阅读说明：本技术 半导体装置及半导体封装 (Semiconductor device and semiconductor package ) 是由 刘玮玮 翁辉翔 于 2020-02-21 设计创作，主要内容包括：本申请提供一种半导体装置及一种包括所述半导体装置的半导体封装。所述半导体裝置包含：半导体元件；保护层,其被安置邻近于所述半导体元件的表面,所述保护层界定开口以暴露所述半导体元件；第一凸块,其安置于所述半导体元件上；及第二凸块,其安置至所述保护层的表面上。所述第一凸块相比于所述第二凸块具有较大横截面表面积。(The present application provides a semiconductor device and a semiconductor package including the same. The semiconductor device includes: a semiconductor element; a protective layer disposed adjacent to a surface of the semiconductor element, the protective layer defining an opening to expose the semiconductor element; a first bump disposed on the semiconductor element; and a second bump disposed onto a surface of the protective layer. The first bumps have a larger cross-sectional surface area than the second bumps.)

1. A semiconductor device, comprising:

a semiconductor element;

a protective layer disposed adjacent to a surface of the semiconductor element, the protective layer defining an opening to expose the semiconductor element;

a first bump disposed on the semiconductor element; and

a second bump disposed onto a surface of the protective layer,

wherein the first bumps have a larger cross-sectional surface area than the second bumps.

2. The semiconductor device of claim 1, wherein the first bump has a shape different from a shape of the second bump.

3. The semiconductor device of claim 2, wherein the first bump has an oval shape and the second bump has a circular shape.

4. The semiconductor device according to claim 1, wherein the first bump has the same shape as that of the second bump.

5. The semiconductor device of claim 4, wherein the first bump has a circular shape and the second bump has a circular shape.

6. The semiconductor device of claim 1, wherein the first bump has a first length relative to a first direction and a second length relative to a second direction, and the second bump has a third length relative to the first direction and a fourth length relative to the second direction, wherein a ratio of the first length to the second length is about 1 and a ratio of the third length to the fourth length is about 1.

7. The semiconductor device of claim 1, wherein the first bump comprises a first solder layer and the second bump comprises a second solder layer, wherein the first solder layer has a cap ratio of 0.55 to 0.65 and the second solder layer has a cap ratio of 0.50 to 0.70, wherein the cap ratio is determined by a thickness of the solder layer to a length of the bump relative to a first direction.

8. The semiconductor device of claim 1, wherein the first bump comprises a first solder layer and the second bump comprises a second solder layer, wherein the first solder layer has a cap ratio of 0.55 to 0.65 and the second solder layer has a cap ratio of 0.60 to 0.80, wherein the cap ratio is determined by a thickness of the solder layer to a length of the bump relative to a first direction.

9. The semiconductor device of claim 1, wherein the first bump has a first length relative to a first direction and a second length relative to a second direction, and the second bump has a third length relative to the first direction and a fourth length relative to the second direction, wherein the third length is in a range of 90-110% of a difference between the first length and about 10 μ ι η.

10. The semiconductor device of claim 1, wherein the first bump has a first length relative to a first direction and a second length relative to a second direction, and the second bump has a third length relative to the first direction and a fourth length relative to the second direction, wherein the third length is in a range of 90-110% of a product of the first length and 0.7.

11. The semiconductor device according to claim 1, wherein a first height measured from a surface of the first bump in contact with the semiconductor element to a top of the first bump is substantially the same as a second height measured from the surface of the first bump in contact with the semiconductor element to a top of the second bump.

12. The semiconductor device of claim 1, wherein a difference between a top of the first bump and a top of the second bump is less than 8 μ ι η.

13. The semiconductor device of claim 1, wherein the semiconductor element further comprises a bond pad disposed adjacent to a surface of the semiconductor element, and the first bump is disposed on the bond pad.

14. The semiconductor device of claim 1, wherein the first bump and the second bump are pillars.

15. A semiconductor device, comprising:

a semiconductor element;

a first bump disposed proximate to a surface of the semiconductor element, wherein the first bump comprises a first pillar and a first solder; and

a second bump disposed proximate to the surface of the semiconductor element, wherein the second bump includes a second post and a second solder;

wherein the first pillar and the second pillar have substantially the same height, and the first solder and the second solder do not have substantially the same height,

wherein the first bumps have a larger cross-sectional surface area than the second bumps.

