CN117116909A - Copper bridge and semiconductor device - Google Patents

Abstract

The embodiment of the application provides a copper bridge and a semiconductor device, and relates to the technical field of semiconductors. The copper bridge comprises a flat first connecting area (1), a flat second connecting area (2), a first extending area (3) connected with the first connecting area, a second extending area (4) connected with the second connecting area, and a bridge body connected in the first extending area (3) and the second extending area (4). The bridge body is composed of a plurality of conductive elements with square or rectangular cross sections, gaps exist among the conductive elements, and a rectangular connecting rib is arranged in the middle of the bridge and connected with each conductive element. The first extension region (3), the second extension region (4) and the bridge body together form at least one buffer bend. The copper bridge avoids the problems of large stress, easy generation of oblique chip virtual welding and the like of the traditional bridge, and is easy to automate.

Description

Copper bridge and semiconductor device

Technical Field

The application relates to the technical field of semiconductors, in particular to a copper bridge and a semiconductor device.

Background

The copper bridge of the semiconductor product provides the conductive and heat dissipation functions for the semiconductor chip, and the conductive and heat dissipation cost performance is better than that of the copper, and some small-size packages use the copper bridge as a frame and electrode plates.

However, the copper material has a larger expansion coefficient, and the temperature changes in the use process and the production process of the product, so that the copper bridge is subjected to thermal stress which causes thermal expansion and cold contraction, and the thermal stress is enough to cause damage to the chip, thereby directly affecting the product yield and the product reliability.

In the prior art, as shown in fig. 1, a larger welding plane is arranged at the welding end of the chip and the other leading-out welding end, the corresponding welding planes of the copper bridge are the welding planes of the copper bridge on the left and the right, and if the height bending heights of the two welding ends are not met, the welding thickness is uneven or even the virtual welding condition is caused due to the action of gravity of the bridge and the tension of liquid phase soldering tin in the welding process.

In summary, in the prior art, thermal stress is easily generated in the copper bridge, and the expansion coefficient of the copper bridge is not matched with that of the semiconductor chip material, so that the problem of chip damage may occur.

Disclosure of Invention

The application aims to provide a copper bridge and a semiconductor device, which are used for solving the problems that the copper bridge is easy to generate thermal stress and the expansion coefficients of the copper bridge and the semiconductor chip material are not matched, so that the chip is possibly damaged.

In order to achieve the above purpose, the following technical scheme is adopted in the embodiment of the application.

In a first aspect, an embodiment of the present application provides a copper bridge, including a first flat connection area, a second flat connection area, a first extension area connected to the first connection area, a second extension area connected to the second connection area, and a bridge body connected to the first extension area and the second extension area;

the bridge body comprises a plurality of first conductive elements with square or rectangular cross sections, gaps exist among the first conductive elements, and at least one rectangular connecting rib is arranged in the bridge body to connect all the first conductive elements together;

in the projection of the first cross section of the copper bridge, the first extension area, the second extension area and the bridge body form at least one buffer bend together, and the first cross section is a plane parallel to one first conductive element.

Optionally, the first connection area and the second connection area are in a vertical state and are perpendicular to the surface to be welded of the object to be welded.

Optionally, the first extension area is composed of a plurality of second conductive elements, and the second conductive elements of the first extension area are connected with the first conductive elements of the bridge body in a one-to-one correspondence manner.

Optionally, the second extension area is composed of a plurality of third conductive elements, and the third conductive elements of the second extension area are connected with the first conductive elements of the bridge body in a one-to-one correspondence manner.

Optionally, the included angle between the first connection region and the first extension region and the included angle between the second connection region and the second extension region are all 150 to 170 °.

Optionally, the end of the bridge body is horizontal, and the included angle between the first extension area and the end of the bridge body and the included angle between the second extension area and the end of the bridge body are all 100-120 degrees.

Optionally, the first connection area is used for welding with an electrode slice, the electrode slice is connected with a chip through a first welding layer, the chip is connected with a bottom plate through a second welding layer, and the second connection area is used for welding with the bottom plate;

the height difference between the first connection area and the second connection area is the sum of the thickness of the chip, the thickness of the electrode plate, the thickness of the first welding layer and the thickness of the second welding layer.

Optionally, the distance from the rectangular connecting rib to the first extension area is equal to the distance from the rectangular connecting rib to the second extension area.

Optionally, the width of the gap between the conductive elements is 0.1-1mm, the width of the conductive elements is 0.3-3mm, the thickness of the conductive elements is 0.1-2mm, the width of the rectangular connecting rib is 0.5-3.5mm, and the height difference between the first connecting area and the second connecting area is 0.5-3mm.

In a second aspect, embodiments of the present application provide a semiconductor device comprising the copper via of the first aspect.

