Package substrate processing method and package substrate

Abstract

The application provides a packaging substrate processing method and a packaging substrate. The method comprises the following steps: drilling a tool hole on a packaging substrate to form the tool hole; preparing a solder resist layer on the packaging substrate, and the solder resist layer accumulates to form accumulated material in the tool hole; and performing laser ablation on the tool hole to remove the accumulated material in the tool hole. The packaging substrate processing method provided by the application can drill the required tool hole on the packaging substrate before preparing the solder resist layer, and then remove the accumulated material in the tool hole by ablation after preparing the solder resist layer, so that the required tool hole is obtained. The packaging substrate does not need to be classified according to expansion and contraction, and then be positioned by a pin for drilling, so that the processing precision of the tool hole on the packaging substrate can be improved. The laser ablation is a non-contact processing method for ablating the accumulated material in the tool hole, so that the tool hole is not damaged again, and quality problems such as hole mouth damage and burr edge are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packaging substrate processing, in particular to a packaging substrate processing method and a packaging substrate. BACKGROUND

[0002] The tool hole on the packaging substrate is a key mechanical functional element in its manufacturing and assembly, and is mainly used for mechanical fixation, electrical connection, process reference and functional expansion, etc., which has irreplaceable significance for improving the assembly efficiency, structural stability and long-term reliability of the packaging substrate.

[0003] In the related art in the industry, the machining of the tool hole of the finished product packaging substrate with a thickness of 0.35 mm or more is performed by using mechanical drilling to drill the required tool hole after the solder mask process is completed on the packaging substrate. This method requires full shrinkage size measurement of the packaging substrate before the second mechanical drilling, and the packaging substrate is processed in different shrinkage intervals. The shrinkage classification workload is large, the drilling precision is low due to the use of pins for secondary positioning, and quality problems such as tool hole opening damage, burr and burr may occur during drilling of multiple pieces in a stack. SUMMARY

[0004] The packaging substrate processing method and packaging substrate provided by the embodiments of the present application can improve the machining precision of the tool hole on the packaging substrate, and will not cause secondary damage to the tool hole, and there are no quality problems such as tool hole opening damage, burr and burr.

[0005] The packaging substrate processing method provided by the embodiments of the present application comprises the following steps.

[0006] Drilling the packaging substrate to form a tool hole;

[0007] Preparing a solder mask layer on the packaging substrate, and the solder mask layer accumulates to form accumulated material in the tool hole;

[0008] Performing laser ablation on the tool hole to remove the accumulated material in the tool hole.

[0009] In some embodiments, the laser ablation on the tool hole to remove the accumulated material in the tool hole comprises:

[0010] Performing laser ablation along a straight line path from a first point on the tool hole wall to a second point on the tool hole wall, wherein the straight line connecting the first point and the second point passes through the axis of the tool hole, so as to cut the accumulated material in the tool hole into at least two parts.

[0011] In some embodiments, the first point and the second point are both a plurality of intervals, and the laser ablation along the straight line path from the first point on the tool hole wall to the second point on the tool hole wall comprises:

[0012] laser ablation along straight lines from different first points on the wall of the tool hole towards corresponding second points on the wall of the tool hole to cut the accumulated material in the tool hole into multiple parts.

[0013] In some embodiments, the first points and the second points are spaced four apart to cut the accumulated material in the tool hole into eight parts.

[0014] In some embodiments, the laser ablation along straight lines from the first points on the wall of the tool hole towards the second points on the wall of the tool hole further comprises:

[0015] laser ablation along a closed annular path circumferentially around the wall of the tool hole to separate the at least two parts of the accumulated material from the wall of the tool hole.

[0016] In some embodiments, the package substrate includes first and second opposite faces, the tool hole extends through the first and second faces, and the laser ablation of the tool hole to remove the accumulated material includes:

[0017] first laser ablation of the tool hole from the first face;

[0018] turning over the package substrate;

[0019] second laser ablation of the tool hole from the second face;

[0020] wherein the sum of the depth of the first laser ablation and the depth of the second laser ablation is greater than or equal to the thickness of the accumulated material.