16. The semiconductor device of claim 15, wherein a height of the first bump is substantially the same as a height measured from a bottom of the first bump to a top of the second bump.

17. The semiconductor device of claim 15, wherein a difference between a top of the first bump and a top of the second bump is less than 8 μ ι η.

18. The semiconductor device of claim 15, wherein the first bump has a first length along a first direction and a second length along a second direction, and the second bump has a third length along the first direction and a fourth length along the second direction, wherein a ratio of the first length to the second length is about 1 and a ratio of the third length to the fourth length is about 1.

19. The semiconductor device of claim 15, wherein the first bump has a first length relative to a first direction and a second length relative to a second direction, and the second bump has a third length relative to the first direction and a fourth length relative to the second direction, wherein the third length is in a range of 90-110% of a difference between the first length and about 10 μ ι η.

20. The semiconductor device of claim 15, wherein the first bump has a first length relative to a first direction and a second length relative to a second direction, and the second bump has a third length relative to the first direction and a fourth length relative to the second direction, wherein the third length is in a range of 90-110% of a product of the first length and 0.7.

21. A semiconductor package, comprising:

a semiconductor device, comprising:

a first semiconductor element;

a protective layer disposed adjacent to a surface of the first semiconductor element, the protective layer defining an opening to expose the first semiconductor element;

a first bump disposed on the first semiconductor element; and

a second bump disposed onto a surface of the protective layer,

wherein the first bumps have a larger cross-sectional surface area than the second bumps; and

a second semiconductor element including:

a first bonding pad disposed adjacent to a surface of the second semiconductor element and corresponding to the first bump; wherein the first bump is bonded to the first bond pad.

22. The semiconductor package of claim 21, wherein the second semiconductor element further comprises a second bond pad disposed adjacent to the surface of the second semiconductor element and corresponding to a second bump, the first bond pad is provided with an opening having a first width W1 and the second bond pad is provided with an opening having a second width W2, and the first width W1 is greater than the second width W2.

Technical Field

The present invention relates to a semiconductor device, and more particularly, to a semiconductor device including a bump and a semiconductor package including the same.

Background

In a semiconductor flip chip bonding process, a chip is placed on a substrate (or another chip). The chip may be electrically connected to the substrate via metal bumps disposed on the chip and via bond pads disposed on the substrate. Solder may be used to physically connect the metal bumps and the bond pads.

Miniaturization has had a serious impact on assembly stresses generated during molding of metal bumps on semiconductor devices. Such stresses may cause cracks in the bumps or even separation of the chip or die, causing poor electrical connection between the chip and the substrate. Accordingly, it would be desirable to provide a semiconductor device having a novel and inventive bump to reduce assembly stress generated during the molding process and prevent poor electrical connection between the chip and the substrate.

Disclosure of Invention

In one aspect, a semiconductor device includes: a semiconductor element; a protective layer disposed adjacent to a surface of the semiconductor element, the protective layer defining an opening to expose the semiconductor element; a first bump disposed on the semiconductor element; and a second bump disposed onto a surface of the protective layer. The first bumps have a larger cross-sectional surface area than the second bumps.

In one aspect, a semiconductor device includes: a semiconductor element; a first bump disposed proximate to a surface of the semiconductor element, wherein the first bump comprises a first pillar and a first solder layer; and a second bump disposed proximate to the surface of the semiconductor element, wherein the second bump includes a second pillar and a second solder layer. The first pillar and the second pillar have substantially the same height, and the first solder layer and the second solder layer do not have substantially the same height. In addition, the first bumps have a larger cross-sectional surface area than the second bumps.

