TWI737312B - 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. The first, second, and third regions constitute a separate chamber, which transfers a heat source into the separate chamber via a ventilation duct to uniform a temperature in the separate chamber.

Description

Reflow device and joining method

The embodiment of the present 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 the components of the integrated circuit. Take the joining of two integrated circuit components as an example. The two integrated circuit components can be placed together with solder, reflow is performed to melt the solder, and then the two integrated circuit components can be joined together when the solder is cooled. .

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

The embodiment of the present invention provides a reflow device for joining an integrated circuit, which includes an independent chamber and a vent pipe. The independent chamber includes an area configured to heat, press, and cool the integrated circuit. The ventilation pipe transmits the heat source to the independent chamber to uniform the temperature in the independent chamber. The pressure treatment includes the use of a pressure head to make the curved surface of the integrated circuit into a flat surface. The pressing head includes a main body and a buffer layer. The buffer layer is arranged on one side of the main body. The buffer layer has elasticity to conformally fit the integrated circuit.

The embodiment of the present invention provides a joining method, the steps of which are as follows. Bonding the first substrate and the second substrate so that the first solder regions on the first substrate are respectively aligned with the second solder regions on the second substrate; and heat treatment and heating are performed in the independent chamber of the reflow device Pressure treatment. The pressure treatment includes pressurizing the second substrate by a pressure head, wherein the heating treatment includes transferring a heat source to an independent chamber through a vent pipe to uniformize the temperature in the independent chamber, thereby reducing the first solder area It is fused with the second solder area to form a plurality of bonding solders.

The embodiment of the present invention provides another reflow device for joining integrated circuits, which 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 the integrated circuit so that the surface of the integrated circuit forms a curved shape. The second area includes a pressure head, which applies pressure processing to 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 arranged on one side of the main body. The buffer layer has elasticity to conformally fit the integrated circuit. The third area is configured to cool the integrated circuit. The first area, the second area, and the third area constitute an independent chamber, which transmits the heat source to the independent chamber through the vent pipe to uniform the temperature in the independent chamber.

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 disclosure in a simplified manner. Of course, these are just examples and not for limitation. For example, in the following description, forming the first feature above or on the second feature may include an embodiment in which the first feature and the second feature are formed in direct contact, and may also include the first feature and the second feature. An embodiment in which an additional feature may be formed between the two features, so that the first feature and the second feature may not directly contact. In addition, the present disclosure may reuse component symbols and/or letters in various examples. The repeated use of component symbols is for the sake of simplicity and clarity, and does not indicate the relationship between the various embodiments and/or configurations to be discussed.

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

It can also include other features and processes. 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 enabling the testing of 3D packages or 3DIC, the 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 including intermediate verification of known good dies to improve 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, a conveyor type (Convey type) reflow device 100 is taken as an example for description, but the embodiments of the present invention are 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), I will explain in detail later.

In this embodiment, the integrated circuit 10 (for example, a package structure, hereinafter referred to as the package structure 10) is conveyed by a conveyor belt 104 through the first area 110, the second area 120, and the third area 130, thereby implementing the reflow process . The multiple arrows 106 represent that the package 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 package 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 turned upside down 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 pillar 16 and a solder cover 18 disposed on the metal pillar 16; and the second solder area 24 may be a solder bump. However, the embodiment of the present invention is not limited thereto. In other embodiments, the second solder area 24 may be a metal pillar and a solder cap disposed on the metal pillar; and the first solder area 14 may be a solder bump. In an alternative embodiment, both the first solder area 14 and the second solder area 24 may be solder bumps or metal pillars and solder caps arranged 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, combinations thereof, or other suitable materials, etc., which can be achieved by, for example, evaporation, 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 embodiment of the present invention is not limited thereto. In other embodiments, the first substrate 12 and the second substrate 22 may each include semiconductor dies (which have active components such as transistors and diodes in them), packages Substrate, interposer (interposer), printed circuit board (PCB), package body 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 substrates 22 is greater than the number of the first substrates 12, the embodiment of the present invention is not limited thereto. In other embodiments, the area and quantity 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 each other to form a die stack structure.

