a hole with excellent quality can be processed. . However, in the case of the above method, the processed workpiece often becomes defective when the emission angle changes.

  Further, when a part of the laser beam 2 oscillated from the laser oscillator 1 is branched and the energy intensity of the laser beam 2 is measured, and the energy intensity of the laser beam 2 does not satisfy the specification, the laser beam 2 is processed. There is also a laser processing method in which the portion is further irradiated.

  When a printed circuit board is processed, a large number of printed circuit boards (hereinafter referred to as “child boards”) are often arranged and processed on one large printed circuit board (hereinafter referred to as “mother board”). When processing the mother board with the pulsed laser beam 2, if an error occurs for any reason, the error occurrence date, processing program name, lot number, processing area number (child board number), etc. are recorded, and the mother board is recorded. There are a case where processing of the substrate itself is stopped and a case where processing of the child substrate in which an error has occurred is stopped and the next child substrate is processed.

  When the processing of the child substrate in which the error has occurred is stopped and the next child substrate is processed, it is necessary to make it possible to identify the child substrate in which the error has occurred from other child substrates. Therefore, when there is a child board in which an error has occurred in the mother board, the operator often puts an identification mark that informs that a processing error has occurred at a location (child board) where the error has occurred in the mother board.

JP-A-2005-118815

  Since the diameter of the hole processed with the laser beam 2 is almost 50 μm or less, it is difficult to visually recognize the processed hole. For this reason, the worker has to put an identification mark based on the coordinates of the error occurrence location recorded as data, and the work takes time. Further, when the number of sub-boards is large, there is a case where the position for attaching the identification mark is wrong.

  An object of the present invention is to provide a laser processing method capable of solving the above-described problems and easily identifying a child board in which an error has occurred and improving the work efficiency.

  In order to achieve the above object, the present invention provides a laser processing method for processing a hole in a workpiece by irradiating the workpiece with a pulsed laser beam, wherein the specifications of the laser beam are determined in advance, and the irradiated laser beam Is out of the specification, an identification mark indicating that the workpiece is defective is processed on the workpiece by the laser beam.

  A child board in which an error has occurred can be easily identified. In addition, work efficiency can be improved.

It is a flowchart which shows the whole processing procedure of this invention. It is a flowchart which shows the process sequence of an identification mark. It is a top view of a mother board. It is a figure which shows the relationship between a scanning area | region and a child substrate. It is an example of an identification mark. It is a block diagram of a laser processing machine.

  FIG. 1 is a flowchart showing the entire processing procedure of the present invention, and FIG. 2 is a flowchart showing the processing procedure of an identification mark. 3 is a plan view of the mother substrate, FIG. 4 is a diagram showing the relationship between the scan region and the child substrate, FIG. 5 is an example of an identification mark, (a) is the whole of x, (b ) Is an enlarged view of a portion C in FIG.

  First, the mother board, the child board, and the scan area will be described.

  As shown in FIG. 3, the mother board 10 has E sub-boards 11 each having an a length in the X direction and a length b in the Y direction arranged in the X direction and F in the Y direction. . In some cases, a cutting allowance (1-2 mm) for cutting in a subsequent process may be provided between adjacent child substrates 11 separately. Here, the coordinates of the four corners of each child substrate 11 are determined by an XY coordinate system with the lower left corner of the mother substrate 10 as the origin. That is, the coordinates KA, KB, KC, and KD of the four corners of the sub board 11ij in the i-th in the X direction and the j-th in the Y direction are KA ((i-1) a, jb), KB ((i- 1) a, (j-1) b), KC (ia, (j-1) b), KD (ia, jb).

  Since the size of the scan area is constant, the size of the sub-board 11 varies, and therefore, as shown in FIG. 4A, several sub-boards 11 (four in the illustrated case) scan. If it is included in the region 7, as shown in FIG. 4B, some of the sub-boards 11 and some of the sub-boards 11 (in the case of illustration, two are 100%, the other two May be included in the scan area.

  Next, the identification mark will be described.

  The shape of the identification mark 20 is not particularly limited, but here, it is assumed that a general figure X is processed (hereinafter referred to as “× processing”), and is defined as follows.

(1) The identification mark 20 is composed of two lines of length L, and the sine of L is Lx and the cosine of L is Ly.

(2) Lx is 25 mm when the side length a of the sub-board 11 is 25 mm or more, and Lx = 0.8a when a is less than 25 mm. In addition, when the side length b of the sub board 11 is 25 mm or more, Ly is 25 mm, and when b is less than 25 mm, Ly = 0.8b.

(3) The intersection of the two lines constituting x is aligned with the center of the daughter board 11 where the processing defect has occurred.

(4) The lines constituting x are formed by arranging pulsed laser beams at irradiation intervals k.

