TWI482244B - Heat exchanger and semiconductor module - Google Patents

Description

Heat exchanger and semiconductor module

The present application relates to a heat exchanger and a semiconductor module using the same to achieve a good heat dissipation effect.

In recent years, the process technology of Integrated Circuit (IC) has developed rapidly, which has greatly improved the functions of electronic components. However, as the processing speed and performance of electronic components increase, the amount of heat generated when the electronic components operate increases. If the waste heat is not effectively removed, the electronic components may fail or fail to achieve optimum performance.

Power electronic components, such as Insulated Gate Bipolar Transistors (IGBTs), are widely used in electric vehicles. The development of electric vehicles emphasizes lightness and volume reduction and saves power consumption. One of the key points to achieve the above goals lies in the operational efficiency of the IGBT power module. Since the IGBT power module is affected by the environment of high temperature, vibration, humidity and dust pollution for a long time, and the IGBT power module itself is a high-voltage and high-current module, the heat dissipation has always been related to its operational efficiency.

The conventional IGBT power module includes an IGBT chip, a diode (Diode) chip, a driver chip, a direct bond copper (DBC) substrate, a base, and the like, and is equipped with a cooling module such as a heat-sink. The heat generated during operation of the IGBT wafer and the diode wafer is first transferred to the DBC substrate, and the heat is spread on the DBC substrate and then transferred to the substrate. The base passes through thermal grease and then to the heat sink The heat dissipation module is configured to dissipate heat to the outside through the heat sink. In other words, the heat sink that is in contact with the IGBT power module, the IGBT power module and the thermal paste at the heat sink, and the base will have significant thermal resistance, so that the heat dissipation performance of the IGBT power module is limited.

On the other hand, since the heating power of the IGBT power module is relatively high, it is known that a liquid-cooled heat sink is used to dissipate heat from the IGBT power module. However, in addition to the aforementioned thermal resistance problems, such designs require additional pumping power to drive the working fluid in the liquid-cooled heat sink, increasing the energy consumption of the overall system. For example, when this type of IGBT power is applied to an electric vehicle, the power consumption of the electric vehicle is increased, and the travel time and distance of the electric vehicle are shortened.

According to an embodiment of the present application, the heat exchanger includes a base plate, a cover plate, a plurality of first heat dissipation fins, a plurality of second heat dissipation fins, and a working fluid. The bottom plate has a bearing surface and a back side opposite to the bearing surface, wherein the bearing surface is for carrying a heat source, such as an electronic component. The cover plate is disposed on the back side of the bottom plate, and the cover plate and the bottom plate together form a cavity. The chamber has an inlet and an outlet on the same side of the chamber. The first heat dissipation fins are disposed side by side between the bottom plate and the cover plate to form a plurality of first flow channels and a bypass channel parallel to each other in the chamber. Each of the first flow passages and the bypass flow passages extend from the inlet to a mixed flow zone in the chamber, and the width of the bypass flow passages is greater than the width of each of the first flow passages. The ratio of the width of the bypass flow path to the width of the first flow path is, for example, less than or equal to 9. The second heat dissipation fins are disposed side by side between the bottom plate and the cover plate to form a plurality of second flow paths parallel to each other in the chamber. Each of the second flow passages extends from the mixed flow region to the outlet, and the width of the bypass flow passage is greater than the width of each of the second flow passages. The working fluid is adapted to enter the chamber from the inlet, wherein a portion of the working fluid passes through the first flow passage and another portion of the working fluid passes through the bypass flow passage, and the portion of the working fluid and the other portion of the working fluid are mixed in the mixed flow region, Enter the second flow path and exit the chamber from the outlet.

The above-described features and advantages of the present application will become more apparent and understood.

First, the heat exchanger of the present application can be applied to various compatible semiconductor modules to transfer heat generated by the electronic components in the semiconductor module to the outside. Hereinafter, only the architecture of the heat exchanger of the present application applied to the IGBT power module will be described as an example, but the application is not limited thereto.