[0021] In some embodiments, the depth of the first laser ablation is 1 / 3 to 1 / 2 of the thickness of the accumulated material.

[0022] In some embodiments, the laser ablation of the tool hole to remove the accumulated material further comprises:

[0023] using a suction device to suction the removed accumulated material in the tool hole.

[0024] In some embodiments, the method further comprises, before the preparation of the solder resist layer on the package substrate:

[0025] copper electroplating of the package substrate to form a conductive layer on the inner wall of the tool hole;

[0026] developing and etching of the package substrate to form a circuit pattern and remove the conductive layer on the inner wall of the tool hole.

[0027] The application further provides a packaging substrate, which is processed by the packaging substrate processing method of any one of the above embodiments.

[0028] The packaging substrate processing method of the application can improve the processing precision of the tool holes on the packaging substrate, and the laser ablation is a non-contact processing method for ablation of the accumulated material in the tool hole, which does not cause secondary damage to the tool hole, and does not cause quality problems such as hole mouth damage and burr. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0030] Figure 1 It is a flowchart of the packaging substrate processing method of the application.

[0031] Figure 2 It is a flowchart of the packaging substrate processing method of the application, which is used for laser ablation of the tool hole to remove the accumulated material in the tool hole.

[0032] Figure 3 It is a schematic diagram of the packaging substrate processing method of the application, which is used for laser ablation along the straight line path from the first point to the second point.

[0033] Figure 4 It is a schematic diagram of the packaging substrate processing method of the application, which is used for laser ablation along the annular closed path along the circumference of the tool hole wall.

[0034] Figure 5 It is a flowchart of the packaging substrate processing method of the application, which is used for laser ablation of the first surface and the second surface of the packaging substrate.

[0035] Figure 6 It is a schematic diagram of the packaging substrate processing method of the application, which is used for laser ablation of the first surface and the second surface of the packaging substrate. DETAILED DESCRIPTION

[0036] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0037] The packaging substrate processing method provided in the embodiments of the present application can improve the processing precision of the tool hole 2 on the packaging substrate 1, and will not cause secondary damage to the tool hole 2, and will not cause quality problems such as orifice breakage and burr.

[0038] Reference Figure 1 , Figure 1 FIG. 1 is a flowchart of a packaging substrate processing method according to an embodiment of the present application. The packaging substrate processing method comprises the following steps:

[0039] 10. Drilling the packaging substrate 1 to form a tool hole 2;

[0040] 20. Preparing a solder resist layer on the packaging substrate 1, and the solder resist layer accumulates to form accumulated material 3 in the tool hole 2;

[0041] 30. Laser ablation is performed on the tool hole 2 to remove the accumulated material 3 in the tool hole 2.

[0042] It should be noted that the tool hole 2 required on the packaging substrate 1 is drilled before the solder resist layer is prepared on the packaging substrate 1. The material (for example, ink) in the tool hole 2 will accumulate into a hole blockage due to the preparation of the solder resist layer. Therefore, after the solder resist layer is prepared, the accumulated material 3 in the tool hole 2 is ablated using a laser drilling machine to finally obtain the required tool hole 2. The tool hole 2 laser ink ablation uses a laser drilling machine CCD to automatically identify the first mechanical drilling target point and automatically perform expansion and contraction compensation, and does not need to be classified and then drilled using a pin. The processing precision is high (position deviation ± 15 um), and the laser ablation is a non-contact processing method for ablating the accumulated material 3 in the tool hole 2. The low-energy laser heat-affected zone is small, and will not cause secondary damage to the tool hole 2, and will not cause quality problems such as orifice breakage and burr.