Please refer 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 area 110 may be a preheating area. The first area 110 includes a plurality of heating sources 115 respectively disposed on the upper and lower sides of the first area 110 to perform the first heating treatment on the packaging structure 10. As shown in FIG. 1, when the package structure 10 is conveyed through the heating source 115, the heating source 115 can preheat the first solder area 14 and the second solder area 24 in the package structure 10. In an embodiment, the heating source 115 may be a radiant heating source (for example, 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 indicates radiant heat, 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 conveys the packaging structure 10 through the first area 110, the temperature experienced by the packaging structure 10 gradually increases from left to right, as shown in FIG. 1. Specifically, when the initial temperature of the package structure 10 is T0, the back (or upper surface) 22b of the second substrate 22 is bowed upward. As shown in FIG. 1, the center of the back (or upper surface) 22 b of the second base 22 is higher than the two ends thereof, and has a curved surface protruding upward. When the packaging structure 10 moves from the heating source 115a to the heating source 115b, the temperature of the packaging 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 warpage changes 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 (or upper surface) 22b of the second substrate 22 has a downwardly curved surface, 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 make the package structure 10 have a ramp-up rate. Here, the so-called heating 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 embodiment of the present invention is not limited thereto. In other embodiments, the heating rate of the package structure 10 can be changed according to the material and process standards of the first solder region 14 and the second solder region 24 of the package 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, during the process of increasing the temperature of the package structure 10 from T0 to T1 (ie, the first heating process), the back (or upper surface) 22b of the second substrate 22 shown in FIG. The camber is changed to camber downward, 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, during the heating process of the first region 110, the back surface (or upper surface) 22b of the second substrate 22 can also be changed from downward arching to Arch upward, or change from plane to arch downward, or change from plane to arch 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, resulting in the first solder regions 14 being difficult to join to their corresponding second solder regions 24, and thus Cold joints are generated between the first solder area 14 and the second solder area 24. Here, the cold welding may cause defects in the package structure and reduce the yield of the package structure manufacturing process. In this embodiment, as shown in FIGS. 1 and 4A to 4C, the warpage of the package structure 10 can be improved by pressure treatment to reduce or prevent the occurrence of 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 area 110 to the second area 120, the second area 120 can become an independent chamber 108 to be separated from the first area 110 and the third area 130 open. In other words, during the reflow process, the second area 120 is not spatially connected with the first area 110 and the third area 130. 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 treatment. 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 (that is, the second heating process). The second area 120 is the area with the highest reflow temperature among the first area 110 to the third area 130, and it can fuse the solder cover 18 of the first solder area 14 and the solder of the second solder area 24 into the joining solder 34. In this case, as shown in FIG. 1, the first substrate 12 and the second substrate 22 can be joined to the metal pillar 16 by the joining solder 34. Here, the combination of the bonding solder 34 and the metal pillar 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 connection member 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, a micro-bump may refer to a connector with 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 pressurize the packaging structure 10 so as to improve the warpage of the packaging structure 10. Specifically, the lifting device 121 is connected to the press head 122, and the press head 122 is lowered and/or raised by the lifting device 121 to perform pressurization actions as shown in FIGS. 4A to 4C, respectively. Referring to FIG. 4A, before pressing, 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 arched downward.

As shown in FIG. 4A, the lifting device 121 is connected to the top surface of the main body 122 a of the pressing head 122. The lifting device 121 is, for example, a lifting pin, which is connected to a lifting motor module with respect to the other end of the pressing head 122 so that the pressing head 122 can move up and down in the axial direction. The pressing head 122 includes a main body 122a and a buffer layer 122b disposed on one side of the main body 122a. In some embodiments, the main body 122a is a solid structure, and its material can be, for example, a metal material, a ceramic material, or a combination thereof. In another embodiment, the material of the main body 122a may be quartz, sapphire or similar materials. In an embodiment, the pressing head 122 may also have a heating function, and therefore, the main body 122a may be a thermally conductive material. In an alternative embodiment, the material of the buffer layer 122b may include metal materials (for example, stainless steel, titanium, aluminum, copper, etc.), rubber materials, and release materials (for example, polytetrafluoroethylene, also known as Teflon) Or a combination. 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 lifting device 121 descends to make the pressing head 122 contact the back surface 22b of the second substrate 22, and apply downward pressure (as indicated by the arrow 123) to the back surface 22b of the second substrate 22 to The back surface 22b of the second base 22 that is curved downward is made into 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 all the back surfaces 22b of 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 simultaneously pressed. 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 not be able to completely cover all the back surfaces 22b of the second substrate 22 on the first substrate 12, but only enough to cover a part of the second substrate 22 on the first substrate 12. The back side 22b of the two base 22. In some embodiments, the bottom area of the pressing head 122 is only enough to cover the back surface 22 b of a 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 plurality of second substrates 22. In other words, the plurality of second substrates 22 on the first substrate 12 may not be pressurized at the same time, but may be pressurized in batches or partitions. Alternatively, a plurality of pressure heads may be included above the second area 120, and these pressure heads may press different back surfaces 22b of the second substrate 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 adhere 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 will correspond to and replicate the shape of the back surface 22b of the second substrate 22, and push 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, the so-called "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. In other words, the area of the lower surface 122t corresponding to the back surface 22b of the second substrate 22 is arched downward along with the back surface 22b of the second substrate 22. 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 pressing, 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 along with the back surface 22b of the second substrate 22, as shown in FIG. 4C.

