TW201820535A - Electrical contact structure and methods for forming the same - Google Patents

Abstract

The disclosure provides an electrical contact structure and a method for forming the electrical contact structure. The method includes forming a thin film material layer on a substrate. The method also includes forming a first barrier layer on the thin film material layer and forming a metal layer on the first barrier layer. The method further includes patterning the metal layer to form a metal pattern. The method also includes forming a spacer on a sidewall of the metal pattern and covering a portion of the first barrier layer. The method further includes etching the first barrier layer, wherein the portion of the first barrier layer located under the spacer is not completely etched. The method further includes removing the spacer and exposing the sidewall of the metal pattern to form an electrical contact structure on the thin film material layer, wherein the first barrier layer has a protrusion part exceeding the sidewall of the metal pattern.

Description

 Electrical contact structure and method of forming same  

Embodiments of the present invention relate to electrical contact structures and methods of forming the same, and more particularly to electrical contact structures on thin film material layers and methods of forming the same.

Semiconductor devices have been widely used in various electronic products such as personal computers, mobile phones, and digital cameras. The semiconductor device is usually fabricated by sequentially depositing an insulating layer or a dielectric layer material, a conductive layer material, and a semiconductor layer material on a semiconductor substrate, and then patterning the various material layers formed by using a lithography process, whereby the semiconductor substrate is formed thereon. Circuit parts and components are formed on top.

In a semiconductor device, an element fabricated using a thin film material such as a thin film resistor or a magnetoresistive element can reduce the element size of the semiconductor device and exhibit the stability of the element and the required electrical performance, however, currently in the film material The fabrication of electrical contact structures on the layers still suffers from a number of problems, resulting in increased electrical contact structure resistance and damage to the thin film material layer, so the method of fabricating the electrical contact structure remains to be further improved.

According to some embodiments of the present invention, a method of forming an electrical contact structure is provided, the method comprising forming a thin film material layer on a substrate, forming a first barrier layer on the thin film material layer, forming a metal layer on the first barrier layer, and forming the metal The layer is patterned to form a metal pattern, a spacer is formed on the sidewall of the metal pattern and covers a portion of the first barrier layer, and the first barrier layer is etched, wherein the portion of the first barrier layer under the spacer is not completely Etching, and removing spacers, expose sidewalls of the metal pattern to form an electrical contact structure on the layer of thin film material, wherein the first barrier layer has protrusions beyond the sidewalls of the metal pattern.

According to some embodiments of the present invention, an electrical contact structure is provided on a layer of a thin film material on a substrate, the first barrier layer is disposed on the thin film material layer, and the metal pattern is disposed on the first barrier layer, wherein the first barrier layer There is a protrusion beyond the side wall of the metal pattern.

100‧‧‧Base

102‧‧‧film material layer

104‧‧‧First barrier

106‧‧‧metal layer

106’‧‧‧Metal pattern

106S‧‧‧ side wall

108‧‧‧second barrier

108’‧‧‧ patterned second barrier

110‧‧‧Anti-reflective layer

110’‧‧‧ patterned anti-reflective layer

112‧‧‧ photoresist layer

114‧‧‧ spacers

116‧‧‧ Cover

118‧‧‧ openings

120‧‧‧Electrical parts

122‧‧‧Electrical contact structure

W _1, W _2, W ₃ ‧ ‧ width

P‧‧‧Prominence

A‧‧‧ area

The full disclosure is based on the following detailed description and in conjunction with the drawings. It should be noted that various components in the drawings are not necessarily drawn to scale in accordance with the general operation of the industry. In fact, it is possible to arbitrarily enlarge or reduce the size of various components for a clear explanation.

1A-1I are schematic cross-sectional views showing stages of a method of forming an electrical contact structure in accordance with some embodiments.

Fig. 2 is an enlarged schematic view showing a region A in Fig. 1F.

The manner of making and using the embodiments of the present invention will be described in detail below. It should be noted that the embodiments of the present invention provide many inventive concepts that can be applied in various forms. The examples discussed herein are merely illustrative of the invention and are not intended to limit the scope of the invention. In addition, in the description, the first process and the second process may include an embodiment in which the second process is performed immediately after the first process, and may include other additional processes between the first process and the second process. Example. Many components may be arbitrarily drawn to different scale ratios. This is only for the simplification and clarity of the schema. Further, when the first material layer is referred to or on the second material layer, an embodiment comprising the first material layer in direct contact with the second material layer or one or more other material layers is disposed. Some variations of the embodiments are described below. In the various figures and the description of the embodiments, like reference numerals may be used to indicate similar elements. It will be appreciated that additional operational steps may be performed before, during or after the method, and that in other embodiments of the method, portions of the operational steps may be substituted or omitted.