According to the design of the heat exchanger of the present application, the base of the IGBT power module can be integrated with the heat exchanger, that is, the base of the original IGBT power module is omitted, and the carrier substrate carrying the electronic component is directly bonded to The top of the heat exchanger. In this way, the heat generated by the operation of the electronic component can be transmitted to the heat exchanger only through the carrier substrate to dissipate heat to the outside through the heat exchanger. Since the base of the IGBT power module and the heat exchanger are integrated, the base of the original IGBT power module is omitted, thereby reducing the number of interfaces between components and reducing the heat generated by the interface between components. Resistance helps to improve heat transfer efficiency and improve heat dissipation.

FIG. 1A illustrates a semiconductor module in accordance with an embodiment of the present application. The semiconductor module 100 includes a heat exchanger 110, a carrier substrate 120, and electronic components 132 and 134. The electronic components 132 and 134 are, for example, a diode wafer and an insulated gate bipolar transistor (IGBT) wafer, respectively, and are disposed on the carrier substrate 120. The carrier substrate 120 is a ceramic metallization substrate such as a direct bond copper (DBC) substrate or a direct copper plated substrate (DPC), that is, a ceramic core layer 122 and a double-sided copper layer 124. Composite substrate with 126. The material of the ceramic core layer 122 is, for example, alumina (Al ₂ O ₃ ), aluminum nitride (AlN), or aluminum lanthanum carbide (AlSiC). The electronic components 132 and 134 are bonded to the copper clad layer 124 by the first solder layer 142, and the copper clad layer 124 can be patterned into the surface wiring 124a to provide circuitry for connecting the electronic components 132 and 134 to the outside. The electronic components 132 and 134 of the present embodiment are electrically connected to each other by a bonding wire 192, and the electronic component 132 is electrically connected to the surface wiring 124a formed by the copper-clad layer 124 by a bonding wire 194.

Here, the types, numbers, and connections of the electronic components 132 and 134 are for illustrative purposes only. In fact, the number of electronic components of other embodiments of the present application may be one or more than the actual demand, and the types of electronic components 132 and 134 are not limited to diode chips or IGBT chips. The electronic components 132 and 134 may be externally connected through the carrier substrate 120, or may be connected to the outside by other circuit components. In addition, the electronic components 132 and 134 of the present embodiment share a carrier substrate 120. However, in other embodiments, the two components may be disposed independently of each other. On the substrate, or on other possible types of interposer substrates.

The electronic components 132 and 134 are disposed on the bottom plate 112 of the heat exchanger 110 by the carrier substrate 120. The carrier substrate 120 and the heat exchanger 110 are bonded to each other by, for example, the second solder layer 144.

The structure of the heat exchanger 110 will be further described below.

1B is a bottom view of the heat exchanger 110, in which the cover 114 is omitted to clearly illustrate the internal structure of the heat exchanger 110. 1C is a perspective view of the structure of FIG. 1B. Fig. 1D is an enlarged view of a region A of Fig. 1B.

Referring to FIGS. 1A to 1D simultaneously, the plate 112 of the heat exchanger 110 has a bearing surface 112a and a back side 112b with respect to the bearing surface 112a, and the carrier substrate 120 is disposed on the bearing surface 112a of the bottom plate 112. The cover plate 114 is disposed on the back side 112b of the bottom plate 112 and is coupled to the bottom plate 112 to form a chamber 119. A plurality of first heat dissipation fins 116 and a plurality of second heat dissipation fins 118 are disposed between the bottom plate 112 and the cover plate 114 to form a plurality of flow paths between the bottom plate 112 and the cover plate 114. In addition, the housing 150 is disposed on the bottom plate 112 of the heat exchanger 110 to cover the electronic components 132, 134 and the carrier substrate 120. The surface line 124a is connected to the contacts 184a, 184b on the surface of the housing 150 by wires 182a, 182b.

The chamber 119 formed by the cover plate 114 and the bottom plate 112 has an inlet 119a and an outlet 119b. In this embodiment, the design of the inlet and outlet is limited by the design of the single side inlet and outlet. Therefore, the inlet 119a and the outlet 119b are disposed on the same side adjacent to the chamber 119, and enter and exit via the side of the chamber 119.

