Apparatus and method for wafer oxide removal and reflow processing

Abstract

To provide an apparatus and method for wafer oxide removal and reflow treatment.SOLUTION: The present invention relates to an apparatus and method for wafer oxide removal and reflow treatment. In particular, the present invention relates to an apparatus for wafer oxide removal and reflow treatment, comprising: a heating plate; a sample plate for supporting a wafer sample above the heating plate, and an electron attachment pin plate above the sample plate, where the heating plate is configured to be capable of moving up and down, and contacting and heating the sample plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to wafer processing, and more particularly to wafer oxide removal and reflow processing. [Background technology]

[0002] Wafer bumping is a process used to create thick metal bumps on chip bond pads for inner lead attachment. The bumps are typically created by depositing solder on the pads and then reflowing (referred to herein as the first reflow) to alloy and change the shape of the solder bump from a mushroom to a hemispherical shape. The chip with the first reflowed bumps is "flipped" to correspond to the footprint of the solder-wettable terminals on the substrate and then subjected to a second reflow to form the solder joints.

[0003] Reflow and soldering are important processing steps in the assembly of electronic components to create solder joints. The term "reflow" refers to the process of causing pre-applied solder on a substrate to melt and flow upon application of an energy source, such as thermal energy.

[0004] To ensure good wetting of the molten solder on the joining surfaces, organic fluxes are usually included in solder pastes to remove initial surface oxides on both the solder and the base metal, leaving the surfaces clean before solidification.

[0005] Electron attachment is known to those skilled in the art. Summary of the Invention

[0006] The present disclosure aims to provide a batch fluxless process for wafer bumping / reflow, particularly for wafer oxide removal and reflow processing, and also aims to provide rapid heating and cooling of sample plates.

[0007] The present disclosure provides an apparatus for wafer oxide removal and reflow processing, comprising a heating plate, a sample plate for supporting a wafer sample on the heating plate, and an electron attachment pin plate above the sample plate, the heating plate being configured to move up and down and to contact and heat the sample plate.

[0008] The present disclosure also provides a wafer oxide removal and reflow processing method using the apparatus of the present disclosure, further comprising: moving a heating plate up to contact and lift the sample plate until a surface of a wafer sample on the sample plate is sufficiently close to the electron attachment pin plate to be processed by electron attachment; heating the wafer sample on the sample plate while the heating plate is in contact with the sample plate; removing oxide on the surface of the wafer sample by electron attachment; and moving the heating plate down until the sample plate is placed on a shelf and separated from the heating plate.

[0009] Using the apparatus and method, wafer oxide removal and reflow processing can be performed in a stepwise manner, such as for wafers up to 12 inches in length and / or width and / or diameter. Separation of the sample plate supporting the wafer sample from the heating plate after reflow is performed for rapid and controlled sample cooling. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the structure of the device of the present disclosure;

[0011] [Figure 2] FIG. 2 is another diagram showing the structure of the device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] In one aspect, the present disclosure relates to an apparatus for wafer oxide removal and reflow processing, comprising a heating plate, a sample plate for supporting a wafer sample on the heating plate, and an electron attachment pin plate above the sample plate, the heating plate configured to move up and down to contact and heat the sample plate.

[0013] In one aspect, the heating plate is further configured to be rotatable. Rotation of the heating plate supporting the sample plate can provide uniform oxide removal on the sample surface.

[0014] In one aspect, the heating plate is controlled by an air cylinder or screw rod for up and down movement and / or rotation.

[0015] In one embodiment, the heating plate can contact the sample plate at a heating rate of up to 50°C / min and heat to a temperature of up to 500°C.

[0016] In one aspect, the apparatus further comprises a shelf for supporting the sample plate, the shelf being positioned between the sample plate and the heating plate and configured to allow the heating plate to lift the sample plate.

[0017] In one embodiment, the shelf is separated from the electron attachment pin plate such that when the sample plate is placed on the shelf, the gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is greater than 10 mm.

[0018] In one aspect, the heating plate, the sample plate, and the electron attachment pin plate are contained in a chamber.

[0019] In one aspect, the electron attachment pin plate can emit electrons that collide with hydrogen molecules to produce hydrogen anions, reducing oxides to metals and producing water vapor.

[0020] In one aspect, the apparatus comprises an electron attachment kit comprising an electron attachment pin plate, a high voltage power supply, and a pulse generator.

[0021] In one aspect, the apparatus includes a heating subsystem that includes a heating plate and a heating control means.

[0022] In one embodiment, the heating plate is made from silicon nitride.

[0023] In one embodiment, the apparatus comprises a gas delivery means for N2, H2, or a mixture thereof.

