A Tangent Process for a Power Semiconductor Wire Bonding Machine

Abstract

The present invention relates to the technical field of semiconductor packaging and testing, and discloses a wire cutting process for a power semiconductor wire bonder, which includes the following steps: S1: After welding, when the End solder joint is welded, the lower pressure generator cancels the lower pressure; S2: The bonding tool is lifted, and the welding head rises under the action of the driving arm, and the bonding tool is lifted; S3: Movement, the bonding tool of the welding head moves a proper distance along the connection line direction of the penultimate solder joint and the End solder joint and then moves downward; S4: Lower movement, at this time, the welding head is lowered to the predetermined position of the displacement sensor; S5: Wire cutting, the bonding tool of the welding head directly moves downward through the pre-calibrated wire cutting depth to complete the wire cutting action. This wire cutting process for a power semiconductor wire bonder realizes the use of a displacement sensor for pressure depth positioning, ensures the repeatability and consistency of the cutting process, the wire cutting depth is calculated through pre-calibration, and the cutting is directly carried out downward, with high efficiency and fast speed.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging and testing, and particularly relates to a tangent process for a power semiconductor wire bonder. Background Art

[0002] In the production process of power semiconductor products, it is divided into three processes: design, manufacturing, and packaging and testing. In the packaging and testing production link, the main processing processes are Die Bond (chip bonding) and Wire Bond (wire bonding); the tangent process of wire bonding refers to the process of cutting the aluminum wire after the last solder joint of the aluminum wire bonding. Since the last solder joint may be on the pad of the wafer, the cutting action will also occur on the pad of the wafer, which may damage the wafer.

[0003] To solve the above problems, we propose a tangent process for a power semiconductor wire bonder. Summary of the Invention

[0004] The purpose of the present invention is to provide a tangent process for a power semiconductor wire bonder, which uses a displacement sensor for depth pressing positioning to ensure the repeatability and consistency of the cutting process. The tangent depth is calculated in advance through calibration and directly cuts downward, with high efficiency and speed.

[0005] The embodiments of the present invention are implemented as follows:

[0006] The embodiments of the present invention provide a tangent process for a power semiconductor wire bonder, which includes the following steps:

[0007] S1: Welding Ended

[0008] After the End solder joint is welded, the downward pressure generator cancels the downward pressure;

[0009] S2: Lifting the Wedge

[0010] The welding head rises under the action of the driving arm, and the wedge is lifted;

[0011] S3: Moving

[0012] The wedge of the welding head runs a proper distance along the connection line direction of the penultimate solder joint and the End solder joint and then moves downward;

[0013] S4: Lowering

[0014] At this time, let the welding head move down to the predetermined position of the displacement sensor;

[0015] S5: Tangenting

[0016] The wedge of the welding head directly moves downward through the pre-calibrated tangent depth to complete the tangent action.

[0017] Optionally, step S1 occurs after the welding of the End solder joint is completed, at which time the bonding tool is pressing on the End solder joint.

[0018] Optionally, the distance that the bonding tool is lifted in step S2 is one millimeter.

[0019] Optionally, in step S3, the bonding tool first continues to move 1.5 millimeters along the line connecting the penultimate solder joint and the End solder joint, and then moves down 1 millimeter.

[0020] Optionally, the welding head includes a displacement sensor, a down-force generator, an ultrasonic transducer, an aluminum wire feeding tube, a bonding tool, and a cutting tool. Among them, the displacement sensor and the down-force generator are integrally and rigidly connected to the driving arm, and the ultrasonic transducer, the aluminum wire feeding tube, the bonding tool, and the cutting tool are integrally and flexibly connected to the driving arm and can move slightly up and down relative to the displacement sensor and the down-force generator.

[0021] Optionally, the displacement sensor can detect the relative position of the ultrasonic transducer, the aluminum wire feeding tube, the bonding tool, and the cutting tool as a whole relative to the displacement sensor and the down-force generator.

[0022] Optionally, the cutting tool is installed close to the bonding tool but does not touch it, the aluminum wire feeding tube is installed close to the bonding tool but does not touch it, the aluminum wire passes through the aluminum wire feeding tube and is placed directly below the end of the bonding tool, and the ultrasonic transducer and the bonding tool are tightly and fixedly connected.

