Magnetic flux test device for 3D planar Hall chip

Abstract

The present invention provides a magnetic flux testing device for a 3D planar Hall chip, comprising: a 2D magnetic flux testing device installed at a first station, comprising: a first test fixture for placing a chip to be tested; a rotatable coil base, arranged around the first test fixture; double coils parallel to each other, arranged on the coil base; a first gold finger, electrically connected to the first test fixture; a gear, arranged between the coil base and the first test bracket; and a magnetic switch, connected to the gear through a belt; and a Z-axis magnetic flux testing device installed at a second station, comprising: a second test fixture; a single coil, arranged around the second test fixture; and a second gold finger. The magnetic flux testing device for a 3D planar Hall chip of the present invention completes three axial magnetic flux tests simultaneously through a feeding of a manipulator, and avoids the problem that the chip cannot be transported to the test fixture, without having to be re-sorted and tested again, thereby improving the test efficiency.

Description

Technical Field

[0001] The invention relates to a magnetic flux testing device, in particular to a magnetic flux testing device for a 3D planar Hall chip. Background Art

[0002] Hall sensor is a kind of magnetoelectric effect. When the current passes through the conductor in the magnetic field in a direction perpendicular to the external magnetic field, a potential difference will appear between the two end faces of the conductor perpendicular to the magnetic field and the current direction. This phenomenon is called the Hall effect. The Hall sensor is a sensor that uses the Hall element to convert the measured physical quantity (such as current, magnetic field, displacement, pressure, etc.) into an electromotive force output based on the Hall effect principle. It has a simple structure, small size, no contacts, high reliability, and easy miniaturization. Therefore, it has been widely used in measurement technology. In the production process of Hall products, the magnetic flux of the Hall products needs to be tested.

[0003] At present, in the magnetic flux test of 3D planar Hall products, the magnetic flux test is usually achieved by applying an external magnetic field to the Hall chip under test. Since it is necessary to test the magnetic flux in the X-axis, Y-axis and Z-axis directions, a set of double coils is generally used to add a magnetic field to test the X-axis, another set of double coils is used to test the Y-axis, and another set of double coils is used to test the Z-axis. The double coil magnetization method is to install the double coils on both sides of the test fixture, and place the chip under test parallel to the two coils. The magnetic field generated by the two coils passes through the chip under test in parallel; and the two sets of coils are parallel to the chip surface, and one set will block the nozzle, causing the chip to be unable to be transported to the test fixture for normal testing.

[0004] In addition, in the SOT23 package test, since the traditional SOT23 package test sorting machine does not have a variable magnetic field, it is impossible to test the magnetic flux of the Hall chip. In addition, the test head and nozzle of the traditional SOT23 package test sorting machine are made of magnetic materials. Therefore, even if a magnetic field is applied to the Hall chip for magnetic flux testing in the SOT23 package test, the magnetic conductive material used above will be permanently magnetized after magnetization, resulting in residual magnetism when no external magnetic field is generated, which will cause test deviation and misjudgment. Summary of the invention

[0005] The object of the present invention is to provide a magnetic flux testing device for a 3D planar Hall chip, so as to simultaneously complete three axial magnetic flux tests during chip testing and avoid the problem that the chip cannot be transported to a test fixture.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a magnetic flux testing device for a 3D planar Hall chip, which is installed on a packaging test sorting machine, the packaging test sorting machine includes a workbench and a turntable located above the workbench, the turntable is provided with a plurality of suction nozzles evenly distributed along its circumference, during testing, two of the suction nozzles are respectively aligned with a first station and a second station of the workbench, including: a 2D magnetic flux testing device, installed at the first station, including: a first test fixture, used to place the chip to be tested; a rotatable coil base, arranged around the first test fixture; a group of double coils parallel to each other, arranged on the coil base; a first gold finger, electrically connected to the first test fixture; a gear, arranged between the coil base and the first test bracket and fixed to the bottom of the coil base; and a magnetic switch, which is connected to the gear through a belt; and a Z-axis magnetic flux testing device, which is installed at the second station, including: a second test fixture, used to place the chip to be tested; a single coil, arranged around the second test fixture; and a second gold finger, electrically connected to the second test fixture.

