TWI523145B - Bond pad structure and fabricating method thereof - Google Patents

Description

Pad structure and manufacturing method thereof

The present invention relates to a semiconductor device and a method of fabricating the same, and more particularly to a pad structure for an element and a method of fabricating the same.

With the advancement of technology, consumer electronics products are constantly moving toward miniaturization, and their performance and functions are constantly improving. Various types of consumer electronics such as mobile phones, notebook computers, MP3 players and personal digital assistants Products such as (PDA) are constantly evolving toward thin, short, powerful and low-cost. In order to meet the above requirements, we have developed Micro-Electro-Mechanical System (MEMS) components such as micro-acoustical sensors and micro-gyro sensors. Detector), accelerometer or clock generation and oscillator.

A typical micro-motor component uses a semiconductor process to form a plurality of MEMS components directly on the surface of the wafer and integrate them with electronic circuits that process or transmit signals from the MEMS components. It is then die sawing.

However, since both the pad and the micro-motor component require an opening on the surface of the wafer. Therefore, when the pad opening is formed, it is often affected by an etching process for forming the opening of the micro-motor component, and an undercut is generated on the opening of the pad, which causes the pad to be easily generated by subsequent process steps such as a die cutting process. The stress is impacted, resulting in a phenomenon of material peeling.

Therefore, how to prevent the solder pads of the components of the micro-electric system from being damaged by the stress of the subsequent process is still an urgent problem to be solved in the industry.

In view of the above, one of the objects of the present invention is to provide a pad structure including: an interconnect structure and a cover spacer. Wherein, the interconnect structure has at least one opening and at least one metal pad. The cover layer is over the interconnect structure and extends over the sidewalls of the opening to contact the metal pads such that a portion of the metal pads are exposed from the openings.

In an embodiment of the invention, the material constituting the cover layer is selected from the group consisting of alumina (Al ₂ O ₃ ), tantalum nitride (SiN), amorphous silicon, and niobium nitriding (SiCN). ), an organic polymer or a combination of any of the above. In one embodiment of the invention, the cover spacer has a lead angle formed at a location adjacent the sidewall of the opening to the metal pad.

In an embodiment of the invention, the interconnect structure includes an inner dielectric layer and a passivation layer. Wherein, the inner dielectric layer is used to support or the metal pad; the passivation layer covers the inner dielectric layer, and the opening penetrates the passivation layer to expose a portion of the metal pad to outer.

In an embodiment of the invention, the pad structure further comprises: a hard mask layer on the cover spacer layer and not in contact with the metal pad. In one embodiment of the invention, the hard mask layer is an aluminum metal layer. In an embodiment of the invention, the pad structure further includes a ceria layer embedded between the cover spacer layer and the hard mask layer. In an embodiment of the invention, the pad structure further includes a metal oxide layer formed on the same side of the opening but not exposed to the surface of the outer metal pad.

Another object of the present invention is to provide a Micro-Electro-Mechanical System (MEMS) comprising: a substrate and a transistor element, a micro-motor component and a pad structure formed on the substrate . The pad structure includes: an interconnect structure and a cover isolation layer. The interconnect structure is formed over the substrate and has at least one opening and at least one metal pad electrically coupled to the transistor component and the micromachine component. The cover spacer is over the interconnect structure and extends over the sidewall of the opening to contact the metal pad and expose a portion of the metal pad from the opening.

In one embodiment of the invention, the micro-electrical system component further includes a hard mask layer overlying the isolation barrier and not in contact with the metal pads. In one embodiment of the invention, the cover spacer has a lead angle formed above the sidewall of the opening adjacent the metal pad. In an embodiment of the invention, the micro-electric system component further includes: a ceria layer embedded between the cover isolation layer and the hard mask layer. In one embodiment of the invention, the micro-electric system component further includes a metal oxide layer formed on the same side of the metal pad as the opening but not exposed to the outer surface.

