JP2016135491A - Discharge auxiliary type laser hole machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge auxiliary type laser hole machining method which hardly causes necking and/or cracking on a through-hole.SOLUTION: A discharge auxiliary type laser hole machining method is characterized in that a tip of a first electrode is arranged on a position which is separated by a distance of 0.1 mm or more from a surface of an insulation substrate and is deviated by 0.2 mm or more in a first direction from a center of an irradiation spot of a laser beam on the insulation substrate, when a through-hole already formed on the insulation substrate is called as an existing through-hole, a position on which the existing through-hole is formed is called as an existing through-hole formation position and a position for forming the through-hole subsequently onto the insulation substrate is called as an object through-hole formation position, a position which is separated by a distance of 0.5 mm or less along a second direction crossing orthogonally with the first direction, from the existing through-hole is set as the object through-hole formation position and, when inter-electrode discharge is performed after applying the laser beam to the object through-hole formation position, the tip of the first electrode is located on a position closer to the object through-hole formation position than the position of the existing through-hole.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a discharge assist type laser hole machining method.

  As a technique for forming a through hole in an insulating substrate, a laser melting type discharge removal technique has been proposed (for example, Patent Document 1). In this laser melting type discharge removal technique, an insulating material is melted by laser light irradiation, and then the insulating material melted by an interelectrode discharge phenomenon is removed to form a through hole in an insulating substrate.

International Publication No. WO2011 / 038788

  As described above, in the laser melting type discharge removal technique, after the insulating material is melted by laser light irradiation, the insulating material melted by the interelectrode discharge phenomenon is removed to form a through hole in the insulating substrate.

  Here, in the conventional laser melting type discharge removal method, there is often a problem that no discharge occurs at an appropriate place in the discharge after the laser light irradiation. For example, when a laser beam is irradiated to the through hole formation target position and an electric discharge is generated at the through hole formation target position by the inter-electrode discharge, the discharge is not generated at the through hole formation target position and is already formed. Discharge may occur through the formed through hole (existing through hole).

  When such a phenomenon occurs, a discharge does not occur at the through hole formation target position, which causes a problem that the through hole is not formed at the through hole formation target position. In addition, when a discharge occurs in the existing through hole, excessive energy is input to the existing through hole, which may cause a problem that a crack occurs in the existing through hole.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a discharge assist type laser hole processing method in which cracks are unlikely to occur in a through hole.

According to the present invention, there is provided a discharge assisted laser hole machining method in which a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the hole shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes. There,
The tip of the first electrode is at a distance of 0.1 mm or more from the surface of the insulating substrate, and is shifted by 0.2 mm or more in the first direction from the center of the laser beam irradiation spot on the insulating substrate. Placed in
A through-hole already formed on the insulating substrate is referred to as an existing through-hole, a position where the existing through-hole is formed is referred to as an existing through-hole forming position, and a position where the next through-hole is formed on the insulating substrate is defined as When called the target through-hole formation position,
From a certain existing through-hole, along the second direction orthogonal to the first direction, a position at a distance of 0.5 mm or less is set as a target through-hole forming position, and the target through-hole forming position is irradiated with laser light. Thereafter, when the interelectrode discharge is performed, the discharge-assisted laser hole machining method is characterized in that the tip of the first electrode is located closer to the target through-hole formation position than the position of the existing through-hole. Provided.

Further, in the present invention, a discharge-assisted laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes. Because
The tip of the first electrode is a distance of 0.1 mm or more from the surface of the insulating substrate, and the + (plus) direction along the first direction from the center of the laser beam irradiation spot on the insulating substrate Arranged at a position shifted by 0.2 mm or more,
The insulating substrate has a pattern of n-th column × m-th row matrix through-hole formation positions,
Each column is parallel to the first direction, and each row is parallel to a second direction orthogonal to the first direction;
Each of the columns extends from the first column to the nth column along the + (plus) direction of the second direction, and each of the rows extends from the first row to the mth row in the first direction. Extends along the + (plus) direction of
The through hole forming positions in each row are arranged with a pitch Py of 0.5 mm or less,
After the through holes are formed at the positions where all the through holes are formed in the first row, the through holes are formed at the positions where all the through holes are formed in the second row. Similarly, the through holes are sequentially formed until the m th row. There is provided a discharge assisted laser drilling method characterized by comprising the steps of:

  Here, in the discharge assisted laser hole machining method according to the present invention, the through hole formation positions in each row may be arranged at a pitch Px of 0.5 mm or less.

Further, in the present invention, a discharge assist type laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes. Because
The tip of the first electrode is a distance of 0.1 mm or more from the surface of the insulating substrate, and the + (plus) direction along the first direction from the center of the laser beam irradiation spot on the insulating substrate Arranged at a position shifted by 0.2 mm or more,
The insulating substrate has a pattern of through-hole formation positions, and the pattern has a defect portion in which a part of the through-hole formation positions is missing in a matrix of through-hole formation positions in the nth column × mth row. ,
Each column is parallel to the first direction, and each row is parallel to a second direction orthogonal to the first direction;
Each of the columns extends from the first column to the nth column along the + (plus) direction of the second direction, and each of the rows extends from the first row to the mth row in the first direction. Extends along the + (plus) direction of
The through hole formation position in each row is arranged with a pitch Py of 0.5 mm or less, excluding the defective portion,
After the through holes are formed at the positions where all the through holes are formed in the first row, the through holes are formed at the positions where all the through holes are formed in the second row. Similarly, the through holes are sequentially formed until the m th row. There is provided a discharge assisted laser drilling method characterized by comprising the steps of:

  Here, in the discharge assisted laser hole machining method according to the present invention, the defect portion may be disposed at a central portion of the matrix of the through hole formation position of the nth column × mth row.

