TWM609258U - Heat sink for semiconductor device - Google Patents

Abstract

A heat sink for a semiconductor device including an ultrasonic receiving surface, an ultrasonic welding surface, a plurality of side surfaces and at least one heat sink cavity is provided. The ultrasonic welding surface is arranged opposite to the ultrasonic receiving surface. A plurality of heat transfer bumps are on the ultrasonic welding surface. A plurality of side surfaces connect the ultrasonic receiving surface and the ultrasonic welding surface. At least one heat dissipation cavity is between the ultrasonic receiving surface and the ultrasonic welding surface, and is covered by the ultrasonic receiving surface, the ultrasonic welding surface, and the side surface.

Description

Heat sink for semiconductor components

This disclosure relates to heat sinks for semiconductor devices.

The statements here only provide background information related to the present disclosure, and do not necessarily constitute prior art.

In recent years, the heat dissipation of electronic components has gradually become an important issue. Compared with traditional pumps, compressors and other large parts, the heat dissipation of electronic components or electronic packages requires a small area to achieve good heat dissipation and temperature uniformity due to the limitation of volume, and it is necessary to consider the effects of heat dissipation components. The cost cannot be too high, so it is actually quite a challenging issue in the field of heat dissipation.

With the continuous improvement of the precision of the minimum line width process in the semiconductor industry, the size of electronic components is further reduced, but the heat generation and heat density per unit area are increasing. In order to maintain the operating temperature of the electronic components, it is common practice to install various types of heat sinks (for example, heat sinks, temperature equalizing plates, water cooling devices, etc.) on the electronic components. Most of the currently known mounting structures use thermally conductive glue as a fixing and heat transfer medium between the heat sink and the electronic component, and the high plasticity of the thermally conductive glue improves the bonding quality of the thermal contact surface.

However, the thermal conductivity of the thermal conductive glue used in the above heat dissipation method is still an order of magnitude difference compared to metals with better thermal conductivity (for example, gold, aluminum, copper, etc.), and the aforementioned electronic components are gradually shrinking. It will gradually be insufficient to cope with such a high density and large amount of heat energy sources. Therefore, it is necessary to propose a structure and method to further improve the heat dissipation effect.

In view of this, some embodiments of the present disclosure disclose a heat sink for semiconductor devices. The radiator includes an ultrasonic receiving surface, an ultrasonic welding surface, a plurality of side surfaces, and at least one heat dissipation cavity. The ultrasonic welding surface is arranged relative to the ultrasonic receiving surface. A plurality of heat transfer bumps are arranged on the ultrasonic welding surface. The multiple side surfaces are connected to the ultrasonic receiving surface and the ultrasonic welding surface. At least one heat dissipation cavity is located between the ultrasonic receiving surface and the ultrasonic welding surface, and is covered by the ultrasonic receiving surface, the ultrasonic welding surface and the side surface.

In one or more embodiments of the present disclosure, the ultrasonic receiving surface includes a concave surface, a first convex surface, a second convex surface, and two connecting surfaces. The plane extending directions of the concave surface, the first convex surface and the second convex surface are parallel to each other. The concave surface is located between the first convex surface and the second convex surface and is connected to the first convex surface and the second convex surface through the connecting surface.

In one or more embodiments of the present disclosure, a water-cooled pipe is included in the heat dissipation cavity, and the inlet and the outlet of the water-cooled pipe are arranged on one of the side surfaces.

In one or more embodiments of the present disclosure, the heat dissipation cavity further includes a plurality of heat dissipation fins, and the two ends of the heat dissipation fins are respectively connected to the ultrasonic receiving surface and the ultrasonic welding surface.

In one or more embodiments of the present disclosure, the heat dissipation fins respectively contact the water-cooled pipeline.

In one or more embodiments of the present disclosure, the heat transfer bumps include at least a first type heat transfer bump and a second type heat transfer bump. Compared with the ultrasonic welding surface, the first type of heat transfer bump has a first height. The second type of heat transfer bump has a second height compared to the ultrasonic welding surface. The first height is greater than the second height.