In other embodiments of the present application, the openings as the inlet 119a and the outlet 119b may also be selectively formed on the cover plate 114 or the bottom plate 112. E.g, FIG. 1E illustrates another configuration in which the present application places the inlet 119a and the outlet 119b on the bottom plate 112.

In view of the design in which the inlet 119a and the outlet 119b of the present embodiment are located on the same side of the chamber 119, the first heat radiation fins 116 and the second heat radiation fins 118 form a plurality of U-shaped flow passages in the chamber 119. In more detail, the first heat dissipation fins 116 are disposed side by side between the bottom plate 112 and the cover plate 114 to form a plurality of first flow channels 162 and a bypass flow path 164 that are parallel to each other in the chamber 119. Each of the first flow passage 162 and the bypass flow passage 164 extends from the inlet 119a to a mixed flow region 166 in the chamber 119, and the width W1 of the bypass flow passage 164 is greater than the width W2 of each of the first flow passages 162. Specifically, the ratio of the width W1 of the bypass flow path 164 to the width W2 of the first flow path 162 is, for example, less than or equal to 9, to achieve a good balance between the heat dissipation and the effect of reducing the flow resistance.

On the other hand, in the embodiment, in order to distribute the fluid uniformly in the flow channel, the heights of the first heat dissipation fins 116 and the second heat dissipation fins 118 may be varied, and flow paths of different depths may be formed therebetween to make the fluid Different impedances are created upon entry to achieve a more uniform fluid flow distribution.

In the present embodiment, the inlet 119a and the outlet 119b are located on the first side S1 of the chamber 119, and the mixed flow zone 166 is located on the second side S2 of the chamber 119. Each of the first heat dissipation fins 116 is, for example, L-shaped, and each of the first heat dissipation fins 116 includes a first portion 116a and a second portion 116b. The first portion 116a extends from the first side S1 in a first direction D1 to the second side S2, while the second portion 116b connects the first portion 116a and extends in a second direction D2 to the mixed flow region 166. The first direction D1 intersects the second direction D2, such as each other vertical. In addition, the position of the bypass flow path 164 can be adjusted as needed. For example, the present embodiment selects the bypass flow path 164 to be disposed at the outermost side of the first flow path 162 and adjacent to the inner wall of the chamber 119.

The second heat dissipation fins 118 are disposed side by side between the bottom plate 112 and the cover plate 114 to form a plurality of second flow paths 168 parallel to each other in the chamber 119. Each of the second flow passages 168 extends from the mixed flow region 166 to the outlet 119b, and the width W1 of the bypass flow passage 164 is greater than the width W3 of each of the second flow passages 168.

In this embodiment, each of the second heat dissipation fins 118 is L-shaped mirrored to the first heat dissipation fins 116 , and each of the second heat dissipation fins 118 includes a third portion 118 a and a fourth portion 118 b . The third portion 118a extends from the first side S1 in the first direction D1 to the second side S2, while the fourth portion 118b connects the third portion 118a and extends in the third direction D3 to the mixed flow region 166. The third direction D3 is opposite to the second direction D2.

The working fluid 170 is adapted to enter the chamber 119 from the inlet 119a, wherein the first portion of the working fluid 172 passes through the first flow passage 162 and the second portion of the working fluid 174 passes through the bypass flow passage 164, after which the first portion of the working fluid 172 and the second portion A portion of the working fluid 174, after mixing in the mixed flow zone 166, enters the second flow channel 168 and exits the chamber 119 from the outlet 119b.

In view of the above, since the width W1 of the bypass flow passage 164 is larger than the width W2 of each of the first flow passages 162, the flow resistance of the second portion of the working fluid 174 flowing in the bypass flow passage 164 is smaller than that of the first partial working fluid. The flow resistance experienced by the 172 flowing in the first flow passage 162, that is, the pressure loss of the second portion of the working fluid 174 in the bypass flow passage 164 may be less than the pressure of the first portion of the working fluid 172 in the first flow passage 162. damage. Electronic component When the heat generated by the operation of the 132 and 134 is transmitted to the heat exchanger 110 through the carrier substrate 120, the heat can be generated by the bottom plate 112, the cover plate 114, the first heat dissipation fins 116, and the second heat dissipation fins 118. Heat exchange to carry heat away by working fluid 170.