In one embodiment, the second substrate 22 of the package structure 10 is subjected to the second heat treatment and pressure treatment by the press head 122, so that the curved back surface 22b of the second substrate 22 becomes relatively flat, or even becomes flat. The surface, thereby improving the warpage of the package structure 10. In this case, the first solder area 14 of the first substrate 12 is in contact with the second solder area 24 of the second substrate 22, and the two are fused to form the bonding solder 34 to reduce or prevent the occurrence of cold soldering, thereby improving the package structure The yield of the process. In addition, compared with the non-pressurized reflow process, the amount of the connection member 20 with the pressurized reflow process of this embodiment is less, and the connection member between the second substrate 22 and the first substrate 12 The standoff difference of 20 decreases, and it approaches the same. 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 close. In addition, the reflow process of this embodiment can be produced in batches 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 with 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 margin of the reflow process. In another embodiment, the second heating treatment and the pressure treatment may be performed in the second region 120 at the same time. In an alternative embodiment, the second heating treatment and the pressurizing treatment can also be sequentially performed in the second region 120, and vice versa.

Referring back to FIG. 1, after performing the second heating and pressure processing, the lifting device 121 rises to move the pressure head 122 upwards, away from the back surface 22b 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 area 130 may be a cooling area, which includes a plurality of cooling sources 135 respectively disposed on the upper and lower sides of the third area 130 to cool the packaging structure 10. Specifically, the third area 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 shrinkage rate of the connector 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 to the packaging structure 10. The temperature of the air blown to 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, no cooling source may be provided on a single side or upper and lower sides of the third region 130, so that the packaging structure 10 is naturally cooled.

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

Please refer 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 configuration have been described in detail in the above embodiment paragraphs, and will not be repeated here. The difference between the above two is: 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 cools down The sources 135 are respectively arranged on a single side (ie, below) of the third region 130. In this case, the radiant heat energy and/or cold air is transferred from below to the packaging structure 10 to achieve heating and/or cooling effects. In some embodiments, the package structure 10 is conveyed 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 independent chambers separated from each other, and the packaging structure 10 is transferred to the first area 110 by a robot arm. , The second area 120 and the third area 130.

Fig. 3 is a schematic cross-sectional view of a reflow device according to a third embodiment of the present invention. In this embodiment, an oven-type reflow device 300 is taken as an example for description.

The reflow device 300 of the third embodiment integrates the above-mentioned first area, second area, and third area in the same area 301. In other words, the area 301 of the reflow device 300 may be subjected to heating 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 also includes a container 304, a bearing seat 306, a lifting device 321, a pressurizing head 322, and a ventilation pipe 308. The supporting base 306, the pressing head 322 and the packaging structure 10 are all arranged 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 air 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 to the other side wall along the air 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 passed into the independent chamber 302. For example, nitrogen or inert gas may be additionally introduced into the independent chamber 302. The operation of the fan 310 can drive the nitrogen gas to enter the ventilation duct 308. When the nitrogen gas is heated to a specific temperature through the heating source 315, the heated nitrogen gas is brought into the independent chamber 302 by the vent pipe 308, and reaches the container 304 through the vent 305, thereby heating the packaging structure 10.

