Magnetoresistive device and method of forming the same

Abstract

The present invention provides a magnetoresistive device and a method for forming the same. The magnetoresistive device includes a magnetoresistance disposed on a substrate, a stress release structure covering side surfaces of the magnetoresistance, an electrical connection structure disposed on the magnetoresistance, and a passivation layer disposed on the electrical connection structure and the stress release structure. By forming the stress release structure to cover the side surfaces of the magnetoresistance, the stress applied to the magnetoresistance is released, which can avoid local cracking at the pattern edges of the magnetoresistance, and further avoid the problem of local peeling at the pattern edges of the magnetoresistance. Therefore, the present invention can improve the manufacturing yield of the magnetoresistive device.

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetoresistive device, and more particularly to a magnetoresistive device including a stress relief structure and a method of forming the same. Background Art

[0002] Magnetoresistive devices have been widely used in various electronic products, for example, such as personal computers, mobile phones, and digital cameras. A magnetoresistive device includes a magnetoresistance composed of a magnetoresistive material, and the alignment direction of the magnetic moment of the magnetoresistance is changed by an applied magnetic field, so that the resistance value of the magnetoresistance is changed. Common magnetoresistances include anisotropic magnetoresistor (AMR), giant magnetoresistor (GMR), and tunneling magnetoresistor (TMR). For example, in anisotropic magnetoresistor (AMR), generally the alignment direction of its magnetic moment is parallel to the length direction of the magnetoresistance; when the alignment direction of the magnetic moment is parallel to the current direction flowing through the magnetoresistance, the magnetoresistance has the maximum resistance value; when the alignment direction of the magnetic moment is perpendicular to the current direction flowing through the magnetoresistance, the magnetoresistance has the minimum resistance value.

[0003] For example, in a magnetoresistive device including anisotropic magnetoresistor AMR, its electrical connection is generally to form a wiring of a conductive structure on the AMR. For applications for sensing the direction and magnitude of a magnetic field, a BBP conductive structure having a pattern similar to a barber pole is formed on the AMR. The ideal design is to make the current direction flowing through the AMR along the shortest distance between the BBP conductive structures between the BBP conductive structures. Generally, the design is to make the length direction of the BBP conductive structure form an angle of 45 degrees with the length direction of the AMR, so that the resistance value of the AMR has an optimal linear response to the change of the applied magnetic field.

[0004] Currently, in the manufacturing process of magnetoresistive devices, there are still many challenges in the process of electrical connection structures, especially reducing the damage to magnetoresistive elements. Therefore, the method of forming magnetoresistive devices still needs to be further improved. Summary of the Invention

[0005] Some embodiments of the present invention provide a magnetoresistive device, which includes a magnetoresistance disposed on a substrate, a stress relief structure covering the side surface of the magnetoresistance, an electrical connection structure disposed on the magnetoresistance, and a passivation layer disposed on the electrical connection structure and the stress relief structure.

[0006] Some embodiments of the present invention provide a method for forming a magnetoresistive device, the method including forming a magnetoresistive element on a substrate, forming a dielectric material on the magnetoresistive element, etching the dielectric material to form a stress relief structure surrounding the side surface of the magnetoresistive element, forming an electrical connection structure on the magnetoresistive element, and forming a passivation layer covering the electrical connection structure and the stress relief structure.

[0007] By forming a stress relief structure covering the side surface of the magnetoresistive element, the present invention releases the stress applied to the magnetoresistive element, which can avoid local cracking at the pattern edge of the magnetoresistive element, and further avoid the problem of local peeling at the pattern edge of the magnetoresistive element. Therefore, the present invention can improve the manufacturing yield of the magnetoresistive device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present invention can be better understood through the following detailed description and examples in conjunction with the accompanying drawings. For the drawings to be clearly shown, the various different elements in the drawings may not be drawn to scale, where:

[0009] Figures 1A - 1D are cross-sectional schematic views showing the magnetoresistive device at various different process stages according to some examples.

[0010] Figure 2 is a magnetoresistive device according to some other examples.

[0011] Figures 3A - 1 to 3I - 1 and Figures 3A - 2 to 3I - 2 are schematic views showing the magnetoresistive device including a stress relief structure at various different process stages according to some embodiments.

[0012] Figures 4A - 1 to 4H - 1 and Figures 4A - 2 to 4H - 2 are schematic views showing the magnetoresistive device including a stress relief structure at various different process stages according to some embodiments.

[0013] Figure 5A and Figure 5B are a part of the magnetoresistive device according to some embodiments to illustrate some details of the stress relief structure.