[0007] The first test fixture is located at the midpoint of the center line of the double coil, and the center line of the double coil is parallel to the surface of the chip to be tested when the magnetic switch is turned on or off.

[0008] The double coil comprises two coils of equal size, equal number of coil turns and co-linear axes, and the distance between the double coils is greater than the size of the suction nozzle and its fixing parts.

[0009] The magnetic switch is configured to drive the coil base to rotate 90 degrees through the gear and belt when power is applied.

[0010] The second test fixture is located on the center line of the single coil, and the center line of the single coil is perpendicular to the surface of the chip to be tested.

[0011] The height of the second test fixture is flush with the upper end surface of the single coil.

[0012] The first test fixture is installed on the upper end of a first test bracket, which is fixed on a first test base, which is fixed at the first workstation; and the second test fixture is installed on the upper end of a second test bracket, which is fixed on a second test base, which is fixed at the second workstation.

[0013] The first test bracket and / or the second test bracket are made of aluminum, and the first test fixture and / or the second test fixture are made of copper, ceramic or non-magnetic stainless steel.

[0014] Both ends of the first and second test fixtures are snap-fitted with a fixture base, and the fixture base is fixed to the first test bracket by a first or fourth screw; two cover plates are provided above the first gold finger and the second gold finger, and each first and second gold finger is fixed between the fixture base and the cover plate by a second or fifth screw respectively; the double coils are fixed to the coil base by a third screw respectively.

[0015] One or more of the clamp base and the cover plate are made of epoxy resin, and one or more of the first screw, the second screw, the fourth screw and the fifth screw are made of glass material, and the third screw is made of stainless steel.

[0016] The magnetic flux testing device for 3D planar Hall chip of the present invention adopts a set of rotatable double coils to complete the magnetic flux test of two axes of X-axis and Y-axis at the first station by rotating, and adopts a single coil to complete the magnetic flux test of Z-axis at the second station, so as to complete the magnetic flux test of three axes at the same time through one feeding of the manipulator, and avoid the problem that the chip cannot be transported to the test fixture, without the need to re-test it on the sorting machine, thereby improving the test efficiency. In addition, the present invention realizes non-magnetic transformation by adopting non-magnetic conductive materials, thereby avoiding residual magnetism. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic diagram of the overall structure of a magnetic flux testing device for a 3D planar Hall chip according to an embodiment of the present invention.

[0018] Figure 2 For Figure 1 A top view of a 2D magnetic flux testing device for a 3D planar Hall chip is shown.

[0019] Figure 3 For Figure 1 A top view of a 2D magnetic flux testing device for a Z-axis magnetic flux testing device of a 3D planar Hall chip is shown.

[0020] Figure 4 Schematic diagram of the direction of magnetic field application for a 3D planar Hall chip.

[0021] Figure 5 It is a schematic diagram of the magnetization direction when double coils are used for magnetization.

[0022] Figure 6 This is a schematic diagram of the magnetization direction when a single coil is used for magnetization. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0024] like Figure 1 As shown in FIG. 1 , a magnetic flux testing device 10 for a 3D planar Hall chip according to the present invention is shown. Figure 1 As shown, the Hall chip magnetic flux testing device 10 is installed on a SOT23 chip packaging test sorting machine 300 to achieve the test of the Hall chip magnetic flux by magnetizing the SOT23 packaging test sorting machine. The existing SOT23 chip packaging test sorting machine 300 adopts a turntable structure. The packaging test sorting machine 300 includes a workbench 301 and a turntable 302 located above the workbench 301. The turntable 302 is provided with a plurality of suction nozzles 303 evenly distributed along its circumference. During the test, two of the suction nozzles 303 are respectively aligned with the first station and the second station of the workbench 301.