[0043] In order to effectively remove the accumulated material 3 in the tool hole 2 during ablation and not to expand the tool hole 2, in addition to setting a reasonable laser energy, a special laser ablation path needs to be designed to cut the large accumulated material 3 in the tool hole 2 into several small portions, so as to facilitate the subsequent cleaning of the accumulated material 3. For reference Figures 2-4 , Figure 2 FIG. 3 is a flowchart of laser ablation of the tool hole 2 to remove the accumulated material 3 in the tool hole 2 in the packaging substrate processing method according to the embodiment of the present application, Figure 3Fig. 1 is a schematic diagram of the laser ablation along the straight line path from the first point 4 to the second point 5 in the packaging substrate processing method of the embodiment of the present application, Figure 4 Fig. 2 is a schematic diagram of the laser ablation along the annular closed path along the circumference of the hole wall of the tool hole 2 in the packaging substrate processing method of the embodiment of the present application.

[0044] As shown in Fig. 1, the step of laser ablation on the tool hole 2 to remove the accumulated material 3 in the tool hole 2 includes: Figure 3

[0045] 301, laser ablation along the straight line path from the first point 4 on the hole wall of the tool hole 2 to the second point 5 on the hole wall of the tool hole 2, wherein the straight line connecting the first point 4 and the second point 5 passes through the axis of the tool hole 2, so as to cut the accumulated material 3 in the tool hole 2 into at least two parts.

[0046] As shown in Fig. 1, after laser ablation along the straight line path from the first point 4 on the hole wall of the tool hole 2 to the second point 5 on the hole wall of the tool hole 2, the step of laser ablation on the tool hole 2 to remove the accumulated material 3 in the tool hole 2 further includes: Figure 4

[0047] 302, laser ablation along the annular closed path along the circumference of the hole wall of the tool hole 2, so as to separate the at least two parts of the accumulated material 3 cut by the laser ablation from the hole wall of the tool hole 2.

[0048] It should be noted that when ablation is performed on the accumulated material 3 in the tool hole 2, the starting point (the first point 4) and the ending point (the second point 5) of cutting the accumulated material 3 need to be determined on the tool hole 2 first, and the straight line connecting the first point 4 and the second point 5 passes through the axis of the tool hole 2, so as to cut the accumulated material 3 more uniformly, easily separate the accumulated material 3 from the hole wall during the subsequent circumferential ablation of the accumulated material 3, and reduce the cutting difficulty and the risk of residue. In actual application, for the case that the diameter of the tool hole 2 is small or the accumulated material 3 is easy to clean, the first point 4 and the second point 5 can be set to one, so as to divide the accumulated material 3 into two parts; for the case that the diameter of the tool hole 2 is large or the accumulated material 3 is not easy to clean, the second point 5 and the second point 5 can also be set to multiple, so as to divide the accumulated material 3 into multiple parts, facilitating the subsequent cleaning of the accumulated material 3. After the accumulated material 3 is divided (i.e. after laser ablation along the straight line path from all the first points 4 to the second points 5), laser ablation along the annular closed path along the circumference of the hole wall of the tool hole 2 is required, so as to sequentially cut and remove the divided accumulated material 3 from the hole wall of the tool hole 2, so as to complete the removal of the accumulated material 3 in the tool hole 2.

[0049] ​​In actual production, the radius of the effective spot formed by the laser beam is used as the coordinate point of the laser ablation output at equal distances on the straight line connecting the first point 4 and the second point 5, and then the ablation is performed along the track with a diameter of the diameter of the tool hole 2 minus the radius of the effective spot formed by the laser beam, so as to avoid ablation of the hole wall of the tool hole 2 by the laser beam and to be as close as possible to the hole wall of the tool hole 2 to reduce the residue of the accumulated material 3.

[0050] In order to more easily separate the accumulated material 3 from the hole wall during circumferential ablation of the accumulated material 3, reduce the cutting difficulty and the risk of residue, it is necessary to divide the accumulated material 3 into multiple parts with smaller size and more uniform size. Referring to Figure 3 , the first point 4 and the second point 5 are both spaced multiple, and the multiple first points 4 and the multiple second points 5 correspond one by one, and the step of laser ablation along the straight line path of the first point 4 on the hole wall of the tool hole 2 towards the second point 5 on the hole wall of the tool hole 2 includes:

[0051] Multiple laser ablation along the straight line path of different first points 4 on the hole wall of the tool hole 2 towards the corresponding second points 5 on the hole wall of the tool hole 2 to cut the accumulated material 3 in the tool hole 2 into multiple parts.

