TWI697087B - Reflow apparatus and bonding method - Google Patents

Abstract

Provided is a reflow apparatus used for bonding integrated circuits (ICs) including a main chamber. The main chamber includes a first region, a second region, and a third region. The first region is configured to perform a heat treatment on the ICs. The second region includes a press head which performs a press treatment on the ICs, so that a curved surface of the ICs becomes a flat surface. The press head includes a body portion and a buffer layer at a side of the body portion. The buffer layer is elastic to conformally attach onto the ICs. The third region is configured to perform a cooling treatment on the ICs.

Description

Reflow device and joining method

The embodiment of the invention relates to a reflow device and a joining method.

In integrated circuit packaging, soldering is one of the most commonly used methods for joining components of an integrated circuit. Taking the example of joining two integrated circuit components as an example, the two integrated circuit components can be placed together by solder, reflowed to melt the solder, and then the two integrated circuit components are joined when the solder cools .

However, the traditional reflow process will limit the warpage range and solder volume of the integrated circuit device to achieve good contacts. In this case, the process margin of the contacts is limited, especially in the packaging process of large-area integrated circuit elements and fine pitch contacts.

Embodiments of the present invention provide a reflow device for joining integrated circuits, including a main chamber. The main chamber includes: a first area, a second area, and a third area. The first area is configured to heat-treat the integrated circuit to form a curved shape on the surface of the integrated circuit. The second area includes a pressurizing head that pressurizes the integrated circuit so that the curved surface of the integrated circuit becomes a flat surface. The pressing head includes a main body and a buffer layer disposed on one side of the main body. The buffer layer has elasticity to conformally conform to the integrated circuit. The third area is configured to cool the integrated circuit.

An embodiment of the present invention provides a bonding method, and the steps are as follows. Laminating the first substrate and the second substrate so that the plurality of first solder regions on the first substrate are respectively aligned with the plurality of second solder regions on the second substrate; and performing a reflow process. Performing the reflow process includes: performing a first heating process in the first region of the reflow device, wherein the difference in thermal expansion coefficient between the first substrate and the second substrate causes the surface of the second substrate to form a curved shape during the first heating process ; Performing a second heat treatment and a pressure treatment in the second area of the reflow device, the pressure treatment includes pressing the second substrate with a pressure head so that the curved surface of the second substrate becomes a flat surface, wherein the first One area and the second area are separated and independent from each other.

An embodiment of the present invention provides another joining method, and the steps are as follows. Laminating the first substrate and the second substrate so that the plurality of first solder regions on the first substrate are aligned with the plurality of second solder regions on the second substrate; and performing heat treatment and addition in a separate chamber of the reflow device The pressure treatment includes pressurizing the second substrate by the pressure head, wherein the heat treatment includes transferring the heat source to the independent chamber through the vent pipe to uniform the temperature in the independent chamber, thereby transferring the first solder area A plurality of bonding solders are fused with the second solder area.

The following disclosure provides many different embodiments or examples for implementing different features of the provided goals. The specific examples of components and configurations described below are for the purpose of conveying the present disclosure in a simplified manner. Of course, these are only examples and not limiting. For example, in the following description, forming the first feature above or on the second feature may include an embodiment where the first feature and the second feature are formed in direct contact, and may also include the first feature and the second feature An additional feature may be formed between the two features, so that the first feature and the second feature may not directly contact the embodiment. In addition, the present disclosure may reuse element symbols and/or letters in various examples. The repeated use of element symbols is for simplicity and clarity, and does not represent the relationship between the various embodiments and/or configurations to be discussed.

In addition, for ease of description, this article may use, for example, "beneath", "below", "lower", "above", "upper" ”And other spatial relative terms to illustrate the relationship between one element or feature shown in the figure and another element or features. The spatial relative terminology is intended to cover different orientations of elements in use or operation. The device can be otherwise oriented (rotated 90 degrees or at other orientations), and the spatial relative terms used herein are interpreted accordingly.

Other features and processes can also be included. For example, a test structure may be included to illustrate the verification test of a three-dimensional (3D) package or a three-dimensional integrated circuit device. The test structure may include, for example, test pads formed in the redistribution layer or on the substrate, the test pads enable testing of 3D packages or 3DICs, use of probes and/or probe cards, and the like. Verification tests can be performed on the intermediate structure and the final structure. In addition, the structures and methods disclosed herein can be used in conjunction with test methods that include intermediate verification of known good dies to increase yield and reduce costs.

