Jig for wire welding of intrusive pressure sensor

Abstract

The utility model discloses a wire welding jig for an intrusive pressure sensor, which comprises a chip bearing platform and a three-wire guide wire bearing platform which are respectively connected with a three-way fine tuning platform through bolts. The chip bearing platform comprises a jig base and a six-lug rotary table which are connected through bolts, and the three-wire guide wire bearing platform comprises a three-wire guide wire straightening channel, a connecting base and four through holes. The six-lug rotary table comprises three structures, the first structure is a hexahedron located in the center, the second structure is six cuboids perpendicularly connected with the side faces of the hexahedron, the third structure is composed of six second cylinders, and three kinds of chip positioning grooves are cut in the upper surface of the six-lug rotary table. A groove is formed in the connecting base and used for bearing the three-wire guide wire straightening channel. And the chip positioning groove is matched with the adjustment of the three-way fine adjustment platform, so that the accurate positioning of the bonding pad can be improved, and the problems existing in the process of connecting the three-wire guide wire and the MEMS pressure chip bonding pad with the bonding wire in the packaging process are solved.

Description

Technical Field

[0001] The utility model belongs to the field of MEMS pressure sensor packaging, and in particular relates to a fixture for welding wires of an invasive pressure sensor. Background Art

[0002] In the biomedical field, MEMS sensors are like the eyes of human organs. They convert the physiological signals of the human body into medical electrical signals and are an important bridge connecting medical instruments and human organs.

[0003] The invasive pressure sensor is a MEMS pressure sensor that can perform fixed-point measurements in human blood vessels. Due to its advantages such as high sensitivity, good stability, and small size, it can be used in different minimally invasive surgical scenarios and combined with a variety of medical devices to increase the function of pressure monitoring, playing a huge role in clinical medicine.

[0004] The smallest invasive MEMS pressure sensor chip in mass production is currently known in the world. Its size is only 0.65mm×0.22mm×0.075mm, and its chip pad size is also the smallest known, at only 0.15mm×0.045mm.

[0005] In order to accurately detect the pressure changes in the narrow blood vessels of the human body, a three-wire guide wire of a specific diameter is used to output the pressure changes sensed by the MEMS pressure chip to the external medical equipment of the human body for display. How to connect such a small pad structure with a three-wire guide wire of a specific specification has become the biggest difficulty in the packaging of invasive pressure sensors.

[0006] Usually, the connection between the pressure chip pad of the intrusive MEMS pressure sensor and the three-wire guide wire is to use anisotropic conductive tape (ACF tape) attached to the MEMS pressure chip pad, and then the gold balls in the ACF tape are broken by hot pressing, and the gold balls are combined with the pad; then the guide wire is connected to the pad with broken gold balls by hot pressing using a precision placement machine. This operation method requires a considerable number of broken gold balls on the chip pad, which is complicated to operate and the number of broken gold balls is difficult to control. Moreover, whether the guide wire can overlap with the broken gold balls when overlapping with the pad is also an uncertain factor in the operation, resulting in low production efficiency and unguaranteed product quality. Utility Model Content

[0007] In order to solve the above-mentioned problems existing in the process of connecting the three-wire guide wire with the MEMS pressure chip pad during the packaging process of the invasive pressure sensor, the utility model discloses a fixture for the invasive pressure sensor wire bonding.

[0008] The technical solution adopted by the utility model is as follows: a fixture for welding wires of an invasive pressure sensor, the fixture is composed of two parts, namely, a left chip bearing platform and a right three-wire guide wire bearing platform. The left and right bearing platforms are respectively connected to the left and right three-way fine-tuning platforms by four sunken hexagonal bolts (numbered 101). The welding wire fixture of the utility model refers to a mechanism for welding wires connected to the left and right three-way fine-tuning platforms.

[0009] The left chip carrying platform includes a fixture base, a six-ear turntable and bolts (numbered 109) connecting the six-ear turntable and the fixture base.