It is still another object of the present invention to provide a method of fabricating a pad structure comprising the steps of first providing an interconnect structure having an inner dielectric layer and at least one metal pad. Next, an opening is formed in the inner dielectric layer to expose a portion of the metal pad to the outside. A cover spacer is formed over the inner dielectric layer and extends over the sidewalls of the opening and the metal pads. Then, the overlying isolation layer is patterned to expose a portion of the metal pads to the outside.

In an embodiment of the invention, the step of forming the interconnect structure comprises the steps of: first providing a substrate, forming a plurality of patterned metal wire layers on the substrate, and isolating the patterned metal wire layers. Inner dielectric layer. Next, a passivation layer is formed over the patterned metal wiring layer and the inner dielectric layer.

In an embodiment of the invention, at least one of the transistor elements and a portion of the micro-motor component are formed on the substrate prior to forming the interconnect structure.

In an embodiment of the invention, before forming the passivation layer, a metal oxide layer is further formed on the metal pad.

In one embodiment of the present invention, the material forming the cover layer is selected from the group consisting of alumina, tantalum nitride, amorphous tantalum, niobium nitridide, organic polymer, or any combination thereof.

In an embodiment of the invention, a hard mask layer is formed on the cover spacer layer and is not in contact with the metal pad.

In an embodiment of the invention, before forming the hard mask layer, the method further comprises: forming a ruthenium dioxide layer on the cover spacer layer, and leaving the ruthenium dioxide layer not extending beyond the opening.

According to the above embodiment, the present invention provides a pad structure and a method of fabricating the same. An opening is defined in an interconnect structure and a portion of the metal pad is exposed. A cover layer is then covered to cover the sidewalls of the pad opening and the exposed metal pads. Thereafter, the overlying isolation layer on the metal pad is patterned to expose a portion of the metal pad to the opening again.

Since the material covering the isolation layer has better etching resistance than the inner dielectric layer of the interconnect structure. Therefore, when the covering isolation layer completely covers the sidewall of the opening, the subsequent etching process for forming the opening of the micro-motor component can be prevented, the side etching of the inner dielectric layer can be caused, and the probability that the pad structure is damaged by the subsequent process stress can be reduced. Moreover, the above process can reduce the number of masks used in subsequent processes, and has the advantages of simplifying the process and reducing the cost compared with other conventional technologies, and achieving the above object.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

The object of the present invention is to provide a pad structure and a manufacturing method thereof, which not only solves the problem that the conventional pad structure is susceptible to stress damage in subsequent processes, but also has a cost advantage in the manufacturing process. In order to make the above and other objects, features and advantages of the present invention more apparent and obvious, the following is a preferred embodiment of the structure and fabrication method of the micro-electrical system component, and the detailed description is as follows .

1A-1E, FIG. 1A to FIG. 1E are cross-sectional views showing a process of fabricating a micro-electric system component 100 according to a preferred embodiment of the present invention. In some embodiments of the invention, the micro-electrical system component 100 may include a micro-motor component 104, such as a microsonic sensor, a microgyroscope sensor, an acceleration sensor, or a clock generation and oscillator.

The process of forming the micro-electrical system component 100 includes the steps of first providing a substrate 101 and forming at least one micro-motor component 104 on the substrate 101, and for processing, receiving, or transmitting the micro-motor component 104. The electronic component of the generated electronic signal (as shown in Figure 1A). For example, in the present embodiment, the substrate 101 is a tantalum substrate, preferably a wafer. The electronic component formed on the substrate 101 includes at least one complementary metal-oxide-semiconductor (CMOS) transistor 102.

Next, an interconnect structure 103 (shown in FIG. 1B) is formed over the substrate 101 and the complementary metal-oxide-semiconductor transistor 102. The interconnect structure 103 includes a plurality of patterned metal wire layers stacked on each other, such as metal wire layers 103a and 103b; an inner dielectric layer 103c separating the metal wire layers 103a and 103b; and a conductive metal wire layer 103a and 103b. Contact window or via window 103d.