  When determined as described above, x is processed at the center of the defective child substrate 11. In addition, here, the number of repetitions R and the pitch P are determined. As shown in FIG. 5B, the number of repetitions R is the number of times x is processed. When R = 1, the center of the sub-board 11 is X (hereinafter referred to as “reference ×”), R. In the case of = 2, in addition to the reference x, the reference x is translated by the pitch P to the left in the X direction and indicated by a dotted line in the figure. In the case of R = 3, in addition to the case of R = 2, only the pitch P This is a case where each x shown by a one-dot chain line translated in the right direction is processed. That is, the repetition number R corresponds to the line width indicated by x.

  Next, the entire procedure of the present invention will be described with reference to FIG.

  Prior to processing, the length LX in the X direction and the length LY in the Y direction of the mother substrate 10, the length a in the X direction and the length b in the Y direction, the repetition number R, and the irradiation interval k And the pitch P and the necessity of processing the identification mark 20 are input.

  When a start button (not shown) is turned on, machining data is read (procedure S10), the entire machining area is divided into scan areas (procedure S20), the read data is divided into scan areas, and each scan is scanned. Numbers 1 to N (where N is the total number of divided scan areas) are assigned to the areas (step S30).

  Next, after setting the number of the scan area n to n = 1 (procedure S40), the data of the scan area n is read (procedure S50), and the axis of the condenser lens 4 is positioned at the center of the scan area n (procedure S60). . When the axis of the condensing lens 4 is positioned at the center of the scan area n, the laser beam is irradiated in accordance with a predetermined order (step S70). Then, it is confirmed whether or not the irradiated laser beam 2 satisfies a predetermined specification (procedure S80). If it is OK, the process of step S90 is performed, and otherwise, the process of step S190 is performed. The specifications of the laser beam 2 include an allowable range of energy intensity and an allowable range of inclination of the optical axis of the laser beam 2.

  In step S90, it is confirmed whether or not there is a next machining point. If there is a next machining point, the process of step S70 is performed, and otherwise, the process of step S100 is performed. In step S100, the number of the scan area n is set to n = n + 1, and n and N are compared. If n ≦ N, the process of step S50 is performed, and in all other cases, the processing is completed. The process is terminated.

  As shown in FIG. 2, in step S190, after recording error information such as a processing error occurrence date and time, a processing program name, a lot number, a processing area number (child board number), it is confirmed whether or not × processing is necessary. (Procedure S200). If x machining is required, the process of step S210 is performed. In other cases, the process of step S320 is performed. When the number of sub-boards 11 accommodated in the mother board 10 is less than or equal to several, it is relatively easy to specify the location where the processing defect has occurred, and therefore, × processing may not be performed.

  In step S210, it is confirmed whether or not the length a in the X direction of the daughter board 11 is 25 or more. If the length a is 25 or more, Lx = 25 is set (step S220), and the length a is less than 25. In the case of Lx = 0.8a (procedure S230), the process of procedure S240 is performed. In step S240, it is confirmed whether or not the length b in the Y direction of the daughter board 11 is 25 or more. If the length b is 25 or more, Ly = 25 is set (step S250), and the length b is less than 25. In this case, Ly = 0.8b (procedure S260), and the process of procedure S270 is performed.

  In step S270, it is confirmed whether or not the entire region of the sub-substrate 11 where the processing defect has occurred is within the current scan region n. If all the regions of the sub-substrate 11 are within the current scan region n, x is processed. Later (procedure S280), the process of procedure S320 is performed. In addition, when the entire area of the sub-board 11 is not within the current scan area (that is, a part of the sub-board 11 is outside the current scan area n), the entire area of the sub-board 11 where the processing defect has occurred is After moving the table so as to fall within the scan area (procedure S290), X is processed (procedure S300), and then the table is moved to the original position (procedure S310), and then the process of step S320 is performed. . In step S320, the remaining processed data of the sub-board 11 processed with x is deleted, and then the process of step S90 is performed.

  In this embodiment, the cosine Lx and the sine Ly having the side length of x are set to 25 mm which is easy to visually recognize, so that it does not take more work time than necessary.

  In addition, in order to make the identification mark 20 easy to visually recognize, it is desirable that the length of the x side is 10 mm or more. If the identification mark 20 cannot be increased, for example, the repetition number R may be set to a large value.

  In addition, although x was processed as the identification mark 20, you may make it other figures, such as a circle and a square.

2 Laser light 5 Workpiece 20 Identification mark (×)

Claims (2)

  In a laser processing method of irradiating a workpiece with a pulsed laser beam to form a hole in the workpiece, the specification of the laser beam is determined in advance, and if the irradiated laser beam deviates from the specification, the workpiece In addition, a laser processing method characterized in that an identification mark indicating that the workpiece is defective is processed by the laser beam.   The laser processing method according to claim 1, wherein the size of the identification mark is set to a size that allows easy visual recognition.

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