[0025] The magnetic flux testing device 10 for the 3D planar Hall chip is located below the turntable 302, and includes a 2D magnetic flux testing device 10a installed at a first station of the workbench 301 and a Z-axis magnetic flux testing device 10b installed at a second station of the workbench 301, wherein the 2D magnetic flux testing device includes a first test base 1 fixed at the first station and a first test bracket 2 fixed on the first test base 1, and the Z-axis magnetic flux testing device includes a second test base 201 fixed at the second station and a second test bracket 202 fixed on the second test base 201.

[0026] like Figure 2 The figure shows a top view of a 2D magnetic flux testing device 10a, wherein a first test fixture 3 for placing a chip to be tested and a coil base 5 arranged around the first test fixture 3 are installed at the upper end of the first test bracket 2, and the coil base 5 is rotatable, and a group of double coils 6 parallel to each other are arranged thereon. The double coil 6 includes two coils of equal size, equal number of coil turns, and colinear axes. The two ends of the first test fixture 3 are snap-fitted with a first fixture base 31, and the first fixture base 31 is fixed to the first test bracket 2 by a first screw 41. The first test fixture 3 is located at the midpoint of the center line of the double coil 6, so that the chip to be tested is located at the midpoint of the center line of the double coil 6, and combined with Figure 2 and Figure 4, the center line of the double coil 6 is parallel to the surface of the chip to be tested (i.e., the X-axis and Y-axis directions in the figure) when the magnetic switch 53 is turned on and off, wherein, when the magnetic switch 53 is not turned on, a magnetic field in the X-axis direction is provided to the chip to be tested to test the magnetic flux in the X-axis direction. The first test fixture 3 is electrically connected to two rows of first gold fingers 7, so that the first gold fingers 7 are electrically in contact with each pin of the chip to be tested placed in the first test fixture 3. The first gold fingers 7 are connecting components between the pins of the chip to be tested and the external test circuit, and all electrical signals are transmitted through the first gold fingers 7. The first gold fingers 7 are composed of a large number of golden conductive contacts, and are called "gold fingers" because their surfaces are gold-plated and the conductive contacts are arranged like fingers. The gold fingers are actually a layer of gold coated on the copper clad board through a special process, because gold has extremely strong oxidation resistance and strong conductivity. In addition, two first cover plates 8 are provided above the two rows of first gold fingers 7, and the function of the first cover plates 8 is to press the first gold fingers 7. Because there are two groups of first gold fingers 7 , two first cover plates 8 are required, and each first gold finger 7 is fixed between the first fixture base 31 and the first cover plate 8 by a second screw 42 .

[0027] See also Figure 1 A gear 51 fixed to the bottom of the coil base 5 is provided between the coil base 5 and the first test bracket 2, and the gear 51 is connected to a magnetic switch 53 through a belt 52. The magnetic switch 53 is preferably a blade swinging rotary cylinder, which is fixed to the first test base 1 and is configured to drive the gear 51 to rotate through the belt 52, thereby driving the coil base 5 to rotate. The double coils 6 are respectively fixed to the coil base 5 by a third screw 43 to rotate with the gear 51.

[0028] See also Figure 2 , the magnetic switch 53 is set to drive the coil base 5 to rotate 90 degrees through the gear 51 and the belt 52 when power is applied. Therefore, when a 24V, 50mA current is applied to the magnetic switch 53, the magnetic switch 53 is turned on, so that the belt 52 drives the double coil 6 to rotate 90 degrees, and the magnetic flux in the Y-axis direction is tested at this time. When the 24V power supply is turned off, the blade swinging rotating cylinder serving as the magnetic switch 53 is sent back to the 0-degree position by compressed air to continue testing the X-axis of the next chip.

[0029] like Figure 3The figure shows a top view of the Z-axis magnetic flux testing device 10b, wherein a second test fixture 203 for placing the chip to be tested and a single coil 206 arranged around the second test fixture 203 and fixed on the second test bracket 202 are installed on the upper end of the second test bracket 202, wherein the second test fixture 203 is located on the center line of the single coil 206, so that the chip to be tested is located on the center line of the single coil 206, so that the magnetic field in the Z-axis direction acting on the chip by the single coil is also a uniform magnetic field, ensuring the stability and accuracy of the test; the height of the second test fixture 203 is flush with the upper end surface of the single coil 206, so that the magnetic field on the surface of the single coil 206 will be divergent, and there will be a component in the vertical direction of the chip. A slight change in the position of the chip will cause a large change in the magnetic field, thereby improving the sensitivity of the measuring device.