  In the discharge assisted laser hole machining method according to the present invention, the defect may exist in the first row or the m-th row of the matrix of through-hole formation positions of the nth column × mth row. .

  Further, in the discharge assisted laser hole machining method according to the present invention, the defect portion is the i-th column (where i is from 2 to n−1) in the matrix of the through-hole formation position of the n-th column × m-th row. ) And the j-th row (where j is an integer from 2 to m-1).

  In the discharge assisted laser hole machining method according to the present invention, the through hole formation positions in each row may be arranged at a pitch Px of 0.5 mm or less except for the defective portion.

  In the laser induced electrical discharge machining method according to the present invention, the tip of the first electrode may be disposed at a distance of 0.3 mm to 1.0 mm from the surface of the insulating substrate.

  Further, in the discharge assisted laser hole machining method according to the present invention, the tip of the first electrode is 0.5 mm to 1.5 mm along the first direction from the center of the laser beam irradiation spot. It may be arranged at a distance.

  In the discharge-assisted laser hole machining method according to the present invention, the laser beam irradiation spot may have a maximum dimension in a range of 10 μm to 300 μm.

  In the discharge-assisted laser hole machining method according to the present invention, the second electrode may be substantially plate-shaped and disposed on the bottom surface of the insulating substrate.

  In the present invention, it is possible to provide a discharge assist type laser hole machining method in which cracks are unlikely to occur in the through hole.

It is the figure which showed roughly an example of the structure of the general laser melting type electric discharge removal apparatus. It is the figure which showed roughly the relationship between the three axes of the three-dimensional coordinate used by this application, and the coordinate of the front-end | tip of a 1st electrode. It is the figure which showed typically the arrangement pattern of a through-hole at the time of forming a through-hole in an insulated substrate with the 1st discharge assistance type | formula laser hole processing method. It is the figure which showed typically the arrangement pattern of a through-hole at the time of forming a through-hole in an insulated substrate with the 2nd discharge auxiliary type laser hole processing method. It is the figure which showed typically another example of the arrangement pattern of a through-hole. It is the figure which showed typically another example of the arrangement pattern of a through-hole. In Example 1, it is the figure which showed typically the order at the time of forming a through-hole in a glass substrate. 3 is a diagram illustrating an example of a cross section of one through hole after processing in Example 1. FIG. In the comparative example 1, it is the figure which showed typically the order at the time of forming a through-hole in a glass substrate. 6 is a view showing an example of a cross section of one through hole after processing in Comparative Example 1. FIG. In Example 2, it is the figure which showed typically the order at the time of forming a through-hole in a glass substrate.

  Hereinafter, the present invention will be described with reference to the drawings.

(Discharge assisted laser drilling technology)
First, the difference between the conventional “laser melting type discharge removal technique (method)” and the “discharge assist type laser hole machining technique (method)” applied to the present invention will be briefly described.

  In the conventional “laser melting type discharge removal technology”, a through hole is formed in an insulating substrate by melting an insulating material by laser light irradiation and then removing the molten insulating material by an interelectrode discharge phenomenon. In the “laser melting type discharge removal technology”, necking is likely to occur in the processed through hole. “Necking” means a protruding portion formed in a through-hole after processing. When such necking occurs in the through hole, the dimensional accuracy of the through hole is lowered. For this reason, it is said that it is desirable to suppress necking as much as possible.

  In contrast, in the “discharge assist type laser hole processing technology” applied to the present invention, after a plurality of through holes are formed in the insulating substrate by laser light irradiation, a discharge phenomenon between the first and second electrodes is performed. Thus, the shape of the through hole is adjusted. The adjustment of the shape of the through hole means that necking that occurs when a plurality of through holes are formed in the insulating substrate by laser light irradiation is reduced. The “discharge assist type laser hole processing technique” has a feature that necking that can occur after processing of the through hole can be significantly suppressed as compared with the “laser melt type discharge removal technique”.

  Hereinafter, with reference to FIG. 1, the “discharge assist type laser drilling technology” used in the present invention will be described in detail.

  FIG. 1 schematically shows an example of the configuration of a general discharge-assisted laser drilling apparatus used in the discharge-assisted laser drilling technique.

  As shown in FIG. 1, the discharge-assisted laser hole machining apparatus 100 includes a laser light source 110, a direct current high voltage power supply 125, a first electrode 140, and a second electrode 145.

  The first electrode 140 and the second electrode 145 are electrically connected to the conductors 150 and 155, respectively, and these conductors 150 and 155 are connected to the DC high voltage power source 125.

  In the example of FIG. 1, the first electrode 140 and the second electrode 145 are different in shape and arrangement form. In other words, the first electrode 140 has a needle shape and is arranged away from the insulating substrate 190. On the other hand, the second electrode 145 has a substantially flat plate shape and is disposed immediately below the insulating substrate 190 so as to be in contact with the insulating substrate 190. The second electrode 145 can also serve as a stage on which the insulating substrate 190 is placed.