FIG. 1 is a schematic cross-sectional view of a reflow device according to a first embodiment of the present invention. In the following embodiments, the conveying type (Convey type) reflow device 100 is used as an example for description, but the embodiment of the present invention is not limited thereto. In other embodiments, it may also be a hot plate type reflow device 200 (as shown in FIG. 2) or an oven type (Oven type) reflow device 300 (as shown in FIG. 3), This will be explained in detail later.

In this embodiment, the integrated circuit 10 (for example, a package structure, hereinafter referred to as the package structure 10) is transmitted through the first region 110, the second region 120, and the third region 130 by the conveyor belt 104, thereby implementing a reflow process . The multiple arrows 106 represent that the packaging structure 10 is passing through a certain area of the first area 110, the second area 120 and the third area 130. In detail, the packaging structure 10 includes a first substrate 12 having a plurality of first solder regions 14 and a plurality of second substrates 22 having a plurality of second solder regions 24. The second substrate 22 is inverted on the first substrate 12 so that the second solder regions 24 are aligned with the first solder regions 14 respectively. In some embodiments, the first solder area 14 includes a metal post 16 and a solder cap 18 disposed on the metal post 16; and the second solder area 24 may be a solder bump. However, the embodiment of the present invention is not limited to this. In other embodiments, the second solder region 24 may be a metal pillar and a solder cap disposed on the metal pillar; and the first solder region 14 may be a solder bump. In an alternative embodiment, both the first solder region 14 and the second solder region 24 may be solder bumps or metal pillars and solder caps disposed on the metal pillars. In an embodiment, the materials of the first solder region 14 and the second solder region 24 each include tin, silver, copper, a combination thereof, or other suitable materials, etc., which may be, for example, vapor deposition, electroplating, ball dropping, or screen printing (Screen printing) and other suitable processes are formed.

In this embodiment, the first substrate 12 may be a semiconductor wafer, and the second substrate 22 may be a semiconductor wafer to form a chip-on-wafer (CoW) package. However, the embodiments of the present invention are not limited thereto. In other embodiments, the first substrate 12 and the second substrate 22 may each include semiconductor dies (which have active elements such as transistors, diodes, etc.), packages Substrates, interposers, printed circuit boards (PCBs), packages, and similar components. Although the area of the second substrate 22 shown in FIG. 1 is smaller than the area of the first substrate 12 and the number of the second substrate 22 is greater than the number of the first substrate 12, the embodiments of the present invention are not limited thereto. In other embodiments, the area and number of the first substrate 12 and the second substrate 22 can be adjusted according to requirements. For example, the first substrate 12 and the second substrate 22 may both be semiconductor dies, which are stacked on top of each other in a die stack structure.

Referring to FIG. 1, the reflow device 100 of the first embodiment includes a main chamber 102. The main chamber 102 includes a first area 110, a second area 120, and a third area 130. The second area 120 is disposed between the first area 110 and the third area 130.

Specifically, in some embodiments, the first region 110 may be a preheating region. The first region 110 includes a plurality of heating sources 115 respectively disposed on the upper and lower sides of the first region 110 to perform the first heating process on the package structure 10. As shown in FIG. 1, when the packaging structure 10 is transferred to pass through the heating source 115, the heating source 115 may preheat the first solder area 14 and the second solder area 24 in the packaging structure 10. In an embodiment, the heating source 115 may be a radiant heating source (such as an infrared radiation source) or may be configured to blow hot air toward the packaging structure 10. The direction of the arrow leaving the heating source 115 represents radiant heat energy, hot air, and the like.

In another embodiment, each heating source 115 may be controlled to have a different heating temperature so that the temperature of the heating source 115b is greater than the temperature of the heating source 115a. For example, when the conveyor belt 104 transmits the package structure 10 through the first region 110, the temperature experienced by the package structure 10 gradually increases from left to right, as shown in FIG. Specifically, when the initial temperature of the packaging structure 10 is T0, the back surface (or upper surface) 22b of the second substrate 22 bows upward. As shown in FIG. 1, the center of the back surface (or upper surface) 22 b of the second substrate 22 is higher than its two end portions, and has a curved surface protruding upward. When the package structure 10 moves from the heating source 115a to the heating source 115b, the temperature of the package structure 10 increases to T1. In some embodiments, T0 is, for example, 25°C to 150°C; T1 is, for example, 150°C to 220°C. In this case, due to the mismatch of the coefficient of thermal expansion (CTE) of different materials in the package structure 10, the package structure 10 may undergo a warp change during the temperature change process (ie, T0 becomes T1) . For example, the thermal expansion coefficient of the upper portion of the second substrate 22 may be greater than the thermal expansion coefficient of the lower portion of the second substrate 22. Therefore, the back surface (or upper surface) 22b of the second substrate 22 has a curved surface curved downward, as shown in FIG. 1 shown. In one embodiment, the process of increasing the temperature T0 to T1 may preheat the package structure 10 and provide the package structure 10 with a ramp-up rate. Here, the temperature increase rate refers to the temperature change rate of the package structure 10. In some embodiments, the heating rate of the package structure 10 may be 0.5°C/sec to 3°C/sec. However, the embodiments of the present invention are not limited thereto. In other embodiments, the heating rate of the packaging structure 10 may be changed according to the materials and manufacturing standards of the first solder area 14 and the second solder area 24 of the packaging structure 10.