Compared with the prior art, the application has the following beneficial effects:

firstly, because the bridge body is composed of a plurality of conductive elements with square or rectangular cross sections, and at least one buffer bend is formed by the first extension area, the second extension area and the bridge body together, the whole bridge structure is similar to a blister copper bonding process, and bridge stress is dispersed on the plurality of conductive elements and absorbed by the buffer bend;

secondly, the copper gap bridge comprises a flat first connecting area and a flat second connecting area which are respectively connected with an electrode slice of a chip and a DBC (Direct Bond Copper, direct copper bonding substrate) bottom plate, compared with the traditional bending welding area, the copper gap bridge is different from the traditional bending welding area, the flat first connecting area and the flat second connecting area form narrower contact surfaces, the influence of liquid tension during welding is reduced, and the problems of oblique slice of the electrode slice and cold welding caused by height matching deviation are eliminated to a great extent;

thirdly, a rectangular connecting rib is arranged in the middle of the gap bridge body and is connected with each conductive element, the problem of deformation caused by insufficient strength of each conductive element is avoided by the rectangular connecting rib, and meanwhile, the rectangular connecting rib can be used as a pick-up position in automatic assembly.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a prior art copper via;

FIG. 2 is a schematic diagram of a copper bridge according to an embodiment of the present application;

FIG. 3 is a perspective view of the copper bridge of FIG. 2 in a first cross-section;

FIG. 4 is a schematic diagram of a copper bridge with two buffer bends according to an embodiment of the present application;

FIG. 5 is a perspective view of the copper bridge of FIG. 4 in a first cross-section;

FIG. 6 is a schematic diagram of a copper bridge with 3 buffer bends according to an embodiment of the present application;

FIG. 7 is a perspective view of the copper bridge of FIG. 6 in a first cross-section;

fig. 8 is a schematic diagram of a copper bridge, a chip and a base plate according to an embodiment of the present application.

Reference numerals illustrate:

1-first connection region

2-second connection region

3-first extension region

4-second extension region

5-first conductive element

6-gap

7-rectangle connecting bar

8-included angle between first connecting region and first extending region

9-included angle between the second connection region and the second extension region

10-first extension area and the end of the gap bridge body

11-the second extension area forms an included angle with the end part of the gap bridge body

20-chip

21-electrode plate

30-DBC

H-difference in height between first and second connection regions

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and the described embodiments are some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application. The following embodiments and features of the embodiments may be combined with each other without conflict.

In describing the present application, it should be noted that:

1. relational terms such as "first" and "second", and the like may be used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities or operations.

2. The term "coupled" is to be interpreted broadly, as being a fixed connection, a removable connection, or an integral connection, for example; can be directly connected or indirectly connected through an intermediate medium.

3. Spatially relative terms, such as "under … …," "under … …," "below," "under … …," "above … …," "above," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "under … …" and "under … …" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly.

4. The terms "comprises," "comprising," and/or "including" are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

As with the background and fig. 1, there are two problems:

1. the expansion coefficient of the copper material is larger, the temperature changes in the use process and the production process of the product, and the thermal stress which causes the thermal expansion and the cold contraction of the copper bridge is enough to cause the damage of the chip, and the qualification rate and the reliability of the product are directly affected;

2. the welding ends of the chip and the other leading-out welding end are provided with larger welding planes, the two rectangular horizontal plates corresponding to the left side and the right side of the copper bridge are planes used for welding the copper bridge, and if the height bending heights of the two welding ends are not met, uneven welding thickness and even virtual welding conditions can be caused in the welding process due to the action of bridge gravity and liquid phase soldering tin tension.

In order to overcome the above problems, referring to fig. 2, an embodiment of the present application provides a copper bridge, which includes a first connection region 1, a second connection region 2, a first extension region 3 connected to the first connection region, a second extension region 4 connected to the second connection region, and a bridge body connected to the first extension region 3 and the second extension region 4.

In fig. 2, the bridge body is the area of the highest top surface parallel to the xOy plane, the first connection area 1 and the second connection area 2 are the lowest two blocks perpendicular to the xOy plane, the first extension area 3 is the block between the first connection area 1 and the bridge body, and the second extension area 4 is the block between the second connection area 2 and the bridge body. The first connecting area 1, the second connecting area 2, the first extending area 3, the second extending area 4 and the bridge body are all planar, and smooth round corners are used for transition.

The bridge body comprises a plurality of first conductive elements 5. The first conductive elements 5 of (a) are square or rectangular in cross section, and gaps 6 exist between a plurality of first conductive elements.

At least one rectangular connecting rib 7 is provided in the bridge body to connect all the first conductive elements 5 together, that is, although fig. 2 shows only one rectangular connecting rib 7 in the bridge body, the rectangular connecting rib 7 may be a plurality of rectangular connecting ribs 7, and the rectangular connecting ribs 7 are connected by the first conductive elements 5 at different positions.