  However, this is merely an example. For example, the second electrode 145 may be disposed on the bottom surface side of the insulating substrate 190 and separated from the insulating substrate 190. The second electrode 145 may have a needle shape similar to that of the first electrode 140. In this case, a set of electrode pairs is configured between the first electrode 140 and the second electrode located opposite to each other with the insulating substrate 190 interposed therebetween.

  When the through hole is formed in the insulating substrate 190 using the discharge assist type laser hole processing apparatus 100, the insulating substrate 190 is first disposed between the electrodes 140 and 145. Further, the insulating substrate 190 is disposed at a predetermined position by moving the second electrode 145 (or a separate stage) in the horizontal direction.

  Next, laser light 113 is irradiated from the laser light source 110 toward the insulating substrate 190. Thereby, the temperature of the irradiation position 183 of the laser beam 113 on the insulating substrate 190 is locally increased, the insulating material is sublimated, and a through hole 185 is formed here.

  After irradiation with the laser beam 113, a DC high voltage is applied between the electrodes 140 and 145 using the DC high voltage power supply 125. Thereby, discharge occurs between the electrodes 140 and 145. Discharge tends to occur through the through hole 185. This is because at this position, the resistance is lower than the other parts.

  Due to the occurrence of discharge, necking that can be formed in the through hole 185 is reduced, and the dimensional accuracy of the through hole 185 is improved.

  Next, the second electrode 145 (or a separate stage) is moved in the horizontal direction, and the insulating substrate 190 is disposed at a predetermined position. Thereafter, the second through hole is formed by the same process.

  By repeating such steps, a plurality of through holes can be formed in the insulating substrate 190.

  Although not shown in FIG. 1, the discharge assist type laser hole machining apparatus 100 may further include a high frequency high voltage power source. The purpose of installing the high-frequency and high-voltage power supply is to prevent the temperature of the through-hole 185 portion of the insulating substrate 190 and the vicinity thereof from decreasing before the discharge is started. That is, by applying a high-frequency high voltage to the insulating substrate 190 using a high-frequency high-voltage power supply, the high-temperature state of the through-hole 185 portion of the insulating substrate 190 heated by the irradiation of the laser beam 113 is reliably ensured until the start of discharge. Can be maintained. However, the installation of the high-frequency and high-voltage power supply is optional.

  Here, in a general discharge assist type laser hole machining method, there is often a problem that discharge does not occur at an appropriate place during discharge after laser light irradiation (hereinafter also referred to as “erroneous discharge”). . For example, when an attempt is made to generate a discharge at the irradiation position 183 by the inter-electrode discharge after the irradiation with the laser beam 113, no discharge is generated at the irradiation position 183, and the already formed through hole (existing through hole) In some cases, discharge may occur.

  When such an erroneous discharge phenomenon occurs, discharge does not occur at the irradiation position 183, so that there is a problem that necking occurs at the irradiation position 183. In addition, when a discharge occurs in the existing through hole, excessive energy is input to the existing through hole, which may cause a problem that a crack occurs in the existing through hole.

In order to cope with such a problem, the inventors of the present application have conducted intensive studies on the cause of erroneous discharge and countermeasures. As a result, the inventors of the present application
(1) In the normal discharge assist type laser hole processing apparatus 100, the tip of the first electrode 140 is fixed so as to have a certain relationship with the irradiation spot position of the laser beam, and once set, It is difficult to change until all the through-holes are formed, and (2) erroneous discharge is greater than the distance from the tip of the first electrode 140 to the irradiation position of the laser beam 113 (that is, the through-hole formation target position). It has been found that this can frequently occur when the distance from the tip of one electrode 140 to the existing through-hole formation position is shorter, and the present invention has been achieved.

That is, in the present invention, a discharge assist type laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes. Because
The tip of the first electrode is at a distance of 0.1 mm or more from the surface of the insulating substrate, and is shifted by 0.2 mm or more in the first direction from the center of the laser beam irradiation spot on the insulating substrate. Placed in
A through-hole already formed on the insulating substrate is referred to as an existing through-hole, a position where the existing through-hole is formed is referred to as an existing through-hole forming position, and a position where the next through-hole is formed on the insulating substrate is defined as When called the target through-hole formation position,
From a certain existing through-hole, along the second direction orthogonal to the first direction, a position at a distance of 0.5 mm or less is set as a target through-hole forming position, and the target through-hole forming position is irradiated with laser light. Thereafter, when the interelectrode discharge is performed, the discharge-assisted laser hole machining method is characterized in that the tip of the first electrode is located closer to the target through-hole formation position than the position of the existing through-hole. Provided.

  In such a discharge assist type laser hole machining method, since the through hole is formed at the target through hole formation position, the first high voltage is applied after irradiating the target through hole formation position with the laser beam. The tip of the electrode 140 is inevitably disposed at a position closer to the target through-hole formation position than the existing through-hole formation position. For this reason, discharge is generated at the existing through-hole forming position, that is, erroneous discharge is significantly suppressed, and discharge can be appropriately generated at the target through-hole forming position.