In some embodiments of the present invention, the metal wiring layers 103a and 103b are preferably formed of a patterned aluminum metal layer for electrically connecting the micro-motor component 104 and the complementary metal-oxide-semiconductor transistor 102. Among them, a portion of the uppermost metal wiring layer 103a is provided as a bonding pad (for the sake of clarity, the following is indicated by a metal pad 107). The metal pad 107 can be electrically connected to an external electronic component (not shown) by solder balls or wire bonding.

Thereafter, the inner dielectric layer 103c and the metal pad 107 cover a passivation layer 105. The passivation layer 105 is preferably a tantalum nitride layer. Next, an etching process is performed to remove a portion of the surface of the passivation layer 105 to form an opening 106 and expose a portion of the metal pad 107 (as shown in FIG. 1C).

It should be noted, however, that in other embodiments of the present invention (please refer to FIG. 1C'), a deposition film process or a thermal process (eg, a thermal oxidation process) may preferably be performed before the passivation layer 105 has been formed. A thin layer of aluminum oxide is formed on the metal pad 107. And a portion of the aluminum oxide layer, after forming the passivation layer 105, is removed by the etching process, and forms a patterned metal on the same side of the metal pad 107 and the opening 106, but not exposed to the outer surface. Oxide layer 112.

Then, over the passivation layer 105 and the portion where the metal pad 107 is exposed, a cover spacer 108 is formed, and a hard mask layer 110 formed on the cover spacer 108 is formed. As shown in FIG. 1D, a portion of the cover spacer 108 extending into the opening 106 covers the sidewall 106a of the opening 106; and a leading angle θ is formed at a position where the sidewall 106a of the opening 106 abuts the metal pad 107.

In a preferred embodiment of the present invention, the material forming the cover spacer 108 is selected from the group consisting of alumina, tantalum nitride, amorphous germanium, niobium oxynitride, organic polymer or any combination thereof. . The cover isolation layer 108 may be an aluminum oxide layer deposited on the passivation layer 105 and a portion of the metal pad 107, a tantalum nitride, an amorphous germanium or a single deposited layer or a multi-layer stack of niobium carbide, or by spin The coating process coats the organic polymer layer on the passivation layer 105 and a portion of the metal pad 107. The hard mask layer 110 is preferably an aluminum metal layer.

Next, a second etching process is performed to remove a portion of the hard mask layer 110 and the capping isolation layer 108 in the opening 106, thereby again exposing a portion of the metal pad 107 through the opening 106. The patterned hard mask layer 110 is not in contact with the metal pad 107.

After the second etching process, at least one etching process (for example, a structural anisotropic etching process) is performed to form the micro-motor component opening 113 in the inner dielectric layer 103c, and the micro-motor component 104 is exposed to form a pattern. The micro-electrical system component 100 illustrated in 1E.

In still other embodiments of the present invention (continuing the embodiment of FIG. 1C'), in order to increase the insulation of the cover spacer 108, it is preferable to form a cover between the cover spacer 108 and the hard mask layer 110. The cerium oxide layer 111. In order to prevent the ruthenium dioxide layer 111 from being damaged by subsequent etching processes, the ruthenium dioxide layer 111 preferably has to be embedded in the hard mask layer 110. The step of forming the cerium oxide layer 111 includes: forming a cerium oxide layer 111 on the overlying isolation layer 108 before the hard mask layer 110 is formed, and then the cerium oxide layer 111 is not formed by the patterning step. Extending beyond the opening 106. Next, a hard mask layer 110 is formed on the cover spacer layer 108 to completely cover the patterned ceria layer 111 (as shown in FIG. 1D'). After the second etching process, the patterned ceria layer 111 is still completely encapsulated in the capping spacer layer 108 and the hard mask layer 110.

After the second etching process, at least one etching process (for example, a structural anisotropic etching process) is performed, and the micro-motor component opening 113 is formed in the inner dielectric layer 103c to expose the micro-motor component 104 to form a figure. The micro-electrical system component 100' depicted in 1E'.

In the present embodiment, the micro-electric system component 100' includes a substrate 101, a transistor element (complementary metal-oxide-semiconductor transistor 102), a micro-motor component 104, and a pad structure. The complementary metal-oxide-semiconductor transistor 102, the micro-motor component 104, and the pad structure are all formed on the substrate 101. The pad structure includes: an interconnect structure 103 (including at least a metal pad 107, an inner dielectric layer 103c and a passivation layer 105), a patterned ceria layer 111, a metal oxide layer 112, a capping layer 108, and Hard mask layer 110.