The method for forming the electrical contact structure of the embodiment of the present invention overcomes the problem of the underlying structure caused by over-etching of the barrier layer under the metal pattern by forming a spacer on the sidewall of the metal pattern, thereby improving the electrical contact structure. The electrical stability and reliability of the electrical contact structure are prevented from increasing.

1A-1I are schematic cross-sectional views showing stages of a method of forming an electrical contact structure in accordance with some embodiments.

Referring to FIG. 1A, a substrate 100 is provided. In some embodiments, the substrate 100 can be a single crystal germanium substrate, an epitaxial germanium substrate, a germanium substrate, a silicon on insulator (SOI) substrate, a compound semiconductor. Substrate or other suitable semiconductor substrate. A thin film material layer 102 is formed on the substrate 100. The thickness of the thin film material layer 102 ranges from about 100 Å to about 200 Å. In some embodiments, the thin film material layer 102 may comprise a thin film resistive material such as yttrium chromium (SiCr), nickel. Chromium (NiCr), tantalum nitride (TaN) or other suitable thin film resistor material. In some other embodiments, the thin film material layer 102 may comprise a thin film material of a magnetoresistive element, such as a thin film material of a magnetoresistive element such as anisotropic magnetoresistance (AMR) or giant magnetoresistance (GMR), The thin film material of the magnetoresistive element is, for example, nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron (CoFeB), copper (Cu), platinum manganese (PtMn), lanthanum manganese (IrMn) or other suitable thin film magnetoresistance. material. In some embodiments, the thin film material layer 102 can be subjected to a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, an atomic layer deposition (ALD) method, Plasma-enhanced chemical vapor deposition (PECVD), high-density plasma chemical vapor deposition (HDPCVD), and organometallic chemical vapor deposition (metal- A suitable process method such as organic chemical vapor deposition (MOCVD) or pulsed laser deposition (PLD) is used.

In some embodiments, a first barrier layer 104 is formed over the substrate 100 and the thin film material layer 102. The first barrier layer 104 covers and directly contacts the upper surface of the substrate 100 and the thin film material layer 102. In some embodiments, the first barrier layer 104 can comprise titanium tungsten (TiW), titanium nitride (TiN), titanium (Ti), or other suitable materials. In some embodiments, the weight ratio of titanium to tungsten in the titanium tungsten (TiW) used by the first barrier layer 104 is 1:9. In some embodiments, the first barrier layer 104 is permeable to chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), and plasma assisted chemical vapor deposition (PECVD). Formed by a suitable process such as high density plasma chemical vapor deposition (HDPCVD), organometallic chemical vapor deposition (MOCVD) or pulsed laser deposition (PLD).

Referring to FIG. 1B, in accordance with some embodiments, a metal layer 106 is then formed over the first barrier layer 104. In some embodiments, the metal layer 106 includes, for example, aluminum copper (AlCu) or aluminum beryllium copper (AlSiCu). Suitable material. Next, a second barrier layer 108 is formed over the metal layer 106. In some embodiments, the second barrier layer 108 can comprise the same material as the first barrier layer 104, such as titanium tungsten (TiW), titanium (Ti), or Titanium nitride (TiN). In some embodiments, the second barrier layer 108 can comprise a different material than the first barrier layer 104, such as a suitable material such as tantalum (Ta) or tantalum nitride (TaN).

In some embodiments, the anti-reflective layer 110 is then formed on the second barrier layer 108, and the anti-reflective layer 110 may comprise a material such as hafnium oxynitride (SiON) or tantalum nitride (SiN). In some embodiments, the metal layer 106, the second barrier layer 108, and the anti-reflective layer 110 are permeable to chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), and plasma. Suitable process methods such as assisted chemical vapor deposition (PECVD), high density plasma chemical vapor deposition (HDPCVD), organometallic chemical vapor deposition (MOCVD) or pulsed laser deposition (PLD) are separately formed. .