In an alternative embodiment, the temperature T1 of the package structure 10 may be maintained for a period of time, so that the first solder region 14 and the second solder region 24 of the package structure 10 are thermally soaked.

In this embodiment, in the process of increasing the temperature of the package structure 10 from T0 to T1 (ie, the first heating process), the back surface (or upper surface) 22b of the second substrate 22 depicted in FIG. The arching is changed to downward arching, but the embodiment of the present invention is not limited to this. In other embodiments, according to the thermal expansion coefficient of the material in the second substrate 22, the back surface (or upper surface) 22b of the second substrate 22 may also change from downwardly curved to Arch upward, or change from flat to downward, or from flat to upward.

Similarly, the active surface (or upper surface) 12a of the first substrate 12 and the active surface (or lower surface) 22a of the second substrate 22 also have curved surfaces. In this case, during the reflow process, some of the first solder regions 14 may not contact their corresponding second solder regions 24, which makes it difficult for the first solder regions 14 to be joined to their corresponding second solder regions 24. Cold joints are generated between the first solder area 14 and the second solder area 24. Here, the cold welding will cause defects in the package structure and reduce the yield of the package structure process. In this embodiment, as shown in FIGS. 1 and 4A to 4C, the warpage phenomenon of the package structure 10 can be improved by pressure treatment to reduce or prevent cold welding, which will be described in detail in the following paragraphs.

As shown in FIG. 1, when the conveyor belt 104 transfers the packaging structure 10 from the first region 110 to the second region 120, the second region 120 may become an independent chamber 108 to be separated from the first region 110 and the third region 130 open. In other words, during the reflow process, the second region 120 does not communicate with the first region 110 and the third region 130 in space. In some embodiments, the second region 120 may be a reflow region, which includes a plurality of heating sources 125 respectively disposed on a single side or upper and lower sides of the second region 120 to perform the second heating process. When the packaging structure 10 moves from the heating source 115b to the heating source 125, the temperature of the packaging structure 10 increases from T1 to T2 (ie, the second heating process). The second region 120 is the region with the highest reflow temperature among the first region 110 to the third region 130, and can fuse the solder cover 18 of the first solder region 14 and the solder of the second solder region 24 into the bonding solder 34. In this case, as shown in FIG. 1, the first substrate 12 and the second substrate 22 may be bonded to the metal post 16 by bonding solder 34. Here, the combination of the bonding solder 34 and the metal post 16 can be regarded as the connecting member 20 to electrically connect the first substrate 12 and the second substrate 22. In some embodiments, the connector 20 may be, for example, a micro-bump, a controlled collapse chip connection (C4) bump, a solder bump, a solder ball, or a combination thereof. Here, the micro-bump may refer to a connector having a horizontal size of 1 μm to 50 μm. The temperature T2 of the second region 120 is, for example, 220°C to 240°C.

It is worth noting that, in this embodiment, the second area 120 further includes a lifting device 121 and a pressing head 122 to apply pressure to the packaging structure 10, thereby improving the warping phenomenon of the packaging structure 10. Specifically, the lifting device 121 is connected to the pressing head 122, and the lifting device 121 lowers and/or raises the pressing head 122 to perform the pressing operation as shown in FIGS. 4A to 4C, respectively. Referring to FIG. 4A, before the pressing is performed, the pressing head 122 does not contact the back surface 22b of the second substrate 22, and the back surface 22b of the second substrate 22 is curved downward.