Some embodiments of the present disclosure disclose a method for joining a semiconductor element and a semiconductor element of a heat sink, which includes contacting an ultrasonic generator with an ultrasonic receiving surface of the heat sink and generating ultrasonic vibration on the ultrasonic receiving surface. The ultrasonic vibration is transmitted to the plurality of heat transfer bumps on the ultrasonic welding surface of the heat sink via the ultrasonic receiving surface, multiple side surfaces and at least one heat dissipation cavity of the heat sink. These heat transfer bumps transfer ultrasonic vibration to at least one heat transfer pad of the semiconductor device, and make the heat transfer bump and the heat transfer pad bond. The ultrasonic welding surface is set relative to the ultrasonic receiving surface. The side connects the ultrasonic receiving surface and the ultrasonic welding surface. The heat dissipation cavity is located between the ultrasonic receiving surface and the ultrasonic welding surface, and is covered by the ultrasonic receiving surface, the ultrasonic welding surface and the side surface.

In one or more embodiments of the present disclosure, the ultrasonic generator is in contact with the concave surface of the ultrasonic receiving surface. The concave surface is located between the first convex surface and the second convex surface of the ultrasonic receiving surface. The plane extending directions of the concave surface, the first convex surface and the second convex surface are parallel to each other. The concave surface is located between the first convex surface and the second convex surface and is connected to the first convex surface and the second convex surface by two connecting surfaces.

In one or more embodiments of the present disclosure, the heat transfer bumps respectively transfer ultrasonic vibrations to the heat transfer pads of the semiconductor device, and the step of bonding the heat transfer bumps and the heat transfer pads includes: self-heat transfer The first type of heat transfer bump of the bump transfers ultrasonic vibration to the heat transfer pad, so that the first type of heat transfer bump and the heat transfer pad are bonded; and pressure is applied to make the second type of heat transfer in the heat transfer bump The bump contacts and transmits the ultrasonic vibration to the heat transfer pad, so that the second type of heat transfer bump and the heat transfer pad are bonded. The first type of heat transfer bump has a first height compared to the ultrasonic welding surface. The second type of heat transfer bump has a second height compared to the ultrasonic welding surface. The first height is greater than the second height.

The present disclosure uses the ultrasonic receiving surface, the ultrasonic welding surface and the plurality of heat transfer bumps of the heat sink to be configured with better vibration transmission and ultrasonic or thermosonic bonding, which can avoid damage to semiconductor components during processing. Excessively high temperature, only the frictional heat generated by ultrasonic waves and further application of heating and pressure to make the surfaces of the thermally conductive metal bumps installed on the heat sink and the surface of the semiconductor element instantaneously heat and fuse each other, and finally produce a metal bond. Generate a metal layer structure to join the heat sink and the semiconductor element. With the above method, high temperature can be avoided during the bonding process to protect the semiconductor element to be bonded. Moreover, it can be regarded as a metal layer structure instead of the traditional thermal conductive glue to join the heat sink and the semiconductor element, thereby greatly reducing the thermal resistance of the heat transfer path between the heat sink and the semiconductor element, thereby improving the heat dissipation efficiency of the heat sink to the semiconductor element.

In order to make the above-mentioned features and advantages of the present disclosure more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

In order to make the description of the present disclosure more detailed and complete, the following provides an illustrative description for the implementation aspects and specific embodiments of the present disclosure; this is not the only way to implement or use the specific embodiments of the present disclosure. The embodiments disclosed below can be combined or substituted with each other under beneficial circumstances, and other embodiments can also be added to an embodiment without further description or description.

In the following description, many specific details will be described in detail so that the reader can fully understand the following embodiments. However, the embodiments of the present disclosure can be practiced without these specific details. In other cases, in order to simplify the drawings, well-known structures and devices are only schematically shown in the drawings.

