Stress relief structure

A stress relief structure is provided. The stress relief structure includes a stress relief body, at least one first stress relief base and at least one second stress relief base. The stress relief body has an upper surface and a lower surface opposite to each other. The first stress relief base is disposed on the upper surface of the stress relief body. The second stress relief base is disposed on the lower surface of the stress relief body. The at least one first stress relief base and the at least one second stress relief base are interlaced to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 101145178, filed on Nov. 30, 2012. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The technical field relates to a stress relief structure.

BACKGROUND

In recent years, 3D stacking technology has been developing to shorten the length of the leads between the chips, to reduce the dimension of the devices, and to establish a 3D stacked structure of the chips in the semiconductor industry, wherein through-substrate vias are important components in 3D stacking technology for connecting chips stacked vertically.

In the application of the through-substrate vias, in addition to through-silicon vias (TSVs), through-glass vias (TGVs) are also currently available. However, due to coefficient of thermal expansion (CTE) mismatch between the filling material in the through-glass vias and glass and the glass substrate being more brittle and less elastic, uneven thermal stress is generated around the through-glass vias, causing peeling and pop-up in the through-glass vias, and even causing chip cracks.

In the known method for reducing stress, changing the material and the appearance of the through-glass vias, or adding other materials to the structure are usually adopted.

SUMMARY

The disclosure provides a stress relief structure.

One exemplary embodiment provides a stress relief structure including a stress relief body, at least one first stress relief base and at least one second stress relief base. The stress relief body has an upper surface and a lower surface opposite to each other. The first stress relief base is disposed on the upper surface of the stress relief body. The second stress relief base is disposed on the lower surface of the stress relief body. The at least one first stress relief base and the at least one second stress relief base are interlaced to each other.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1Ais a schematic top view of a stress relief structure according to an embodiment of the disclosure.FIG. 1Bis a schematic cross-sectional diagram of a stress relief structure according to an embodiment of the disclosure.FIG. 2is a schematic top view of a stress, relief structure according to another embodiment of the disclosure.

Referring simultaneously toFIG. 1A,FIG. 1B, andFIG. 2, a stress relief structure100and a stress relief structure200include a stress relief body102, at least one stress relief base104a, and at least one stress relief base104b.

The stress relief body102has an upper surface102aand a lower surface102bopposite to each other. A material of the stress relief body102is, for instance, an elastic material or a brittle material. In an embodiment, the material of the stress relief body102is, for instance, a metal, a polymer, or a carbon-based material, wherein the metal is, for instance, copper-tungsten, iron, or an alloy thereof; the polymer is, for instance, polyacetylene; and the carbon-based material is, for instance, an activated carbon, carbon fibers, or carbon nanotubes. A shape of the stress relief body102is, for instance, a circle, a polygon, or a shape having a geometric center. InFIG. 1A,FIG. 1B, andFIG. 2, although the shape of the stress relief body102is illustrated as circular, the disclosure is not limited thereto.

The stress relief base104ais disposed on the upper surface102aof the stress relief body102. A material of the stress relief base104ais, for instance, a metal, a polymer, or a carbon-based material, wherein the metal is, for instance, copper-tungsten, iron, or an alloy thereof; the polymer is, for instance, polyacetylene; and the carbon-based material is, for instance, an activated carbon, carbon fibers, or carbon nanotubes. A shape of the stress relief base104ais, for instance, a rectangle, a circle, or a pointed shape. InFIG. 1A,FIG. 1B, andFIG. 2, although the shape of the stress relief base104ais illustrated as rectangular, the disclosure is not limited thereto. Moreover, when there is a plurality of the stress relief bases104a, the stress relief bases104aare interlaced to each other. Referring toFIG. 2, there are two stress relief bases104ain the stress relief structure200, and the stress relief bases104aare interlaced to each other at 90 degrees. Although the two stress relief bases104aare illustrated inFIG. 2, and the two stress relief bases104aare interlaced to each other at 90 degrees, the disclosure is not limited thereto. In other embodiments, the number of the stress relief bases104amay be greater than three, and the stress relief bases104aare interlaced to each other.