[0023] Optionally, one end of the bonding tool penetrates through the ultrasonic transducer, and the ultrasonic transducer is equipped with a matching ultrasonic generator.

[0024] Optionally, the displacement sensor can set the cutting depth, and in step S5, the bonding tool of the welding head directly moves down to the cutting depth pre-calibrated by the displacement sensor.

[0025] Optionally, in step S4, the predetermined position of the displacement sensor is pre-calibrated and calculated in advance.

[0026] The beneficial effects of the embodiments of the present invention include: The embodiments of the present invention provide a tangent process for a power semiconductor wire bonder. The bonding tool of the welding head moves along the line connecting the penultimate solder joint and the End solder joint for an appropriate distance and then moves down to the predetermined position of the displacement sensor. By using the displacement sensor for depth pressing positioning, the repeatability and consistency of the cutting process are ensured. The bonding tool directly moves down through the pre-calibrated cutting depth to complete the tangent action. The cutting depth is pre-calibrated and calculated in advance, and direct downward cutting is performed, with high efficiency and fast speed. Description of the Drawings

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of a welding head for a wire cutting process of a power semiconductor wire bonder according to the present invention.

[0029] Icon: 1. Displacement sensor; 2. Downward pressure generator; 3. Ultrasonic transducer; 4. Aluminum wire feeding tube; 5. Wedge; 6. Cutting tool. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0032] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0033] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] As Figure 1 shown, an embodiment of the present invention provides a tangent process for a power semiconductor wire bonder, including the following steps:

[0035] S1: Welding completed

[0036] After the welding of the End solder joint is completed, the lower pressure generator 2 cancels the lower pressure;

[0037] S2: The bonding tool 5 is lifted

[0038] The welding head rises under the action of the driving arm, and the bonding tool 5 is lifted;

[0039] S3: Moving

[0040] The bonding tool 5 of the welding head runs a proper distance along the line connecting the penultimate solder joint and the End solder joint and then moves downward;

[0041] S4: Moving down

[0042] At this time, the welding head is lowered to the predetermined position of the displacement sensor 1;

[0043] S5: Tangent

[0044] The bonding tool 5 of the welding head directly moves downward through the pre-calibrated tangent depth to complete the tangent action.

[0045] As an embodiment of the present invention, step S1 occurs after the welding of the End solder joint is completed, and at this time, the bonding tool 5 is pressing on the End solder joint.

[0046] As an embodiment of the present invention, the distance that the bonding tool 5 is lifted in step S2 is one millimeter.

[0047] As an embodiment of the present invention, in step S3, the bonding tool 5 first continues to run 1.5 millimeters along the line connecting the penultimate solder joint and the End solder joint, and then moves downward by 1 millimeter. The bonding tool 5 of the welding head runs a proper distance along the line connecting the penultimate solder joint and the End solder joint and then moves downward to the predetermined position of the displacement sensor 1. By using the displacement sensor 1 for depth pressing positioning, the repeatability and consistency of the cutting process are ensured.

[0048] As an embodiment of the present invention, the welding head includes a displacement sensor 1, a downward pressure generator 2, an ultrasonic transducer 3, an aluminum wire feeding tube 4, a capillary 5, and a cutter 6. Among them, the displacement sensor 1 and the downward pressure generator 2 are integrated and rigidly connected to the driving arm. The ultrasonic transducer 3, the aluminum wire feeding tube 4, the capillary 5, and the cutter 6 are integrated and flexibly connected to the driving arm, and can move slightly up and down relative to the displacement sensor 1 and the downward pressure generator 2.

[0049] As an embodiment of the present invention, the displacement sensor 1 can detect the relative position of the ultrasonic transducer 3, the aluminum wire feeding tube 4, the capillary 5, and the cutter 6 as a whole relative to the displacement sensor 1 and the downward pressure generator 2.

[0050] As an embodiment of the present invention, the cutter 6 is installed close to the capillary 5 but does not touch it, and the aluminum wire feeding tube 4 is installed close to the capillary 5 but does not touch it. The aluminum wire passes through the aluminum wire feeding tube 4 and is placed directly below the end of the capillary 5. The ultrasonic transducer 3 and the capillary 5 are tightly fixed and connected.