  Therefore, in the discharge assist type laser hole machining method according to the present invention, it is possible to significantly suppress problems such as necking in the through hole and cracking in the existing through hole, which may occur as a result of erroneous discharge. Become.

  Here, with reference to FIG. 2, how to determine the three-dimensional coordinates of the tip of the first electrode 140 used in the present application will be described.

  FIG. 2 shows the relationship between the three axes of the three-dimensional coordinates used in the present application, that is, the X axis, the Y axis, and the Z axis, and the coordinates of the tip of the first electrode 140.

  As shown in FIG. 2, first, the center C of the irradiation spot 115 of the laser beam 113 on the insulating substrate 190 is set as the origin of the three-dimensional coordinates. Therefore, C (0,0,0).

  Further, the coordinates of the tip of the first electrode 140 are defined as coordinates A (x, y, z). Here, the Z-axis is a direction of a perpendicular line hanging from the tip of the first electrode 140 with respect to the insulating substrate 190.

  Next, a straight line connecting the point P on the insulating substrate 190 of the straight line L1 hanging from the front end of the first electrode 140 along the Z direction and the center C of the irradiation spot 115 is defined as the Y axis.

  Next, an axis orthogonal to the Y axis on the plane of the insulating substrate 190 is defined as the X axis. According to this definition, since the tip of the first electrode 140 is on the Y axis, the x value of the coordinate A is 0 (zero).

  In this way, the coordinate A of the tip of the first electrode 140 on the three-dimensional coordinate is determined. Incidentally, the coordinates of the tip of the first electrode 140 are represented by A (0, y, z).

  The z value of the coordinate A is 0.1 mm or more. When the z value of the coordinate A is less than 0.1 mm, there is a high possibility that the tip of the first electrode 140 is in contact with the insulating substrate 190 due to vibration during movement of the insulating substrate 190 or vibration during processing. . The z value of the coordinate A is preferably in the range of 0.3 mm to 1.0 mm.

  On the other hand, the y value of coordinate A is 0.2 mm or more. The y value of the coordinate A is preferably in the range of 0.5 mm to 1.5 mm. When the y value of the coordinate A is less than 0.2 mm, it interferes with the optical path of the laser, the laser output decreases, and the processing powder generated during processing adheres to the first electrode. The possibility of interference with the optical path increases. The y value of the coordinate A is preferably in the range of 0.5 mm to 1.5 mm.

  Note that the irradiation spot 115 of the laser beam 113 on the insulating substrate 190 has a maximum dimension in the range of 10 μm to 300 μm, for example. Here, when the irradiation spot 115 is substantially circular or substantially elliptical, “maximum dimension” means the diameter of the circle or the major axis of the ellipse, and when the irradiation spot 115 is substantially polygonal, “maximum dimension”. "Means the maximum diagonal length.

(About the discharge assist type laser drilling method according to one embodiment of the present invention)
Next, with reference to FIG. 3, a discharge assist type laser hole machining method (first discharge assist type laser hole machining method) according to an embodiment of the present invention will be described.

  In the first discharge assist type laser hole machining method, it is assumed that a through hole pattern 360 as shown in FIG. 3 is formed on the insulating substrate 390. In FIG. 3, the positions marked with ○, that is, the coordinates (1, 1) to the coordinates (4, 4) indicate the positions (through-hole forming positions) 385 where the through-holes are formed.

  In this through-hole pattern 360, the through-hole formation positions 385 (385-1 to 385-16) are arranged in a regular array on the XY plane. That is, the through-hole formation positions (385-1 to 385-16) are arranged in a matrix of 4 columns × 4 rows of columns X1 to X4 and rows Y1 to Y4.

  In FIG. 3, a matrix of 4 columns × 4 rows is shown as an example of the through hole pattern 360, but it should be noted that the number of columns and rows constituting the matrix is not particularly limited.

  At each through hole formation position (385-1 to 385-16), the arrangement pitch of the through holes in the X-axis direction is Px, and the arrangement pitch of the through holes in the Y-axis direction is Py. The pitch Px and the pitch Py may be equal or different. The pitch Py is 0.5 mm or less. The pitch Py may be in the range of 20 μm to 400 μm, for example. On the other hand, the pitch Px is not particularly limited, but is, for example, in the range of 20 μm to 400 μm. In the example of FIG. 3, it is assumed that the pitch Px = Py = 200 μm.

  When a through hole is formed at each through hole forming position 385 of the insulating substrate 390 with such a through hole pattern 360, the first through hole is a lower left through hole represented by coordinates (1, 1) in FIG. It is formed at the formation position 385-1.

  Here, as defined above, the coordinate A of the tip of the first electrode when the through hole is formed at the first through hole forming position 385-1 is A (1, y, z). . Moreover, the value of y is 0.2 mm or more, and the value of z is 0.1 mm or more.

  Here, as an example, it is assumed that the y value of the tip of the first electrode is 500 μm. In this case, a position 341 indicated by a cross in FIG. 3 is the position of the tip of the first electrode on the XY plane. Hereinafter, this position 341 is also referred to as “first electrode tip 341”.

  After the first through hole is formed at the through hole formation position 385-1 represented by the coordinates (1, 1), the first row (row Y1) penetrates along the + (plus) direction of the X axis. Through holes are sequentially formed at the hole forming positions 385-2, 385-3, and 385-4.