Referring to FIG. 1C, in some embodiments, a patterning process is successively performed to simultaneously pattern the metal layer 106, the second barrier layer 108, and the anti-reflective layer 110. In some embodiments, the patterning process includes forming a mask pattern (not shown) on the anti-reflective layer 110, and dry etching the metal layer 106, the second barrier layer 108, and the anti-reflective layer 110 using a mask pattern. A process or other suitable etching process to form a metal pattern 106' as shown in FIG. 1C, a patterned second barrier layer 108', and a patterned anti-reflective layer 110', after which the patterned anti-reflective layer 110 is patterned 'The mask pattern above is removed. In some embodiments, the dry etching process is, for example, a reactive-ion etching (RIE), plasma etching process, and the dry etching process is stopped on the first barrier layer 104 and exposed. The upper surface of the first barrier layer 104 and the metal pattern 106', the patterned second barrier layer 108', and the sidewall of the patterned anti-reflective layer 110'. Since the dry etching process is an anisotropic etching, the anisotropic etching is performed only in the vertical direction, and the horizontal direction is not etched, so the metal pattern 106' and the patterned second barrier layer 108' And the patterned anti-reflective layer 110' has a pattern that overlaps completely up and down, as shown in FIG. 1C.

Referring to FIG. 1D, a photoresist layer 112 is formed on the first barrier layer 104, the metal pattern 106', the patterned second barrier layer 108', and the patterned anti-reflective layer 110', and the photoresist layer 112 is filled. A space formed between the metal pattern 106', the patterned second barrier layer 108', and the patterned anti-reflective layer 110'. The photoresist layer 112 can be formed, for example, by a spin coating process, a spray coating process, other suitable processes, or a combination of the foregoing.

Referring to FIG. 1E, in some embodiments, a photoresist etch back process is performed to etch the photoresist layer 112 to form spacers 114 in the metal pattern 106', the patterned second barrier layer 108', and the patterned resist. The sidewall of the reflective layer 110', and the spacer 114 also contacts the upper surface of the first barrier layer 104 and covers a portion of the first barrier layer 104. In some embodiments, the photoresist etchback process employs a dry etch process, such as , reactive ion etching or plasma etching, in some embodiments, the spacers 114 at the bottom of the range of the width W ₁ of between about 0.1μm and about 0.3μm.

Referring to FIG. 1F, in some embodiments, a wet etch process is performed to etch the first barrier layer 104. The wet etch process is isotropic etching and has a high etching option for the thin film material layer 102. ratio. When the first barrier layer 104 is etched by the wet etching process, a portion of the first barrier layer 104 covered by the spacers 114 is not completely etched, so after the wet etching process is finished, the first barrier layer 104 has the protrusions P beyond the metal. The sidewall 106S of the pattern 106' is outside. In some embodiments, the etchant used in the wet etch process is, for example, an etchant based primarily on hydrogen peroxide (H ₂ O ₂ ). The material of the foregoing first barrier layer 104 is, for example, titanium tungsten (TiW), titanium nitride (TiN) or titanium (Ti). The aforementioned thin film material layer 102 may comprise a thin film resistive material such as ruthenium chromium (SiCr), nickel chromium (NiCr), tantalum nitride (TaN) or other suitable thin film resistive material. In some other embodiments, the thin film material layer 102 may comprise a thin film material of a magnetoresistive element, such as a thin film material of a magnetoresistive element such as anisotropic magnetoresistance (AMR) or giant magnetoresistance (GMR). The thin film material of the above magnetoresistive element is, for example, nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron (CoFeB), copper (Cu), platinum manganese (PtMn), lanthanum manganese (IrMn) or other suitable thin film magnetic material. Resistance material.

Referring to FIG. 2, FIG. 2 is an enlarged schematic view showing a region A in FIG. 1F according to some embodiments, the protrusion P protruding outward from the side wall 106S of the metal pattern 106', and the bottom of the protrusion P has a width. W ₂ , and the top of the protrusion P has a width W ₃ , and in some embodiments, the width W ₃ ranges from greater than 0 μm (eg, from about 0.01 μm) to about 0.2 μm, and the width W ₂ ranges from greater than 0 μm ( For example, between about 0.01 μm) and about 0.2 μm, in some embodiments, the width W ₃ can be greater than the width W ₂ , and in some embodiments, the width W ₃ can be less than the width W ₂ , in some embodiments, the width W ₃ can be equal to the width W ₂ .