In one aspect, a semiconductor package includes a semiconductor device and a second semiconductor element. The semiconductor device includes: a first semiconductor element; a protective layer disposed adjacent to a surface of the first semiconductor element, the protective layer defining an opening to expose the first semiconductor element; a first bump disposed on the first semiconductor element; and a second bump disposed onto a surface of the protective layer, wherein the first bump has a larger cross-sectional surface area than the second bump. The second semiconductor element comprises a first bond pad disposed adjacent to a surface of the second semiconductor element and corresponding to the first bump; wherein the first bump is bonded to the first bond pad.

In one aspect, a method of forming a semiconductor device includes: providing a semiconductor element comprising at least one bond pad disposed adjacent to a surface of the semiconductor element; disposing a protective layer adjacent to the surface of the semiconductor element, the protective layer defining an opening to expose the bond pad; disposing a first post on the bond pad; and disposing a second post adjacent to a surface of the protective layer, wherein the first post has a larger cross-sectional surface area than the second post.

Drawings

Fig. 1 shows a cross-sectional view of a semiconductor device according to an embodiment of the present application.

Fig. 2(a) shows a top view of the semiconductor device depicted in fig. 1 according to an embodiment of the present application.

Fig. 2(b) shows a top view of the semiconductor device depicted in fig. 1 according to an embodiment of the present application.

Fig. 3(a) shows a top view of the semiconductor device depicted in fig. 1 according to an embodiment of the present application.

Fig. 3(b) shows a top view of the semiconductor device depicted in fig. 1 according to an embodiment of the present application.

Fig. 4 shows a cross-sectional view of a semiconductor device according to an embodiment of the present application.

Fig. 5 shows a cross-sectional view of an embodiment of a semiconductor package according to an embodiment of the present application.

Fig. 6 shows a cross-sectional view of an embodiment of a semiconductor package according to an embodiment of the present application.

Fig. 7(a) to 7(f) illustrate a manufacturing method according to an embodiment of the present application.

Fig. 8(a) to 8(b) illustrate a manufacturing method according to an embodiment of the present application.

Detailed Description

Unless otherwise specified, spatial descriptions such as "above," "top," "bottom," "upper," "lower," "below," and the like are indicated with respect to the orientation shown in the figures. It is to be understood that the spatial description used herein is for illustrative purposes only and that actual implementations of the structures described herein may be spatially arranged in any orientation or manner, provided that the advantages of the embodiments of the present application are not necessarily so biased.

In a semiconductor flip chip bonding process, a chip is placed on a substrate (or another chip). The chip may be electrically connected to the substrate via metal bumps disposed on the chip and via bond pads disposed on the substrate. Solder may be used to physically connect the metal bumps and the bond pads. The reflow process melts the solder so that the metal bumps can be bonded with the bonding pads to form a flip-chip bonding structure. However, such bonding structures may be fragile because assembly stresses are often generated during the molding process of the metal bumps. Assembly stresses may crack the metal bumps or even cause separation of the chip or die. The result can be poor electrical connection between the chip and the substrate and low reliability.

realizes an improved semiconductor device with improved metal bumps that can reduce assembly stresses that are often generated during the molding process of the metal bumps.

Fig. 1 illustrates a cross-sectional view of a semiconductor device 100 according to an embodiment of the present application . The semiconductor device 100 of fig. 1 includes a semiconductor element 102, a passivation layer 104, a plurality of first bumps 106, and a plurality of second bumps 108.

The semiconductor element 102 may be a die, chip, package, or interposer. The semiconductor device 102 has a first surface 102a, a second surface 102b opposite the first surface 102a, and one or more bonding pads 110. The bonding pad 110 is disposed adjacent to the first surface 102a of the semiconductor element 102. The bond pads 110 may be contact pads such as traces. In the embodiment of fig. 1, the first surface 102a is an active surface, the bonding pad 110 is a contact pad, and the bonding pad 110 is disposed directly on the first surface 102a of the semiconductor element 102. The bond pad 110 may comprise, for example, one or a combination of copper, gold, indium, tin, silver, palladium, osmium, iridium, ruthenium, titanium, magnesium, aluminum, cobalt, nickel, or zinc or other metals or metal alloys.

