Chip circuit board, chip module, camera module and movable platform

Abstract

The utility model discloses a chip circuit board, a chip module, a camera module and a movable platform, the chip circuit board comprises a first bonding pad area and a second bonding pad area which are arranged on the circuit board, a bonding pad in the first bonding pad area is set as a first bonding pad, a bonding pad in the second bonding pad area is set as a second bonding pad, the first bonding pad is a non-resistance-welding definition bonding pad, and the second bonding pad is a resistance-welding definition bonding pad or a local non-resistance-welding definition bonding pad; the first bonding pad needing wiring is provided with an opening, so that wiring on the first bonding pad is set to be inner-layer drilling wiring. According to the utility model, the routing on the first bonding pad is set as the inner-layer drilling routing, so that the shear stress borne by the solder ball in the first bonding pad area can be reduced. Compared with the solution in the prior art, the BOM cost and the manufacturing cost can be effectively reduced, the pollution of glue to the environment is reduced, the pollution risk of the glue to the sensor is also avoided, meanwhile, the product reliability is also improved, and the product competitiveness is increased.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit design technical field especially relates to a chip circuit board, chip module, camera module and movable platform. BACKGROUND

[0002] Some chips adopt BGA (Ball Grid Array, solder ball array package) solder ball package, due to the cyclic change of temperature, in the module of application BGA package chip, the solder ball of chip will be repeatedly subjected to shearing force in thermal expansion and contraction process because of the mismatch of thermal expansion coefficient of chip packaging material and circuit board material. The solder ball will crack under the long-term action of this shearing force.

[0003] In reliability test, sCAM (sensor Camera Module, sensor camera module) product is prone to BGA (Ball Grid Array, solder ball array package) pad cracking after vibration + temperature shock test of reliability test.

[0004] In order to meet the reliability requirements, the scheme of dispensing is usually adopted to reinforce the welding point, and the specific process is as follows: printing-> patch-> reflow soldering-> test-> dispensing-> curing. However, although this method can solve the problem of solder ball pad cracking to some extent, due to the increase of dispensing and curing process, the overall manufacturing cost is increased, and the method needs to add auxiliary glue, which not only increases the BOM (Bill of Materials, material list) cost. At the same time, it is necessary to increase the storage management of chemicals and the processing cost of hazardous chemicals. And the method will dispense in the sensor area, which will increase the pollution risk of the sensor. UTILITY MODEL CONTENT

[0005] The utility model embodiment provides a kind of chip circuit board, chip module, camera module and movable platform, to solve the problem of BGA pad cracking when chip circuit board is carried out in prior art reliability test.

[0006] According to the first aspect of the utility model, a chip circuit board is provided, comprising a first pad area and a second pad area arranged on the circuit board, the pads in the first pad area are arranged as first pads, and the pads in the second pad area are arranged as second pads, wherein the first pads are non-solder mask defined pads, and the second pads are solder mask defined pads or local non-solder mask defined pads.

[0007] The first pads that need wiring are provided with openings to set the wiring on the first pads as inner layer drilled wiring.

[0008] The chip circuit board divides the pad area on the circuit board into a first pad area and a second pad area, wherein the first pad area is an area where solder ball pad cracking is more likely to occur, the pads in the first pad area are set as first pads, i.e., non-solder mask defined pads, thereby effectively reducing the shear stress received by the solder balls in these areas where solder ball pad cracking is more likely to occur, relieving the cracking of the solder balls, and drilling holes in the first pads on the chip circuit board that need to be wired, thereby setting the wiring on these first pads as inner layer drilled wiring, effectively relieving the impact of surface wiring on the solder balls, thereby reducing the shear stress received by the solder balls in the first pad area.

[0009] In some embodiments, the first pad area is a corner on the circuit board, and the first pad includes at least one pad disposed at the corner on the circuit board.