In an embodiment of the present invention, since the spacer 114 covers the sidewall 106S of the metal pattern 106', the spacer 114 may protect the metal pattern 106', the patterned second barrier layer 108 during etching of the first barrier layer 104. And the patterned anti-reflective layer 110', and such that the first barrier layer 104 is not over-etched to within the sidewalls 106' of the metal pattern 106' to create an undercut structure. Therefore, the electrical contact structure of the embodiment of the invention has the advantages of improving electrical stability and reliability, and avoiding an increase in electrical resistance of the electrical contact structure.

Referring to FIG. 1G, the spacers 114 are then removed to form an electrical contact structure 122 on the thin film material layer 102. The electrical contact structure 122 includes a first barrier layer 104, a metal pattern 106', and a patterned second barrier layer 108. 'and patterned anti-reflective layer 110'. In some embodiments, after the spacer 114 is removed, the first barrier layer 104 is exposed from the protrusion P that protrudes outward from the sidewall 106S of the metal pattern 106', and the protrusion P is beyond the sidewall 106S of the metal pattern 106'.

Referring to FIG. 1H, in some embodiments, a protective layer 116 is formed over the substrate 100, covering the thin film material layer 102 and the electrical contact structure 122, and the protective layer 116 contacts the upper surface of the thin film material layer 102, the first barrier layer. The protrusion P and the metal pattern 106' of the 104, the patterned second barrier layer 108', and the sidewall of the patterned anti-reflection layer 110'. In some embodiments, the cap layer 116 has an opening 118 directly over a portion of the metal pattern 106' of the electrical contact structure 122 and removes a portion of the patterned anti-reflective layer 110' exposed by the opening 118, exposing the patterning Part of the upper surface of the second barrier layer 108'. In some embodiments, the opening 118 in the sheath 116 is used as a conductive feature, such as a conductive bump, that is then electrically connected to an external circuit. In some embodiments, the sheath 116 may comprise a suitable material such as tantalum nitride or cerium oxide deposited at a low temperature or a high temperature, such as tantalum nitride (SiN) or cerium oxide deposited at 250 ° C or 400 ° C ( SiO ₂ ). The protective layer 116 can be subjected to chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), plasma-assisted chemical vapor deposition (PECVD), high-density plasma chemical vapor. A suitable process method such as deposition (HDPCVD), organometallic chemical vapor deposition (MOCVD) or pulsed laser deposition (PLD) is used.

Referring to FIG. 1I, in some embodiments, conductive member 120 may be formed in opening 118 and over portion of protective layer 116 to electrically connect electrical contact structure 122 to an external circuit. Conductive member 120 may be permeable to chemical gas. Phase deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), plasma-assisted chemical vapor deposition (PECVD), high-density plasma chemical vapor deposition (HDPCVD), organic A patterning process is performed after deposition by a suitable process such as metal chemical vapor deposition (MOCVD) or pulsed laser deposition (PLD).

According to some embodiments of the present invention, an electrical contact structure and a method of forming the same are provided. In the method of forming an electrical contact structure, a spacer is formed on a sidewall of the electrical contact structure to protect the barrier layer under the metal pattern. The utility model can not only prevent the sidewall of the electrical contact structure from being laterally etched during the barrier etching process, but also avoid the undercut structure of the metal pattern and the underlying barrier layer, thereby improving the electrical stability and reliability of the electrical contact structure. To avoid an increase in the electrical resistance of the electrical contact structure. In addition, the formation of the spacer does not require the use of an additional mask, and thus does not increase the manufacturing cost.

The foregoing is a summary of the various embodiments of the invention, and the embodiments of the invention may be It should be understood by those of ordinary skill in the art that the present invention can be readily adapted or modified, and that other processes and structures can be readily constructed and modified to achieve the same objectives and/or to be described herein. The same advantages of the embodiment. It is to be understood by those of ordinary skill in the art that the invention is Various changes, permutations, or modifications may be made to the embodiments of the present invention without departing from the spirit and scope of the invention.