[0024] In one embodiment, the apparatus includes a monitoring system for monitoring H2 or O2 content, gas flow rate, chamber pressure, temperature, or cooling water flow.

[0025] In one aspect, the apparatus includes a camera or video for monitoring the interior of the chamber.

[0026] In one aspect, the present disclosure relates to a wafer oxide removal and reflow processing method using an apparatus according to the present disclosure, further comprising: moving a heating plate up to contact and lift a sample plate until a surface of a wafer sample on the sample plate is sufficiently close to an electron attachment pin plate to be processed by electron attachment; heating the wafer sample on the sample plate while the heating plate is in contact with the sample plate; removing oxide on the surface of the wafer sample by electron attachment; and moving the heating plate down until the sample plate is placed on a shelf and separated from the heating plate.

[0027] When the heating plate moves down, the sample plate is placed on the shelf and separated from the heating plate. The separation of the sample plate supporting the reflowed wafer sample from the heating plate is performed for fast and controlled sample cooling.

[0028] In one embodiment, the wafer sample is heated to a temperature of up to 500° C. at a heating rate of up to 50° C. / min.

[0029] In one aspect, the heating plate is rotated to obtain uniform oxide removal. When the heating plate supports the sample plate, rotation of the heating plate supporting the sample plate can provide uniform oxide removal on the sample surface.

[0030] In one embodiment, the sample plate is raised by the heating plate until the gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is 10 mm or less.

[0031] In one embodiment, the heating plate, sample plate, and electron attachment pin plate are contained within a chamber, which is under vacuum or contains N2 to achieve an oxygen content of 10 ppm or less, and then switched to a N2 / H2 gas mixture.

[0032] In one aspect, the apparatus includes positive and negative power supplies and a pulse generator for electron attachment, and the heating plate, sample plate, and electron attachment pin plate are contained within a chamber, and the method includes the steps of turning on an N purge to purge the chamber, moving the heating plate and sample plate up while maintaining O below a predetermined value (e.g., 20 ppm), starting heating and delivering an H / N gas mixture, turning on the rotation of the heating plate, enabling the positive and negative power supplies, switching on the pulse generator, switching off the H / N gas mixture and switching back to the N purge, switching off the pulse generator, turning off the rotation, continuing heating to a predetermined reflow temperature (e.g., 260°C) for the reflow process, and moving the heating plate away from the sample plate after the reflow process is completed.

[0033] The complete process, including preheating, electron attachment deoxidation (including temperature soak and electron attachment stabilization), reflow and cooling, can be completed within an hour, making it a low-cost process.

[0034] The apparatus or method is environmentally friendly and applicable to small-scale batch processes, and is suitable for research and development purposes in research and development centers, universities, research institutes, and IC packaging companies.

[0035] Please refer to FIG. 1. FIG. 1 is a diagram showing the structure of the apparatus of the present disclosure. This apparatus includes a heating plate 1, a sample plate 2 for supporting a wafer sample on the heating plate, an electron attachment pin plate 3 above the sample plate, and a shelf 4 for supporting the sample plate. The heating plate 1 is configured to move up and down and contact and heat the sample plate 2. The heating plate 1 can also rotate. The heating plate 1 is controlled by an air cylinder or screw rod for vertical movement and / or rotation. The shelf 4 is located between the sample plate 2 and the heating plate 1 and is configured to allow the heating plate 1 to lift the sample plate 2. The shelf 4 is separated from the electron attachment pin plate 3. When the sample plate 2 is placed on the shelf 4, the gap between the sample surface of the wafer sample on the sample plate 2 and the pin tips of the electron attachment pin plate 3 is greater than 10 mm. The electron attachment pin plate 3 emits electrons that collide with hydrogen molecules to generate hydrogen anions, which can reduce oxides to metals and generate water vapor.

[0036] 2 is another diagram showing the structure of the apparatus of the present disclosure. The heating plate, sample plate, and electron attachment pin plate are contained in chamber 5.

[0037] The apparatus can be used in a method for wafer oxide removal and reflow processing. The method includes the steps of: moving a heating plate 1 up and lifting it into contact with a sample plate 2 until the surface of the wafer sample on the sample plate 2 is close enough to an electron attachment pin plate 3 to be treated by electron attachment (e.g., lifting the sample plate 2 by the heating plate 1 until the gap between the sample surface of the wafer sample on the sample plate 2 and the pin tip of the electron attachment pin plate 3 is 10 mm or less); heating the wafer sample on the sample plate 2 while the heating plate 1 is in contact with the sample plate 2; removing oxide on the surface of the wafer sample by electron attachment; and moving the heating plate 1 down until the sample plate 2 is placed on a shelf and separated from the heating plate 1. The heating plate 1 can be rotated to achieve uniform oxide removal.

