A cpo eutectic machine material transfer, eutectic bonding method and system

Abstract

This invention discloses a CPO eutectic bonding method and system for material transfer, eutectic bonding, and other processes, comprising the following steps: controlling a material movement adjustment mechanism to move to the pick-up station, picking up a chip via a pick-up head, and transferring the chip to the bonding station; preheating the chip to a first set temperature using a heating module; moving the chip above the substrate solder layer and aligning the chip with the substrate solder layer, then controlling the heating end face of the pick-up head to heat up to a second set temperature, melting the eutectic solder between the chip and the substrate; after the heating end face of the pick-up head reaches the eutectic temperature and stabilizes for a first set time, applying a set bonding pressure to evenly spread the molten solder at the interface between the chip and the substrate, and continuously maintaining the temperature and pressure for a second set time to completely melt the solder. This invention can solve the problem of low mass production efficiency and meet the needs of large-scale CPO packaging.

Description

Technical Field

[0001] This invention belongs to the field of CPO eutectic bonding process technology, specifically relating to a CPO eutectic bonding method and system for material transfer and eutectic bonding. Background Technology

[0002] Traditional CPO eutectic bonding processes rely on manual alignment or cooling, which are inefficient and prone to human error. Summary of the Invention

[0003] The purpose of this invention is to overcome at least one defect in the prior art and to provide a CPO eutectic machine material transfer and eutectic bonding method and system.

[0004] The technical solution of this invention is implemented as follows: This invention discloses a method for CPO eutectic bonding material transfer and eutectic bonding, comprising the following steps:

[0005] The material movement adjustment mechanism is moved to the picking station, where the chip is picked up by the suction head and transferred to the bonding station.

[0006] The chip is preheated to a first set temperature using a heating module;

[0007] Move the chip above the substrate solder layer and align the chip with the substrate solder layer. Then control the heating end face of the pick-up tip to heat up to the second set temperature to melt the eutectic solder between the chip and the substrate.

[0008] After the heating end face of the pick-up tip is heated to the eutectic temperature and stabilized for a first set time, the pick-up tip applies a set bonding pressure to spread the molten solder evenly on the interface between the chip and the substrate. The heat and pressure are maintained for a second set time to ensure that the solder is completely melted.

[0009] In some embodiments, after the heat preservation and pressure holding are completed, the following steps are also included: starting the cooling module to cool and reduce the temperature of the chip and the substrate, so that the molten eutectic solder can be quickly solidified to form a bonding layer;

[0010] When the chip temperature drops below the third set temperature, the suction head releases the bonding pressure, shuts off the vacuum adsorption, and then transfers back to the pick-up station, completing the transfer of a chip and eutectic bonding.

[0011] In some embodiments, the first set temperature is lower than the eutectic temperature, the second set temperature is equal to the eutectic temperature, and the third set temperature is lower than the first set temperature.

[0012] In some embodiments, aligning the chip with the substrate solder layer specifically includes:

[0013] Images of the chip and the substrate solder layer are acquired. Based on these images, the center offset and angular offset between the chip and the solder layer are obtained. Based on these offsets, the material movement adjustment mechanism is controlled to adjust the chip's orientation until the chip's geometric center coincides with the center of the solder layer.

[0014] In some embodiments, obtaining the center offset and angular offset between the chip and the solder layer based on images of the chip and the substrate solder layer specifically includes: obtaining the geometric center coordinates and angle of the chip and the center coordinates and angle of the substrate solder layer based on images of the chip and the substrate solder layer, respectively; and obtaining the center offset and angular offset between the chip and the solder layer based on the geometric center coordinates and angle of the chip and the center coordinates and angle of the substrate solder layer.

[0015] The present invention also provides a CPO eutectic bonding material transfer and eutectic bonding system, including a vision system, a material pick-up fixture, and a material movement adjustment mechanism. The material pick-up fixture is fixedly mounted on the material movement adjustment mechanism. The material pick-up fixture includes a suction head and a heating module. The heating module is used to heat the suction head. The vision system is used to acquire images of the chip and the substrate solder layer and transmit the images of the chip and the substrate solder layer to a control unit. The control unit is electrically connected to the material movement adjustment mechanism and the heating module.

[0016] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention includes a temperature sensor, which is connected to the input terminal of the control unit and the output terminal of the control unit is electrically connected to the heating module. The temperature sensor is used to provide real-time feedback of chip temperature data to the control unit so that the control unit can control the temperature of the heating module.

[0017] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a pressure sensor. The pressure sensor is used to collect the actual bonding pressure between the chip and the substrate and feed the pressure signal back to the control unit. The control unit controls the Z-axis displacement of the material movement adjustment mechanism through PID closed-loop adjustment based on the deviation between the set pressure value and the actual pressure, thereby accurately controlling the bonding pressure applied to the chip and ensuring pressure stability during the holding pressure stage.

[0018] In some embodiments, the pressure sensor is integrated into the suction head or its connecting arm.

[0019] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a stage on which a substrate clamp is mounted for fixing the substrate.

[0020] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a cooling unit located on the pick-up head for cooling the chip.