[0052] It can be understood that, by multiple laser ablation along the straight line path of different first points 4 on the hole wall of the tool hole 2 towards the corresponding second points 5 on the hole wall of the tool hole 2, since the straight lines connecting these first points 4 and second points 5 all pass through the axis of the tool hole 2, the parts after ablation are only connected to the hole wall of the tool hole 2, and any two parts are not connected, which facilitates easier separation of the accumulated material 3 from the hole wall during subsequent circumferential ablation of the accumulated material 3.

[0053] Optionally, as shown in Figure 3 , the first point 4 and the second point 5 are both spaced four to divide the accumulated material 3 in the tool hole 2 into eight parts to balance the processing workload and reduce the difficulty and risk of residue during circumferential cutting. If the number of first points 4 and second points 5 is small, for example, two first points 4 and two second points 5 are provided, although the processing workload during straight-line cutting is small, the difficulty and risk of residue during subsequent circumferential cutting are large; if the number of first points 4 and second points 5 is large, for example, eight first points 4 and eight second points 5 are provided, although the cutting difficulty and residue risk during subsequent circumferential cutting can be further reduced, the processing workload during straight-line cutting is significantly increased. Therefore, the first point 4 and the second point 5 are both provided as four, which can reduce the difficulty and risk of residue during subsequent circumferential cutting to a certain extent, without making the processing process too complex.

[0054] Preferably, as shown in Figure 3As shown, for the tool hole 2 with a circular or regular polygon cross-sectional shape, there are four equally spaced first positions 4 and four equally spaced second positions 5. The distance between adjacent first positions 4 is equal, and the distance between adjacent second positions 5 is equal, making the cutting path arranged in a "cross" shape, so that the accumulated material 3 is divided into eight more uniform parts, further reducing the difficulty and residual risk of circumferential cutting, and facilitating the subsequent cleaning of the cut-off parts.

[0055] In the encapsulation substrate processing method of this application embodiment, after drilling the required tool hole 2 before preparing the solder mask layer on the encapsulation substrate 1 and ablating and removing the accumulated material 3 in the tool hole 2 after preparing the solder mask layer, the required tool hole 2 is obtained. There is no need to classify the encapsulation substrate 1 by expansion and contraction and then use pins for positioning and drilling, which can improve the processing accuracy of the tool hole 2 on the encapsulation substrate 1. Moreover, laser ablation is a non-contact processing for fixed-point ablation of the accumulated material 3 in the tool hole 2, which will not cause secondary damage to the tool hole 2, and there are no quality problems such as hole mouth breakage, burrs, and flash.

[0056] For a relatively thick encapsulation substrate 1 (thickness greater than 0.35 mm), when ablating the accumulated material 3 in the tool hole 2 on the front side, the position of the tool hole 2 mouth is at the laser focusing focal position. The deeper towards the hole bottom, the more it deviates from the laser focus. The attenuation of the laser energy density causes the accumulated material 3 at the hole bottom to not be ablated normally. At this time, if the laser energy is increased, the substrate at the tool hole 2 mouth will be affected by higher heat and deformed, resulting in abnormal product quality. Therefore, this application further proposes to use the method of laser ablation on both sides to improve the problem that the laser focal length deviation is affected by the thickness of the encapsulation substrate 1. Refer to Figure 5 and Figure 6 , Figure 5 is the flowchart of laser ablation on the first side and the second side of the encapsulation substrate 1 in the encapsulation substrate processing method of this application embodiment, Figure 6 is the schematic diagram of laser ablation on the first side and the second side of the encapsulation substrate 1 in the encapsulation substrate processing method of this application embodiment. Among them, Figure 6 is the longitudinal sectional view of the encapsulation substrate 1. The up and down directions are used to indicate the first side and the second side of the encapsulation substrate 1. The end face at the upper part is the first side of the encapsulation substrate 1, and the end face at the lower part is the second side of the encapsulation substrate 1. The dotted line above the tool hole 2 refers to the laser beam boundary of the first side laser ablation, and the dotted line below the tool hole 2 refers to the laser beam boundary of the second side laser ablation.