Refer to Figure 1A to Figure 1D. FIG. 1A is a top three-dimensional schematic diagram of the heat sink 100 in some embodiments of the present disclosure. FIG. 1B is a bottom three-dimensional schematic diagram of the heat sink 100 in some embodiments. FIG. 1C is a schematic side sectional view of the heat sink 100 along the line A-A' in FIG. 1A in some embodiments of the present disclosure. FIG. 1D is a schematic side sectional view of the heat sink 100 along the line B-B' in FIG. 1A in some embodiments of the present disclosure. The embodiment of the present disclosure provides a heat sink 100 for a semiconductor device. The heat sink 100 includes an ultrasonic receiving surface 102, an ultrasonic welding surface 104, a plurality of side surfaces 106 and at least one heat dissipation cavity 108. The ultrasonic welding surface 104 is provided relative to the ultrasonic receiving surface 102. A plurality of heat transfer bumps 1042 are provided on the ultrasonic welding surface 104. The side surface 106 connects the ultrasonic receiving surface 102 and the ultrasonic welding surface 104. The heat dissipation cavity 108 is located between the ultrasonic receiving surface 102 and the ultrasonic welding surface 104, and is covered by the ultrasonic receiving surface 102, the ultrasonic welding surface 104 and the side surface 106. The structure of the multiple independent heat transfer bumps 1042 can save/reduce a lot in energy consumption and temperature requirements of the bonding process compared with the structure of the entire surface of the integrated heat transfer metal layer. Due to the low temperature (approximately 100 to 150 degrees Celsius), the heat transfer bump 1042 has less impurities on the metal joint surface in the subsequent manufacturing process, which improves the joint quality. The heat sink 100 can be mainly made of copper, but is not limited to this.

In some embodiments, the lateral length of the heat transfer bump 1042 (along the X-Y direction) may be about 25 microns, and the thickness (along the Z direction) may be about 2 microns to achieve a better ultrasonic welding process effect. However, the aforementioned size selection is not used to limit the protection scope of the present disclosure. In addition, the size ratio shown in FIG. 1B is only a schematic diagram, and is not intended to limit the actual size ratio between the ultrasonic welding surface 104 and the heat transfer bump 1042.

Refer to Figure 1A. In some embodiments, the ultrasonic receiving surface 102 includes a concave surface 1022, a first convex surface 1024, a second convex surface 1026, and two connecting surfaces 1028. The plane extending directions of the first convex surface 1024 and the second convex surface 1026 are parallel to each other (for example, the X-Y direction in Figure 1A). The concave surface 1022 is located between the first convex surface 1024 and the second convex surface 1026 and is connected to the first convex surface 1024 and the second convex surface 1026 by the connecting surface 1028. The height of the concave surface 1022 in the Z direction is smaller than that of the first convex surface 1024 and the second convex surface 1026.

The radiator 100 further includes an inlet 1082A and an outlet 1082B that provide a pipeline (the figure omitted) through which the heat dissipation cavity 108 communicates with the outside. In some embodiments, when there are two heat dissipation cavities 108, the inlet 1082A and the outlet 1082B of different heat dissipation cavities 108 may be arranged on the same side surface 106 of the heat sink 100. Refer to Figure 1A, Figure 1C and Figure 1D. In detail, the heat dissipation cavity 108, which is close to B'of the line segment B-B' and extends along the Y axis, has an inlet 1082A on the side 106 in the figure. The liquid flow direction is from the positive y direction to the negative y. The direction flows out from exit 1082B (shown in dotted lines in Figure 1A). In addition, for another heat dissipation cavity 108 (Figure 1A is not a cross-sectional view, and its position is not shown, so the label is omitted) that is close to B of the line segment B-B' and extends along the Y axis, its liquid flow direction is conceited. The direction flows in through the inlet 1802A (shown in dashed lines in Figure 1A), and flows out from the outlet 1082B located on the side surface 106 in the positive y direction. The heat sink 100 formed by the adjacent two heat dissipation cavities 108 with different liquid flow directions can make the temperature of the heat sink 100 more evenly distributed.

Refer to Figure 1C and Figure 1D. The heat dissipation cavity 108 may also include at least one heat dissipation fin 1084 to further increase the heat dissipation efficiency. In some embodiments, the two ends 1084A and 1084B of the heat dissipation fin 1084 are respectively connected to the ultrasonic receiving surface 102 and the ultrasonic welding surface 104 to help the transmission of ultrasonic vibration and heat conduction.