[0030] Combination Figure 3 and Figure 4 The center line of the single coil 206 is perpendicular to the surface of the chip to be tested (ie, the Z-axis direction in the figure), thereby providing a magnetic field in the Z-axis direction to the chip to be tested to test the magnetic flux in the Z-axis direction.

[0031] The second test fixture 203 is installed in the same manner as the first test fixture 3 described above, with both ends thereof being snap-fitted with a second fixture base 2031 , and the second fixture base 2031 being fixed to the second test bracket 202 by fourth screws 2041 .

[0032] In addition, similar to the first test fixture 3 described above, the second test fixture 203 is also electrically connected to two rows of second gold fingers 207, so that the second gold fingers 207 are electrically contacted with each pin of the chip to be tested placed in the second test fixture 203, and the material and installation method of the two rows of second gold fingers 207 are the same as those of the first gold fingers 7 described above. Two second cover plates 208 are arranged above the two rows of second gold fingers 207, and the function of the second cover plates 208 is to press the second gold fingers 207. Because there are two groups of second gold fingers 207, two second cover plates are required, and each second gold finger 207 is fixed between the second fixture base 2031 and the second cover plate 208 by a fifth screw 2042.

[0033] During the test, since two of the suction nozzles 303 are respectively aligned with the first station and the second station of the workbench, one of the suction nozzles 303 is located directly above the first test fixture 3, and one of the suction nozzles 303 is located directly above the second test fixture 203, so that each chip to be tested is sequentially sent to the first test fixture 3 and the second test fixture 203 through the suction nozzle 303. Due to the structure of the packaging test sorting machine 300, it is not possible to use the 4-coil magnetization method to magnetize the existing SOT23 chip packaging test sorting machine in the X direction and the Y direction. Therefore, in the present invention, a rotatable double coil is used to magnetize the SOT23 chip packaging test sorting machine 300 by rotating, and the magnetic flux is tested on the X axis and the Y axis (rotated 90 degrees). The magnetic flux test in the X-axis and Y-axis directions is switched by rotating the coil. In addition, due to the existence of the suction nozzle 303, the magnetic flux test in the Z-axis direction can only use a single coil to apply a magnetic field. Due to the spacing limit between the coil base 5 of the double coil 6 and the nozzle 303, the Z-axis coil cannot be placed directly under the 2D coil and needs to be placed separately in a station for testing. Therefore, the 3D Hall chip first tests the magnetic flux in the X-axis and Y-axis directions on the double coil 6 located at the first station, and then transports it to the single coil 206 of the Z-axis at the second station for the Z-axis magnetic flux test. The packaging test sorting machine 300 simultaneously transports two chips to the first station and the second station of the workbench respectively. The testing machine energizes the X-axis and Z-axis coils at the same time to generate a magnetic field, and completes the test of the X-axis and Z-axis magnetic flux. After rotating the coil, the Y-axis magnetic flux is tested, and the Z-axis is not powered by the program. In this way, the sorting machine can complete the magnetic flux measurement of the 3D chip in three magnetic field directions at one time.

