A micro-module connection process

Abstract

The present invention relates to the field of endoscope welding methods, and specifically to a micro-module connection process, comprising: step one, respectively setting multiple original welding points on the back of a chip into metal welding points, and setting connection points on a circuit board that correspond one to one with the metal welding points of the chip; step two, electrically connecting the metal welding points on the chip to the connection points on the circuit board; step three, aligning the connection points on the circuit board with the flexible wires, bonding the connection points to the flexible wires through gold fingers, and curing them with glue, so that the flexible wires, the circuit board, and the chip are arranged in sequence in the axial direction and form an overall "|" shape, thereby completing the three-dimensional connection of the micro-module. The present invention eliminates the waiting time for the solder balls to melt, and does not require soldering pin by pin, has a high processing speed, and can greatly improve the production and processing efficiency of the micro-modules during mass production.

Description

Technical Field

[0001] The present invention relates to the field of endoscope welding methods, and in particular to a micro-module connection process. Background Art

[0002] Micromodules are core components of medical or industrial detection equipment that can penetrate targets through the mouth, pipes, or other natural orifices. For example, micromodules in endoscopes can detect lesions that X-rays cannot. To ensure that detection devices embedded with micromodules can be inserted into the mouth, natural orifices, or pipes, the devices generally need to be extremely small, and so too must the micromodules. For example, the image sensor and optical lens of an endoscope are typically less than 1 mm in size.

[0003] The micromodule consists of a PCB, a chip, and an optical lens. Currently, the connection between the PCB and the chip is achieved through solder balls. Soldering the PCB and chip with solder balls involves transferring the solder balls from a tin box to a nozzle, melting them with laser heat, and then ejecting them from the nozzle onto the pads, completing the soldering process. The optical lens and PCB are then connected to the control circuit board via flexible cables, all on the same plane, to form the micromodule.

[0004] However, when using solder ball welding, it takes a long time to melt the solder balls using laser heating, and the production and processing efficiency is low. If the processing efficiency is improved by adding laser equipment, the laser equipment is expensive, which will lead to increased production costs. Summary of the Invention

[0005] The present invention aims to provide a micro-module connection process to solve the problem of low welding connection efficiency of existing micro-modules.

[0006] The micro-module connection process in this solution includes the following steps:

[0007] Step 1: Set multiple original welding points on the back of the chip into metal welding points, and set connection points on the circuit board that correspond to the metal welding points of the chip one by one;

[0008] Step 2: electrically connect the metal solder joints on the chip to the connection points on the circuit board;

[0009] Step three: align the connection points on the circuit board with the flexible wires, connect the connection points and the flexible wires through gold finger bonding, and solidify them with glue, so that the flexible wires, circuit board and chip are arranged in sequence in the axial direction and form an overall "|" shape, completing the three-dimensional connection of the micro-module.

[0010] The beneficial effects of this program are:

[0011] Before the micro-module is packaged and processed, the original solder points on the chip are set as metal solder points. The connection points between the chip and the circuit board are connected through gold finger bonding. Then, glue is dispensed and solidified. The multiple components of the module are arranged in sequence in the axial direction to form an overall "|" shape. The micro-module is connected in three dimensions in the same axial direction. This does not increase the radial size of the micro-module, allowing the micro-module to meet the miniaturization requirements of smaller-sized probes. This solution only uses two targets for gold finger bonding, and can connect multiple metal solder points simultaneously, eliminating the waiting time for the solder ball to melt and the need for manual soldering of each pin. The processing speed is fast, which can greatly improve the production and processing efficiency of the micro-module during mass production and save processing costs.

[0012] Furthermore, in the step 1, the chip packaging shell is first removed, and the chip pins are rearranged according to a preset arrangement to form metal solder joints.

[0013] The beneficial effect is that the processing of the chip can facilitate the change and arrangement of the metal solder joints, and will not limit the improvement of the subsequent connection process due to the pins that have been brought out.

[0014] Furthermore, in step 2, the radial dimension of the circuit board is set to be smaller than or equal to the radial dimension of the chip.

[0015] The beneficial effect is that the radial dimension of the circuit board is set to be smaller than the radial dimension of the chip, so that the radial dimension of the module after connection is kept very small.

[0016] Furthermore, in step 1, the connection point is located on a side surface opposite to or a circumferential side surface of the circuit board where the chip is located.