[0010] Since the span distance between the solder balls at the corners of the circuit board is the longest, the solder balls at the corners receive the maximum shear stress during testing, and the solder balls at the corners are most likely to crack at the connection with the pads. Therefore, by the above design, the pads at the corners can be designed as first pads, thereby changing the connection between the solder balls and the pads to a combination from the side position, effectively relieving the concentration of shear stress.

[0011] In some embodiments, the first pad area is a corner on the circuit board, and the first pad includes three pads disposed at the edges of the corner on the circuit board.

[0012] Therefore, by such design, the range of the first pad area can be further expanded, and the risk of solder ball pad cracking at the corners on the circuit board can be further reduced.

[0013] In some embodiments, the opening is processed by a POFV process.

[0014] Therefore, by such design, the formed pad hole can be more wettable.

[0015] In some embodiments, the interval between the solder tin disposed on the first pad and the solder tin disposed on the adjacent pad is not less than 0.2 mm.

[0016] Therefore, by such design, it can be ensured that the formed solder tin does not affect each other.

[0017] In some embodiments, the solder on the first pad at each corner of the circuit board is arranged to move 0.1mm in a 45° angle away from the second pad.

[0018] Thus, by such design, it can be ensured that the formed solders do not affect each other.

[0019] In some embodiments, the size of the first pad is greater than the size of the second pad.

[0020] Thus, by such design, the contact area of the pad and the solder ball can be increased by increasing the size of the first pad, so as to enhance the welding strength.

[0021] In some embodiments, the size of the first pad is not less than 0.5mm.

[0022] Thus, by such design, the contact area of the pad and the solder ball can be increased by increasing the size of the first pad, so as to enhance the welding strength.

[0023] According to a second aspect of the present application, a chip module is provided, comprising the chip circuit board of the first aspect and a chip welded on the chip circuit board.

[0024] The chip module of the present application adopts the above-mentioned chip circuit board, so as to ensure the connection stability between the solder ball and the pad during testing, effectively alleviating the cracking of the solder ball pad in the prior art. Compared with the solution in the prior art, the BOM cost and the manufacturing cost can be effectively reduced, the environmental pollution of the glue is reduced, the pollution risk of the glue to the sensor is avoided, the product reliability is improved, and the product competitiveness is increased.

[0025] According to a third aspect of the present application, a camera module is provided, comprising the chip module of the second aspect.

[0026] The camera module provided by the present application adopts the above-mentioned chip circuit board, so as to ensure the connection stability between the solder ball and the pad during testing, effectively alleviating the cracking of the solder ball pad, thereby improving the reliability of the product. At the same time, since the camera module adopts the above-mentioned chip circuit board, the overall cost can be further reduced, the BOM cost and the manufacturing cost are effectively reduced, the environmental pollution of the glue is reduced, the pollution risk of the glue to the sensor is avoided, and the product competitiveness is increased.

[0027] According to a fourth aspect of the present application, a movable platform is provided, comprising the camera module of the second aspect.

[0028] The reliability of the camera module arranged on the movable platform is higher, meanwhile, the overall cost can be reduced, and the product competitiveness is improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows, obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0030] Figure 1 It is an overall structure schematic diagram of the chip circuit board of an embodiment of the present application.

[0031] Figure 2 It is a wiring scheme schematic diagram of the chip circuit board of an embodiment of the present application.

[0032] Figure 3 It is a steel mesh structure schematic diagram corresponding to the chip circuit board of an embodiment of the present application.

[0033] Figure 4 It is a slice result schematic diagram corresponding to the chip circuit board of an embodiment of the present application.

[0034] The reference signs are as follows: 1, circuit board; 21, first solder pad area; 22, second solder pad area; 31, first solder pad; 32, second solder pad; 4, steel mesh; 41, mesh hole. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0036] It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0037] In the description of the present application, it needs to be understood that if the terms "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to 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. The features defined as "first", "second" are used to distinguish the feature names, not to have special meanings, and in addition, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0038] In the description of the present application, it needs to be explained that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] It also needs to be explained that in this paper, the terms "including", "containing", not only include those elements, but also include other elements not explicitly listed, or include elements inherent to the process, method, article or device. Without more limitation, the elements defined by the sentence "including" do not exclude the presence of other identical elements in the process, method, article or device including the elements. The terms used in this paper are generally the terms commonly used by those skilled in the art, and if they are inconsistent with the commonly used terms, the terms in this paper shall prevail.