  Next, a through hole is formed at a through hole forming position 385-8 represented by coordinates (4, 2), and then the second row (row Y2) along the − (minus) direction of the X axis. Through holes are sequentially formed at the through hole forming positions 385-7, 385-6, and 385-5.

  Or after forming a through-hole in the through-hole formation position 385-5 represented by coordinates (1,2), the 2nd line (row Y2) penetration along the + (plus) direction of the X-axis Through holes may be sequentially formed at the hole forming positions 385-6, 385-7, and 385-8. However, in this order, it is necessary to move the insulating substrate 390 greatly in the X-axis direction after forming all the through holes in the first row (row Y1), so that the processing time increases.

  After the through hole is formed at the through hole formation position in the second row (row Y2), each through hole formation position 385 in the third row (row Y3) along the + (plus) direction of the X axis. Through holes are sequentially formed in 9, 385-10, 385-11, and 385-12. The direction in which a through hole is formed at each through hole formation position in the third row (row Y3) may be either + (plus) or-(minus). However, normally, in order to shorten the processing time, each through hole in the third row (row Y3) is formed along the + (plus) direction of the X axis.

  Similarly, through holes are sequentially formed at the through hole forming positions 385-16, 385-15, 385-14, and 385-13 in the fourth row (row Y4).

  Here, when each through hole is formed in this order, the formation position of the already formed through hole (the existing through hole formation position) moves so as to always move away from the tip 341 of the first electrode.

  For example, if all the through holes in the first row (row Y1) are formed and then the through holes are formed in the through hole formation positions 385-5 to 485-8 in the second row (row Y2), the insulating substrate 390 moves along the − (minus) direction of the Y-axis. On the other hand, the tip 341 of the first electrode is on the + (plus) side along the Y axis from the through hole formation positions 385-5 to 485-8 in the second row (row Y2). For this reason, when forming a through-hole in the through-hole formation position 385-5 to 485-8 of the 2nd row (row Y2), each through-hole of the 1st row (row Y1) It moves away from the tip 341 of the electrode.

  As a result, the tip 341 of the first electrode is always closer to the through-hole forming position 385 to be processed than the existing through-hole forming position.

  Therefore, in the first discharge assist type laser hole machining method, discharge occurs at the existing through hole formation position, that is, erroneous discharge is significantly suppressed, and it is possible to appropriately generate discharge at the target through hole formation position. Become. This also significantly suppresses the problem of necking in the through hole and cracking in the existing through hole, which may occur as a result of erroneous discharge, in the first discharge assist type laser hole machining method. Is possible.

  It should be noted that the above order is merely an example. For example, in the above example, the through-hole forming position 385-1 at the position of the coordinates (1, 1) is selected as the first through-hole forming position. However, the through hole forming position 385-4 at the position of coordinates (4, 1) may be selected as the first through hole forming position. In this case, after the first through-hole is formed at the through-hole forming position 385-4 represented by the coordinates (4, 1), the first row (row Y1) along the − (minus) direction of the X axis. ) Through-hole forming positions 385-3, 385-2, and 385-1 are sequentially formed. Thereafter, as described above, through holes are sequentially formed at the through hole forming positions in the second row (row Y2), the third row (row Y3), and the fourth row (row Y4). .

  That is, what is important in the first discharge-assisted laser hole machining method is that when the interelectrode discharge is performed after irradiating a laser beam to a target through-hole formation position, the tip 341 of the first electrode is The through holes are sequentially formed so as to be arranged at a position closer to the target through hole formation position than the position of the existing through holes, and as long as this is satisfied, the order of forming the through holes is particularly limited. I can't.

(About the discharge assist type laser drilling method according to another embodiment of the present invention)
Next, with reference to FIG. 4, a discharge assist type laser hole machining method (second discharge assist type laser hole machining method) according to another embodiment of the present invention will be described.

  In the second discharge assist type laser hole machining method, it is assumed that a through hole pattern 460 as shown in FIG. 4 is formed on the insulating substrate 490. In FIG. 4, the position indicated by a circle indicates a position (through hole forming position) 485 where the through hole is formed.

  Also in the through hole pattern 460, the through hole forming positions 485 (485-1 to 485-32) are substantially arranged regularly on the XY plane, like the through hole pattern 360 shown in FIG. Be placed. That is, the through-hole formation positions (485-1 to 485-32) are substantially arranged in a matrix of 6 columns × 6 rows of columns X1 to X6 and rows Y1 to Y6.

  However, in this through-hole pattern 460, there is a portion that does not correspond to the through-hole formation position (a position indicated by Δ) in each intersection of the matrix of the through-hole formation position 485 of the nth column × mth row. Hereinafter, this portion is referred to as a through hole defect position 489.

  For example, in the example of FIG. 4, the coordinates (3, 3), the coordinates (4, 3), the coordinates (3,4), and the coordinates (4, 4) are the through-hole defect positions 489-1, 489-, respectively. 2, 489-3, and 489-4.