[0057] Among them, as Figure 6 shown, the encapsulation substrate 1 includes a first side and a second side facing away from each other. The tool hole 2 penetrates the first side and the second side. The steps of laser ablation on the tool hole 2 to remove the accumulated material 3 in the tool hole 2 include:

[0058] 303. performing first laser ablation on the tool hole 2 from the first side;

[0059] 304. turning over the package substrate 1;

[0060] 305. performing second laser ablation on the tool hole 2 from the second side;

[0061] wherein the sum of the depth of the first laser ablation and the depth of the second laser ablation is greater than or equal to the thickness of the accumulated material 3.

[0062] It should be noted that in order to avoid the deformation of the tool hole 2 caused by the high heat of the tool hole 2 caused by the increase of the laser energy, the accumulated material 3 is ablated by laser multiple times, and the accumulated material 3 is removed from the tool hole 2 by the first laser ablation from the first side (such as the upper side shown in FIG. 3A), and then the second laser ablation from the second side (such as the lower side shown in FIG. 3B), and the sum of the depth of the first laser ablation and the depth of the second laser ablation is greater than or equal to the thickness of the accumulated material 3, so as to avoid the increase of the laser energy and the removal of the accumulated material 3 from the tool hole 2. Figure 6 Figure 6 Figure 6 It should be noted that in order to avoid the deformation of the tool hole 2 caused by the high heat of the tool hole 2 caused by the increase of the laser energy, the accumulated material 3 is ablated by laser multiple times, and the accumulated material 3 is removed from the tool hole 2 by the first laser ablation from the first side (such as the upper side shown in FIG. 3A), and then the second laser ablation from the second side (such as the lower side shown in FIG. 3B), and the sum of the depth of the first laser ablation and the depth of the second laser ablation is greater than or equal to the thickness of the accumulated material 3, so as to avoid the increase of the laser energy and the removal of the accumulated material 3 from the tool hole 2.

[0063] In some embodiments, the depth of the first laser ablation is 1 / 3 to 1 / 2 of the thickness of the accumulated material 3. It should be noted that if the depth of the first laser ablation is shallow (for example, 1 / 5 of the thickness of the accumulated material 3), in order to completely remove the additive, the second laser ablation needs more laser energy, which is easy to cause the deformation of the tool hole 2 caused by the high heat of the tool hole 2. Therefore, the depth of the first laser ablation is 1 / 3 to 1 / 2 of the thickness of the accumulated material 3, so that the two laser ablations can be ablated by smaller laser energy, reducing the risk of deformation of the tool hole 2 caused by the high heat of the tool hole 2.

[0064] In some embodiments, after the laser ablation on the tool hole 2 to remove the accumulated material 3 in the tool hole 2, the method further comprises: using a suction device to suck the accumulated material 3 removed from the tool hole 2. In order to clean the tool hole 2 and avoid the accumulation of the cut accumulated material 3 in the tool hole 2, the suction device can use the dust collection device provided with the laser drilling machine, or use an external negative pressure suction device.

[0065] In some embodiments, before preparing the solder resist layer on the package substrate 1, the method further comprises:

[0066] performing copper electroplating on the package substrate 1 to form a conductive layer on the inner wall of the tool hole 2;

[0067] developing and etching the package substrate 1 to form a circuit pattern and remove the conductive layer on the inner wall of the tool hole 2.

[0068] ​It can be understood that, by carrying out copper electroplating and developing etching on the packaging substrate 1, forming a circuit pattern on the packaging substrate 1, and removing the conductive layer on the inner wall of the tool hole 2 by etching, it is convenient for subsequent electrical connection such as element pin connection. Subsequently, a solder resist layer is prepared on the packaging substrate 1, and when laser ablation is performed on the tool hole 2, the inner wall of the tool hole 2 is free of the conductive layer.