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0041] The present application will be described in further detail below with reference to the accompanying drawings.

[0042] Figure 1 The overall structure of the chip circuit board in an embodiment of the present application is schematically shown, referring to Figure 1 The chip circuit board of the present application comprises a first pad area 21 and a second pad area 22 arranged on the circuit board 1. The first pad area 21 is a pad area on the chip circuit board which is prone to solder cracking during reliability testing, and the second pad area 22 is a pad area on the chip circuit board which is less prone to solder cracking compared with the first pad area 21. In the first pad area 21, the pads in the area are arranged as first pads 31, and in the second pad area 22, the pads in the area are arranged as second pads 32. The first pads 31 are non-solder mask defined pads (NSMD), and the second pads 32 are solder mask defined pads (SMD) or partial NSMD. The difference between SMD (or partial NSMD) and NSMD (complete NSMD) is that the SMD or partial NSMD has a small portion of the copper foil pad covered by the solder mask, and the NSMD has a ring of solder mask surrounding the copper foil pad to expose the entire copper foil pad. The solder mask defined pads have stress concentration points, and the SMD or partial NSMD pads have copper foil covered by the solder mask. During the reflow soldering process, the connection between the solder balls and the periphery of the copper foil pad forms a sharp corner. During temperature shock, the solder balls are subjected to repeated shear forces, and the stress concentration points on the connection pad are more likely to cause cracks on the mounting surface, i.e., cracking at the sharp corner. The possibility of passing the temperature shock reliability test is lower.

[0043] Meanwhile, in the first pad area 21, the first pads 31 that need to be wired are provided with openings, and the wiring on the first pads 31 is arranged as inner layer drilled wiring. The inner layer drilled wiring can effectively alleviate the influence of the pad wiring on the connection between the solder balls, thereby effectively reducing the shear stress on the solder balls in the first pad area 21. Referring to Figure 2 and Figure 4 In this wiring scheme, the first pads 31 no longer have surface wiring on the circuit board to alleviate the influence of the pad wiring on the connection between the solder balls. It can be understood that not all pads necessarily need to be wired, and whether they need to be wired is related to the packaging of the chip to be installed. For example, there may be empty pins on the chip, in which case the first pads 31 corresponding to the empty pins do not need to be opened and do not need to implement inner layer drilled wiring. The welding strength of the solder balls on the corresponding first pads 31 can be improved by other designs for the first pads 31.

[0044] In some possible implementations, the first pad region 21 is located at the four corners of the circuit board 1. Because the span between solder balls is longest at the corners, the solder balls at the corners of the circuit board 1 experience the greatest shear stress during reliability testing, making the connection between the solder balls and the copper foil at these corners most prone to cracking. Corresponding to the location of the first pad region 21, the first pad 31 includes at least one pad located at each of the four corners of the circuit board 1. For example, referring to… Figure 1 As shown, in Figure 1 In the illustrated embodiment, the circuit board 1 has a square structure, with its first pad area 21 located at the four corners. Correspondingly, all four pads at the four corners of the circuit board 1 are designated as first pads 31. However, in practice, during reliability testing, the solder pads at the four corners of the circuit board 1 are most prone to cracking. Therefore, to prevent cracking of the solder pads near the corners of the circuit board 1, in this embodiment, three pads at the edges of the four corners of the circuit board 1 are designed as first pads 31 to reduce the risk of cracking at the corners.