As shown in FIG. 4A, the lifting device 121 is connected to the top surface of the main body 122 a of the pressure head 122. The lifting device 121 is, for example, a lifting pin, and the other end of the pressing head 122 is connected to a lifting motor module (lifting motor module) so that the pressing head 122 can move up and down in the axial direction. The pressing head 122 includes a main body portion 122a and a buffer layer 122b disposed on one side of the main body portion 122a. In some embodiments, the body portion 122a is a solid structure, and its material may be, for example, a metal material, a ceramic material, or a combination thereof. In another embodiment, the material of the body portion 122a may be quartz, sapphire, or the like. In an embodiment, the pressing head 122 may also have a heating function, therefore, the main body portion 122a may be a thermally conductive material. In an alternative embodiment, the material of the buffer layer 122b may include metal materials (such as stainless steel, titanium, aluminum, copper, and similar metals), rubber materials, and release materials (such as polytetrafluoroethylene, also known as Teflon) Or a combination thereof. In other embodiments, the buffer layer 122b may be an elastic material or structure, such as a spring.

Next, as shown in FIG. 4B, the elevating device 121 descends to bring the pressure head 122 into contact with the back surface 22b of the second substrate 22, and applies downward pressure on the back surface 22b of the second substrate 22 (as indicated by arrow 123) to The back surface 22b of the downwardly curved second base 22 becomes a flat surface. Here, the flat surface means that the flatness of the back surface 22b is maintained within ±5000 nm.

In this embodiment, the bottom area of the pressing head 122 is sufficient to cover the back surfaces 22b of all the second substrates 22 on the first substrate 12, so that all the back surfaces 22b of the second substrates 22 on the first substrate 12 are pressed simultaneously. In addition, the pressure applied by the pressing head 122 to the back surface 22b of each second substrate 22 is, for example, 0.05 Kg to 1 Kg.

However, the embodiment of the present invention is not limited to this. The bottom area of the pressing head 122 may be unable to completely cover the back surfaces 22b of all the second substrates 22 on the first substrate 12, but only enough to cover a portion of the first substrate 12 on the first substrate 12. The back surface 22b of the second substrate 22. In some embodiments, the bottom area of the pressing head 122 is only sufficient to cover the back surface 22b of the single second substrate 22. In other embodiments, the bottom area of the pressing head 122 is only sufficient to cover the back surfaces 22b of the second substrates 22. In other words, the plurality of second substrates 22 on the first substrate 12 may no longer be pressed at the same time, but may be pressed in batches or zones. Alternatively, a plurality of pressing heads may be included above the second region 120, and these pressing heads may press the back surfaces 22b of different second substrates 22 at the same time or at different times.

In addition, the buffer layer 122b of the pressing head 122 has elasticity, so it can conformally conform to the back surface 22b of the second substrate 22. That is, the back surface 22b having a curved surface contacts the lower surface 122t of the buffer layer 122b. When the downward pressure 123 gradually increases, the lower surface 122t of the elastic buffer layer 122b corresponds to and replicates the shape of the back surface 22b of the second substrate 22, and pushes the second substrate 22 toward the first substrate 12, so that the second The solder area 24 and the first solder area 14 are in contact with each other. In this case, the lower surface 122t of the buffer layer 122b and the back surface 22b of the second substrate 22 substantially match (substantially matches). Here, “substantially matching” means that the curvature or degree of curvature of the area of the lower surface 122t corresponding to the back surface 22b of the second substrate 22 is substantially the same as the curvature or degree of curvature of the back surface 22b of the second substrate 22. That is, the area of the lower surface 122t corresponding to the back surface 22b of the second substrate 22 is curved downward as the back surface 22b of the second substrate 22 is. As the downward pressure 123 gradually increases, the curvature or total thickness variation (TTV) of the back surface 22b of the second substrate 22 gradually decreases, thereby becoming a flat surface, as shown in FIG. 4C. Here, the TTV refers to the distance between the highest point and the lowest point of the back surface 22b. After pressurization, in some embodiments, the back surfaces 22b of the plurality of second substrates 22 can be regarded as coplanar. In this case, the area of the lower surface 122t corresponding to the back surface 22b of the second substrate 22 also becomes a flat surface with the back surface 22b of the second substrate 22, as shown in FIG. 4C.