The interconnect structure 103 is formed over the substrate 101 and has an opening 106. The metal pad 107 is located in the interconnect structure 103 and is electrically coupled to the complementary metal-oxide-semiconductor transistor 102 and the micro-motor component 104. The cover spacer layer 108 is over the dielectric layer and extends over the sidewall 106a of the opening 106 to be in contact with the metal pad 107 such that a portion of the metal pad 107 is exposed from the opening 106. The hard mask layer 110 is on the cover spacer layer 108 and is not in contact with the metal pad 107. The patterned ceria layer 111 is embedded between the cover spacer layer 108 and the hard mask layer 110. A metal oxide layer 112a is formed on the metal pad 107 on the same side as the opening 106 but not exposed to the outer surface.

Since the material selected for covering the spacer layer 108 is compared with the material of the cap layer of the inner dielectric layer 103c, it provides insulation equivalent to that of the dielectric layer 103c. Moreover, the hard mask layer 110 and the overlying isolation layer 108 are also much more resistant to etchants (eg, hydrofluoric acid (HF)) than cerium oxide. Thus, the hard mask layer 110 and the overlying isolation layer 108 that completely encase the sidewalls 106a of the opening 106 prevent the etching process used to form the microelectromechanical component opening 113 from causing side erosion at the sidewall 106a of the opening 106. The pad structure formed by the above process will be less likely to cause delamination due to subsequent process stress.

Moreover, the above process does not need to define an additional isolation structure around the opening 106, such as an isolation ring, which is not only simple in structure and process, but also reduces the number of masks used in subsequent processes. Therefore, the pad structure and the manufacturing method thereof provided by the above embodiments have obvious cost advantages.

According to the above embodiment, the present invention provides a pad structure and a method of fabricating the same. The pad structure is completed by two etching processes. An opening is defined in an interconnect structure and a portion of the metal pad is exposed. A cover layer is then covered to cover the sidewalls of the pad opening and the exposed metal pads. Thereafter, the overlying isolation layer on the metal pad is patterned to expose a portion of the metal pad to the opening again.

Since the material of the covering spacer layer has better etching resistance than the inner dielectric layer of the interconnect structure, the subsequent etching process can prevent side etching of the inner dielectric layer, and the conventional soldering is solved. The pad structure is susceptible to stress damage in subsequent processes. Moreover, the above process can reduce the number of masks used in subsequent processes, and has the advantages of simplifying the process and reducing the cost compared with other conventional technologies, and achieving the above object.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

100. . . Micro-electrical system component

100’. . . Micro-electrical system component

101. . . Substrate

102. . . Complementary metal-oxide-semiconductor transistor

103. . . Inline structure

103a. . . Metal wire layer

103b. . . Metal wire layer

103c. . . Inner dielectric layer

103d. . . Contact window

104. . . Micro motor component

105. . . Passivation layer

106. . . Opening

106a. . . Side wall of the opening

107. . . Metal pad

108. . . Covering the isolation layer

110. . . Hard mask layer

111. . . Ceria layer

112. . . Metal oxide layer

113. . . Micro motor component opening

θ. . . Leading angle

1A-1E are cross-sectional views showing a series of processes for fabricating micro-electric system components in accordance with a preferred embodiment of the present invention.

1C' to 1E' are cross-sectional views showing a portion of a process for fabricating a micro-electric system component in accordance with another preferred embodiment of the present invention.