  In each through-hole formation position 485-1 to 485-32, except for the through-hole defect position 489 (489-1 to 489-4), the arrangement pitch of the through-holes in the X-axis direction is Px, and in the Y-axis direction The arrangement pitch of the through holes is Py. The pitch Px and the pitch Py may be equal or different. The pitch Py is 0.5 mm or less. The pitch Py may be in the range of 20 μm to 400 μm, for example. On the other hand, the pitch Px is not particularly limited, but is, for example, in the range of 20 μm to 400 μm. In the example of FIG. 4, it is assumed that the pitch Px = Py = 200 μm.

  In the case of forming a through hole at each through hole forming position 485 of the insulating substrate 490 with such a through hole pattern 460, each through hole is formed in the same order as in the first discharge assist type laser hole processing method. A through hole is formed at position 485.

  That is, first, through holes are formed at the through hole forming positions 485-1 to 485-6 in the Y1th row. The order in this case is not particularly limited, but normally, the lower left through hole formation position 485-1 represented by coordinates (1, 1) or the lower right penetration represented by coordinates (6, 1). After the through hole is formed at the hole forming position 485-6, the through hole is formed at the adjacent through hole defect position. Thereby, the time required for the movement of the insulating substrate 490 can be minimized.

  Note that the coordinate A of the tip of the first electrode when the through hole is first formed at the through hole forming position 485-1 is A (1, y, z). Moreover, the value of y is 0.2 mm or more, and the value of z is 0.1 mm or more.

  Here, as an example, it is assumed that the y value of the tip of the first electrode is 500 μm. In this case, a position 441 indicated by a cross in FIG. 4 is the position of the tip of the first electrode on the XY plane. Hereinafter, this position 441 is referred to as “first electrode tip 441”.

  After the through hole is formed at the through hole formation position of the first row (row Y1), the through hole is formed at each of the through hole formation positions 485-7 to 485-12 of the second row (row Y2). . The order in this case is not particularly limited. However, when the through holes are sequentially formed in the direction opposite to the formation direction of the through holes in the first row (row Y1), the through holes can be formed most efficiently.

  Thereafter, similarly, through holes are sequentially formed by repeating the same operation from the third row (row Y3) to the sixth row (row Y6).

  Here, when each through hole is formed in such an order, the formation position of the already formed through hole (the existing through hole formation position) moves so as to always move away from the tip 441 of the first electrode.

  Therefore, also in this second discharge assisted laser hole machining method, the above-described effects can be obtained, that is, erroneous discharge is significantly suppressed, and discharge can be appropriately generated at the target through hole forming position. It will be clear that this is possible.

  Here, the through-hole patterns used in the first and second discharge-assisted laser hole machining methods are not limited to the modes shown in FIGS. 3 and 4.

  For example, in the through-hole pattern 460 shown in FIG. 4, the through-hole defect position 489 does not necessarily have to be arranged at the central portion of the matrix of the through-hole formation position 485.

  For example, the through-hole defect position may exist in the first or last row, such as the first row (row Y1) or the sixth row (row Y6). Alternatively, the through-hole defect position may be present in the first or last row such as the first column (column X1) or the sixth column (column X6).

  In addition, various modes are conceivable as the arrangement of the through-hole defect positions.

  FIG. 5 schematically shows another example of the through-hole pattern having such a through-hole defect position.

  As shown in FIG. 5, in this example, the through-hole pattern 560 includes (1, 4) to (1, 7) in the first row in the matrix of through-hole formation positions in the 10th column × 10th row. , (2,4) to (2,7) in the second row, (3,4) to (3,7) in the third row, (4,4) to (4,7) in the fourth row ), (5,4) to (5,7) in the fifth row, (6,4) to (6,7) in the sixth row, and (7,4) to (7 in the seventh row. , 7) has a through-hole deficient position at each coordinate position.

  FIG. 6 schematically shows another example of a through hole pattern having a through hole defect position.

As shown in FIG. 6, in this example, the through-hole pattern 660 has the third column (3, 3), (4, 3) in the matrix of the ninth column × 9th row of through-hole formation positions. , (6,3), and (7,3),
(3,4), (4,4), (6,4) and (7,4) in the fourth row, (3,6), (4,6), (6, 6) and (7, 6), and (3, 7), (4, 7), (6, 7), and (7, 7) in the seventh row, the through hole defect position Have

  Thus, the through hole deficit positions are the i-th column (where i is an integer of 2 to n-1) and the j-th row (where j is 2 to m-1) of the matrix of the nth column x the mth row. May be present in each of the four areas partitioned by an integer).

  Next, examples of the present invention will be described.

Example 1
Three glass substrates (non-alkali glass) with a thickness of 0.3 mm having an upper surface and a lower surface were prepared, and a total of 400 through holes were formed in this glass substrate in a matrix of 20 columns × 20 rows. The arrangement pitch of the through holes was set to 200 μm for both the pitch Px between the columns and the pitch Py between the rows.

For the formation of the through hole, the discharge assist type laser hole processing apparatus 100 as shown in FIG. 1 was used. The laser light source was a CO ₂ laser and the laser output was 50 W. The laser beam irradiation time was 800 μsec, and the applied DC voltage was 5000V.

  The coordinate A of the tip of the first electrode for discharge was A (0, 0.5 mm, 0.3 mm). That is, when the distance between the tip of the first electrode and the glass substrate is 0.3 mm, and the intersection point on the glass substrate and the straight line hanging from the tip of the first electrode in the Z-axis direction is P, irradiation is performed. The distance between the center of the spot and P was 0.3 mm.