Refer to Figure 2. FIG. 2 is a schematic side sectional view of the heat sink 100A in some embodiments of the present disclosure, and the viewing angle is the same as that of FIG. In some embodiments, the heat transfer bump 1042 includes at least a first type heat transfer bump 1042A and a second type heat transfer bump 1042B. Compared with the ultrasonic welding surface 104, the first type heat transfer bump 1042A has a first height H1. Compared with the ultrasonic welding surface 104, the second type heat transfer bump 1042B has a second height H2. The first height H1 is greater than the second height H2. In addition, in some embodiments, the second type of heat transfer bump 1042B is disposed farther from the geometric center C of the ultrasonic welding surface 104 than the first type of heat transfer bump 1042A, but it is not limited thereto. In other embodiments, a structure in which the second type heat transfer bump 1042B is inside and the first type heat transfer bump 1042A surrounds the second type heat transfer bump 1042B outside may also be provided. In other embodiments, the third type of heat transfer bump 1042C may be included, that is, the case where the heat transfer bump 1042 exceeds two different heights. In the embodiment shown in FIG. 2, the third type of heat transfer bump 1042C has a third height H3 whose height is between the first height H1 and the second height H2.

Since the slight height difference in the ultrasonic welding process can produce the phenomenon of joining at different times, the height difference between the above three heights can be on the order of micrometers, and can even be on the order of 0.1 micrometers at the time of operation. Of course, the present disclosure does not exclude the case where the height difference is large, for example, a height difference of more than tens of micrometers. It should be noted that these height differences are not caused by process errors or tolerances, but are deliberate regional height differences. In other words, the same height will be concentrated in the same area. The above structure allows the ultrasonic welding to expand from a small part of the area instead of the entire surface at the same time, so it can achieve the effect of reducing the power and temperature during welding, thereby saving process costs and reducing the internal heat dissipation of semiconductor components (detailed later) The probability of damage to circuit components.

Refer to Figures 3A to 4B. FIG. 3A is a schematic side cross-sectional view of the ultrasonic vibration generated on the heat sink 100 along the line A-A' in some embodiments of the present disclosure. FIG. 3B is a schematic side sectional view of the ultrasonic vibration generated on the heat sink 100 along the line B-B' in some embodiments of the present disclosure. FIG. 4A is a schematic side sectional view of an intermediate step of bonding the heat sink 100 and the semiconductor device 200 in some embodiments of the present disclosure. FIG. 4B is a schematic side cross-sectional view of the heat sink 100 and the semiconductor device 200 after joining the heat sink 100 and the semiconductor device 200 in some embodiments of the present disclosure. Some embodiments of the present disclosure disclose a method of joining the semiconductor device 200 and the heat sink 100. In this method, the ultrasonic generator S contacts the ultrasonic receiving surface 102 of the radiator 100 and generates ultrasonic vibration on the ultrasonic receiving surface 102. This ultrasonic vibration is transmitted to the plurality of heat transfer bumps 1042 on the ultrasonic welding surface 104 of the heat sink 100 through the ultrasonic receiving surface 102, the plurality of side surfaces 106, and the at least one heat dissipation cavity 108 of the heat sink 100 (refer to the section The arrows in Figures 3A to 4B point to). In detail, the ultrasonic generator S contacts the concave surface 1022, and the ultrasonic vibration is transmitted to the first convex surface 1024 and the second convex surface 1026 through the concave surface 1022, and is transmitted to the ultrasonic wave through the heat dissipation cavity 108 or the side surface 106 The welding surface 104 and the heat transfer bump 1042. These heat transfer bumps 1042 transfer ultrasonic vibration to the heat transfer pad 210 of the semiconductor device 200, and the heat transfer bump 1042 and the heat transfer pad 210 are bonded to form a single metal layer structure 300.

As described in other embodiments above, in the application of this method, the ultrasonic welding surface 104 is disposed relative to the ultrasonic receiving surface 102. The side surface 106 connects the ultrasonic welding surface 104 and the ultrasonic welding surface 104. The heat dissipation cavity 108 is located between the ultrasonic receiving surface 102 and the ultrasonic welding surface 104, and is covered by the ultrasonic receiving surface 102, the ultrasonic welding surface 104 and the side surface 106. Other structural features such as the concave surface 1022, the first convex surface 1024, and the second convex surface 1026 are also applicable to the methods mentioned here. The multiple independent heat transfer bumps 1042 can save/reduce the energy consumption and temperature requirements of joining compared with the implementation of the entire surface of the integral and continuous heat transfer metal layer.