[0010] The jig base is in the shape of a first flat cylinder. The base (No. 100) is connected to the three-way fine-tuning platform below by four sunken hexagonal bolts (No. 101). The upper surface of the base (No. 100) has six non-through holes (No. 110) with a diameter and a depth of 1.2 mm evenly distributed along the circumferential direction. Six copper balls (No. 111) with a diameter of 1.5 mm are connected to the six non-through holes (No. 110) by soldering. Figure 1 Only one copper ball connection method is indicated in the figure), and the center of the fixture base has a threaded hole for connection with the six-ear turntable. The purpose of this design is that the six non-through holes (numbered 110) are used to receive and fix the six copper balls (numbered 111). The fixture base is precisely positioned with the cylindrical hole at the bottom of the six-ear turntable through the six copper balls, so as to achieve the purpose of precise positioning of the MEMS pressure chip during the wire bonding process.

[0011] The six-ear turntable consists of three structures. The first structure is the central hexagon (numbered 103), the second structure is six rectangular blocks (numbered 104) perpendicular to the six sides of the hexagon, and the third structure is a second flat cylinder (numbered 105) intersecting with the six rectangular blocks, and three types of chip positioning grooves (numbered 106, 107, 108) are cut on the upper surface of the second flat cylinder (numbered 105).

[0012] The first structure of the six-ear turntable is a connecting hexagon (number 103), the center of which has a through hole of the same specification as the center of the fixture base, and the through hole realizes the concentric connection between the fixture base and the six-ear turntable.

[0013] The second structure of the six-ear turntable comprises six rectangular blocks (numbered 104) perpendicular to the six sides of the connected hexagonal blocks. The lower surfaces of the six rectangular blocks (numbered 104) are in the same plane as the lower surfaces of the connected hexagonal blocks (numbered 103), and the upper surfaces of the six rectangular blocks (numbered 104) are not in the same plane as the upper surfaces of the connected hexagonal blocks (numbered 103). The purpose of such design is to prevent the chip in the positioning slot from being touched by foreign objects when the six-ear turntable rotates.

[0014] The second structure of the six-ear turntable is that the six cuboids (numbered 104) have six cylindrical non-through holes (with a diameter and depth of 1.2 mm) at specific positions on the lower surfaces. Figure 2 The six cylindrical non-through holes are not marked in the figure. The six cylindrical non-through holes have the same specifications and positions as the six non-through holes (No. 110) on the upper surface of the fixture base (No. 110) with a diameter and depth of 1.2 mm.

[0015] The third structure of the six-ear turntable is composed of a second flat cylinder (numbered 105) intersecting with the six rectangular blocks of the second structure. The thickness of the cylinder is the same as that of the six rectangular blocks (numbered 104) of the second structure and the lower surface is in the same plane. Three types of chip positioning grooves (type A numbered 106, type B numbered 107, type C numbered 108) are cut on the upper surface of the cylinder (numbered 105).

[0016] The right three-wire guide wire bearing platform includes a three-wire guide wire straightening channel (number 112), a connecting base (number 113) and four sunken hexagonal bolts (number 101), wherein the three-wire guide wire straightening channel is a detailed view of the three-wire guide wire straightening channel. Figure 6 shown.

[0017] The connecting base is a rectangular plate (number 113), which is connected to the right three-way fine-tuning welding platform through four sunken hexagonal bolts (number 101).

[0018] The three-wire guide wire straightening channel is composed of two half cylinders, an upper one (numbered 115) and a lower one (numbered 116). The three-wire guide wire can pass freely in the quasi-cylinder (numbered 114) composed of the upper and lower half cylinders. Since the diameter of the quasi-cylinder (numbered 114) is the same as the diameter of the three-wire guide wire, the upper one (numbered 115) and the lower one (numbered 116) half cylinder are combined to straighten the three-wire guide wire.