The first connection region 1 and the second connection region 2 are flat, wherein flat means flat in the x-direction in fig. 2 and flat in the yOz-plane direction in fig. 2. The projections of the first and second connection regions 1 and 2 on the yOz plane have a rectangular shape, although the first and second connection regions 1 and 2 of the embodiment shown in fig. 2 are short in the z direction, and in other embodiments the first and second connection regions 1 and 2 may be longer in the z direction.

In the projection of the copper bridge in the first section, the first extension area 3, the second extension area 4 and the bridge body form at least one buffer bend together; the first cross-section is a plane parallel to one of the first conductive elements 5, such as the xOz plane in fig. 2, and fig. 3 shows the projection of the copper bridge of fig. 2 on the first cross-section; taking xOy as the bottom surface in fig. 2, up (positive direction of z axis) and then down (negative direction of z axis) is a buffer bend.

Although fig. 2 shows a copper bridge with only one buffer bend, there may be a plurality of buffer bends, fig. 4 shows an embodiment of two buffer bends, fig. 5 shows a projection of fig. 4 in a first section, with two buffer bends from left to right, first upward, first downward, second upward, second downward; fig. 6 shows an embodiment of 3 buffer bends, fig. 7 being a projection of fig. 6 in a first section.

The first extension area 3 and the second extension area 4 can be composed of conductive elements with the same section as the first conductive elements, the first extension area 3 is composed of a plurality of second conductive elements, the second extension area 4 is composed of a plurality of third conductive elements, the first conductive elements, the second conductive elements and the third conductive elements are in one-to-one correspondence, and one first conductive element, one second conductive element and one third conductive element which are mutually corresponding are connected like the same conductive element.

The whole copper bridge can be produced by the following process flow: a thin copper plate is taken, a slit is cut by a laser cutting mode, and conductive elements are arranged between the slits; and then bending to form a buffer bend, a first connecting region 1, a second connecting region 2, a first extending region 3 and a second extending region 4.

The bending angle is exemplified in fig. 3, and the first connection area 1 and the second connection area 2 may be in a vertical state and perpendicular to the surface to be welded of the object to be welded, so that the welding is facilitated. The included angle between the first connecting area 1 and the first extending area 3 is marked as 8, the included angle between the second connecting area 2 and the second extending area is marked as 9, and the included angle 8 and the included angle 9 are both in the range of 150-170 degrees, so that the structure is stable and the higher height difference is spanned. The contained angle mark of the end of first extension area 3 and the gap bridge body is 10, and the contained angle mark of the end of second extension area 4 and the gap bridge body is 11, and contained angle 10 and contained angle 11 are all in 100 to 120 scope, span higher difference in height in this way when being favorable to stable in structure.

Fig. 5 and 7 are the same, wherein the ranges of the included angle 8, the included angle 9, the included angle 10 and the included angle 11 are the same as those of the included angle 8, the included angle 9, the included angle 10 and the included angle 11 in fig. 3, and the included angle 12 is the same as the included angle 11, so that the structure is stable and the higher height difference is spanned.

Fig. 8 shows a schematic diagram of the soldering of the copper bridge 100, the first connection region 1 being intended for soldering with the electrode plate 21, the two sides of the first connection region 1 being perpendicular to the electrode plate, facilitating the soldering. The electrode sheet 21 is connected to the chip 20 through a first bonding layer, the chip 20 is connected to the base plate 30 through a second bonding layer, and the second connection region 2 is used for bonding with the base plate 30. The backplane in the present application may be referred to as DBC (Direct Bond Copper, direct copper bond substrate or ceramic copper clad laminate).

Regarding the height difference H between the first connection region and the second connection region in fig. 3, 5, and 7, it can be obtained in conjunction with fig. 8 that H is the sum of the thickness of the chip 20, the thickness of the electrode sheet 21, the thickness of the first solder layer, and the thickness of the second solder layer.

With respect to specific values of dimensions, the optional dimensional ranges are as follows: the width of the gap 6 between the conductive elements is 0.1-1mm, the width of the conductive element 5 (such as the y direction of figure 2) is 0.3-3mm, the thickness of the conductive element 5 (such as the z direction of figure 2) is 0.1-2mm, the width of the rectangular connecting rib 7 (such as the x direction of figure 2) is 0.5-3.5mm, and the height difference H between the first connecting area and the second connecting area is 0.5-3mm. The width and thickness of the conductive elements may be determined by the number of conductive elements and the current magnitude. The copper gap bridge material can be selected from T2 oxygen-free copper or KFC, KFC refers to CDA No.19210 alloy.

Based on the above embodiment, the embodiment of the application further provides a semiconductor device, which includes the copper bridge.