[0069] The packaging substrate is processed by the packaging substrate processing method of any one of the above embodiments.

[0070] The packaging substrate of the embodiment of the present application is processed by the packaging substrate processing method, and does not need to be classified and then positioned by a pin for drilling, has high processing precision (position deviation ± 15 um), and the laser ablation is a non-contact processing method for ablating accumulated materials in the tool hole at a fixed point, has a small low-energy laser heat-affected zone, does not cause secondary damage to the tool hole, and has no problems such as orifice damage, burr, and the like.

[0071] In the description of the present application, it should be understood that terms such as "first", "second", etc. are only used to distinguish similar objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features.

[0072] It should be pointed out that "connection" in the embodiment of the present application can be understood as electrical connection, and the connection between two electrical elements can be direct or indirect connection between the two electrical elements. For example, A and B are connected, which can be direct connection between A and B, or indirect connection between A and B through one or more other electrical elements.

[0073] It should be understood that the terms "thickness", "upper", "lower", "left", "right", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0074] The packaging substrate processing method and the packaging substrate 1 provided by the embodiments of the present application are described in detail above. In this paper, specific examples are applied to describe the principles and implementation modes of the present application, and the above description of the embodiments is only used to help understand the present application. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as a limitation on the present application.

Claims

1. A packaging substrate processing method characterized by, include: Drill holes in the packaging substrate to form tool holes; A solder resist layer is prepared on the packaging substrate, and the solder resist layer accumulates in the tool hole to form an accumulation material; Laser ablation of the tool hole to remove accumulated material within the tool hole includes: performing laser ablation along a straight path from a first point on the tool hole wall toward a second point on the tool hole wall, wherein the straight line connecting the first point and the second point passes through the axis of the tool hole, thereby cutting the accumulated material within the tool hole into at least two parts; and performing laser ablation along a closed annular path circumferentially along the tool hole wall, so that the at least two parts of the accumulated material cut into them are separated from the tool hole wall.

2. The method of claim 1, wherein The first point and the second point are both multiple points spaced apart. The laser ablation along a straight path from the first point on the tool hole wall toward the second point on the tool hole wall includes: Laser ablation is performed multiple times along a straight path from different first points on the tool hole wall toward corresponding second points on the tool hole wall to cut the accumulated material inside the tool hole into multiple parts.

3. The method of claim 2, wherein The first point and the second point are both four points spaced apart, so as to cut the accumulated material in the tool hole into eight parts.

4. The method of processing a package substrate according to any one of claims 1 to 3, wherein The packaging substrate includes a first side and a second side facing away from each other, and the tool hole penetrates through the first side and the second side. The step of laser ablation of the tool hole to remove accumulated material within the tool hole includes: The tool hole is subjected to a first laser ablation from the first surface; Flip the packaging substrate over once; A second laser ablation is performed on the tool hole from the second surface; Wherein, the sum of the depth of the first laser ablation and the depth of the second laser ablation is greater than or equal to the thickness of the aggregate material.

5. The method of processing a package substrate according to claim 4, wherein The depth of the first laser ablation is 1 / 3 to 1 / 2 of the thickness of the aggregate material.

6. The method of processing a package substrate according to any one of claims 1 to 3, wherein After laser ablation of the tool hole to remove the accumulated material within the tool hole, the method further includes: The adsorption device is used to adsorb the accumulated material removed from the tool hole.

7. The method of processing a package substrate according to any one of claims 1 to 3, wherein Before fabricating the solder resist layer on the packaging substrate, the method further includes: The packaging substrate is subjected to copper plating to form a conductive layer on the inner wall of the tool hole; The packaging substrate is developed and etched to form a circuit pattern, and the conductive layer on the inner wall of the tool hole is removed.

8. A package substrate, characterized by, The packaging substrate is obtained by the packaging substrate processing method according to any one of claims 1 to 7.

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