[0034] See also Figure 5During the test, the two coils of the double coil 6 are respectively connected to the tester (not shown), and the tester can change the size of the input current of the double coil 6 to control the size of the magnetic flux of the external magnetic field generated by the double coil 6. The tester is preferably an ATE tester, which is used to provide a voltage source and a current source and measure voltage and current and communicate with the packaging test sorting machine 300 to realize automated testing. The magnetic field generated by the double coil 6 is a uniform magnetic field perpendicular to the cross section of the coil at the common axis of the two coils. The magnitude of the magnetic field strength is superimposed by the two coils, which prevents the magnetic lines from diverging as the distance increases, and at the same time, a uniform magnetic field is generated in the area near the center point between the two coils. In this embodiment, the spacing of the double coil 6 is greater than the size of the suction nozzle 303 and its fixing parts of the packaging test sorting machine 300, so that when the chip to be tested can be placed in the first test fixture 3 through the suction nozzle 303 in the turntable 302 and pressed down to make good contact with the gold finger 7, the surface of the chip to be tested is parallel to the central magnetic lines of the double coil. Each time the nozzle transports the chip to be tested to the test fixture, it will accurately place the chip in the center of the test fixture, ensuring that the chip to be tested is always in the center of the double coil. At the same time, the magnetic field linearity of the South Pole and the North Pole is exactly the same (the number of coil turns and the wire diameter of the enameled wire are exactly the same), and the same coefficient can be used to calculate the working point and release point of the chip. This device can fully make the external magnetic field pass through the Hall chip in parallel during the Hall chip magnetic flux test, so as to achieve the most accurate magnetic induction intensity measurement. The specific magnetic flux test principle is as follows: After the nozzle 303 presses down the chip, it sends a start test signal to the tester. After receiving the signal, the tester provides 24V, 50mA current to the magnetic switch, and the coil rotates 90 degrees. At this time, the coil provides a magnetic field in the Y-axis direction. Then, a working voltage is added to the input pin of the chip to be tested. At this time, the output pin of the chip changes from 0V to a high level. Then, the double coil 6 is energized to add an external magnetic field to the Hall chip. The strength of the external magnetic field changes from small to large. When the output pin level changes from high to low, the magnetic field strength at this point is the working point magnetic field strength required for the test. Then, the magnetic field is reduced. When the output level changes from low to high, the magnetic field strength at this point is the release point magnetic field strength required for the test. The difference between the working point magnetic field strength and the release point magnetic field strength is the magnetic width of the Hall chip. In this test, the measured magnetic width is compared with the test specification to see if it is within the set range. If it is within the test specification, it is a qualified Hall chip, otherwise it is an unqualified Hall chip to be tested.

[0035] Similarly, the magnetic flux of the Hall chip in the Z-axis direction can be tested by using a single coil 206. Figure 6 As shown, the method of testing the magnetic flux using a single coil 206 is exactly the same as the method of testing the magnetic flux using a double coil described above, and will not be described in detail here.

[0036] In the magnetic flux test of the Hall chip, the magnetic conductive material used in the conventional test sorter test device will be permanently magnetized due to the application of an external magnetic field. Therefore, when the double coil 6 and the single coil 206 do not generate a magnetic field, residual magnetism will also appear. The Hall chip magnetic flux test device 10 of the present invention uses non-magnetic conductive materials to achieve non-magnetic transformation, thereby avoiding residual magnetism, wherein the first test bracket 2 and / or the second test bracket 202 for coil installation can be made of non-magnetic conductive material aluminum. The first test fixture 3 and / or the second test fixture 203 for placing the Hall chip are made of non-magnetic conductive material copper, ceramic or non-magnetic stainless steel. One or more of the first fixture base 31, the second fixture base 2031, the first cover plate 8 and the second cover plate 208 can be made of non-conductive material epoxy resin; and one or more of the first screw 41, the second screw 42, the fourth screw 2041 and the fifth screw 2042 are made of glass material. The material of the third screw 43 is stainless steel. Therefore, the present invention uses non-magnetic conductive materials to carry out non-magnetic transformation on some components of the test device, thereby eliminating the residual magnetism phenomenon, reducing test deviation and misjudgment, and obtaining accurate magnetic flux test results.

[0037] In addition, in other embodiments, one or more of the first clamp base 31, the second clamp base 2031, the first cover plate 8 and the second cover plate 208 may also be made of metal materials, which are more durable. One or more of the first screw 41, the second screw 42, the fourth screw 2041 and the fifth screw 2042 may also be stainless steel screws. However, residual magnetism may occur over time.