The protection layer 104 is disposed adjacent to the first surface 102a of the semiconductor element 102. As shown in fig. 1, the protective layer 104 is disposed over the first surface 102a of the semiconductor element 102. The protective layer 104 defines one or more openings 104 c. Each opening 104c corresponds to a respective bond pad 110 and exposes at least a portion of the bond pad 110. The protective layer 104 comprises polyimide or other suitable material (e.g., a photosensitive material). The protection layer 104 may be a passivation layer or an insulating layer (which may be silicon oxide or silicon nitride, or another insulating material). In some embodiments, such as the embodiment depicted in fig. 1, the protective layer 104 may be disposed on an insulating layer (or another protective layer) 112. An insulating layer (or another protective layer) 112 may cover portions of the bonding pad 110 and cover the first surface 102a of the semiconductor element 102.

The first bump 106 is a conductive pillar structure. The first bump 106 is disposed adjacent to the first surface 102a of the semiconductor device 102. The first bump 106 illustrated in fig. 1 is disposed on the exposed portion of the illustrated bonding pad 110. As seen in fig. 1, the first bump 106 may include a first Under Bump Metallization (UBM) layer 1061, a first pillar 1063, a first barrier layer 1065, and a first solder layer 1067. In some embodiments, one, two, or three of the first UBM layer 1061, the first barrier layer 1045, and the first solder layer 1047 are omitted from the first bump 106 (e.g., the first bump is a pillar).

The second bump 108 is a conductive or insulating pillar structure. The second bump is disposed adjacent to the first surface 102a of the semiconductor device 102. The second bump 108 is disposed adjacent to the surface 104a of the passivation layer 104. The second bump 108 illustrated in fig. 1 is disposed on the surface 104a of the passivation layer 104. As seen in fig. 1, the second bump 108 may include a second Under Bump Metallization (UBM) layer 1081, a second pillar 1083, a second barrier layer 1085, and a second solder layer 1087. In some embodiments, one, two, or three of the second UBM layer 1081, the second barrier layer 1085, and the second solder layer 1087 are omitted from the second bump 108 (e.g., the second bump is a pillar). As described above, the bonding structures may be fragile because assembly stresses are often generated during the molding process of the metal bumps. Thus, the second bump 108 is disposed adjacent to the surface 104a of the protective layer 104 to share and reduce the assembly stress generated to the first bump 106 during the molding process of the metal bump. Accordingly, cracking of the first bumps 106 or separation of the chip or die, which may occur during a molding process of the metal bumps, may be reduced or eliminated, and electrical connections and reliability may be correspondingly improved.

As seen in fig. 1, the second bump 108 is disposed at a higher level than the first bump 106. Thus, if the first bump 106 and the second bump 108 have the same height (e.g., the first UBM layer 1061 and the second UBM layer 1081 have the same height; the first pillar 1063 and the second pillar 1083 have the same height; the first barrier layer 1065 and the second barrier layer 1085 have the same height; and the first solder layer 1067 and the second solder layer 1087 have the same height), there will be a height difference between the top of the first bump 106 and the top of the second bump 108. Such height differences may cause poor coplanarity and, in turn, poor solder connections, resulting in poor electrical connections. Thus, the present disclosure further provides that the first bump 106 should have a larger cross-sectional surface area than the second bump 108 so that the height S1 of the first solder layer 1067 after reflow may be greater than the height S2 of the second solder layer 1087, and thus, the difference between the first height H1 of the first bump 106 measured from the surface of the first bump 106 in contact with the semiconductor element 102 to the top of the first bump 106 and the third height H3 measured from the bottom of the first bump 106 to the top of the second bump 108 may be controlled to be less than 15 μm, less than 12 μm, less than 8 μm, or substantially the same (e.g., within manufacturing tolerances) after solder reflow.

It has been surprisingly found that if the solder layer is disposed on a pillar having a larger cross-sectional surface area, the solder layer will have a smaller thickness after reflow. This may be associated with surface tension between the solder layers 1067, 1087 and the barrier layers 1065, 1085 and/or the underlying pillars 1063, 1083.