[0019] The three-wire guide wire straightening channel and the connecting base (numbered 113) are connected through pin holes (numbered 117) that penetrate through both sides of the lower half cylinder. After the three-wire guide wire straightening channel and the connecting base are connected, the right side structure of the fixture of the utility model is formed.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0021] When the fixture of the utility model is used for wire welding operation, the positioning groove fixture equipped with the tiny chip pad cooperates with the adjustment of the three-way fine-tuning platform to realize the precise positioning of the pad. At the same time, multiple chips are carried in the chip positioning groove of the six-ear turntable during operation. When the chip in a positioning groove is used up, it is only necessary to rotate the six-ear turntable to the other ear to realize the upper chip switching of the welding wire, thereby improving the efficiency of the wire welding operation. At the same time, the three-wire guide wire on the right side is straightened in the cylinder-like shape, which improves the alignment of the three-wire guide wire and the tiny chip pad, greatly improves the operation accuracy, and ensures the reliability of the product after wire welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the overall appearance of the chip carrying platform on the left side of the wire bonding fixture of the utility model after assembly.

[0023] Figure 2 This is the overall appearance of the three-wire guide wire bearing platform on the right side of the welding wire fixture of the utility model after assembly.

[0024] Figure 3 This is the overall appearance of the chip carrying platform fixture base on the left side of the wire bonding fixture of the utility model.

[0025] Figure 4 This is the overall appearance of the six-ear turntable of the chip carrying platform on the left side of the wire bonding fixture of the utility model.

[0026] Figure 5 This is a partial structural diagram of the three-wire guide wire bearing platform on the right side of the welding wire fixture of the utility model.

[0027] Figure 6 This is a partial structural diagram of the straightening channel of the three-wire guide wire bearing platform on the right side of the welding wire fixture of the utility model.

[0028] Specific manufacturing method

[0029] In order to make the technical solutions and advantages of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model and with reference to the accompanying drawings. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] It should be noted that the same function is represented by the same number in the drawings of the present invention, and the name terms of the fixture of the present invention are also for the convenience of description. The directional terms "front", "rear", "left", "right", "up" and "down" used in the present invention refer to the directions in the drawings.

[0031] In the description of the present utility model, it should be noted that the terms "first", "second" and "third" are only used for the purpose of describing the application and cannot be understood as indicating or implying relative importance.

[0032] The examples are as follows:

[0033] The overall appearance of the chip carrier platform fixture on the left side of the wire bonding fixture is as follows: Figure 1 The overall appearance of the left chip carrier platform fixture base is as follows Figure 3 During operation, first connect the bearing platform (No. 100) to the three-way fine-tuning platform on the left with the matching countersunk bolts (No. 101) and tighten them, connect the six-ear turntable to the center hole of the bearing platform (No. 100) with the hexagonal bolts (No. 109) and tighten them, make the cylindrical holes on the lower surface of the cuboid (No. 104) contact and tighten the six copper balls (No. 111), and then tighten the hexagonal bolts (No. 109). At this time, the connection between the six-ear turntable and the left fixture base is realized.

[0034] Before the above-mentioned connection, the invasive pressure sensor MEMS pressure chip should be transferred to the positioning groove of the corresponding width of the second flat cylinder (No. 105) through a picking device. This embodiment discloses positioning grooves of three widths of chips, and the widths correspond to the widths of the MEMS pressure chip, from left to right: Class A 0.305mm~0.355mm, Class B 0.195mm~0.245mm, Class C 0.700mm~0.750mm.

[0035] After the chips of the three types of widths are picked up into the positioning grooves as described above, a silicone rod is used to push the chip along the length direction of the positioning groove to the edge away from the hexagonal bolt (No. 109). After the corresponding positioning grooves of the six second flat cylinders are filled with chips of corresponding widths, the hexagonal bolts (No. 109) are tightened to achieve precise positioning of the left chip carrier platform. At this point, the left fixture connection and chip loading operations are completed.

[0036] After the left chip carrying platform fixture connection and chip loading are completed, the right side fixture connection and three-wire guide wire bearing straightening are implemented.

[0037] The overall structure of the three-wire guide wire bearing platform on the right side of the welding wire fixture is as follows: Figure 2 Before the operation, first connect the connecting base plate (No. 113) to the right three-way fine-tuning platform with the matching countersunk bolts (No. 101) and tighten them, and align the lower half cylinder (No. 116) and the upper half cylinder (No. 115) of the three-wire guide wire straightening channel according to the Figure 6As shown, it is fixed in the three-wire guide wire groove and tightened. At this time, the three-wire guide wire straightening channel is formed. However, in order to facilitate the operation, the upper half cylinder (No. 115) is used to put the three-wire guide wire in and then close the upper half cylinder with the lower half cylinder. At this time, the pin hole (No. 117) connects the upper and lower half cylinders to realize the locking of the three-wire guide wire straightening mechanism. At this point, the installation of the three-wire guide wire bearing platform on the right side is completed.