[0038] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A magnetic flux testing device (10) for a 3D planar Hall chip, which is installed on a packaging test sorting machine (300), wherein the packaging test sorting machine (300) comprises a workbench (301) and a turntable (302) located above the workbench (301), and the turntable (302) is provided with a plurality of suction nozzles (303) evenly distributed along its circumference. During testing, two of the suction nozzles (303) are respectively aligned with a first station and a second station of the workbench (301), characterized in that: include: A 2D magnetic flux testing device (10a), installed at the first station, comprising: A first test fixture (3), used for placing the chip to be tested; A rotatable coil base (5) is arranged around the first test fixture (3); A group of double coils (6) parallel to each other, arranged on the coil base (5); A first gold finger (7) electrically connected to the first test fixture (3); a gear (51), disposed between the coil base (5) and the first test bracket (2) and fixed to the bottom of the coil base (5); and a magnetic switch (53) connected to the gear (51) via a belt (52); and a Z-axis magnetic flux testing device (10b) installed at the second station, comprising: A second test fixture (203), used for placing the chip to be tested; A single coil (206) is disposed around the second test fixture (203); and The second gold finger (207) is electrically connected to the second test fixture (203).

2. The magnetic flux testing device for a 3D planar Hall chip according to claim 1, characterized in that: The first test fixture (3) is located at the midpoint of the center line of the double coil (6), and the center line of the double coil (6) is parallel to the surface of the chip to be tested when the magnetic switch (53) is turned on or off.

3. The magnetic flux testing device for a 3D planar Hall chip according to claim 1, characterized in that: The double coil (6) comprises two coils of equal size, equal number of coil turns and co-linear axes, and the spacing between the double coils (6) is greater than the size of the suction nozzle (303) and its fixing parts.

4. The magnetic flux testing device for a 3D planar Hall chip according to claim 1, characterized in that: The magnetic switch (53) is configured to drive the coil base (5) to rotate 90 degrees through the gear (51) and the belt (52) when power is applied.

5. The magnetic flux testing device for a 3D planar Hall chip according to claim 1, characterized in that: The second test fixture (203) is located on the center line of the single coil (206), and the center line of the single coil (206) is perpendicular to the surface of the chip to be tested.

6. The magnetic flux testing device for a 3D planar Hall chip according to claim 5, characterized in that: The height of the second test fixture (203) is flush with the upper end surface of the single coil (206).

7. The magnetic flux testing device for a 3D planar Hall chip according to claim 1, characterized in that: The first test fixture (3) is installed on the upper end of a first test bracket (2), the first test bracket (2) is fixed on a first test base (1), and the first test base (1) is fixed at the first workstation; and the second test fixture (203) is installed on the upper end of a second test bracket (202), the second test bracket (202) is fixed on a second test base (201), and the second test base (201) is fixed at the second workstation.

8. The magnetic flux testing device for a 3D planar Hall chip according to claim 7, characterized in that: The first test bracket (2) and / or the second test bracket (202) are made of aluminum, and the first test fixture (3) and / or the second test fixture (203) are made of copper, ceramic or non-magnetic stainless steel.

9. The magnetic flux testing device for a 3D planar Hall chip according to claim 7, characterized in that: Both ends of the first and second test fixtures (3, 203) are snap-fitted with a fixture base (31, 2031), and the fixture base (31, 2031) is fixed to the first test bracket (2) by a first screw (41) or a fourth screw (2041); two cover plates (8, 208) are provided above the first gold finger (7) and the second gold finger (207), and each first and second gold finger (7, 207) is fixed between the fixture base (31, 2031) and the cover plate (8, 208) by a second screw (42) or a fifth screw (2042); and the double coil (6) is fixed to the coil base (5) by a third screw (43).

10. The magnetic flux testing device for a 3D planar Hall chip according to claim 9, characterized in that: One or more of the clamp base (31, 2031) and the cover plate (8, 208) are made of epoxy resin, and one or more of the first screw (41), the second screw (42), the fourth screw (2041) and the fifth screw (2042) are made of glass material, and the third screw (43) is made of stainless steel.

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