[0045] Since the first pads 31 requiring routing in the first pad area 21 have openings to enable inner layer drilling routing, in some possible embodiments, the openings on the first pads 31 can be treated using a POFV (Plated Over Filled Via) process. The specific flow of the POFV process can be found in existing technical documents and will not be elaborated here. The POFV process, through electroplating and filling of vias, effectively improves the wiring density, signal integrity, and mechanical strength of the circuit board 1, and makes the formed vias more wettable.

[0046] In addition, in addition to setting the pads in the first pad area 21 as the first pads 31, in some possible embodiments, the size of the first pads 31 is further designed. Specifically, in some possible embodiments, the size of the first pads 31 can be designed to be larger than the size of the second pads 32, so as to increase the contact area between the solder ball pads on the first pads 31, improve the connection stability of the solder ball pads, and further alleviate the cracking of the solder ball pads. The size of the first pads 31 can be designed to be 0.1 mm to 0.3 mm larger in diameter than the size of the second pads 32. Since the size of the second pads 32 is usually designed to be 0.3 mm in diameter, the size of the first pads 31 can be designed to be 0.4 mm to 0.6 mm. Such a design can ensure that the contact area between the solder ball pads on the first pads 31 is increased and the soldering strength is enhanced, without making the area of the first pads 31 too large to affect the soldering of the adjacent pads. For example, the size of the first pads 31 can be set to be 0.5 mm or larger in diameter.

[0047] Since the size of the first pads 31 on the chip circuit board is increased, the spacing between the pads and the adjacent pads at the position where the first pads 31 are provided on the chip circuit board is reduced. When soldering, the spacing between the solder balls is reduced, and the solder balls on the adjacent pads are likely to interfere with each other. Therefore, in some possible embodiments, the solder tin provided on the first pads 31 is designed to have a spacing of no less than 0.2 mm with the solder tin provided on the adjacent pads. It can be understood that for the first pads 31, the adjacent pads can be the first pads 31 or the second pads 32. Regardless of whether the adjacent pads are the first pads 31 or the second pads 32, the spacing between the solder tin on the adjacent two pads needs to be ensured to be no less than 0.2 mm to avoid interference between the adjacent solder tin during soldering. In addition, referring to FIG. 6, in the embodiment shown in FIG. 6, the first pads 31 are provided at the edges of the four corners of the circuit board 1. At this time, the solder tin on the first pads 31 is designed to move 0.1 mm away from the second pads 32 along the 45° angle. Figure 1 Figure 1 In the embodiment shown in FIG. 6, the three pads at the edges of the four corners of the circuit board 1 are designed as the first pads 31. At this time, one pad at each corner of the circuit board 1 has two adjacent pads that are the first pads 31. Therefore, the solder tin on the one pad at each corner is designed to move 0.1 mm away from the second pads 32 along the 45° angle.

[0048] Specifically, the above design of the position of the solder tin can be achieved by transferring the accurate amount of solder tin to the accurate position on the circuit board 1 through the steel mesh 4 during the actual soldering. At this time, referring to FIG. 6, in the embodiment shown in FIG. 6, the first pads 31 are provided at the edges of the four corners of the circuit board 1. At this time, the solder tin on the first pads 31 is designed to move 0.1 mm away from the second pads 32 along the 45° angle. Figure 3 Figure 3 ​​The square portion is the mesh 41 on the stencil 4. The stencil 4 can be further adjusted to adjust the position of its mesh 41 according to the above-mentioned solder position design, so that the position of the mesh 41 corresponding to the first pad 31 is adjusted, and the spacing between the mesh 41 corresponding to the first pad 31 and the mesh 41 corresponding to the adjacent pad is designed to be no less than 0.2mm. The mesh 41 corresponding to the first pad 31 at each corner is designed to move 0.1mm away from the mesh 41 corresponding to the second pad 32 at a 45° angle. This ensures that the position of the solder can meet the above-mentioned position spacing requirements when soldering through the stencil 4.