The stress relief base104bis disposed on the lower surface102bof the stress relief body102. A material of the stress relief base104bis, for instance, a metal, a polymer, or a carbon-based material, wherein the metal is, for instance, copper-tungsten, iron, or an alloy thereof; the polymer is, for instance, polyacetylene; and the carbon-based material is, for instance, an activated carbon, carbon fibers, or carbon nanotubes. A shape of the stress relief base104bis, for instance, a rectangle, a circle, or a pointed shape. InFIG. 1A,FIG. 1B, andFIG. 2, although the shape of the stress relief base104bis illustrated as rectangular, the disclosure is not limited thereto. Moreover, inFIG. 1A,FIG. 1B, andFIG. 2, although the shapes of the stress relief base104aand the stress relief base104bare illustrated as rectangular, the disclosure is not limited thereto. The shapes of the stress relief base104aand the stress relief base104bmay be the same or different. Moreover, when there is a plurality of the stress relief bases104b, the stress relief bases104bare interlaced to each other. Referring toFIG. 2, there are two stress relief bases104bin the stress relief structure200, and the two stress relief bases104bare interlaced to each other at 90 degrees. Although the two stress relief bases104bare illustrated inFIG. 2, and the two stress relief bases104bare interlaced to each other at 90 degrees, the disclosure is not limited thereto. In other embodiments, the number of the stress relief bases104bmay be more than three, and the stress relief bases104bare interlaced to each other.

Referring toFIG. 1AandFIG. 1B, the at least one stress relief base104aand the at least one stress relief base104bare, for instance, interlaced to each other. In the embodiment, the number of each of the stress relief base104aand the stress relief base104bis one, and both of which are, for instance, interlaced to each other at 90 degrees. Although the stress relief base104aand the stress relief base104bare illustrated as being interlaced to each other at 90 degrees inFIG. 1AandFIG. 1B, the disclosure is not limited thereto. In other embodiments, an angle between the stress relief base104aand the stress relief base104binterlaced to each other may be other angles less than 180 degrees.

Moreover, the stress relief structure100and the stress relief structure200may be applied to a 3D-integrated circuit (3D-IC) structure having a glass interposer as illustrated inFIG. 3.

FIG. 3is a schematic cross-sectional diagram of a 3D-IC structure containing a stress relief structure according to an embodiment of the disclosure.

Referring toFIG. 3, the 3D-IC structure includes the stress relief structure100, an interposer106, a die108, and a bump110.

The stress relief structure100is disposed between the interposer106and the die108, the at least one stress relief base104ais disposed between the stress relief body102and the die108, and the at least one stress relief base104bis disposed between the stress relief body102and the interposer106.

The interposer106includes a glass substrate107and at least one through-glass via109. The at least one through-glass via109is disposed in the glass substrate107. A material of the through-glass vias109is, for instance, copper-tungsten, iron, or an alloy thereof.

The bump110is disposed between the interposer106and the die108to electrically connect the interposer106and the die108. A material of the bump110is, for instance, copper-tungsten, iron, or an alloy thereof.

Moreover, the coefficient of thermal expansion of the stress relief body102is, for instance, 80% to 120% of the coefficient of thermal expansion of the through-glass vias109. In other words, when the material of through-glass vias109is copper, the stress relief body102may be a metal or a polymer material having a coefficient of thermal expansion of, for instance, 6 ppm/° C. to 21 ppm/° C. The coefficients of thermal expansion of the stress relief base104aand the stress relief base104bare, for instance, 80% to 120% of the coefficient of thermal expansion of the through-glass vias109.

In the 3D-IC structure, the stress relief body102may be used as an absorber for crack energy, and the absorbed energy in the stress relief body102may be dissipated by the stress relief base104aand the stress relief base104binto the interposer106, which may in principle achieve a goal of reducing thermal stress.

It should be mentioned that, the stress relief structure100of the embodiment used to absorb energy is disposed using the following layout: when the at least one through-glass via109comprises a plurality of through-glass vias109, at least one of the stress relief structures100may be disposed in a circle202with a circle center as a geometric center P of a polygon300composed of the through-glass vias109as vertices, wherein the circle202is located in the polygon300, and a radius Cr of the circle202is less than twice a radius R of the through-glass vias109. Moreover, in the above-described layout, when the shape of the stress relief body102is circular and the shapes of the at least one stress relief base104aand the at least one stress relief base104bare rectangular, the relationships among the radius R of the through-glass vias109, the radius r of the stress relief body102, a distance L between the center of the at least one through-glass via109and the center of the stress relief body102, a short-side length W1of the at least one stress relief base104aand a short-side length W2of the at least one stress relief base104bare defined by the following Formula 1 to Formula 3, but the disclosure is not limited thereto.
0.2R≦rFormula 1
0≦L≦4(R+r)  Formula 2
0≦W1,W2≦8rFormula 3

Hereinafter,FIG. 4toFIG. 6Care used to explain the layout with the stress relief body102being circular and the stress relief base104aand the stress relief base104bbeing rectangular. The stress relief structure100ofFIG. 1AandFIG. 1Bis taken as an example inFIG. 4toFIG. 6Cfor illustration purposes, but the disclosure is not limited thereto. In other embodiments, the stress relief structure200ofFIG. 2or other stress relief structures having different numbers of the stress relief bases may also be used.