Moreover, since the first portion of the working fluid 174 has a smaller pressure loss in the bypass flow passage 164 and the flow rate is faster, the temperature of the working fluid 174 passing through the first portion of the bypass flow passage 164 may be lower than the passage through the first flow passage 162. The temperature of the second portion of the working fluid 172, and the inlet temperature when the two enter the second flow passage 168 after mixing in the mixed flow zone 166, will have a lower inlet temperature than the structure designed without the bypass flow passage 164. The working fluid 170 is provided in the second flow path 168 to provide a better heat exchange effect.

In other words, the bypass flow path 164 of the present embodiment can reduce the pressure loss of the working fluid 170 in the flow channel, can effectively reduce the flow resistance of the flow of the working fluid 170, and reduce the pumping power required to push the system. Or, at the same pump power consumption, provide greater liquid flow and heat transfer than known designs for better heat dissipation. Further, when the semiconductor module 100 of the present embodiment is used as an IGBT power module of an electric vehicle, the power consumed by the electric vehicle can be reduced, and the travel time and distance of the electric vehicle can be prolonged.

In the process, the heat exchanger 110 can be fabricated by techniques such as machining, welding, mechanical sealing, and the like. First, for example, a first flow path 162, a bypass flow path 164, a mixed flow area 166, a second flow path 168, and corresponding first heat dissipation fins 116 and a first surface are formed on a metal plate by a CNC (Computer Numerical Control) machining method. Two heat sink fins 118 Wait. That is, the bottom plate 112, the first heat dissipation fins 116, and the second heat dissipation fins 118 are integrally formed. Further, a cover plate 114 which is additionally machined is joined to the bottom plate 112 via welding, mechanical sealing or the like to form the heat exchanger 110. In this embodiment, the selected metal plate may be a copper plate or other metal material having a good thermal conductivity. In addition, a composite plate may be used instead of the metal plate to fabricate the heat exchanger 110.

The possible variations of the semiconductor module and its heat exchanger of the present application are described in more detail below, in which the parts already described in the foregoing embodiments are omitted, the main differences are described, and the same or similar component symbols are used. Represents similar components.

2 illustrates a heat exchanger in accordance with another embodiment of the present application. Figure 2 omits the cover to clearly express the internal structure of the heat exchanger.

As shown in FIG. 2, the heat exchanger 210 of the present embodiment is similar to the heat exchanger 110 shown in FIG. 1B. The main difference between the two is that the structure of the second heat dissipation fin 218 is changed to adjust the mixed flow region 266. shape. More specifically, the present embodiment omits the fourth portion 118b of the second heat dissipation fin 118 of the heat exchanger 110 of the foregoing embodiment (as shown in FIG. 1B) to leave the area where the fourth portion 118b is originally disposed. The flow area 266 of the present embodiment is enlarged. Each of the second heat dissipation fins 218 is linear and extends from the first side S1 in the first direction D1 to the mixed flow region 266.

Of course, the shape, size, and position of the mixed flow zone 266 can be adjusted according to actual needs. The structure of the first heat dissipation fin 216 and the second heat dissipation fin 218 can also be changed correspondingly according to the design of the mixed flow area 266.

On the other hand, the present application may choose to provide an additional spoiler structure in the mixed flow zone to improve the mixing effect of the working fluid in the mixed flow zone. The heat exchanger 310 of another embodiment of the present application, as shown in FIG. 3, depicts the design of an additional flow 363 disposed within the mixed flow zone 366. Here, the flow absorbing member 367 is, for example, a spacer which is separated from the first heat radiation fin 316 and the second heat radiation fin 318 and traverses the moving path of the working fluid 370. Moreover, the present application does not limit the number, shape, position and height of the flow mixing members 367. In other embodiments, the desired mixed flow effect can be obtained by changing the number, shape, position and height of the flow mixing members 367.