As shown in FIG. 3, the packaging structure 10 is transferred to the carrier 306. In some embodiments, the supporting base 306 may be a heating plate, which may heat the packaging structure 10 from below. In some other embodiments, another heating source (for example, a heating plate) is disposed under the supporting base 306 to heat the supporting base 306 and the packaging structure 10 from below. Then, the pressing head 322 is approached downward and contacted with the packaging structure 10 by the lifting device 321 to pressurize the packaging structure 10 so as to improve the warpage 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 aforementioned main body portion 122a and the buffer layer 122b, and have been described in detail in the above embodiment paragraphs, and will not be repeated here.

In some embodiments, the heat treatment and the pressure treatment can be performed in the independent chamber 302 at the same time. In an alternative embodiment, the heating treatment and the pressurization treatment can also be sequentially performed 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 embodiment of the present invention is not limited thereto. In other embodiments, the packaging structure 10 may also be cooled in other regions or chambers.

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

Specifically, the pressing action performed by the pressing head 522 is shown in FIGS. 5A to 5C, respectively. Referring to FIG. 5A, before pressing, 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 arched downward. As shown in FIG. 5A, the pressing head 522 includes a main body 522a and a buffer layer 522b disposed on one side of the main body 522a. In one embodiment, the main body 522a is a hollow structure with an air chamber 502. The air chamber 502 is defined by the inner side wall of the main body 522a and the upper surface of the buffer layer 522b. Gas (for example, nitrogen, inert gas, etc.) can be passed into the gas chamber 502 to control the applied pressure of 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 softness of the pressure head 522 can be increased to avoid damage to the packaging structure 10 during subsequent pressure processing. The materials of the main body portion 522a and the buffer layer 522b are similar to the materials of the aforementioned main body portion 122a and the buffer layer 122b, and have been described in detail in the above 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 the arrow 523) to the back surface 22b of the second substrate 22 to make it downward The curved back surface 22b (as shown in FIG. 5B) of the arched second substrate 22 becomes a relatively flat surface (as shown in FIG. 5C).

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

Please refer to FIG. 6, the pressing head 622 of the sixth embodiment is similar to the pressing head 522 of the fifth embodiment, and the detailed components and their configuration 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 one embodiment, the main body 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 side wall of the main body portion 622a and the upper surface of the buffer layer 622b. In an alternative embodiment, the air chambers 602a, 602b, 602c are independent of each other and not connected. In some embodiments, gas (such as nitrogen, inert gas, etc.) can be introduced into the gas chambers 602a, 602b, 602c from the outside, and the gas content in the gas chambers 602a, 602b, 602c can be adjusted to precisely control the pressurization. The pressure is applied to the various areas of the head 622. For example, the processor can precisely control the gas flow into the air chambers in the center and both sides of the pressurizing head 622, so as to control the applied pressure, so as to improve the warpage of the center and both sides of the package structure 10 in zones. The degree of curvature. Although FIG. 6 only illustrates three air chambers 602a, 602b, and 602c, the embodiment of the present invention is not limited thereto. In other embodiments, the number and configuration of the aforementioned air chambers can be adjusted on demand.

FIG. 7 is a flowchart of a bonding method of an integrated circuit according to an embodiment of the present 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 attached 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. Next, a reflow process is performed, which includes step S104, step S106, and step S108. In step S104, a first heating treatment is performed 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 treatment. In step S106, a second heat treatment and a pressure treatment are performed in the second area of the reflow device, wherein the pressure treatment includes pressing the second substrate by 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-mentioned bonding method can improve the warpage 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 an independent chamber and a vent pipe. The independent chamber includes an area configured to heat, press, and cool the integrated circuit. The ventilation pipe transmits the heat source to the independent chamber to uniform the temperature in the independent chamber. The pressure treatment includes the use of a pressure head to make the curved surface of the integrated circuit into a flat surface. The pressing head includes a main body and a buffer layer. The buffer layer is arranged on one side of the main body. The buffer layer has elasticity to conformally fit the integrated circuit.

According to some embodiments, a bonding method includes the following steps. Bonding the first substrate and the second substrate so that the first solder regions on the first substrate are respectively aligned with the second solder regions on the second substrate; and heat treatment and heating are performed in the independent chamber of the reflow device Pressure treatment. The pressure treatment includes pressurizing the second substrate by a pressure head, wherein the heating treatment includes transferring a heat source to an independent chamber through a vent pipe to uniformize the temperature in the independent chamber, thereby reducing the first solder area It is fused with the second solder area to form a plurality of bonding solders.