  In FIG. 7, the order at the time of forming a through-hole in a glass substrate is shown typically. In FIG. 7, the symbol “◯” represents the through hole formation position, and the symbol “X” represents the tip of the first electrode when the through hole is formed at the first through hole formation position (the lower left circle mark). The coordinate A is shown.

  As shown by the arrows in FIG. 7, in Example 1, first, through holes are sequentially formed along the + (plus) direction of the X axis with respect to the through hole forming position (Y1) in the first row, With respect to the through-hole formation position (Y2) in the second row, through-holes are sequentially formed along the − (minus) direction of the X axis, and thereafter the through-hole formation position (Y20) in the 20th row in the same order. Until then, through holes were sequentially formed.

  In such an order, when the through-hole is formed at any through-hole forming position, the tip of the first electrode is always more targeted than the position at which the through-hole has already been formed (the existing through-hole forming position). It should be noted that the closest through hole forming position (target through hole forming position).

  In the three processed glass substrates, the state of the through holes was evaluated by SEM, and the occurrence rate of cracks was determined. As a result, the occurrence rate of cracks was 5/1200 = approximately 0.4%.

  In FIG. 8, an example of the cross section of the through-hole after a process is shown. From this figure, it can be seen that in Example 1, through holes with little necking were formed.

(Comparative Example 1)
By the same method as in Example 1, 20 × 20 = 400 through holes were formed for each of the three glass substrates.

  However, in this comparative example 1, 400 through-holes were formed in a different through-hole formation order from that of the first example.

  In FIG. 9, the order at the time of forming a through-hole in a glass substrate is shown typically. In FIG. 9, the mark “◯” represents the through hole formation position, and the mark “X” represents the first electrode when the through hole is formed at the first through hole formation position (the lower left circle mark). The coordinates A of the tip are shown.

  As shown by the arrows in FIG. 9, in Comparative Example 1, first, through holes are sequentially formed along the + (plus) direction of the Y axis with respect to the through hole forming position (X1) in the first row, With respect to the through-hole formation position (X2) in the second row, through-holes are sequentially formed along the − (minus) direction of the Y axis, and thereafter the through-hole formation position (X20) in the 20th row in the same order. Until then, through holes were sequentially formed.

  In such an order, it is necessary to note that an erroneous discharge may occur in the existing through-hole when discharging at the same position after irradiating the target through-hole forming position with the laser beam. . For example, when the through hole is to be formed with respect to the second through hole formation position (X2) in the second row (the position indicated by the mark ● in FIG. 9), Among the through-hole formation positions (X2) of the row, there is a possibility that erroneous discharge occurs at the position where the first through-hole is formed (the position marked by ◎ in FIG. 9).

  In the three processed glass substrates, the state of the through holes was evaluated by SEM, and the occurrence rate of cracks was determined. As a result, the occurrence rate of cracks was 18/1200 = about 1.50%.

  In FIG. 10, an example of the cross section of the through-hole after a process is shown. From this figure, it can be seen that significant necking is formed in the through hole in Comparative Example 1.

  From the comparison between Example 1 and Comparative Example 1, it was confirmed that in Example 1, the rate of occurrence of cracks was significantly suppressed and through holes with less necking were formed. From this result, in Example 1, it is suggested that the possibility of erroneous discharge occurring in the existing through-holes is significantly suppressed during the discharge process by applying the DC voltage.

(Example 2)
65 through-holes having through-hole patterns 660 as shown in FIG. 6 were formed on the glass substrate by the same method as in Example 1.

  In FIG. 11, the order at the time of forming a through-hole in a glass substrate is shown typically. In FIG. 11, a circle represents a through-hole formation position, and a cross represents a first electrode when the through-hole is formed at the first through-hole formation position (lower left circle). The coordinates A of the tip are shown.

  As shown by the arrows in FIG. 11, in this Example 2, after first forming through holes sequentially along the + (plus) direction of the X axis with respect to the through hole formation position (Y1) of the first row, With respect to the through-hole formation position (Y2) in the second row, through-holes are sequentially formed along the-(minus) direction of the X axis, and thereafter the through-hole formation position (Y9) in the ninth row in the same order. Until then, through holes were sequentially formed.

  In such an order, when the through-hole is formed at any through-hole forming position, the tip of the first electrode is always more targeted than the position at which the through-hole has already been formed (the existing through-hole forming position). It should be noted that the closest through hole forming position (target through hole forming position).

  The same processing was performed 20 times in total. Thereby, 65 × 20 times = 1300 through holes were formed.

  The state of the through hole was evaluated by SEM, and the occurrence rate of cracks was determined. As a result, the occurrence rate of cracks was 5/1300 = about 0.4%. In addition, the state of necking of each through-hole was slight.

  Thus, in Example 2, it was confirmed that the occurrence rate of cracks was significantly suppressed and a through-hole with less necking was formed. From this result, it was suggested in Example 2 that the possibility of erroneous discharge occurring in the existing through-holes was significantly suppressed during the discharge treatment by applying the DC voltage.

  The present invention can be used for a technique for forming a through hole in an insulating substrate such as a glass substrate.