[0017] The beneficial effect is that bonding connection with the flexible wire can be carried out from multiple directions of the circuit board, and the radial size of the module can be reduced in three-dimensional connection without affecting the chip.

[0018] Furthermore, in step three, when the connection points are located on the side opposite to the side of the circuit board where the chip is located, the connection points are arranged in one row, or the connection points are arranged in two rows.

[0019] The beneficial effect is: since the area of the opposite side of the circuit board where the chip is set is larger than the area of the axial side, the connection points are arranged in one or two rows, and the flexible wires can be bonded to the connection points according to actual needs. The connection points arranged in two rows can further reduce the radial size of the chip with a large number of connection points, and have a wider range of use.

[0020] Furthermore, in step three, when the connection points are arranged in a row, the flexible wire and the opposite side are first placed on the same plane to overlap the gold fingers for bonding connection, and then the circuit board is clamped and folded within a preset time after the bonding connection, so that the flexible wire is perpendicular to the opposite side to complete the bonding connection.

[0021] The beneficial effect is: when bonding the connection points arranged in a row, the flexible wire and the opposite side are first placed in the same plane to facilitate the stable placement of the gold fingers and bonding connection, and the folding is performed within a preset time, so that the bonding connection of the flexible wire will not increase the radial size of the module.

[0022] Furthermore, in step three, when the connection points are arranged in two columns, the flexible wire is located in the middle of the two columns of connection points, and one column of connection points is first connected to one side of the flexible wire through a gold finger bond, and then the flexible wire is clamped and flipped to an inclined angle within a preset time, and the other column of connection points is connected to the other side of the flexible wire through a gold finger bond, and the flexible wire is flipped to a three-dimensional direction that is coaxial with the circuit board and the chip within a preset time.

[0023] The beneficial effect is: for the connection points arranged in two columns, the connection points in one column are first bonded to one side of the flexible wire, and then folded to an inclined angle, and then the remaining connection points are bonded to the flexible wire. This prevents the gold fingers that are bonded first from being squeezed by the circuit board and the flexible wire, and avoids the gold fingers between multiple bonded connection points from contacting and short-circuiting each other. At the same time, the inclined angle ensures accurate bonding operation after the gold fingers are stably placed when bonding on the other side.

[0024] Furthermore, in step three, the tilt angle is the angle between the flexible line and the horizontal plane, and the tilt angle ranges from 15° to 30°.

[0025] The beneficial effect is that the range of the tilt angle can avoid short circuit between the bonded connection points, while ensuring the placement stability of the gold finger on the other side.

[0026] Furthermore, in step one, the number of connection points is greater than or equal to four.

[0027] Furthermore, in the step three, the connection points are glued and cured as a whole in rows, or glued and cured point by point.

[0028] The beneficial effect is that the position of glue dispensing and curing can be set, and different glue dispensing and curing positions can be selected according to needs, so as to save glue required during processing according to different numbers of connection points. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flowchart of Example 1 of the micro-module connection process of the present invention;

[0030] Figure 2 This is a schematic diagram of the relationship between the equal sizes of the circuit board and the chip in Example 1 of the micro-module connection process of the present invention;

[0031] Figure 3 This is a schematic diagram showing the relationship between the size of the circuit board being smaller than the chip in the first embodiment of the micro-module connection process of the present invention;

[0032] Figure 4 Schematic diagram of the position of the flexible wire bonding connection on the circumferential side surface of the circuit board in Example 1 of the micro-module connection process of the present invention;

[0033] Figure 5 This is a front view of the circuit board and the flexible wire after bonding in Example 2 of the micro-module connection process of the present invention. DETAILED DESCRIPTION

[0034] The following is further explained in detail through specific implementation methods.

[0035] Example 1

[0036] Micro module connection process, such as Figure 1 As shown, the following steps are included:

[0037] Step 1: Convert multiple original solder joints on the back of the chip into metal solder joints. First, remove the chip's packaging housing. This means the chip is a semiconductor chip without a packaging housing or pins. This chip is directly customized from a semiconductor chip manufacturer, meaning the manufacturer doesn't perform the chip packaging step. The chip can be a CCD image chip used in an endoscopic probe with highly integrated peripheral circuits, such as the OVM6948. The chip pins are then rearranged according to a preset layout to form metal solder joints. This layout can be customized as needed, such as arranging multiple metal solder joints in one or two rows on the same side of the chip.