Fig. 2(a) illustrates a top view of the embodiment of the semiconductor device of fig. 1, with the first bump 106 (including the pillar 1063) positioned on the bonding pad 110 on the semiconductor element 102. The first bump 106 may be any shape as long as the first bump 106 has a larger cross-sectional surface area than the second bump 108. In some embodiments, the first bump 106 has a circular or circular-like shape, or an elliptical or elliptical-like shape. The first bump 106 has a first length L1 with respect to the first direction and a second length L2 with respect to the second direction. The first length L1 may be longer, shorter, or equal to the second length L2. The first bump 106 depicted in fig. 2(a) has an elliptical or oval-like shape, wherein the ratio of the first length L1 to the second length L2 is about 1:1.2, about 1:1.5, about 1:1.7, about 1:1.9, or about 1: 2.

Fig. 2(b) illustrates a top view of the embodiment of the semiconductor device of fig. 1, with the second bump 108 (including the pillar 1083) positioned on the protection layer 104. The second bump 108 may be any shape as long as the second bump 108 has a smaller cross-sectional surface area than the first bump 106. In some embodiments, the second tab 108 has a circular or circular-like shape, or an elliptical or elliptical-like shape. The second bump 108 has a third length L3 relative to the first direction and a fourth length L4 relative to the second direction. The third length L3 may be longer, shorter, or equal to the fourth length L4. The second bump 108 depicted in fig. 2(b) has a circular or round-like shape, wherein the ratio of the third length L3 to the fourth length L4 is about 1:1.

The first bump 106 may have a shape different from that of the second bump 108, or have a shape identical or similar to that of the second bump 108. In some embodiments, the third length L3 of the second bump 108 is in the range of 90% to 110% of the difference between the first length L1 of the first bump 106 and about 10 μm (e.g., when the first bump 106 has an elliptical or elliptical-like shape and the second bump 108 has a circular or circular-like shape). In some embodiments, the third length L3 of the second tab 108 is in the range of 90% to 110% of the product of the first length and 0.7 (e.g., when the first tab 106 has a circular or circular-like shape and the second tab 108 has a circular or circular-like shape). In the embodiment illustrated in fig. 2(a), 2(b) and 1, the first bump 106 has a shape different from that of the second bump 108. The first bump 106 has an elliptical or oval-like shape and the second bump 108 has a circular or round-like shape.

The cap ratio (cap ratio) may be determined by the thickness of the solder layers 1067, 1087 versus the length L1, L3 of the bumps 106, 108 relative to the first direction. The cap portion ratio is determined depending on the design specification. If the cap portion ratio of the solder layer is greater than 0.8, the solder layer may collapse and fail to achieve the purpose of providing an effective electrical connection. On the other hand, if the cap portion ratio of the solder layer is less than 0.3, the solder layer may expose the underlying columns, which also fails to achieve its purpose of providing an effective electrical connection. In some embodiments, first solder layer 1067 has a cap ratio of about 0.55 to about 0.65, a cap ratio of about 0.57 to about 0.63, or a cap ratio of about 0.58 to about 0.59. In some embodiments, second solder layer 1087 has a cap ratio of about 0.50 to about 0.70, a cap ratio of about 0.52 to about 0.68, or a cap ratio of about 0.53 to about 0.66. In some embodiments, first solder layer 1067 has a cap ratio of 0.55 to 0.65 and second solder layer 1087 has a cap ratio of 0.50 to 0.70 (e.g., when first bump 106 has an oval or elliptical-like shape and second bump 108 has a circular or circular-like shape). In some embodiments, first solder layer 1067 has a cap ratio of 0.55 to 0.65 and second solder layer 1087 has a cap ratio of 0.60 to 0.80 (e.g., when first bump 106 has a circular or quasi-circular shape and second bump 108 has a circular or quasi-circular shape).

Fig. 3(a) illustrates a top view of the embodiment of the semiconductor device of fig. 1 with the first bump 107 positioned on the bonding pad 110 on the semiconductor element 102. The semiconductor device is similar to the semiconductor device depicted in fig. 1, except that the first bump 107 in fig. 3(a) has a circular or quasi-circular shape, wherein the ratio of the first length L1 to the second length L2 is about 1:1.