[0051] As an embodiment of the present invention, one end of the capillary 5 penetrates through the ultrasonic transducer 3, and the ultrasonic transducer 3 is adapted with a matching ultrasonic generator.

[0052] As an embodiment of the present invention, the displacement sensor 1 can set the tangent depth. In step S5, the capillary 5 of the welding head directly runs downward to the tangent depth pre-calibrated by the displacement sensor 1.

[0053] As an embodiment of the present invention, in step S4, the predetermined position of the displacement sensor 1 is pre-calibrated and measured. The capillary 5 directly runs downward through the pre-calibrated tangent depth to complete the tangent action. The tangent depth is pre-calibrated and measured, and then directly cut downward, with high efficiency and fast speed.

[0054] It should be noted that the present invention is a tangent process for a power semiconductor wire bonder. After the End solder joint is welded, at this time, the capillary 5 is pressing on the End solder joint. At the same time, the downward pressure generator 2 cancels the downward pressure. The capillary of the welding head runs 1.5 mm along the connection line direction of the penultimate solder joint and the End solder joint and then moves 1 mm downward to the predetermined position of the displacement sensor. By using the displacement sensor for depth pressing positioning, the repeatability and consistency of the cutting process are ensured. The capillary directly runs downward through the pre-calibrated tangent depth to complete the tangent action. The tangent depth is pre-calibrated and measured, and then directly cut downward, with high efficiency and fast speed.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A wire cutting process for a power semiconductor wire bonder, characterized in that, It includes the following steps: S1: Welding is completed After the welding of the End solder joint is completed, the down-force generator (2) cancels the down-force; S2: The splitting knife (5) is lifted The welding head rises under the action of the driving arm, and the splitting knife (5) is lifted; S3: Movement The splitting knife (5) of the welding head runs an appropriate distance along the line connecting the penultimate solder joint and the End solder joint and then moves downward; S4: Moving downward At this time, let the welding head move downward to the predetermined position of the displacement sensor (1); S5: Tangent cutting The cutting knife (6) of the welding head runs directly downward through the pre-calibrated tangent depth to complete the tangent cutting action; Among them, the step S1 occurs after the welding of the End solder joint is completed. At this time, the splitting knife (5) is pressing on the End solder joint; In the step S2, the distance that the splitting knife (5) is lifted is one millimeter; In the step S3, the splitting knife (5) first runs 1.5 millimeters along the line connecting the penultimate solder joint and the End solder joint, and then moves downward by 1 millimeter; The welding head includes a displacement sensor (1), a down-force generator (2), an ultrasonic transducer (3), an aluminum wire feeding tube (4), a splitting knife (5), and a cutting knife (6). Among them, the displacement sensor (1) and the down-force generator (2) are integrally and rigidly connected to the driving arm. The ultrasonic transducer (3), the aluminum wire feeding tube (4), the splitting knife (5), and the cutting knife (6) are integrally and flexibly connected to the driving arm and can move slightly up and down relative to the displacement sensor (1) and the down-force generator (2); The displacement sensor (1) can detect the relative position of the ultrasonic transducer (3), the aluminum wire feeding tube (4), the splitting knife (5), and the cutting knife (6) as a whole relative to the displacement sensor (1) and the down-force generator (2); The cutting knife (6) is installed close to the splitting knife (5) but does not touch it. The aluminum wire feeding tube (4) is installed close to the splitting knife (5) but does not touch it. The aluminum wire passes through the aluminum wire feeding tube (4) and is placed directly below the end of the splitting knife (5). The ultrasonic transducer (3) and the splitting knife (5) are tightly and fixedly connected; The displacement sensor (1) can set the tangent depth. In the step S5, the cutting knife (6) of the welding head runs directly downward to the tangent depth pre-calibrated by the displacement sensor (1); in the step S4, the predetermined position of the displacement sensor (1) is calibrated and calculated in advance.

2. The wire cutting process of a power semiconductor wire bonder according to claim 1, characterized in that: The splitting knife (5) penetrates one end of the ultrasonic transducer (3), and the ultrasonic transducer (3) is equipped with a matching ultrasonic generator.

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