In an embodiment, the second heating process and the pressing process of the second substrate 22 of the packaging structure 10 by the pressing head 122 can make the curved back surface 22b of the second substrate 22 flatter, or even flat Surface, thereby improving the warping phenomenon of the package structure 10. In this case, the first solder regions 14 of the first substrate 12 all contact the second solder regions 24 of the second substrate 22 and fuse the two to form the bonding solder 34 to reduce or prevent cold soldering, thereby improving the package structure The yield of the process. In addition, compared to the unpressurized reflow process, the amount of the connecting member 20 with the reflow process of the pressure treatment in this embodiment is less and the connecting member between the second substrate 22 and the first substrate 12 can be used The difference in the standoff of 20 is reduced and tends to be consistent. That is, in some embodiments, the distance D between the active surface 22a of each second substrate 22 and the active surface 12a of the first substrate 12 is the same or similar. In addition, the reflow process of this embodiment can be batch-produced via a conveyor belt 104, which presses a plurality of second substrates 22 onto a large-area first substrate 12 to manufacture a package structure 10 having a flat surface. Therefore, this embodiment can be applied to a package structure with large area and fine pitch contacts, which can increase throughput and increase the reflow process margin. In another embodiment, the second heating treatment and the pressure treatment may be performed simultaneously in the second area 120. In an alternative embodiment, the second heating treatment and the pressure treatment may be performed in sequence in the second area 120, and vice versa.

Referring back to FIG. 1, after performing the second heat treatment and pressure treatment, the lifting device 121 rises to move the pressure head 122 upward, away from the back surface 22 b of the second substrate 22, and the packaging structure 10 is transferred by the conveyor belt 104 Transfer from the second area 120 to the third area 130. In some embodiments, the third region 130 may be a cooling region, which includes a plurality of cooling sources 135 respectively disposed on the upper and lower sides of the third region 130 to cool the packaging structure 10. Specifically, the third region 130 is used to cool the temperature of the connection member 20 of the packaging structure 10. The cooling rate can be adjusted according to the thermal expansion coefficient and the shrinkage rate of the connecting member 20 of the packaging structure 10, and the embodiment of the present invention is not limited.

In an embodiment, the cooling source 135 may be, for example, blowers that blow air toward the packaging structure 10. The temperature of the air blown toward the packaging structure 10 may be room temperature, for example, between about 20°C and 30°C. However, the embodiments of the present invention are not limited thereto. In other embodiments, the room temperature may be lower than 20°C or higher than 30°C. In an alternative embodiment, any cooling source may not be provided on a single side or both sides of the third region 130, so that the package structure 10 is naturally cooled.

2 is a schematic cross-sectional view of a reflow device according to a second embodiment of the invention. In this embodiment, a hot plate type reflow device 200 will be used as an example for description.

Referring to FIG. 2, the reflow device 200 of the second embodiment is similar to the reflow device 100 of the first embodiment, and the detailed components and their configurations have been described in detail in the paragraphs of the foregoing embodiments, and will not be repeated here. The difference between the above two is that: the heating source 115 of the reflow device 200 is respectively arranged on a single side (ie below) of the first region 110; the heating source 125 is arranged on a single side (ie below) of the second region 120 and is cooled The sources 135 are respectively arranged on a single side (ie, below) of the third area 130. In this case, radiant heat energy and/or cold air is transmitted to the packaging structure 10 from below to achieve heating and/or cooling effects. In some embodiments, the packaging structure 10 is transmitted through the first area 110, the second area 120 and the third area 130 in the reflow device 200 by the conveyor belt 104. In an alternative embodiment, the first area 110, the second area 120, and the third area 130 in the reflow device 200 may also be separate chambers separated from each other, and the packaging structure 10 is transferred to the first area 110 by the robot arm, respectively , The second area 120 and the third area 130.

3 is a schematic cross-sectional view of a reflow device according to a third embodiment of the invention. In this embodiment, an oven-type reflow device 300 will be described as an example.

The reflow device 300 of the third embodiment integrates the first region, the second region, and the third region into the same region 301. That is, the area 301 of the reflow device 300 may be subjected to heat treatment, pressure treatment, and/or cooling treatment. Specifically, as shown in FIG. 3, the area 301 is an independent chamber 302, which includes a chamber wall 307 to define an accommodating space 303. In addition, the area 301 further includes a container 304, a carrier 306, a lifting device 321, a pressurizing head 322, and a ventilation duct 308. The carrier 306, the pressurizing head 322 and the packaging structure 10 are all disposed in the container 304. The side wall of the container 304 has a plurality of vents 305.