Fig. 3(b) is a top view of the embodiment of the semiconductor device of fig. 1, wherein the second bump 109 is positioned on the protection layer 104. The semiconductor device and the second bump 109 are similar to those illustrated in fig. 1, except that the third length L3 of the second bump 109 is in the range of 90% to 110% of the product of the first length L1 and 0.7 of the first bump 107 illustrated in fig. 3 (a).

Figure 4 depicts a cross-sectional view of a semiconductor device according to an embodiment of the present application . The semiconductor device 400 of fig. 4 is similar to the semiconductor device 100 of fig. 1, except that a protection layer 404 covers a portion of the bonding pad 110. The protective layer 404 has or defines one or more openings 404 c. Each opening 404c corresponds to a respective bond pad 110 and exposes at least a portion of the bond pad 110. In the embodiment of fig. 4, the first bump 106 is disposed on the exposed portion of the depicted bond pad 110 and on a portion of the protective layer 404.

Fig. 5 depicts a cross-sectional view of an embodiment of a semiconductor package 500 including the semiconductor device 100 of fig. 1. The semiconductor package 500 of fig. 5 includes the semiconductor device 100 of fig. 1, the second semiconductor element 101, an underfill 524, and a plurality of connection elements 522 for external connection.

The second semiconductor element 101 may be a chip, a substrate, a package, or an interposer. The second semiconductor element 101 includes second and third bond pads 518, 519 disposed adjacent to a surface of the second semiconductor element 101. As seen in fig. 5, the second bonding pads 518 may be electrically connected to the external environment through conductive vias 520 and connection elements 522 (e.g., bonding pads and/or traces) disposed on the second semiconductor element 101. The second bonding pads 518, 519 may comprise, for example, one or a combination of copper, gold, indium, tin, silver, palladium, osmium, iridium, ruthenium, titanium, magnesium, aluminum, cobalt, nickel, or zinc or other metals or metal alloys.

The semiconductor device 100 may be electrically connected to the second semiconductor element 101 via a first bump 106 disposed on the semiconductor device 100 and via a second bond pad 518 disposed adjacent to a surface of the second semiconductor element 101. The second bump 108 may be thermally or insulatively connected to the second semiconductor element 101 via a second bump 108 disposed on the semiconductor device 100 and via a third bond pad 519 disposed on the second semiconductor element 101. It should be noted that the third bonding pad 519 may not be necessary. In some embodiments, the semiconductor device 100 may be thermally connected to the second semiconductor element 101 via a second bump 108 disposed on the semiconductor device 100 and via a third bond pad 519 disposed adjacent to a surface of the second semiconductor element 101. In these embodiments, heat from the semiconductor device 100 may be dissipated through the second bumps 108 and the third bond pads 519.

An underfill 524 is disposed between the semiconductor device 100 and the second semiconductor element 101 to protect the first bump 106 from oxidation, moisture, and other environmental conditions to meet packaging application requirements. In some embodiments, an underfill 524 is disposed between the semiconductor device 100 and the second semiconductor element 101 to protect the first bump 106 and the second bump 108 from oxidation, moisture, and other environmental conditions. It should be noted that underfill 524 may not be necessary.

Fig. 6 depicts a cross-sectional view of a semiconductor package 600 according to an embodiment of the present application . The semiconductor package 600 is similar to the semiconductor package 500 depicted in fig. 5, except that: the second insulating layer 626 is disposed between the semiconductor device 100 and the second semiconductor element 101 to protect the first bump 106 from oxidation, moisture, and other environmental conditions to meet packaging application requirements. In some embodiments, a second insulating layer 626 is disposed between the semiconductor device 100 and the second semiconductor element 101 to protect the first bump 106 and the second bump 108 from oxidation, moisture, and other environmental conditions. In this embodiment, the second insulating layer 626 is a molding layer including a molding compound.

Fig. 7(a) to 7(f) illustrate a method for manufacturing a semiconductor device, such as the semiconductor device 100 of fig. 1.