Based on the above embodiments, the embodiment of the present application further provides an assembly method of a copper bridge, which is applied to the assembly of the copper bridge. The assembly method of the copper bridge comprises the following steps: the rectangular connecting ribs 7 are picked up by a pick-up device to pick up the whole copper bridge and place the copper bridge at a specified position. Namely, the rectangular connecting ribs 7 can be used as pick-up parts of the whole copper bridge, and an automatic process is realized. If other parts are picked up, the copper bridge may be deformed, and the rectangular connecting rib 7 can be used as the strongest part.

For stable pick-up, the rectangular connecting bar 7 may be arranged at a position close to the centre of gravity of the whole copper bridge, for example in fig. 2, the distance of the rectangular connecting bar 7 from the first extension area 3 is equal to the distance of the rectangular connecting bar 7 from the second extension area 4. This can also be understood as follows: the rectangular connecting rib 7 to the first extension area 3 is a small-section conductive element, and the rectangular connecting rib 7 to the second extension area 4 is a small-section conductive element, and the two small-section conductive elements are equal in length and symmetrical.

In general, the application provides a copper bridge and a semiconductor device, and relates to the technical field of semiconductors. The copper bridge comprises a flat first connecting area, a flat second connecting area, a first extending area connected with the first connecting area, a second extending area connected with the second connecting area, and a bridge body connected in the first extending area and the second extending area 4. The bridge body is composed of a plurality of conductive elements with square or rectangular cross sections, gaps exist among the conductive elements, and a rectangular connecting rib is arranged in the middle of the bridge body and is connected with each conductive element. The first extension region, the second extension region and the bridge body together form at least one buffer bend. The copper bridge avoids the problems of large stress, easy generation of oblique chip virtual welding and the like of the traditional bridge, and is easy to automate.

The above-described embodiments of the apparatus and system are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the objectives of the present embodiment. Those of ordinary skill in the art will understand and implement the present application without undue burden.

The foregoing is only a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present application should be covered by the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (10)

1. A copper bridge comprising a first flat connection region (1), a second flat connection region (2), a first extension region (3) connected to the first connection region, a second extension region (4) connected to the second connection region, and a bridge body connected to the first extension region (3) and the second extension region (4);

the bridge body comprises a plurality of first conductive elements (5) with square or rectangular cross sections, gaps (6) are reserved among the first conductive elements (5), and at least one rectangular connecting rib (7) is arranged in the bridge body to connect all the first conductive elements (5) together;

in the projection of the first cross section of the copper bridge, the first extension area (3), the second extension area (4) and the bridge body jointly form at least one buffer bend, and the first cross section is a plane parallel to one first conductive element (5).

2. Copper bridge according to claim 1, characterized in that the first connection region (1) and the second connection region (2) are in a vertical state, perpendicular to the surface to be welded of the object to be welded.

3. Copper bridge according to claim 1, wherein the first extension area (3) consists of a plurality of second conductive elements, the second conductive elements of the first extension area (3) being connected in one-to-one correspondence with the first conductive elements (5) of the bridge body.

4. Copper bridge according to claim 1, wherein the second extension area (4) consists of a plurality of third conductive elements, the third conductive elements of the second extension area (4) being connected in one-to-one correspondence with the first conductive elements (5) of the bridge body.

5. Copper bridge according to claim 1, wherein the angle between the first connection region (1) and the first extension region (3) and the angle between the second connection region (2) and the second extension region (4) are all 150 to 170 °.

6. Copper bridge according to claim 1, wherein the bridge body ends are horizontal, and the first extension area (3) and the bridge body ends are at an angle of 100 to 120 ° and the second extension area (4) and the bridge body ends are at an angle of 100 to 120 °.

7. Copper bridge according to claim 1, characterized in that the first connection region (1) is intended to be welded with an electrode plate, which is connected to a chip by means of a first welding layer, which is connected to a base plate by means of a second welding layer, and the second connection region (2) is intended to be welded with the base plate;

the height difference between the first connecting area (1) and the second connecting area (2) is the sum of the thickness of the chip, the thickness of the electrode plate, the thickness of the first welding layer and the thickness of the second welding layer.

8. Copper bridge according to claim 1, characterized in that the distance of the rectangular connecting ribs (7) from the first extension region (3) is equal to the distance of the rectangular connecting ribs (7) from the second extension region (4).

9. The copper bridge of claim 1, wherein the gap width between the conductive elements is 0.1-1mm, the width of the conductive elements is 0.3-3mm, the thickness of the conductive elements is 0.1-2mm, the width of the rectangular connecting ribs is 0.5-3.5mm, and the height difference between the first connecting area and the second connecting area is 0.5-3mm.

10. A semiconductor device comprising the copper bridge of any one of claims 1-9.