DESCRIPTION OF SYMBOLS 100 Discharge assistance type laser hole processing apparatus 110 Laser light source 113 Laser light 115 Irradiation spot 125 DC high voltage power supply 140 1st electrode 145 2nd electrode 150, 155 Conductor 183 Irradiation position 185 Through-hole 190 Insulating substrate 341 1st electrode 360 through-hole pattern 385 (385-1 to 385-16) through-hole formation position 390 insulating substrate 441 first electrode tip 460 through-hole pattern 485 (485-1 to 485-32) through-hole formation position 489 ( 489-1, 489-2, 489-3, 489-4) Through-hole defect position 490 Insulating substrate 560 Through-hole pattern 660 Through-hole pattern

Claims (12)

A discharge assist type laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes,
The tip of the first electrode is at a distance of 0.1 mm or more from the surface of the insulating substrate, and is shifted by 0.2 mm or more in the first direction from the center of the laser beam irradiation spot on the insulating substrate. Placed in
A through-hole already formed on the insulating substrate is referred to as an existing through-hole, a position where the existing through-hole is formed is referred to as an existing through-hole forming position, and a position where the next through-hole is formed on the insulating substrate is defined as When called the target through-hole formation position,
From a certain existing through-hole, along the second direction orthogonal to the first direction, a position at a distance of 0.5 mm or less is set as a target through-hole forming position, and the target through-hole forming position is irradiated with laser light. Thereafter, when the inter-electrode discharge is performed, the tip of the first electrode is located closer to the target through hole forming position than the position of the existing through hole. A discharge assist type laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes,
The tip of the first electrode is a distance of 0.1 mm or more from the surface of the insulating substrate, and the + (plus) direction along the first direction from the center of the laser beam irradiation spot on the insulating substrate Arranged at a position shifted by 0.2 mm or more,
The insulating substrate has a pattern of n-th column × m-th row matrix through-hole formation positions,
Each column is parallel to the first direction, and each row is parallel to a second direction orthogonal to the first direction;
Each of the columns extends from the first column to the nth column along the + (plus) direction of the second direction, and each of the rows extends from the first row to the mth row in the first direction. Extends along the + (plus) direction of
The through hole forming positions in each row are arranged with a pitch Py of 0.5 mm or less,
After the through holes are formed at the positions where all the through holes are formed in the first row, the through holes are formed at the positions where all the through holes are formed in the second row. Similarly, the through holes are sequentially formed until the m th row. A discharge assist type laser drilling method, characterized by comprising:   The discharge assisted laser hole machining method according to claim 2, wherein the through hole forming positions in each row are arranged at a pitch Px of 0.5 mm or less. A discharge assist type laser hole machining method, wherein a plurality of through holes are formed in an insulating substrate by laser light irradiation, and the shape of the through hole is adjusted by a discharge phenomenon between the first and second electrodes,
The tip of the first electrode is a distance of 0.1 mm or more from the surface of the insulating substrate, and the + (plus) direction along the first direction from the center of the laser beam irradiation spot on the insulating substrate Arranged at a position shifted by 0.2 mm or more,
The insulating substrate has a pattern of through-hole formation positions, and the pattern has a defect portion in which a part of the through-hole formation positions is missing in a matrix of through-hole formation positions in the nth column × mth row. ,
Each column is parallel to the first direction, and each row is parallel to a second direction orthogonal to the first direction;
Each of the columns extends from the first column to the nth column along the + (plus) direction of the second direction, and each of the rows extends from the first row to the mth row in the first direction. Extends along the + (plus) direction of
The through hole formation position in each row is arranged with a pitch Py of 0.5 mm or less, excluding the defective portion,
After the through holes are formed at the positions where all the through holes are formed in the first row, the through holes are formed at the positions where all the through holes are formed in the second row. A discharge assist type laser drilling method, characterized by comprising:   5. The discharge assisted laser hole machining method according to claim 4, wherein the defect portion is arranged at a central portion of a matrix of the through hole formation position of the nth column × mth row.   6. The discharge assisted laser hole machining method according to claim 4, wherein the defect portion exists in a first row or an m-th row of a matrix of through-hole formation positions of the n-th column × m-th row.   The missing portion is the i-th column (where i is an integer from 2 to n−1) and the j-th row (where j is 2) in the matrix of through-hole formation positions of the n-th column × m-th row. The discharge assisted laser hole machining method according to any one of claims 4 to 6, wherein the method is present in each of the four regions separated by an integer of ~ m-1.   8. The discharge-assisted laser hole machining method according to claim 4, wherein the through-hole formation positions in each row are arranged at a pitch Px of 0.5 mm or less excluding the defective portion. 9.   9. The discharge-assisted laser hole machining method according to claim 1, wherein a tip of the first electrode is disposed at a distance of 0.3 mm to 1.0 mm from the surface of the insulating substrate.   The tip of the first electrode is arranged at a distance of 0.5 mm to 1.5 mm along the first direction from the center of the laser beam irradiation spot. The discharge assist type laser hole processing method according to one.   The discharge assist type laser hole machining method according to claim 1, wherein the laser beam irradiation spot has a maximum dimension in a range of 10 μm to 300 μm.   The discharge-assisted laser hole machining method according to claim 1, wherein the second electrode has a substantially plate shape and is disposed on a bottom surface of the insulating substrate.