Referring to fig. 7(a), a semiconductor element (e.g., die) 102 is provided. The semiconductor device 102 includes at least one bond pad 110 on the active surface 102a of the semiconductor device 102. Each semiconductor element 102 may include a substrate, one or more integrated circuit devices, and one or more overlying interconnect structures therein. An integrated circuit device may include one or more active devices, such as transistors, and/or passive devices, such as resistors, capacitors, inductors, or a combination of two or more thereof.

An insulating layer (or protective layer) 112 is disposed on the active surface 102a of the semiconductor device 102. The insulating layer 112 has or defines one or more openings 112c to expose the bonding pads 110. In some embodiments, the insulating layer 112 may cover portions of the bonding pad 110. Instead, the insulating layer 112 completely exposes the bonding pad 110. In some embodiments, the opening 112c may be formed by, for example, routing, etching, or other suitable processes. In some embodiments, insulating layer 112 is a passivation layer comprising silicon oxide, silicon nitride, gallium oxide, aluminum oxide, scandium oxide, zirconium oxide, lanthanum oxide, hafnium oxide, or another metal or nonmetal oxide or nitride.

The protection layer 105 is disposed adjacent to the active surface 102a of the semiconductor device 102. In the embodiment depicted in fig. 7(a), the protection layer 105 is disposed on the surface 112a of the insulating layer 112 and covers the bonding pad 110. In some embodiments, the thickness of the protective layer 105 is about 3 μm to about 7 μm, or about 4 μm to about 7 μm. In some embodiments, the protective layer 105 comprises polyimide or other suitable material (e.g., a photosensitive material).

Referring to fig. 7(b), an opening 104c is formed to expose the bond pad 110 and a portion of the insulating layer 112. As shown in fig. 7(b), the width of opening 104c is greater than the width of opening 112 c. Alternatively, the width of opening 104c may be less than or substantially equal to the width of opening 112c, depending on design specifications. In some embodiments, the opening 104c may be formed by photolithography, etching, laser drilling, or other suitable processes.

Referring to fig. 7(c), a patterned mask 714 is disposed adjacent to the surface 104a of the protection layer 104 to expose portions of the bond pad 110 and portions of the protection layer 104. The patterned mask 714 defines or has a first opening 714c to expose portions of the bond pad 110 and a second opening 714d to expose portions of the protective layer 104. The first opening 714c has a first width L1 from one side of the opening 714c to an opposite side of the opening 714c and has a second width L3 from one side of the opening 714d to an opposite side of the opening 714d, wherein the first width L1 is greater than the second width L3. The patterned mask 1401 may be formed, for example, by a photolithographic technique.

Referring to fig. 7(d), a first UBM layer 1061 is formed on the exposed portion of the bond pad 110 and a second UBM layer 1081 is formed on the exposed portion of the protective layer 104. The first and second UBM layers 1061 and 1081 may be formed to have substantially the same height. The first and second UBM layers 1061, 1081 may be formed, for example, by plating techniques. The first and second UBM layers 1061, 1081 may independently include, but are not limited to, a metal alloy, a multi-metal or a multi-alloy stack, such as a multi-alloy stack, including combinations of copper, nickel, vanadium, chromium, and gold, for example.

A first pillar 1063 having a first height P1 is formed on the first UBM layer 1061, and a second pillar 1083 having a second height P2 is formed on the second UBM layer 1081. The first height P1 may be greater than, less than, or equal to the second height P2. In the embodiment depicted in fig. 7(d), the first height P1 is substantially the same as the second height P2. The first posts 1063 and the second posts 1083 may be formed, for example, by plating techniques. The first column 1063 and the second column 1083 may independently include, but are not limited to, copper or another suitable metal or alloy thereof.

Referring to fig. 7(e), a first barrier layer 1065 is formed on the first posts 1063 and a second barrier layer 1085 is formed on the second posts 1083. The first barrier layer 1065 and the second barrier layer 1085 may be formed to have substantially the same height. The first barrier layer 1065 and the second barrier layer 1085 may be formed, for example, by a plating technique. The first barrier layer 1065 and the second barrier layer 1085 may independently include, but are not limited to, nickel, copper, alloys thereof, or another suitable metal or alloy.