FIG. 4 illustrates a semiconductor module in accordance with another embodiment of the present application. As shown in FIG. 4, the semiconductor module 400 of the present embodiment is similar to the semiconductor module 100 shown in FIG. 1A. The main difference between the two is that the bottom plate 412 of the present embodiment is a vapor chamber. That is, a low-vacuum cavity 412a having a capillary structure 490 is formed inside the bottom plate 412. When heat is conducted from the heat source to the bottom plate 412, the liquid phase in the cavity 412a absorbs heat and is in a low vacuum environment. China vaporization. At this time, the working medium absorbs thermal energy and vaporizes, and the working fluid of the vapor phase quickly fills the entire cavity 412a. Condensation occurs when the vapor phase medium contacts a lower temperature region to release heat absorbed during vaporization by condensation. The condensed liquid phase will return to the evaporation by the capillary action of the capillary structure. In this way, the heat generated by the heat source can be quickly transferred to various portions of the bottom plate 412. In other words, the bottom plate 412 of the present embodiment is a flat-plate heat pipe structure with good two-phase flow characteristics, and can provide an excellent two-dimensional lateral heat conduction effect, and can even quickly carry a distributed heat source with extremely high operating temperature. The heat generated by the heat source spreads out to avoid the formation of hot spots in local areas to extend the life of the product.

FIG. 5A illustrates a semiconductor module in accordance with yet another embodiment of the present application. Figure 5B is a bottom plan view of the heat exchanger of Figure 5A with the cover plate omitted for clarity of the internal structure of the heat exchanger. Fig. 5C is an enlarged view of a region B of Fig. 5B. As shown in FIGS. 5A to 5C, the semiconductor module 500 of the present embodiment is similar to the semiconductor module 100 shown in FIGS. 1A to 1D. The main difference between the two is that the electronic components 532 and 534 are respectively disposed in the first embodiment. A carrier substrate 520a and a second carrier substrate 520b are disposed; and the embodiment selectively forms a plurality of recesses 502 on the surface of the first heat dissipation fin 516, the surface of the second heat dissipation fin 518, or the inner wall of the chamber 519. More specifically, the electronic components 532 and 534 of the present embodiment are, for example, IGBT wafers and diode wafers, respectively, and can be connected to an external circuit by the manner described in the foregoing embodiments or in a known manner. The cavity 502 may be selectively formed on the surface of the bottom plate 512, the cover 514, the first heat dissipation fin 516 or the second heat dissipation fin 518 by, for example, machining, while forming the heat exchanger 510, and the cavity The preferred location of 520 is at the front of the working fluid 570 that enters the fins. As such, the cavity 502 can change the laminar flow characteristics of the working fluid 570 in the chamber 519, because the recess can cause the boundary layer of the original thermal boundary layer and the flow field to "sink" when flowing through the cavity. Phenomenon, therefore, the thermal boundary and the flow field boundary stratification appear thin. The thermal boundary layer is thinned, and the heat transfer effect is naturally improved (the thermal resistance becomes small). When the boundary layer of the flow field is thinned, it is not easy to separate, which makes the working fluid 570 reduce the resistance and strengthen its heat dissipation capability.

FIG. 6 illustrates a semiconductor module in accordance with still another embodiment of the present application. Such as As shown in FIG. 6, the semiconductor module 600 of the present embodiment is similar to the semiconductor module 500 shown in FIG. 5A. The main difference between the two is that the present embodiment selects the recess 602 to be formed corresponding to the heat source (the electronic component 632 and The position of 634) and the recess 602 is passed through the bottom plate 612 to connect the bottom of the heat source. More specifically, the recess 602 can extend through the bottom plate 612 to the bottom of the carrier substrates 620a and 620b, so that the working fluid directly cools the carrier substrates 620a and 620b under the electronic components 632 and 634 to improve the heat dissipation effect. On the other hand, if the carrier substrates 620a and 620b are bonded to the bottom plate 612 by the solder layer 644, air holes may be formed on the subsequent surfaces thereof, and the holes may be discharged by the recesses 602 to improve the carrier substrates 620a and 620b and the bottom plate. Subsequent reliability and heat dissipation between 612. Of course, this embodiment can also be combined with the design of the cavity 502 of the embodiment shown in FIGS. 5A to 5C, that is, the surface of the bottom plate 612, the cover 614, and the heat dissipation fin 616 of the heat exchanger 610 can be formed. pit.