Claims (17)

 A method for forming an electrical contact structure, comprising: forming a thin film material layer on a substrate; forming a first barrier layer on the thin film material layer; forming a metal layer on the first barrier layer; and patterning the metal layer Forming a metal pattern; forming a spacer on a sidewall of the metal pattern and covering a portion of the first barrier layer; etching the first barrier layer, wherein the first barrier is under the spacer The portion of the layer is not completely etched; and the spacer is removed to expose the sidewall of the metal pattern to form an electrical contact structure on the layer of thin film material, wherein the first barrier layer has a protrusion beyond the Outside the side wall of the metal pattern.    The method of forming an electrical contact structure according to claim 1, wherein the forming the spacer comprises forming a photoresist layer over the metal pattern and the first barrier layer, and performing a photoresist etchback process The spacer is formed.    The method of forming an electrical contact structure according to claim 1, wherein the film material layer comprises a thin film material of a thin film resistive material or a magnetoresistive element, and the thin film resistive material comprises chrome (SiCr), nickel chrome (NiCr). Or tantalum nitride (TaN), the magnetoresistive element comprises an anisotropic magnetoresistive or giant magnetoresistive element, and the thin film material of the magnetoresistive element comprises nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron ( CoFeB), copper (Cu), platinum manganese (PtMn) or lanthanum manganese (IrMn).    The method of forming an electrical contact structure according to claim 1, wherein the metal layer comprises aluminum copper (AlCu) or aluminum beryllium copper (AlSiCu).    The method of forming an electrical contact structure according to claim 1, wherein the first barrier layer comprises titanium tungsten (TiW), titanium (Ti) or titanium nitride (TiN).   The method of forming an electrical contact structure according to claim 1, wherein the etching the first barrier layer comprises a wet etching process, and an etchant used in the wet etching process comprises hydrogen peroxide (H ₂ O ₂ ) .  The method for forming an electrical contact structure according to claim 1, further comprising forming a protective layer on the thin film material layer and the electrical contact structure, and the protective layer has an opening directly above the metal pattern.    The method for forming an electrical contact structure according to claim 1, further comprising forming a second barrier layer over the metal layer, and forming an anti-reflective layer on the second barrier layer, and the The second barrier layer and the anti-reflective layer are simultaneously patterned in the step of patterning the metal layer to form a pattern that completely overlaps the metal pattern.    The method of forming an electrical contact structure according to claim 8, wherein the second barrier layer comprises titanium tungsten (TiW), titanium (Ti), titanium nitride (TiN), tantalum (Ta) or tantalum nitride. (TaN), the antireflection layer includes bismuth oxynitride (SiON) or tantalum nitride (SiN).    The method of forming the electrical contact structure of claim 8, further comprising etching the anti-reflective layer to expose an upper surface of the second barrier layer.    The method of forming an electrical contact structure according to claim 1, wherein the patterning the metal layer comprises a dry etching process, and the dry etching process is stopped on the first barrier layer.    An electrical contact structure, disposed on a film material layer on a substrate, comprising: a first barrier layer disposed on the film material layer; and a metal pattern disposed on the first barrier layer, wherein the first A barrier layer has a protrusion that extends beyond a sidewall of the metal pattern.    The electrical contact structure of claim 12, wherein the thin film material layer comprises a thin film material of a thin film resistive material or a magnetoresistive element, and the thin film resistive material comprises bismuth chromium (SiCr), nickel chromium (NiCr) or nitrogen. TaN, the magnetoresistive element comprises an anisotropic magnetoresistive or giant magnetoresistive element, and the thin film material of the magnetoresistive element comprises nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron (CoFeB), Copper (Cu), platinum manganese (PtMn) or strontium manganese (IrMn).    The electrical contact structure of claim 12, wherein the material of the metal pattern comprises aluminum copper (AlCu) or aluminum beryllium copper (AlSiCu).    The electrical contact structure of claim 12, wherein the first barrier layer comprises titanium tungsten (TiW), titanium (Ti) or titanium nitride (TiN).    The electrical contact structure of claim 12, further comprising a protective layer disposed on the thin film material layer and the metal pattern, and the protective layer has an opening directly above the metal pattern.    The electrical contact structure of claim 12, further comprising a second barrier layer disposed on the metal pattern, and an anti-reflective layer disposed on the second barrier layer, wherein the second barrier layer comprises titanium Tungsten (TiW), titanium (Ti), titanium nitride (TiN), tantalum (Ta) or tantalum nitride (TaN), the antireflection layer comprising bismuth oxynitride (SiON) or tantalum nitride (SiN), and The opening of the sheath exposes an upper surface of the second barrier layer.