In some embodiments, the heat sink 100 may be heated (ie, thermosonic waves) at the same time or before the ultrasonic bonding is performed, so that the heat transfer bump 1042 is easier to bond with the heat transfer pad 210. The heating temperature range is about 100-150 degrees Celsius. This temperature range can effectively reduce the bonding temperature due to the implementation mode in which multiple points are respectively generated for bonding, which can better protect the semiconductor device 200. In some embodiments, the heat may be heated first, and then pressure may be applied to make the heat transfer bump 1042 contact the heat transfer pad 210. Then, a short ultrasonic vibration is performed to make the heat transfer bump 1042 and the heat transfer pad 210 bond.

In some embodiments, the material of the heat transfer bump 1042 includes gold and nickel, and the nickel contacts the ultrasonic receiving surface 102. The material of the heat transfer pad 210 also includes gold and nickel, and the aforementioned bonding is generated at the contact interface between the gold of the heat transfer bump 1042 and the gold of the heat transfer pad 210. This arrangement can be compared during ultrasonic or thermosonic bonding. Other combinations of materials that are not specifically excluded by the present disclosure (for example, one of the heat transfer bump 1042 and the heat transfer pad 210 is a combination of aluminum and nickel, and the other is a combination of gold and nickel) to achieve a better bonding effect. In the aforementioned heterojunction (gold to aluminum), due to the difference in the diffusion rate of gold and aluminum, Kirkendall voids are prone to occur when the two are bonded, and these pores are easy to gather into cracks. , Reduce the heat transfer quality, and thus reduce the heat dissipation effect of the heat sink 100 to the semiconductor element 200 after bonding.

In the foregoing embodiment, the frequency of thermosonic bonding is greater than 16 kHz, and can be 40 kHz to 120 kHz, but is not limited to this. In addition, if the nickel of the heat transfer bump 1042 is formed on the ultrasonic welding surface 104 in the form of a nickel film, it can further assist the ultrasonic power to be better transferred to the heat transfer bump 1042 and the heat transfer pad 210. , Help to produce bonding.

Cooperate with Figure 2 and refer to Figures 3A to 4B above. In some embodiments, the aforementioned heat transfer bumps 1042 respectively transfer ultrasonic vibrations to the heat transfer pad 210 of the semiconductor device 200, and the step of bonding the heat transfer bumps 1042 and the heat transfer pad 210 further includes the following Detailed stage. First, the first type heat transfer bump 1042A of the self-heat transfer bump 1042 transmits ultrasonic vibration to the heat transfer pad 210, so that the first type heat transfer bump 1042A and the heat transfer pad 210 are bonded. Then, pressure is applied to make the second type heat transfer bump 1042B in the heat transfer bump 1042 contact and transmit ultrasonic vibration to the heat transfer pad 210, so that the second type heat transfer bump 1042B and the heat transfer pad 210 are bonded. In other embodiments, the feature that the first height H1 of the first type heat transfer bump 1042A is greater than the second height H2 of the second type heat transfer bump 1042B is also adopted in this embodiment. Of course, the characteristics of the third type of heat transfer bump 1042C can also be adopted in the embodiment herein.

In summary, the embodiments of the present disclosure provide a heat sink for a semiconductor element and a method for joining the semiconductor element and the heat sink. With the ultrasonic receiving surface, ultrasonic welding surface and multiple heat transfer bumps of the heat sink, the ultrasonic or thermosonic bonding can be combined with better vibration transmission, so that the heat conductive metal of the heat sink is directly on the semiconductor chip. The thermally conductive metal produces bonding. This method can avoid applying excessively high temperature to the semiconductor element during the processing, and only use the frictional heat generated by ultrasonic waves and further use heating and pressure to make the surface of the thermal conductive metal bumps respectively arranged on the surface of the heat sink and the semiconductor element Mutual instantaneous heating produces metal bonding, forming a metal layer structure to join the heat sink and the semiconductor element. In addition, the embodiments provided by the present disclosure replace the thermally conductive glue used in the prior art, and improve the efficiency of conducting the heat generated by the semiconductor element to the heat sink.