100’. . . Micro-electrical system component

101. . . Substrate

102. . . Complementary metal-oxide-semiconductor transistor

103. . . Inline structure

103a. . . Metal wire layer

103b. . . Metal wire layer

103c. . . Inner dielectric layer

103d. . . Contact window

104. . . Micro motor component

105. . . Passivation layer

106. . . Opening

106a. . . Side wall of the opening

107. . . Metal pad

108. . . Covering the isolation layer

110. . . Hard mask layer

111. . . Ceria layer

112. . . Metal oxide layer

113. . . Micro motor component opening

θ. . . Leading angle

Claims (20)

A pad structure comprising: an interconnect structure having at least one opening and at least one metal pad; and a cover isolation layer over the interconnect structure and extending over the sidewall of the opening The metal pads are in contact such that a portion of the metal pads are exposed from the opening. The pad structure according to claim 1, wherein the material constituting the cover layer is selected from the group consisting of alumina (Al ₂ O ₃ ), tantalum nitride (SiN), and amorphous germanium (amorphous). A group of silicon, silicon lanthanum carbide (SiCN), organic polymer or any combination of the above. The solder pad structure of claim 1, wherein the interconnect structure comprises: an inner dielectric layer for carrying the metal pad; and a passivation layer covering the The inner dielectric layer is formed through the passivation layer to expose a portion of the metal pad to the outside. The pad structure according to claim 1, further comprising a hard mask layer on the cover isolation layer and not in contact with the metal pad. The pad structure of claim 4, wherein the hard mask layer is an aluminum metal layer. The solder pad structure of claim 1, further comprising a layer of germanium dioxide embedded between the cover spacer layer and the hard mask layer. The pad structure according to claim 1, further comprising a metal oxide layer formed on the same side of the metal pad but not exposed to the outer surface. The pad structure of claim 1, wherein the cover spacer has a lead angle formed at a position adjacent to the metal pad of the sidewall of the opening. A Micro-Electro-Mechanical System (MEMS) comprising: a substrate; a transistor element formed on the substrate; a micro-motor component formed on the substrate; a pad structure comprising: an interconnect structure formed on the substrate, having an opening and at least one metal pad disposed in the interconnect structure and the transistor component and the micromotor Electrically connecting the component; and a cover isolation layer over the interconnect structure and extending over the sidewall of the opening to contact the metal pad and exposing a portion of the metal pad to the opening outer. The micro-electric system component of claim 9, further comprising a hard mask layer on the cover isolation layer and not in contact with the metal pad. The micro-electric system component of claim 9, wherein the covering spacer has a lead angle formed at a position adjacent to a sidewall of the opening. The micro-electrical system component as described in claim 9 further comprising a ruthenium dioxide layer embedded between the overlying isolation layer and the hard mask layer. The micro-electric system component as described in claim 9 further comprising a metal oxide layer formed on the same side of the metal pad but not exposed to the outer surface. A method for fabricating a pad structure includes: providing an interconnect structure comprising at least one metal pad and an inner dielectric layer; forming an opening in the inner dielectric layer to enable a portion of the metal bond The pad is exposed to the outside; a cover spacer is formed on the inner dielectric layer, and the sidewall covering the opening and the metal pad are extended; and the cover spacer is patterned to expose a portion of the metal pad Outside. The method of manufacturing the pad structure of claim 14, wherein the step of forming the interconnect structure comprises: providing a substrate; forming a plurality of patterned metal wire layers on the substrate; and isolating the substrate The inner dielectric layer of the patterned metal wiring layer; and a passivation layer formed on the patterned metal wiring layer and the inner dielectric layer. The method of manufacturing the pad structure of claim 15, wherein before forming the metal wire layer, further comprising forming at least one transistor component and a portion of the micro-motor component on the substrate. The method for manufacturing the pad structure according to claim 15, wherein before forming the passivation layer, further comprising forming a metal oxide layer on the metal pad. The method for manufacturing the pad structure according to claim 14, wherein the material for forming the covering spacer layer is selected from the group consisting of alumina, tantalum nitride, amorphous germanium, niobium nitriding, and organic polymer. Or a group of any combination of the above. The method for manufacturing the pad structure of claim 14, further comprising: forming a hard mask layer on the cover spacer layer and not contacting the metal pad. The method of manufacturing the pad structure of claim 19, wherein before forming the hard mask layer, further comprising forming a ceria layer on the cover spacer layer, and forming the ceria layer The layer does not extend beyond the opening.