Although the present application has been disclosed in the above embodiments, it is not intended to limit the present application, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the present application. The scope of protection of this application is subject to the definition of the scope of the patent application.

100‧‧‧Semiconductor Module

110‧‧‧ heat exchanger

112‧‧‧floor

112a‧‧‧ bearing surface of the bottom plate

112b‧‧‧Back side of the bottom plate

114‧‧‧ Cover

116‧‧‧First heat sink fin

116a‧‧‧The first part of the first fin

116b‧‧‧The second part of the first fin

118‧‧‧Second heat sink fins

118a‧‧‧The third part of the second heat sink fin

118b‧‧‧The fourth part of the second heat sink fin

119‧‧‧ chamber

119a‧‧‧ entrance to the chamber

119b‧‧‧Export of the chamber

120‧‧‧bearing substrate

122‧‧‧Ceramic core layer

124, 126‧‧‧ copper layer

124a‧‧‧ surface line

132, 134‧‧‧ Electronic components

142‧‧‧First solder layer

144‧‧‧Second solder layer

150‧‧‧shell

162‧‧‧First runner

164‧‧‧ bypass flow passage

166‧‧‧ mixed flow area

168‧‧‧Second runner

170, 172, 174‧‧ working fluids

182a, 182b‧‧‧ wires

184a, 184b‧‧‧ joints

192,194‧‧‧welding line

D1‧‧‧ first direction

D2‧‧‧ second direction

D3‧‧‧ third direction

First side of the S1‧‧ ‧ chamber

Second side of the S2‧‧ ‧ chamber

W1‧‧‧ width of bypass flow channel

W2‧‧‧ width of the first runner

W3‧‧‧ width of the second runner

210‧‧‧ heat exchanger

216‧‧‧First heat sink fin

218‧‧‧Second heat sink fins

266‧‧‧ mixed flow area

310‧‧‧ heat exchanger

316‧‧‧First heat sink fin

318‧‧‧Second heat sink fins

366‧‧‧ mixed flow area

367‧‧‧Breaker

370‧‧‧Working fluid

400‧‧‧Semiconductor Module

412‧‧‧floor

412a‧‧‧ cavity

490‧‧‧Capillary structure

500‧‧‧Semiconductor Module

502‧‧‧

510‧‧‧ heat exchanger

512‧‧‧floor

514‧‧‧ Cover

516‧‧‧First heat sink fin

518‧‧‧Second heat sink fins

519‧‧‧室

520a‧‧‧First carrier substrate

520b‧‧‧second carrier substrate

532, 534‧‧‧ Electronic components

570‧‧‧Working fluid

600‧‧‧Semiconductor Module

602‧‧‧Deep

610‧‧‧ heat exchanger

612‧‧‧floor

614‧‧‧ Cover

616‧‧‧heat fins

620a‧‧‧First carrier substrate

620b‧‧‧second carrier substrate

632, 634‧‧ Electronic components

644‧‧‧ solder layer

FIG. 1A illustrates a semiconductor module in accordance with an embodiment of the present application.

Figure 1B is a bottom view of the heat exchanger of Figure 1A.

1C is a perspective view of the structure of FIG. 1B.

Fig. 1D is an enlarged view of a region A of Fig. 1B.

1E is a perspective view of a heat exchanger according to another embodiment of the present application.

2 illustrates a heat exchanger in accordance with another embodiment of the present application.

FIG. 3 illustrates a heat exchanger in accordance with yet another embodiment of the present application.

FIG. 4 illustrates a semiconductor module in accordance with another embodiment of the present application.

FIG. 5A illustrates a semiconductor module in accordance with yet another embodiment of the present application.

Figure 5B is a bottom view of the heat exchanger of Figure 5A.

Fig. 5C is an enlarged view of a region B of Fig. 5B.