In addition, a first solder layer 1068 having a first height S1 is formed on the first barrier layer 1065, and a second solder layer 1088 having a second height S2 is formed on the second barrier layer 1085. The first height S1 may be greater than, less than, or equal to the second height S2. In the embodiment illustrated in fig. 7(e), the first height S1 is substantially the same as the second height S2. The solder layer 1047a may be formed, for example, using photolithography and etching techniques.

Referring to fig. 7(f), the patterned mask 714 is removed. Then, the first solder layer 1068 and the second solder layer 1088 are reflowed to form the semiconductor device 100 as illustrated in fig. 1. As seen in fig. 7(f), prior to solder reflow, a first height H1 measured from the surface of the first UBM layer 1061 in contact with the semiconductor element 102 to the top of the first solder layer 1068 is less than a third height H3 measured from the bottom of the surface of the first UBM layer 1061 in contact with the semiconductor element 102 to the top of the second solder layer 1088 because the second posts 1083 are disposed on a plane higher than the first posts 1063 and the first height S1 is substantially the same as the second height S2, the first height P1 is substantially the same as the second height P2, and the thickness of the first UBM layer 1061 together with the first barrier layer 1065 is substantially the same as the thickness of the second UBM layer 1081 together with the second barrier layer 1085.

Fig. 8(a) to 8(b) illustrate a method for manufacturing a semiconductor package such as the semiconductor device 500 of fig. 5.

Referring to fig. 8(a), a semiconductor device 100 and a semiconductor element 101 are provided. The semiconductor device 100 of fig. 8(a) is the same as the semiconductor device of fig. 1, and has a first bump 106 and a second bump 108. The first bump 106 has a first length L1 with respect to the first direction, and the second bump 108 has a third length L3 with respect to the first direction.

The second semiconductor element 101 of fig. 8(a) is the same as the second semiconductor element 101 of fig. 5, and has second and third bonding pads 518, 519 disposed adjacent to a surface of the second semiconductor element 101. The first bond pad 518 corresponds to the first pillar 106 and has a first width W1, wherein the first width W1 is greater than or equal to the first length L1 of the first bump 106. The second bond pad 519 corresponds to the second post 108 and has a second width W2, wherein the second width W2 is greater than or equal to the second length L2 of the second bump 108. When the first length L1 is greater than the second length L2, the first width W1 is greater than the second width W2.

Referring to fig. 8(b), the first pillar 106 of the semiconductor device 100 is bonded to the first bonding pad 518 of the second semiconductor element 101, and the second pillar 108 of the semiconductor device 100 is bonded to the second bonding pad 519 of the second semiconductor element 101. The bonding process may be formed by thermal compression bonding. Next, an underfill 524 is disposed between the semiconductor device 100 and the second semiconductor element 101 to form the semiconductor package 500 as illustrated in fig. 5.

As used herein, and without further definition, the terms "substantially," "generally," "about," and "about" are used to describe and account for minor variations. When used in conjunction with an event or context, the terms may encompass an instance in which the event or context occurs precisely, as well as an instance in which the event or context occurs in close proximity. For example, when used in conjunction with numerical values, the term can encompass variations that are less than or equal to ± 10% of the stated numerical value, such as less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%. As another example, a line or plane can be substantially flat if its peaks or valleys are no greater than 5 μm, no greater than 1 μm, or no greater than 0.5 μm.

While the invention has been described and illustrated with reference to specific embodiments thereof, these descriptions and illustrations are not intended to be limiting. It should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention as defined by the appended claims. The drawings may not necessarily be to scale. Due to manufacturing processes and tolerances, there may be a distinction between artistic renderings in the present invention and actual devices. Other embodiments of the invention may exist that are not specifically illustrated. The specification and drawings are to be regarded in an illustrative rather than a restrictive sense. Modifications may be made to adapt a particular situation, material, composition of matter, method, or process to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. Although the methods disclosed herein have been described with reference to particular operations performed in a particular order, it should be understood that these operations may be combined, sub-divided, or reordered to form equivalent methods without departing from the teachings of the present disclosure. Accordingly, unless specifically indicated herein, the order and grouping of the operations is not a limitation.