The vent pipe 308 connects one side wall and the other side wall of the container 304 through the vent 305 to achieve the effect of gas circulation or temperature circulation. The ventilation duct 308 has a fan 310 and a heating source 315. A plurality of arrows 314 represent that the heat source of the heating source 315 communicates from one side wall of the container 304 along the ventilation duct 308 and circulates to the other side wall to uniform the temperature in the independent chamber 302. In some embodiments, the atmosphere in the independent chamber 302 is air. In other embodiments, other gases may be introduced into the independent chamber 302. For example, nitrogen or an inert gas may be additionally introduced into the independent chamber 302. The operation of the fan 310 can drive nitrogen gas into the ventilation duct 308. When the nitrogen gas is heated to a specific temperature through the heating source 315, the heated nitrogen gas will be brought into the independent chamber 302 by the vent pipe 308, and reach the container 304 through the vent 305, thereby heating the packaging structure 10.

As shown in FIG. 3, the packaging structure 10 is transferred onto the carrier 306. In some embodiments, the carrier 306 may be a heating plate, which may heat the packaging structure 10 from below. In other embodiments, another heating source (for example, a heating plate) is also disposed below the carrier 306 to heat the carrier 306 and the packaging structure 10 from below. Then, the lifting device 321 moves the pressing head 322 close to and contacts the packaging structure 10 to pressurize the packaging structure 10, thereby improving the warping phenomenon of the packaging structure 10. In addition, the pressing head 322 may also have a heating function, which may heat the packaging structure 10 from above. The pressing head 322 includes a main body portion 322a and a buffer layer 322b disposed on one side of the main body portion 322a. The materials of the main body portion 322a and the buffer layer 322b are similar to the materials of the above-mentioned main body portion 122a and the buffer layer 122b, and have been described in detail in the foregoing embodiment paragraphs, and will not be repeated here.

In some embodiments, the heat treatment and the pressure treatment may be performed simultaneously in the independent chamber 302. In an alternative embodiment, heat treatment and pressurization treatment may be performed sequentially in the independent chamber 302, and vice versa.

In addition, in an embodiment, the package structure 10 may be cooled in the area 301. However, the embodiments of the present invention are not limited thereto. In other embodiments, the packaging structure 10 may also be cooled in other regions or chambers.

5A to 5C are schematic diagrams of the pressurizing operation performed by the pressurizing head of the fifth embodiment of the present invention. Although the main parts of the pressing head shown in the above embodiments are all solid structures, the embodiments of the present invention are not limited thereto. In other embodiments, the main body of the pressurizing head may also be a hollow structure with an air chamber.

Specifically, the pressing operation by the pressing head 522 is shown in FIGS. 5A to 5C, respectively. Referring to FIG. 5A, before the pressing is performed, the pressing head 522 does not contact the back surface 22b of the second substrate 22, and the back surface 22b of the second substrate 22 is curved downward. As shown in FIG. 5A, the pressurizing head 522 includes a main body portion 522a and a buffer layer 522b disposed on one side of the main body portion 522a. In an embodiment, the body portion 522a is a hollow structure having an air chamber 502. The air chamber 502 is defined by the inner side wall of the body portion 522a and the upper surface of the buffer layer 522b. Gas (for example, nitrogen, inert gas, etc.) may be passed into the gas chamber 502 to control the pressure applied by the pressurizing head 522 by adjusting the gas content in the gas chamber 502. Since the gas can contact the upper surface of the buffer layer 522b, the flexibility of the pressing head 522 can be increased to avoid damaging the packaging structure 10 during the subsequent pressing process. The materials of the main body portion 522a and the buffer layer 522b are similar to the materials of the main body portion 122a and the buffer layer 122b, and have been described in detail in the foregoing embodiment paragraphs, and will not be repeated here.

Next, as shown in FIGS. 5B to 5C, the pressing head 522 contacts the back surface 22b of the second substrate 22, and applies downward pressure (as indicated by arrow 523) to the back surface 22b of the second substrate 22 to make the downward The curved back surface 22b (as shown in FIG. 5B) of the curved second base 22 becomes a relatively flat surface (as shown in FIG. 5C).

6 is a schematic cross-sectional view of a pressure head according to a sixth embodiment of the present invention.