[0021] The present invention has at least the following beneficial effects: The present invention can realize the full-process automation (material picking-transfer-alignment-bonding-cooling-reset) control, and no manual intervention is required from material picking to reset, which shortens the bonding cycle of a single chip, solves the problem of low mass production efficiency, and meets the needs of CPO large-scale packaging.

[0022] This invention also improves bonding accuracy and interface quality by adopting a timing design of preheating, precise temperature rise to the eutectic temperature, and pressure application after temperature stabilization. This avoids stress damage to the chip caused by thermal shock, while ensuring uniform melting of the eutectic solder and reducing the void rate at the bonding interface. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of the CPO eutectic machine material transfer and eutectic bonding method provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the CPO eutectic machine material transfer and eutectic bonding system provided in an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0029] See Figure 1 This invention discloses a method for CPO eutectic bonding material transfer and eutectic bonding, comprising the following steps:

[0030] The material movement adjustment mechanism is moved to the picking station, where the chip is picked up by the suction head and transferred to the bonding station.

[0031] The chip is preheated to a first set temperature using a heating module;

[0032] Move the chip above the substrate solder layer and align the chip with the substrate solder layer. Then control the heating end face of the pick-up tip to heat up to the second set temperature to melt the eutectic solder between the chip and the substrate.

[0033] After the heating end face of the pick-up tip is heated to the eutectic temperature and stabilized for a first set time, the pick-up tip applies a set bonding pressure to spread the molten solder evenly on the interface between the chip and the substrate. The heat and pressure are maintained for a second set time to ensure that the solder is completely melted.

[0034] In some embodiments, after the heat preservation and pressure holding are completed, the following steps are also included: starting the cooling module to cool and reduce the temperature of the chip and the substrate, so that the molten eutectic solder can be quickly solidified to form a bonding layer;

[0035] When the chip temperature drops below the third set temperature, the suction head releases the bonding pressure, shuts off the vacuum adsorption, and then transfers back to the pick-up station, completing the transfer of a chip and eutectic bonding.

[0036] This invention enables precise alignment and temperature and pressure control, ensuring submicron-level alignment between the chip and the substrate solder layer, improving the optical transmission efficiency of subsequent fiber coupling in the CPO module, and reducing optical loss.

[0037] This invention adds an active cooling step after heat preservation and pressure holding, which enables the molten solder to solidify rapidly, inhibits the abnormal growth of intermetallic compounds, forms a dense and uniform bonding layer, and improves bonding strength and thermal conductivity.

[0038] In some embodiments, the first set temperature is lower than the eutectic temperature, the second set temperature is equal to the eutectic temperature, and the third set temperature is lower than the first set temperature. The solder completely solidifies when the chip temperature drops below the third set temperature.

[0039] In some embodiments, aligning the chip with the substrate solder layer specifically includes:

[0040] Images of the chip and the substrate solder layer are acquired. Based on these images, the center offset and angular offset between the chip and the solder layer are obtained. Based on these offsets, the material movement adjustment mechanism is controlled to adjust the chip's orientation until the chip's geometric center completely coincides with the center of the solder layer.

[0041] In some embodiments, obtaining the center offset and angular offset between the chip and the solder layer based on images of the chip and the substrate solder layer specifically includes: obtaining the center offset and angular offset between the chip and the solder layer based on images of the chip and the substrate solder layer specifically includes:

[0042] The vision module is controlled to capture images of reference marks on the substrate and establish a substrate coordinate system.

[0043] After the pick-up head picks up the chip, the vision module is controlled to capture an image of the chip and extract the chip's edge contour and reference marks.

[0044] Based on the substrate coordinate system, calculate the offset between the geometric center of the chip and the center of the solder layer;

[0045] Calculate the rotational angular offset between the chip and the solder layer.

[0046] Based on the same inventive concept, see [link to inventive concept] Figure 2 The present invention also provides a CPO eutectic bonding machine material transfer and eutectic bonding system, including a vision system, a material suction fixture, and a material movement adjustment mechanism. The material suction fixture is fixedly mounted on the material movement adjustment mechanism and includes a suction head and a heating module. The heating module is used to heat the suction head. The vision system is used to acquire images of the chip and the substrate solder layer and transmit the images of the chip and the substrate solder layer to a control unit. The control unit is electrically connected to the material movement adjustment mechanism and the heating module. The control unit is used to implement the steps in the CPO eutectic bonding machine material transfer and eutectic bonding method described in any of the above embodiments.

[0047] The vacuum adsorption system provides a stable and controllable negative pressure suction to the suction head. The vacuum adsorption system is connected to the control unit.

[0048] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention includes a temperature sensor, which is connected to the input terminal of the control unit and the output terminal of the control unit is electrically connected to the heating module. The temperature sensor is used to provide real-time feedback of chip temperature data to the control unit so that the control unit can control the temperature of the heating module.

[0049] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a pressure sensor. The pressure sensor is used to collect the actual bonding pressure between the chip and the substrate and feed the pressure signal back to the control unit. The control unit controls the Z-axis displacement of the material movement adjustment mechanism through PID closed-loop adjustment based on the deviation between the set pressure value and the actual pressure, thereby accurately controlling the bonding pressure applied to the chip and ensuring pressure stability during the holding pressure stage.