[0038] After the right three-wire guide wire platform is installed, the three-wire guide wire and the left MEMS pressure chip pad are aligned by adjusting the three-way fine-tuning platform connected under the bottom plate. This alignment process can be completed under the CCD high-power microscope of the resistance hot pressing welding machine.

[0039] After the three-wire guide wire is aligned with the left MEMS pressure chip pad, the parameters of the resistance hot pressing welding machine are adjusted. At this time, the spot welding head descends to the set position, and the three-wire guide wire is connected to the MEMS pressure chip by resistance heat.

[0040] The above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in the field should understand that they can still modify the technical solution recorded in the embodiment with reference to the embodiment, or make equivalent replacements for some of the technical features therein.

Claims

1. A jig for welding wires of an invasive pressure sensor, characterized in that: It includes a chip carrying platform and a three-wire guide wire carrying platform, wherein the chip carrying platform and the three-wire guide wire carrying platform are respectively connected to the three-way fine-tuning platform by four sunken hexagonal bolts; the chip carrying platform includes a fixture base, a six-ear turntable and bolt accessories for connecting the six-ear turntable and the fixture base, and the three-wire guide wire carrying platform includes a three-wire guide wire straightening channel, a connecting base and four sunken hexagonal through holes; Among them, the appearance of the fixture base is a first flat cylinder; the six-ear turntable includes three structures, the first structure is a hexagon located in the center of the six-ear turntable, the second structure is six rectangular blocks vertically connected to the six sides of the hexagon, and the third structure is composed of a flat second cylinder intersecting the six rectangular blocks, and three types of chip positioning grooves are cut on the upper surface of the second flat cylinder; the upper surface of the connecting base is provided with a groove for carrying a three-wire guide wire straightening channel; the three-wire guide wire straightening channel is composed of two upper and lower half cylinders, and the three-wire guide wire straightening channel and the connecting base are connected by a pin hole passing through the lower half cylinder. After the three-wire guide wire straightening channel is connected to the connecting base, it constitutes the right side structure of the fixture of the present application.

2. A jig for welding wires of an invasive pressure sensor according to claim 1, characterized in that: The center of the fixture base has a threaded hole for connection with the six-ear turntable. The fixture base is connected to the lower three-way fine-tuning platform through four sunken hexagonal bolts. The upper surface of the fixture base has six non-through holes with a diameter and depth of 1.2 mm evenly distributed along the circumferential direction. Six copper balls with a diameter of 1.5 mm are connected to the six non-through holes by soldering. The first structure of the six-ear turntable is a hexagon, with a through hole of the same specifications as the center of the first flat cylinder of the above-mentioned jig base in the center; the lower surface of the second structure of the six-ear turntable is in the same plane as the lower surface of the first structure of the six-ear turntable, and the lower surface of the second structure of the six-ear turntable is not in the same plane as the first structure of the six-ear turntable; there are six cylindrical non-through holes with a diameter and a depth of 1.2 mm at specific positions on the lower surface of the second structure of the six-ear turntable, and the six cylindrical non-through holes have the same specifications and positions as the six non-through holes with a diameter and a depth of 1.2 mm on the upper surface of the above-mentioned jig base; the thickness of the third structure of the six-ear turntable is the same as the thickness of the second structure of the six-ear turntable, and the lower surface is in the same plane.

3. The jig for welding wires of an invasive pressure sensor according to claim 1, characterized in that: The three types of chip positioning grooves are of three different sizes and can accommodate pressure sensor chips of different sizes and thicknesses.

4. The jig for welding wires of an invasive pressure sensor according to claim 1, characterized in that: The connecting base is a rectangular plate with four sunken through holes, which is connected to the three-way fine-tuning welding station using four matching sunken hexagonal bolts.

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