According to some embodiments, another reflow device for bonding integrated circuits 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 the integrated circuit so that the surface of the integrated circuit forms a curved shape. The second area includes a pressure head, which applies pressure processing to 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 arranged on one side of the main body. The buffer layer has elasticity to conformally fit the integrated circuit. The third area is configured to cool the integrated circuit. The first area, the second area, and the third area constitute an independent chamber, which transmits the heat source to the independent chamber through the vent pipe to uniform the temperature in the independent chamber.

The features of several embodiments are summarized above, so that those skilled in the art can better understand the various aspects of the present invention. Those skilled in the art should know that they can easily use the present invention as a basis for designing or modifying other processes and structures to perform the same purpose as the embodiment described in this article and/or to achieve the implementation described in this article Example of the same advantages. Those skilled in the art should also realize that these equivalent structures do not depart from the spirit and scope of the present invention, and they can make various changes, substitutions and alterations to it without departing from the spirit and scope of the present invention.

10: Package structure 12: The first substrate 12a: Active surface of the first substrate 14: The first solder area 16: metal pillar 18: Solder cover 20: connecting piece 22: second base 22a: Active surface of the second substrate 22b: The back of the second substrate 24: The 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: The 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 bottom surface of the buffer layer 123, 523: Stress 130: The third area 135: Cooling Source 301: area 303: accommodating space 304: container 305: Vent 306: Carrier 307: Chamber Wall 308: Ventilation Pipe 310: Fan 502, 602a, 602b, 602c: air chamber D: distance S102, S104, S106, S108: steps T0, T1, T2, T3: temperature

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

10: Package structure

300: Reflow device

301: area

302: independent chamber

303: accommodating space

304: container

305: Vent

306: Carrier

307: Chamber Wall

308: Ventilation Pipe

310: Fan

314: Arrow

315: heating source

321: Lifting device

322: Pressure head

322a: main body

322b: buffer layer

Claims (10)

A reflow device for joining integrated circuits, including: An independent chamber, including an area configured to heat, press, and cool the integrated circuit; and The ventilation pipe transmits the heat source to the independent chamber to uniform the temperature in the independent chamber, Wherein the pressure treatment includes turning the curved surface of the integrated circuit into a flat surface by a pressure head, wherein the pressure head includes: The main body; and The buffer layer is disposed on one side of the main body, wherein the buffer layer has elasticity to conformally adhere to the integrated circuit. The reflow device according to claim 1, further comprising a bearing seat for bearing the integrated circuit, wherein the bearing seat is a heating plate. The reflow device according to claim 1, wherein the pressure head has a heating function to simultaneously perform the pressure treatment and the heating treatment on the integrated circuit. The reflow device according to claim 1, wherein the material of the main body part 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 according to claim 1, wherein the main body portion includes a solid structure. The reflow device according to claim 1, wherein the main body part includes a hollow structure having an air chamber. A joining method includes: Bonding 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 Heat treatment and pressurization treatment are performed in an independent chamber of the reflow device, and the pressurization treatment includes pressurizing the second substrate by a pressurizing head, Wherein the heating treatment includes transferring a heat source to the independent chamber through a vent pipe to uniform the temperature in the independent chamber, thereby fusing the first solder area and the second solder area into a plurality of Join the solder. The joining method according to claim 7, wherein the heating treatment and the pressing treatment are performed simultaneously or sequentially. The joining method according to claim 7, further comprising performing a cooling process in the independent chamber of the reflow device. A reflow device for joining integrated circuits, comprising a main chamber, wherein the main chamber includes: The first area is configured to heat the integrated circuit; The second area includes a pressure head, which performs pressure treatment on the integrated circuit so that the curved surface of the integrated circuit becomes a flat surface, wherein the pressure head includes: The main body; and The buffer layer is disposed on one side of the main body part, wherein the buffer layer has elasticity to conformally adhere to the integrated circuit; and The third area is configured to cool the integrated circuit, wherein the first area, the second area, and the third area constitute an independent chamber, which transmits a heat source to the independent chamber through a ventilation pipe In the chamber, to uniform the temperature in the independent chamber.

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