[0050] In some embodiments, the pressure sensor is integrated into the suction head or its connecting arm.

[0051] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a stage on which a substrate clamp is mounted for fixing the substrate.

[0052] In some embodiments, the CPO eutectic machine material transfer and eutectic bonding system of the present invention further includes a cooling unit located on the pick-up head or stage for cooling the chip.

[0053] This invention employs closed-loop pressure control (combined with pressure sensor feedback) and segmented temperature control to avoid damage to the active area of ​​the optical chip caused by local overheating or uneven pressure, thereby extending the service life of the CPO module.

[0054] In some embodiments, the material movement adjustment mechanism is a six-axis displacement stage.

[0055] Because this invention can improve bonding accuracy and interface quality, it adopts a timing design of preheating, precise temperature rise to the eutectic temperature, and pressure application after temperature stabilization, which avoids stress damage to the chip due to thermal shock, while ensuring uniform melting of the eutectic solder and reducing the void rate at the bonding interface.

[0056] This invention enables fully automated control of the entire process (material picking-transfer-alignment-bonding-cooling-reset), requiring no manual intervention from material picking to reset, shortening the bonding cycle of a single chip, solving the problem of low mass production efficiency, and meeting the needs of CPO large-scale packaging.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for material transfer and eutectic bonding in a CPO eutectic machine, characterized in that, Includes the following steps: The material movement adjustment mechanism is moved to the picking station, where the chip is picked up by the suction head and transferred to the bonding station. The chip is preheated to a first set temperature using a heating module; Move the chip above the substrate solder layer and align the chip with the substrate solder layer. Then control the heating end face of the pick-up tip to heat up to the second set temperature to melt the eutectic solder between the chip and the substrate. After the heating end face of the pick-up tip is heated to the eutectic temperature and stabilized for a first set time, the pick-up tip applies a set bonding pressure to spread the molten solder evenly on the interface between the chip and the substrate. The heat and pressure are maintained for a second set time to ensure that the solder is completely melted.

2. The method as described in claim 1, characterized in that: After the heat preservation and pressure holding are completed, the following steps are also included: start the cooling module to cool down the chip and substrate, so that the molten eutectic solder can be quickly solidified to form a bonding layer; When the chip temperature drops below the third set temperature, the suction head releases the bonding pressure, shuts off the vacuum adsorption, and then transfers back to the pick-up station, completing the transfer of a chip and eutectic bonding.

3. The method as described in claim 2, characterized in that: The first set temperature is lower than the eutectic temperature, the second set temperature is equal to the eutectic temperature, and the third set temperature is lower than the first set temperature.

4. The method as described in claim 1, characterized in that: Aligning the chip with the substrate solder layer specifically includes: Images of the chip and the substrate solder layer are acquired. Based on these images, the center offset and angular offset between the chip and the solder layer are obtained. Based on these offsets, the material movement adjustment mechanism is controlled to adjust the chip's orientation until the chip's geometric center coincides with the center of the solder layer.

5. The method as described in claim 4, characterized in that: The center offset and angular offset of the chip and the solder layer are obtained from the images of the chip and the substrate solder layer. Specifically, this includes obtaining the geometric center coordinates and angle of the chip and the center coordinates and angle of the substrate solder layer from the images of the chip and the substrate solder layer, respectively, and obtaining the center offset and angular offset of the chip and the solder layer from the geometric center coordinates and angle of the chip and the center coordinates and angle of the substrate solder layer.

6. A CPO eutectic machine material transfer and eutectic bonding system, characterized in that: The device includes a vision system, a material suction fixture, and a material movement adjustment mechanism. The material suction fixture is fixedly mounted on the material movement adjustment mechanism. The material suction fixture includes a suction head and a heating module. The heating module is used to heat the suction head. The vision system is used to acquire images of the chip and the substrate solder layer and transmit the images of the chip and the substrate solder layer to the control unit. The control unit is electrically connected to the material movement adjustment mechanism and the heating module.

7. The system as described in claim 6, characterized in that: It includes a temperature sensor, which is connected to the input terminal of the control unit. The output terminal of the control unit is electrically connected to the heating module. The temperature sensor is used to provide real-time feedback of chip temperature data to the control unit so that the control unit can control the temperature of the heating module.

8. The system as described in claim 6, characterized in that: It also includes a pressure sensor, which is used to collect the actual bonding pressure between the chip and the substrate and feed the pressure signal back to the control unit. The control unit controls the Z-axis displacement of the material movement adjustment mechanism through PID closed-loop adjustment based on the deviation between the set pressure value and the actual pressure, thereby accurately regulating the bonding pressure applied to the chip and ensuring pressure stability during the holding pressure stage.

9. The system as described in claim 6, characterized in that: It also includes a stage on which a substrate clamp is mounted for fixing the substrate.

10. The system as described in claim 6 or 9, characterized in that: It also includes a cooling unit, which is located on the suction head and is used to cool the chip.

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