Referring to FIG. 6, the pressure head 622 of the sixth embodiment is similar to the pressure head 522 of the fifth embodiment, and the detailed components and their configurations have been described in detail in the paragraphs of the above embodiments, and will not be repeated here. The difference between the above two is that the main body portion 622a of the pressure head 622 of the sixth embodiment is a hollow structure having a plurality of air chambers 602a, 602b, and 602c. Specifically, the pressing head 622 includes a main body portion 622a and a buffer layer 622b disposed on one side of the main body portion 622a. In an embodiment, the main body portion 622a is a hollow structure having a plurality of air chambers 602a, 602b, and 602c. The air chambers 602a, 602b, and 602c are defined by the inner wall of the main body portion 622a and the upper surface of the buffer layer 622b. In an alternative embodiment, the gas chambers 602a, 602b, 602c are independent of each other and are not in communication. In some embodiments, gas (such as nitrogen, inert gas, etc.) can be passed into the gas chambers 602a, 602b, and 602c from outside, and the gas content in the gas chambers 602a, 602b, and 602c can be adjusted to precisely control the pressurization Pressure is applied to various areas of the head 622. For example, the processor can precisely control the gas flow rate into the gas chambers in the center and both sides of the pressurizing head 622, thereby controlling the applied pressure to improve the center and both sides of the package structure 10曲度。 Degree. Although FIG. 6 only shows three gas chambers 602a, 602b, and 602c, the embodiment of the present invention is not limited thereto. In other embodiments, the number and configuration of the above-mentioned gas chambers can be adjusted as required.

7 is a flowchart of an integrated circuit bonding method according to an embodiment of the invention. It should be understood that the embodiment method shown in FIG. 7 is only an example of many possible embodiment methods. Those skilled in the art should understand that there are many variations, alternatives, and modifications in this joining method. For example, the various steps illustrated in FIG. 7 can be added, removed, replaced, rearranged, and repeated.

Referring to FIG. 7, in step S102, the first substrate and the second substrate are bonded so that the plurality of first solder regions on the first substrate are aligned with the plurality of second solder regions on the second substrate, respectively. Next, a reflow process is performed, which includes step S104, step S106, and step S108. In step S104, a first heating process is performed in the first area of the reflow device, wherein the difference in thermal expansion coefficient between the first substrate and the second substrate causes the surface of the second substrate to form a curved shape during the first heating process. In step S106, a second heating process and a pressing process are performed in the second region of the reflow device, wherein the pressing process includes pressing the second substrate with a pressing head so that the curved surface of the second substrate becomes Flat surface. In step S108, a cooling process is performed in the third area of the reflow device. In some embodiments, the above bonding method can improve the warpage phenomenon of the bonded package structure, so as to improve the process yield.

According to some embodiments, a reflow device for joining an integrated circuit includes a main chamber. The main chamber includes: a first area, a second area, and a third area. The first area is configured to heat-treat the integrated circuit to form a curved shape on the surface of the integrated circuit. The second area includes a pressurizing head which pressurizes the integrated circuit, which pressurizes the integrated circuit by the pressing head so that the curved surface of the integrated circuit becomes a flat surface. The pressing head includes a main body and a buffer layer disposed on one side of the main body. The buffer layer has elasticity to conformally conform to the integrated circuit. The third area is configured to cool the integrated circuit.

According to some embodiments, a bonding method has the following steps. Laminating the first substrate and the second substrate so that the plurality of first solder regions on the first substrate are respectively aligned with the plurality of second solder regions on the second substrate; and performing a reflow process. Performing the reflow process includes: performing a first heating process in the first region of the reflow device, wherein the difference in thermal expansion coefficient between the first substrate and the second substrate causes the surface of the second substrate to form a curved shape during the first heating process ; And performing second heat treatment and pressure treatment in the second area of the reflow device, wherein the pressure treatment includes pressing the second substrate with a pressure head so that the curved surface of the second substrate becomes a flat surface, The first area and the second area are separated and independent from each other.

According to some embodiments, in another bonding method, the steps are as follows. Laminating the first substrate and the second substrate so that the plurality of first solder regions on the first substrate are aligned with the plurality of second solder regions on the second substrate; and performing heat treatment and addition in a separate chamber of the reflow device The pressure treatment includes pressurizing the second substrate by the pressure head, wherein the heat treatment includes transferring the heat source to the independent chamber through the ventilation pipe to uniform the temperature in the independent chamber, thereby transferring the first solder area A plurality of bonding solders are fused with the second solder area.

The above summarizes the features of several embodiments so that those skilled in the art may better understand the various aspects of the present invention. Those skilled in the art should understand that they can easily use the present invention as a basis for designing or modifying other processes and structures to perform the same purposes and/or achieve the implementations as described in the embodiments described herein. Examples have the same advantages. Those skilled in the art should also realize that these equivalent constructions do not depart from the spirit and scope of the present invention, and they can make various changes, substitutions, and alterations to them without departing from the spirit and scope of the present invention.