FIG. 4is a schematic diagram of a layout of three through-glass vias according to an embodiment of the disclosure.

Referring toFIG. 4, for illustration purposes, the number of the through-glass vias109is three, and the polygon300composed of the through-glass vias109as vertices is an equilateral triangle (illustrated by dash lines) in the embodiment, for example, but the disclosure is not limited thereto. In other embodiments, the number of the through-glass vias109may be greater than three, and the polygon composed of the through-glass vias109as vertices may be a regular polygon or an arbitrary polygon. Two stress relief structures100are disposed in the circle202located in the polygon300and having the circle center as the geometric center P of the polygon300. In the embodiment, although two stress relief structures100are illustrated as being disposed in the circle202, the disclosure is not limited thereto. In other embodiments, the number of the stress relief structure100is not limited by the present disclosure, as long as at least one stress relief structure100is disposed in the circle202.

In the embodiment, the radius Cr of the circle202is twice the radius R of the through-glass vias109, the radius r of the stress relief body102is half the radius R of the through-glass vias109, the distance L between the center of the through-glass vias109and the center of the stress relief body102is four times less than the sum of the radius r of the stress relief body102and the radius R of the through-glass vias109, and the short-side length W1of the stress relief base104aand the short-side length W2of the stress relief base104bare eight times less than the radius r of the stress relief body102, but the disclosure is not limited thereto. In other embodiments, the number of the through-glass vias109, the type of the polygon composed thereby, and the number of the stress relief structure100disposed may be adjusted according to different actual needs. The dimensional relationships among the radius Cr, the radius R, the radius r, the distance L, the short-side length W1, and short-side length W2may also be adjusted according to different actual needs, as long as the dimensional relationships fall within the scope of the definition described above.

It should be mentioned that, in the layout of the embodiment, the polygon300composed of the through-glass vias109as vertices is not limited to the polygon300composed of all the through-glass vias109as vertices. Different polygons300may be composed of any three or more through-glass vias109selected from all the through-glass vias109as vertices.

Hereinafter,FIG. 5AtoFIG. 5DandFIG. 6AtoFIG. 6Care used to explain a polygon composed of more than three through-glass vias, and the other conditions and the size definitions of the layout provided are not specified otherwise. However, it should be understood thatFIG. 5AtoFIG. 5DandFIG. 6AtoFIG. 6Care similar to the layout and the size definitions provided above.

FIG. 5AtoFIG. 5Dare schematic diagrams of layouts of four through-glass vias according to an embodiment of the disclosure.FIG. 6AtoFIG. 6Care schematic diagrams of layouts of five through-glass vias according to an embodiment of the disclosure.

Referring toFIG. 5A, a polygon composed of through-glass vias109a,109b,109c, and109das vertices includes a tetragon300acomposed of the through-glass vias109a,109b,109c, and109das vertices. Moreover, the circle center of a circle202ain the tetragon300ais a geometric center P1of the tetragon300a. Moreover, at least one stress relief structure100may be disposed in the circle202aaccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Referring toFIG. 5B, a polygon composed of the through-glass vias109a,109b,109c, and109das vertices includes a triangle300band a triangle300c. The triangle300bis composed of the through-glass vias109a,109b, and109cas vertices. The triangle300cis composed of the through-glass vias109b,109c, and109das vertices. In particular, the circle center of a circle202bin the triangle300bis a geometric center P2of the triangle300b, and the circle center of a circle202cin the triangle300cis a geometric center P3of the triangle300c. Similarly, at least one stress relief structure100may be respectively disposed in the circle202band the circle202caccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Referring toFIG. 5C, a polygon composed of the through-glass vias109a,109b,109c, and109das vertices includes a triangle300dand a triangle300e. The triangle300dis composed of the through-glass vias109a,109b, and109das vertices. The triangle300eis composed of the through-glass vias109a,109c, and109das vertices. In particular, the circle center of a circle202din the triangle300dis a geometric center P4of the triangle300d, and the circle center of a circle202ein the triangle300eis a geometric center P5of the triangle300e. Similarly, at least one stress relief structure100may be respectively disposed in the circle202dand the circle202eaccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Referring toFIG. 5D, a polygon composed of the through-glass vias109a,109b,109c, and109das vertices includes the triangle300band the triangle300e. The triangle300bis composed of the through-glass vias109a,109b, and109cas vertices. The triangle300eis composed of the through-glass vias109a,109c, and109das vertices. In particular, the circle center of the circle202bin the triangle300bis the geometric center P2of the triangle300b, and the circle center of the circle202ein the triangle300eis the geometric center P5of the triangle300e. Similarly, at least one stress relief structure100may be respectively disposed in the circle202band the circle202eaccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Based on the above, it may be acquired fromFIG. 5AandFIG. 5BtoFIG. 5Dthat, when there are four through-glass vias (e.g. the through-glass vias109a,109b,109c, and109d), a tetragon may be composed from the four through-glass vias as vertices or a triangle may be composed from any three through-glass vias among those as vertices. Moreover, it is acquired fromFIG. 5BtoFIG. 5Dthat, triangles (e.g. the triangles300b,300c,300d, and300e) composed of any three through-glass vias as vertices may be used in combination according to different actual needs and the selectivity of the application. Moreover, referring simultaneously toFIG. 5Ato FIG.5D, the tetragon300acomposed of four through-glass vias as vertices and the triangles300b,300c,300d, and300ecomposed of any three through-glass vias as vertices may be used in combination according to different actual needs and the selectivity of the application to define circles (e.g. the circles202a,202b,202c,202d, and202e) in the polygons, thereby determining the range of installation of the stress relief structure100.