Although the present disclosure has been disclosed in the above embodiments, it is not intended to limit the present disclosure. Anyone who is familiar with this technique can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure When the scope of the attached patent application is defined, it shall prevail.

100, 100A: radiator 102: Ultrasonic receiving surface 1022: sunken surface 1024: the first raised surface 1026: second raised surface 1028: connecting surface 104: Ultrasonic welding surface 1042: Heat transfer bump 1042A: The first type of heat transfer bump 1042B: The second type of heat transfer bump 1042C: The third type of heat transfer bump 106: side 108: radiating cavity 1082A: Entrance 1082B: Exit 1084: heat sink fins 1084A, 1084B: end 200: Semiconductor components 210: Heat transfer pad 300: Metal layer structure S: Ultrasonic generator A-A’, B-B’: Line segment C: geometric center H1: first height H2: second height H3: third height

FIG. 1A is a top three-dimensional schematic diagram of the heat sink in some embodiments of the present disclosure. FIG. 1B is a bottom three-dimensional schematic diagram of the heat sink in some embodiments of the present disclosure. FIG. 1C is a schematic side sectional view of the heat sink in some embodiments of the present disclosure. FIG. 1D is a schematic side cross-sectional view of the heat sink in another direction in some embodiments of the present disclosure. FIG. 2 is a schematic side sectional view of the heat sink in some embodiments of the disclosure. FIG. 3A is a schematic side sectional view of ultrasonic vibration generated on the heat sink in some embodiments of the present disclosure. FIG. 3B is a schematic side sectional view of another direction in which ultrasonic vibration is generated on the heat sink in some embodiments of the present disclosure. FIG. 4A is a schematic side sectional view of an intermediate step of bonding the heat sink and the semiconductor device in some embodiments of the present disclosure. FIG. 4B is a schematic side cross-sectional view of the heat sink and the semiconductor device after bonding in some embodiments of the present disclosure.

100: radiator

1042: Heat transfer bump

108: radiating cavity

1084: heat sink fins

1084A, 1084B: end

S: Ultrasonic generator

B-B’: Line segment

Claims (6)

A heat sink for semiconductor components, including: An ultrasonic receiving surface; An ultrasonic welding surface is arranged relative to the ultrasonic receiving surface, and a plurality of heat transfer bumps are arranged on the ultrasonic welding surface; A plurality of side surfaces, connecting the ultrasonic receiving surface and the ultrasonic welding surface; and At least one heat dissipation cavity is located between the ultrasonic receiving surface and the ultrasonic welding surface, and is covered by the ultrasonic receiving surface, the ultrasonic welding surface and the side surfaces. The heat sink according to claim 1, wherein the ultrasonic receiving surface includes a concave surface, a first convex surface, a second convex surface, and two connecting surfaces, the concave surface and the first convex surface The plane extending direction of the second convex surface and the second convex surface are parallel to each other. The concave surface is located between the first convex surface and the second convex surface and is connected to the first convex surface and the first convex surface through the connecting surfaces. The two convex surfaces are connected. The radiator according to claim 1, wherein the heat dissipation cavity includes a water-cooling pipe, and the inlet and the outlet of the water-cooling pipe are arranged on one of the side surfaces. The heat sink according to claim 3, wherein the heat dissipation cavity further includes a plurality of heat dissipation fins, and two ends of the heat dissipation fins are respectively connected to the ultrasonic receiving surface and the ultrasonic welding surface. The heat sink according to claim 4, wherein the heat dissipation fins respectively contact the water-cooling pipeline. The heat sink according to claim 1, wherein the heat transfer bumps at least include: A first type of heat transfer bump, which has a first height compared to the ultrasonic welding mask; and A second type of heat transfer bump has a second height compared to the ultrasonic welding mask, and the first height is greater than the second height.

Images