FIG. 6 illustrates a semiconductor module in accordance with still another embodiment of the present application.

110‧‧‧ heat exchanger

112‧‧‧floor

116‧‧‧First heat sink fin

116a‧‧‧The first part of the first fin

116b‧‧‧The second part of the first fin

118‧‧‧Second heat sink fins

118a‧‧‧The third part of the second heat sink fin

118b‧‧‧The fourth part of the second heat sink fin

119‧‧‧ chamber

119a‧‧‧ entrance to the chamber

119b‧‧‧Export of the chamber

162‧‧‧First runner

164‧‧‧ bypass flow passage

166‧‧‧ mixed flow area

168‧‧‧Second runner

170, 172, 174‧‧ working fluids

D1‧‧‧ first direction

D2‧‧‧ second direction

D3‧‧‧ third direction

First side of the S1‧‧ ‧ chamber

Second side of the S2‧‧ ‧ chamber

W3‧‧‧ width of the second runner

Claims (13)

A heat exchanger comprising: a base plate having a bearing surface and a back side opposite to the bearing surface, wherein the bearing surface is for carrying a heat source; and a cover plate disposed on the back of the bottom plate a side surface, the cover plate and the bottom plate together form a chamber, and the chamber has an inlet and an outlet on the same side of the chamber; a plurality of first heat dissipation fins are arranged side by side on the bottom plate and the cover plate Between the plurality of first flow channels and a bypass channel formed in the chamber, wherein each of the first flow channels and the bypass flow path extend from the inlet to the chamber a mixed flow zone, wherein the width of the bypass flow channel is greater than a width of each of the first flow channels; a plurality of second heat dissipation fins are disposed side by side between the bottom plate and the cover plate for forming parallel to each other in the cavity a plurality of second flow passages each extending from the mixed flow region to the outlet, wherein a width of the bypass flow passage is greater than a width of each of the second flow passages; and a working fluid adapted to be accessed by the inlet Entering the chamber, a portion of the working fluid is passed Passing through the first flow passages, another portion of the working fluid passes through the bypass flow passages, and the working fluid of the portion and the working fluid of the other portion are mixed in the mixed flow region, enter the second flow passages, and then The outlet exits the chamber. The heat exchanger of claim 1, wherein the flow resistance of the working fluid in the first flow passages is greater than the flow resistance of the other portion of the bypass flow passages. The heat exchanger of claim 1, wherein the chamber has an opposite first side and a second side, the inlet and the outlet are located on the first side, and the mixed flow area is located on the second side . The heat exchanger of claim 3, wherein each of the first heat dissipation fins has an L shape, and each of the first heat dissipation fins comprises: a first portion, the first side being along a first direction Extending to the second side; and a second portion connecting the first portion and extending in a second direction to the mixed flow region, the first direction intersecting the second direction. The heat exchanger of claim 4, wherein each of the second heat dissipation fins is L-shaped, and each of the second heat dissipation fins comprises: a third portion, the first side being along the first a direction extending to the second side; and a fourth portion connecting the third portion and extending in a third direction to the mixed flow region, the third direction being opposite the second direction. The heat exchanger of claim 4, wherein each of the second heat dissipation fins is linear and extends from the first side in the first direction to the mixed flow region. The heat exchanger of claim 1, further comprising a flow mixing member disposed in the mixed flow region and separated from the first heat dissipation fins and the second heat dissipation fins. The heat exchanger of claim 7, wherein the flow mixing member comprises a partition traversing the moving path of the working fluid. The heat exchanger according to claim 1, wherein the side is The flow passage is located at an outermost side of the first flow passages and adjacent to an inner wall of the chamber. The heat exchanger of claim 1, wherein the bottom plate comprises a vapor chamber. The heat exchanger of claim 1, wherein at least one of a surface of the first heat dissipation fins, a surface of the second heat dissipation fins, and an inner wall of the chamber has a plurality of recesses . The heat exchanger of claim 11, wherein the recesses correspond to the location of the heat source and extend through the bottom plate to connect the bottom of the heat source. The heat exchanger of claim 1, wherein the material of the bottom plate comprises a metal or a composite material.