Then, referring toFIG. 6A, a polygon composed of through-glass vias109e,109f,109g,109h, and109ias vertices includes a pentagon300fcomposed of the through-glass vias109e,109f,109g,109h, and109ias vertices. Moreover, the circle center of a circle202fin the pentagon300fis a geometric center P6of the pentagon300f. Moreover, at least one stress relief structure100may be disposed in the circle202faccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Referring toFIG. 6B, a polygon composed of the through-glass vias109e,109f,109g,109h, and109ias vertices includes a triangle300gand a tetragon300h. The triangle300gis composed of the through-glass vias109e,109h, and109ias vertices. The tetragon300his composed of the through-glass vias109e,109f,109g, and109has vertices. In particular, the circle center of a circle202gin the triangle300gis a geometric center P7of the triangle300g, and the circle center of a circle202hin the tetragon300his a geometric center P8of the tetragon300h. Similarly, at least one stress relief structure100may be respectively disposed in the circle202gand the circle202haccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Referring toFIG. 6C, a polygon composed of the through-glass vias109e,109f,109g,109h, and109ias vertices includes the triangle300g, a triangle300i, and a triangle300j. The triangle300gis composed of the through-glass vias109e,109h, and109ias vertices. The triangle300iis composed of the through-glass vias109e,109h, and109gas vertices. The triangle300jis composed of the vertices of the through-glass vias109e,109g, and109f. In particular, the circle center of the circle202gin the triangle300gis the geometric center P7of the triangle300g, the circle center of a circle202iin the triangle300iis a geometric center P9of the triangle300i, and the circle center of a circle202jin the triangle300jis a geometric center P10of the triangle300j. Similarly, at least one stress relief structure100may respectively be disposed in the circle202g, the circle202i, and the circle202jaccording to the layout and the size definitions provided above (as illustrated inFIG. 4).

Based on the above, it may be acquired fromFIG. 6AandFIG. 6Bthat, when there are five through-glass vias (e.g. the through-glass vias109e,109f,109g,109h, and109i), a pentagon may be composed from the five through-glass vias as vertices, a tetragon may be composed from any four through-glass vias among those as vertices, or a triangle may be composed from any three through-glass vias among those as vertices. Moreover, inFIG. 6BandFIG. 6C, although the triangles300g,300i,300jand the tetragon300hare illustrated, the disclosure is not limited thereto. It should be noted that, a triangle or a tetragon composed of any three or four of the through-glass vias109e,109f,109g,109h, and109imay be used for the polygon300in the layout of the embodiment, and at least one stress relief structure100may also be disposed in the circle with the circle center as the geometric center of the triangle or the tetragon. Moreover, a pentagon composed of five through-glass vias as vertices, a triangle composed of any three through-glass vias as vertices, or a tetragon composed of any four through-glass vias as vertices may be used in combination according to different actual needs and the selectivity of the application to define the circle in any of the polygons, thereby determining the range of installation of the stress relief structure100.

It may be acquired from the above-described embodiment that, damage to the die may be reduced by directly applying a stress relief structure100to the current 3D-IC structure and using a specific layout to effectively absorb energy.

The following uses an experimental example to simulate an effect of a stress relief structure provided in the above-described embodiment on a maximum energy release rate.

Referring to Table 1, when the stress relief structure is not used, the maximum energy release rate is 288 MPa. When two stress relief structures are used, the maximum energy release rate is reduced to 184 MPa, and the reduction ratio is 36.11%. When four stress relief structures are used, the maximum energy release rate is reduced to 166 MPa, and the reduction ratio is 42.36%. It may be acquired that the stress relief structure provided in the above-described embodiment does absorb energy, and that the more stress relief structures are used, the more energy is absorbed.

In summary, the stress relief structure provided in the above-described embodiment may be directly applied to the current fabrication processof3D-ICs by a specific layout.