[0038] The metal solder joints are flush with the surface of the sensor chip. Connection points corresponding to the metal solder joints of the chip are set on the circuit board. The number of connection points is greater than or equal to four. The connection points are located on the opposite side or circumferential side of the side where the chip is located on the circuit board. Whether the connection points are located on the opposite side or circumferential side is selected according to actual needs, such as Figure 4 shown.

[0039] Step 2: Electrically connect the metal solder joints on the chip to the connection points on the circuit board, and set the radial size of the circuit board to be less than or equal to the radial size of the chip to reduce the overall radial size of the module. The radial size refers to the radial cross-sectional area of the module after it is loaded into the cylindrical endoscope probe.

[0040] Step 3: Align the connection points on the circuit board with the flexible wires, connect the connection points and the flexible wires through gold finger bonding, and finally glue and cure them. The flexible wires, circuit boards, and chips are arranged in sequence in the axial direction to form a "|" shape as a whole, completing the three-dimensional connection of the micromodule. The flexible wires are perpendicular to the opposite sides to complete the bonding connection. The positional relationship of the three-dimensional connection is shown in the figure. Figure 2 and Figure 3 As shown, Figure 2 The radial dimensions of the circuit board and the chip are equal, Figure 3 The radial dimension of the circuit board is smaller than that of the chip.

[0041] When bonding the gold fingers, first determine the location of the connection point. When the connection point is on the opposite side of the circuit board chip and the connection points are arranged in a row, first place the flexible wire and the opposite side on the same plane and then overlap the gold fingers for bonding. Then, clamp the circuit board and fold it within the preset time after the bonding connection. The preset time is set according to the length of time the gold fingers will not solidify during the bonding connection. When the connection point is on the circumferential side of the circuit board chip, directly place the gold fingers perpendicular to the opposite side and bond them with the flexible wire. After the bonding connection, there is no need to fold them again. When dispensing and curing, the connection points can be cured as a whole according to the column, or the connection points can be cured point by point. The method of dispensing and curing can be selected according to the actual situation. Gold fingers are existing golden conductive contacts.

[0042] Bonding is a common technique in chip connection processes and will not be discussed in detail here. Bonding the connection points on the circuit board to the flexible wires is performed using existing bonding equipment, which clamps the circuit board to align the metal solder joints with the connection points. The specific equipment structure and control components are not the subject of this application and will not be discussed here.

[0043] This embodiment first improves the basic structure of the chip by converting the original solder joints on the chip into metal solder joints. Then, in the latter half of the module processing process, the circuit board and the flexible wire are connected in a three-dimensional manner by bonding. This allows for simultaneous bonding of multiple metal solder joints without the need to wait for the solder balls to melt, thereby increasing the speed of soldering the chip to the circuit board. This embodiment, combined with improvements to the chip basic structure and the latter half of the module packaging process, significantly improves the production efficiency of micro-modules during mass production. Furthermore, during the process of packaging the micro-module, by connecting the circuit board and the flexible wire in a three-dimensional mounting manner, the lateral dimensions of the micro-module are significantly reduced compared to the existing flexible wiring method of extending and laying out on the same plane. This greatly reduces the radial dimensions of the module, thereby reducing the overall dimensions of the detection device after packaging.

[0044] Because in authoritative processing technologies at home and abroad, micro modules all place the chip on the PCB circuit board, and connect the connection lines of each pin of the chip to the PCB circuit board, flexible cable and control circuit board located on the same plane. Therefore, when improving the design of micro modules, it is generally recommended to reduce the size of the overall structure by adopting smaller chips and circuit boards. This is the recognized default standard in the industry, and people will not think of improving the chip infrastructure and module packaging process when improving the design.

[0045] Furthermore, because semiconductor chip manufacturers and module packaging manufacturers are separate, there are large technical barriers between chip and module packaging process technologies, that is, the chip technology is not known to module packaging manufacturers, and the specific technical details of module packaging are not known to chip manufacturers. Therefore, under the premise that the overall process of micro-modules is the recognized default standard in the industry, the module size will not be reduced or the efficiency of module packaging will not be improved by improving the basic structure of the chip and the latter half of the module process.