10: Package structure

12: The first base

12a: Active surface of the first base

14: First solder area

16: Metal column

18: Solder cover

20: Connector

22: Second base

22a: Active surface of the second base

22b: the back of the second substrate

24: Second solder area

34: Joining solder

100, 200, 300: reflow device

102: main chamber

104: Conveyor belt

106, 314: Arrow

108, 302: independent chamber

110: first area

115, 115a, 115b, 125, 315: heating source

120: Second area

121, 321: Lifting device

122, 322, 522, 622: pressure head

122a, 322a, 522a, 622a: main body

122b, 322b, 522b, 622b: buffer layer

122t: the lower surface of the buffer layer

123, 523: pressure

130: third area

135: Cooling source

301: Area

303: accommodating space

304: container

305: vent

306: Carrier

307: chamber wall

308: Ventilation duct

310: fan

502, 602a, 602b, 602c: air chamber

D: distance

S102, S104, S106, S108: steps

T0, T1, T2, T3: temperature

When reading in conjunction with the accompanying drawings, the present disclosure is best understood from the following embodiments. It should be emphasized that, according to standard practice in the industry, various features are not drawn to scale and are for illustrative purposes only. In fact, the size of various features can be arbitrarily increased or decreased for clarity of discussion. FIG. 1 is a schematic cross-sectional view of a reflow device according to a first embodiment of the present invention. 2 is a schematic cross-sectional view of a reflow device according to a second embodiment of the invention. 3 is a schematic cross-sectional view of a reflow device according to a third embodiment of the invention. 4A to 4C are schematic diagrams of the pressurizing operation performed by the pressurizing head of the fourth embodiment of the present invention. 5A to 5C are schematic diagrams of the pressurizing operation performed by the pressurizing head of the fifth embodiment of the present invention. 6 is a schematic cross-sectional view of a pressure head according to a sixth embodiment of the present invention. 7 is a flowchart of an integrated circuit bonding method according to an embodiment of the invention.

10: Package structure

12: The first base

12a: Active surface of the first base

14: First solder area

16: Metal column

18: Solder cover

20: Connector

22: Second base

22a: Active surface of the second base

22b: the back of the second substrate

24: Second solder area

34: Joining solder

100: reflow device

102: main chamber

104: Conveyor belt

106: Arrow

108: Independent chamber

110: first area

115, 115a, 115b, 125: heating source

120: Second area

121: Lifting device

122: Compression head

130: third area

135: Cooling source

T0, T1, T2, T3: temperature

Claims (7)

A reflow device for joining integrated circuits includes a main chamber, wherein the main chamber includes: a first area configured to heat-treat the integrated circuit; a second area including a pressurizing head, It pressurizes the integrated circuit so that the curved surface of the integrated circuit becomes a flat surface, wherein the pressing head includes: a body portion; and a buffer layer, which is disposed on one side of the body portion , Wherein the buffer layer has elasticity to conformally conform to the integrated circuit; and the third area is configured to cool the integrated circuit, the reflow device further includes: a conveyor belt The integrated circuit passes through the first area, the second area, and the third area. The reflow device as described in item 1 of the patent application scope further includes a plurality of heating sources arranged on one or both sides of the first area and the second area, respectively. The reflow device according to item 1 of the scope of the patent application, wherein the second region is arranged in a separate chamber to be separated from the first region and the third region. The reflow device according to item 1 of the patent application scope, wherein the material of the main body portion includes a metal material, a ceramic material, or a combination thereof, and the material of the buffer layer includes a metal material, a rubber material, a release material, or a combination thereof . The reflow device as described in item 1 of the patent application, wherein the main body portion includes a solid structure or a hollow structure having an air chamber. A bonding method includes: bonding a first substrate and a second substrate to form an integrated circuit, wherein the plurality of first solder regions on the first substrate are respectively aligned with the plurality of second solders on the second substrate Area; and performing a reflow process, including: conveying the integrated circuit to the first area of the reflow device by a conveyor belt for a first heat treatment, wherein the first substrate and the second substrate The difference in coefficient of thermal expansion causes the surface of the second substrate to form a curved shape during the first heating process; and the integrated circuit is transferred to the second area of the reflow device by the conveyor belt for the second A heat treatment and a pressure treatment, the pressure treatment including pressing the second substrate with a pressure head so that the curved surface of the second substrate becomes a flat surface, wherein the first area and the The second areas are separated and independent from each other. The bonding method according to item 6 of the patent application scope, wherein performing the reflow process further includes: after performing the second heating process and the pressurizing process, the integrated circuit is transferred by the conveyor belt Transfer to the third area of the reflow device for cooling.

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