[0038] Specifically, the method may include turning on the N purge to purge the chamber, moving the heating plate and sample plate up while maintaining O below a predetermined value (e.g., 20 ppm), starting heating and delivering a H / N gas mixture, turning on the rotation of the heating plate, enabling positive and negative power supplies, switching on the pulse generator, switching off the H / N gas mixture and switching back to the N purge, switching off the pulse generator, turning off the rotation, continuing heating to a predetermined reflow temperature (e.g., 260°C) for the reflow process, and moving the heating plate away from the sample plate after the reflow process is completed.

[0039] The present invention will be described with reference to preferred embodiments illustrated in the drawings, but it will be understood that various modifications can be made within the spirit and scope of the invention. Examples of embodiments of the present invention are listed in the following items [Aspect 1] to [Aspect 20]. [Aspect 1] 1. An apparatus for wafer oxide removal and reflow processing, comprising: A heating plate; a sample plate for supporting a wafer sample on the heating plate; an electron attachment pin plate above the sample plate; The apparatus is configured such that the heating plate can move up and down to contact and heat the sample plate. [Aspect 2] 2. The apparatus of embodiment 1, wherein the heating plate is further configured to be rotatable. [Aspect 3] 3. The apparatus of embodiment 2, wherein the heating plate is controlled by an air cylinder or a screw rod for up and down movement and / or rotation. [Aspect 4] 2. The apparatus of embodiment 1, wherein the heating plate is in contact with the sample plate and is capable of heating it to a temperature of up to 500° C. at a heating rate of up to 50° C. / min. [Aspect 5] 2. The apparatus of claim 1, further comprising a shelf for supporting the sample plate, the shelf being positioned between the sample plate and the heating plate and configured to allow the heating plate to lift the sample plate. [Aspect 6] An apparatus as described in aspect 5, wherein when the shelf is separated from the electron attachment pin plate and the sample plate is placed on the shelf, a gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is greater than 10 mm. [Aspect 7] 2. The apparatus of embodiment 1, wherein the heating plate, the sample plate, and the electron attachment pin plate are contained in a chamber. [Aspect 8] 2. The apparatus of embodiment 1, wherein the electron attachment pin plate can emit electrons that collide with hydrogen molecules to generate hydrogen anions, reduce oxides to metals, and generate water vapor. [Aspect 9] 2. The apparatus of embodiment 1, wherein the apparatus comprises an electron attachment kit comprising the electron attachment pin plate, a high voltage power supply, and a pulse generator. [Aspect 10] 2. The apparatus of embodiment 1, wherein the apparatus comprises a heating subsystem comprising the heating plate and a heating control means. [Aspect 11] 10. The apparatus of claim 1, wherein the heating plate is made from silicon nitride. [Aspect 12] The device is 2 、H 2 10. The apparatus of claim 1, further comprising a gas delivery means for: [Aspect 13] The device is H 2 Or O 2 8. The apparatus of embodiment 7, comprising a monitoring system for monitoring content, gas flow rate, chamber pressure, temperature, or cooling water flow. [Aspect 14] 8. The apparatus of embodiment 7, wherein the apparatus comprises a camera or video for monitoring the interior of the chamber. [Aspect 15] 1. A wafer oxide removal and reflow processing method using the apparatus of embodiment 1, comprising: moving the heating plate upward to contact and lift the sample plate until a surface of the wafer sample on the sample plate is sufficiently close to the electron attachment pin plate to be treated by electron attachment; heating the wafer sample on the sample plate while the heating plate is in contact with the sample plate; removing oxides on the surface of the wafer sample by electron attachment; and moving the heating plate downward until the sample plate is placed on a shelf and separated from the heating plate. [Aspect 16] 16. The method of embodiment 15, wherein the wafer sample is heated to a maximum of 500° C. at a heating rate of up to 50° C. / min. [Aspect 17] 16. The method of embodiment 15, wherein the heating plate is rotated to obtain uniform oxide removal. [Aspect 18] 16. The method of claim 15, wherein the sample plate is lifted by the heating plate until a gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is 10 mm or less. [Aspect 19] The heating plate, the sample plate, and the electron attachment pin plate are contained within a chamber, and the chamber is under vacuum or N 2 and achieve an oxygen content of 10 ppm or less, and then N 2 / H 2 16. The method of embodiment 15, wherein the gas is switched to a mixed gas. [Aspect 20] The apparatus comprises a positive and negative power supply and a pulse generator for electron attachment, the heating plate, the sample plate, and the electron attachment pin plate are contained within a chamber, and the method comprises: N 2 turning on the purge to purge the chamber; O 2 moving the heating plate and sample plate upward while maintaining the ion concentration below a predetermined value (e.g., 20 ppm); Start heating and 2 / N 2 delivering a gas mixture; turning on the rotation of the heating plate; enabling the positive and negative power supplies; switching on the pulse generator; H 2 / N 2 Switch off the gas mixture and add N 2 switching back to purging; switching off the pulse generator; turning off the rotation; Continuing heating to a predetermined reflow temperature (e.g., 260°C) for reflow processing; a step of: moving the heating plate down and away from the sample plate after the reflow process is completed.