[0049] Reference Figure 4 As shown, Figure 4 The image schematically illustrates a cross-section of the chip circuit board according to this invention. From Figure 4 As can be seen from the cross-section results, the pads on both sides of the cross-section are the first pads, which realize the inner layer drilling traces. After the cross-section, there are no cracks or obvious holes between the solder balls and the pads, and the overall soldering is good.

[0050] The chip circuit board of this invention divides the pad area on the circuit board 1 into a first pad area 21 and a second pad area 22. The first pad area 21 is more prone to solder ball cracking. By designating the pads in the first pad area 21 as first pads 31 (i.e., non-solder resist defined pads), the shear stress on the solder balls in these crack-prone areas can be effectively reduced, mitigating the cracking problem. Furthermore, the chip circuit board of this invention drills holes in the first pads 31 where traces are required, thus designating these traces as inner-layer drilled traces. This effectively mitigates the impact of surface-layer traces on the solder balls, thereby reducing the shear stress on the solder balls in the first pad area 21. Compared with existing solutions, this invention effectively reduces BOM and manufacturing costs, minimizes adhesive pollution, avoids the risk of adhesive contamination of sensors, improves product reliability, and increases product competitiveness.

[0051] This utility model also provides a chip module, which includes a chip circuit board according to any of the above embodiments, and a chip soldered onto the chip circuit board. This chip module uses the aforementioned chip circuit board, thereby ensuring the connection stability between the solder balls and pads during testing, effectively mitigating the solder ball / pad cracking issue present in the prior art. Compared with existing solutions, it effectively reduces BOM and manufacturing costs, reduces adhesive pollution to the environment, avoids the risk of adhesive contamination of sensors, and simultaneously improves product reliability and increases product competitiveness.

[0052] The utility model also provides a kind of camera module, including the chip module above, camera module has adopted the chip circuit board above, to be able to ensure its connection stability between solder ball and pad when testing, effectively alleviate the condition of solder ball pad cracking, to improve the reliability of product.

[0053] The utility model also provides a kind of movable platform, wherein, the movable platform is provided with the camera module above, so that the overall cost can be reduced, improve product competitiveness.

[0054] It should be noted that the movable platform described in the embodiments of the present application can be, for example, a mobile robot, a model airplane, a drone, a robot hand, a car, a ship, etc. It should also be pointed out that the structure of the movable platform is not limited to this, and this is only an illustrative example.

[0055] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A chip circuit board, characterized by, The first pad area (21) and the second pad area (22) are arranged on the circuit board (1), the pads in the first pad area (21) are arranged as first pads (31), the pads in the second pad area (22) are arranged as second pads (32), wherein the first pads (31) are non-solder mask defined pads, and the second pads (32) are solder mask defined pads or partially non-solder mask defined pads. The first pads (31) requiring wiring are provided with openings to arrange the wiring on the first pads (31) as inner layer drilled wiring.

2. The chip-on-board of claim 1, wherein, The first pad area (21) is a corner on the circuit board (1), and the first pads (31) include at least one pad arranged at the corner on the circuit board (1).

3. The chip-on-board of claim 1, wherein, The openings are arranged to be processed by a POFV process.

4. The chip-on-board of claim 2, wherein, The interval between the soldering tin arranged on the first pads (31) and the soldering tin arranged on adjacent pads is not less than 0.2 mm.

5. The chip-on-board of claim 4, wherein, The soldering tin arranged on one first pad (31) at each corner on the circuit board (1) is arranged to move 0.1 mm in a direction away from the second pads (32) along an angle of 45°.

6. The chip-on-board of any one of claims 1 to 5, wherein, The size of the first pads (31) is greater than the size of the second pads (32).

7. The chip-on-board of any one of claims 1 to 5, wherein, The size of the first pads (31) is arranged to be not less than 0.5 mm in diameter.

8. A chip module, characterized by A chip circuit board and a chip soldered on the chip circuit board according to any one of the preceding claims 1 to 7.

9. An image capture module, comprising: A chip module according to the preceding claim 8.

10. A movable platform, characterized by A camera module according to the preceding claim 9.

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