[0046] Furthermore, to ensure functional stability, reliability against damage, and compatibility between different users during chip use, all internal electrical points of the chip are connected via pins through the package. When the chip is in use, the circuit layout is performed through the electrical connection of the pins. To reduce module size and improve module processing efficiency, the technical solution of bonding unpackaged semiconductor chips to circuit boards is not used. Therefore, the solution of this embodiment is not easy to conceive.

[0047] Example 2

[0048] The micro-module connection process is different from the embodiment 1 in that Figure 5 As shown, in step three, when the connection points are located on the opposite side of the circuit board where the chip is located, the connection points are arranged in two columns. When the connection points are arranged in two columns, the flexible line is located in the middle of the two columns of connection points. First, one column of connection points is bonded to one side of the flexible line through a gold finger, and then the flexible line is clamped and flipped to an inclined angle within a preset time. The other column of connection points is bonded to the other side of the flexible line through a gold finger, and the flexible line is flipped to a three-dimensional direction coaxial with the circuit board and the chip within a preset time. The inclination angle is the angle between the flexible line and the horizontal plane, and the range of the inclination angle is 15°-30°.

[0049] Since different chips have different numbers of metal solder joints on them, if the chip size is small and the connection points are still arranged in a row on the circuit board, the radial size of the circuit board needs to be increased, which will be detrimental to the reduction of the radial size of the endoscope probe. When the number of metal solder joints on the chip is large, this embodiment arranges the connection points into two rows, and bond-connects the connection points in one row to one side of the flexible wire. After folding it to an inclined angle, the remaining connection points are bonded to the flexible wire. This prevents the gold fingers that are bonded first from being squeezed by the circuit board and the flexible wire, thus preventing the gold fingers of multiple bonded connection points from contacting and short-circuiting each other. At the same time, the inclined angle ensures accurate bonding operation after the gold fingers are stably placed when bonding on the other side.

[0050] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A micro-module connection process, characterized in that: The following steps are involved: Step 1: Set multiple original solder joints on the back of the chip into metal solder joints, and set connection points on the circuit board that correspond one-to-one to the metal solder joints of the chip, with the connection points being located on the side opposite to or circumferentially around the side of the circuit board where the chip is located; Step 2: electrically connect the metal solder joints on the chip to the connection points on the circuit board; Step 3: Align the connection points on the circuit board with the flexible wires, connect the connection points and the flexible wires with gold finger bonding, and glue and cure them, so that the flexible wires, circuit board, and chip are arranged in sequence in the axial direction to form a "|" shape, completing the three-dimensional connection of the micromodule; When the connection points are located on the side opposite to the side of the circuit board where the chip is located, the connection points are arranged in one row, or the connection points are arranged in two rows; When all the connection points are arranged in a row, first place the flexible wire and the opposite side on the same plane and overlap the gold finger for bonding connection. Then, within the preset time after the bonding connection, clamp the circuit board and fold it over so that the flexible wire is perpendicular to the opposite side to complete the bonding connection. When the connection points are arranged in two columns, the flexible wire is located in the middle of the two columns of connection points. First, one column of connection points is connected to one side of the flexible wire through gold finger bonding. Then, the flexible wire is clamped and flipped to an inclined angle within a preset time. The other column of connection points is connected to the other side of the flexible wire through gold finger bonding. Finally, the flexible wire is flipped to a three-dimensional direction coaxial with the circuit board and the chip within a preset time.

2. The micromodule connection process according to claim 1, wherein: In the step 1, the chip packaging shell is first removed, and the chip pins are rearranged according to a preset arrangement to form metal solder joints.

3. The micromodule connection process according to claim 2, wherein: In the second step, the radial dimension of the circuit board is set to be smaller than or equal to the radial dimension of the chip.

4. The micromodule connection process according to claim 1, wherein: In the step three, the tilt angle is the angle between the flexible line and the horizontal plane, and the range of the tilt angle is 15°-30°.

5. The micromodule connection process according to any one of claims 1 to 4, characterized in that: In step 1, the number of the connection points is greater than or equal to four.

6. The micromodule connection process according to any one of claims 1 to 4, characterized in that: In the step three, the connection points are glued and cured as a whole in rows, or glued and cured point by point.

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