Claims

1. 1. An apparatus for wafer oxide removal and reflow processing, comprising: A heating plate; a sample plate for supporting a wafer sample on the heating plate; an electron attachment pin plate above the sample plate; a shelf for supporting the sample plate; The heating plate is configured to move up and down and contact and heat the sample plate; the shelf is positioned between the sample plate and the heating plate and is configured to allow the heating plate to lift the sample plate; The apparatus is configured to lift the sample plate by the heating plate until a gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is 10 mm or less.

2. The apparatus of claim 1 , wherein the heating plate is further configured to be rotatable.

3. 3. The apparatus of claim 2, wherein the heating plate is controlled by an air cylinder or a screw rod for up and down movement and / or rotation.

4. 10. The apparatus of claim 1, wherein the heating plate contacts the sample plate and is capable of heating it to a temperature of up to 500°C at a heating rate of up to 50°C / min.

5. 5. The apparatus of claim 4, wherein when the shelf is separated from the electron attachment pin plate and the sample plate is placed on the shelf, a gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is greater than 10 mm.

6. The apparatus of claim 1 , wherein the heating plate, the sample plate, and the electron attachment pin plate are contained in a chamber.

7. 10. The apparatus of claim 1, wherein the electron attachment pin plate is capable of releasing electrons that collide with hydrogen molecules to produce hydrogen anions, reducing oxides to metals, and producing water vapor.

8. 10. The apparatus of claim 1, wherein the apparatus comprises an electron attachment kit comprising the electron attachment pin plate, a high voltage power supply, and a pulse generator.

9. The apparatus of claim 1 , wherein the apparatus comprises a heating subsystem comprising the heating plate and a heating control means.

10. The apparatus of claim 1 , wherein the heating plate is made from silicon nitride.

11. The device is 2 , H 2 10. The apparatus of claim 1, further comprising gas delivery means for:

12. The device is H 2 Or O 2 7. The apparatus of claim 6, comprising a monitoring system for monitoring content, gas flow rate, chamber pressure, temperature, or cooling water flow.

13. The apparatus of claim 6 , wherein the apparatus comprises a camera or video for monitoring the interior of the chamber.

14. 10. A wafer oxide removal and reflow processing method using the apparatus of claim 1, comprising: moving the heating plate upward to contact and lift the sample plate until a surface of the wafer sample on the sample plate is sufficiently close to the electron attachment pin plate to be treated by electron attachment; heating the wafer sample on the sample plate while the heating plate is in contact with the sample plate; removing oxides on the surface of the wafer sample by electron attachment; and moving the heating plate downward until the sample plate is placed on the shelf and separated from the heating plate.

15. 15. The method of claim 14, wherein the wafer sample is heated to a maximum of 500°C at a heating rate of up to 50°C / min.

16. 15. The method of claim 14, wherein the heating plate is rotated to provide uniform oxide removal.

17. 15. The method of claim 14, wherein the sample plate is raised by the heating plate until a gap between the sample surface of the wafer sample on the sample plate and the pin tips of the electron attachment pin plate is 10 mm or less.

18. The heating plate, the sample plate, and the electron attachment pin plate are contained within a chamber, and the chamber is under vacuum or N 2 to achieve an oxygen content of 10 ppm or less, and then 2 / H 2 15. The method of claim 14, wherein the gas is switched to a mixed gas.

19. The apparatus comprises a positive and negative power supply and a pulse generator for electron attachment, the heating plate, the sample plate, and the electron attachment pin plate are contained within a chamber, and the method comprises: N 2 turning on the purge to purge the chamber; O 2 moving the heating plate and sample plate upward while maintaining the .DELTA..DELTA. below a predetermined value (e.g., 20 ppm); Start heating and 2 / N 2 delivering a gas mixture; turning on the rotation of the heating plate; enabling the positive and negative power supplies; switching on the pulse generator; H 2 / N 2 Switch off the gas mixture and 2 switching back to purging; switching off the pulse generator; turning off the rotation; Continuing heating to a predetermined reflow temperature (e.g., 260° C.) for reflow processing; and moving the heating plate down and away from the sample plate after the reflow process is completed.

Images