[0014] REFERENCE NUMERALS

[0015] 100, 200, 300, 400 Magnetoresistive device

[0016] 102, 302 Substrate

[0017] 104, 317A, 317B Magnetoresistive element

[0018] 106, 322 First barrier material

[0019] 106’, 323A, 323B Lower barrier layer

[0020] 108, 324 Metal main body material

[0021] 108’, 325A, 325B Metal main body layer

[0022] 110, 326 Second barrier material

[0023] 110’, 327A, 327B Upper barrier layer

[0024] 112 Anti-reflection coating

[0025] 112’ Patterned anti-reflection coating

[0026] 114 Patterned photoresist layer

[0027] 116, 330A, 330B Electrical connection structure

[0028] 202 Adhesive layer

[0029] 303 Semiconductor substrate

[0030] 304 Active element

[0031] 305 Multi-layer interconnection structure

[0032] 308 Contact plug

[0033] 310 Dielectric layer

[0034] 312 Conductor

[0035] 314 Via hole

[0036] 316 Magnetoresistive material

[0037] 318 Protective material

[0038] 319A, 319A’, 319B, 319B’ Protective layer

[0039] 320, 420 Dielectric material

[0040] 321A, 321B, 421 Stress relief structure

[0041] 332 Passivation layer

[0042] 334 Opening

[0043] 422A, 422B, 426A, 426B Protrusion

[0044] 424, 424’ Flat part

[0045] 440, 440’ Photoresist material

[0046] 510M Platform

[0047] 1000 Patterning process

[0048] 1100 Etching process

[0049] 1200 Wet etching process

[0050] Region A

[0051] Depth D Detailed implementation manners

[0052] The following disclosure provides a number of examples or embodiments for implementing different elements of the provided magnetoresistive device. Specific examples of each element and its configuration are described below to simplify the description of the embodiments of the present invention. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. For example, if it is mentioned in the description that the first element is formed on the second element, it may include embodiments where the first and second elements are in direct contact, and may also include embodiments where additional elements are formed between the first and second elements such that they are not in direct contact. In addition, the embodiments of the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the sake of simplicity and clarity and is not intended to indicate the relationship between the different embodiments discussed.

[0053] Some variations of the embodiments are described below. In the embodiments shown in different figures and descriptions, like element symbols are used to denote like elements. It can be understood that additional steps may be provided before, during, and after the method, and some of the described steps may be replaced or deleted in other embodiments of the method.

[0054] Figures 1A - 1D is shown according to some examples Figure 1D a cross-sectional schematic diagram of the magnetoresistive device 100 at various different process stages.

[0055] Please refer to Figure 1D , the magnetoresistive device 100 includes a substrate 102, a magnetoresistive element 104, and an electrical connection structure 116. The substrate 102 may include active elements (e.g., logic circuits) and an interconnect structure located above the active elements. The interconnect structure includes dielectric layers (e.g., interlayer dielectric layers and intermetallic dielectric layers) and conductive components (e.g., contacts, via holes, and / or wires) to electrically connect the active elements to the magnetoresistive element 104. The electrical connection structure 116 is disposed on the magnetoresistive element 104 to change the direction of current flow in the magnetoresistive element 104 between the electrical connection structures 116 such that the resistance value of the magnetoresistive element 104 responds linearly to changes in an applied magnetic field. The electrical connection structure 116 includes a lower barrier layer 106', a metal body layer 108', an upper barrier layer 110', and an anti-reflection coating 112' stacked in sequence on the magnetoresistive element 104. The following description Figure 1DMethod for forming a magnetoresistive device 100.

[0056] Please refer to Figure 1A , a substrate 102 is provided, and a magnetoresistive material, such as a stacked structure of nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron (CoFeB), platinum manganese (PtMn), ruthenium (Ru), iridium manganese (IrMn), copper (cu), and / or tantalum (Ta), is formed on the substrate 102. Then, the magnetoresistive material is patterned to form a magnetoresistance 104, such as anisotropic magnetoresistance (AMR) or giant magnetoresistance (GMR). The patterning process includes a photolithography process and a dry etching process. Generally, the dry etching process over-etches to the dielectric layer of the substrate 102, thereby forming a height difference of depth D1, such as about to about in the range. Please refer to Figure 1B , a first barrier material 106 (e.g., titanium tungsten (TiW)), a metal body material 108 (e.g., aluminum copper (AlCu) alloy), a second barrier material 110 (titanium nitride (TiN)), and an anti-reflection coating 112 are sequentially formed on the substrate 102. Then, a patterning process is performed, which includes forming a patterned photoresist layer 114 on the anti-reflection coating 112, as Figure 1B shown. The patterning process includes performing a dry etching process on the anti-reflection coating 112, the second barrier material 110, and the metal body material 108 to form a patterned anti-reflection coating 112', an upper barrier layer 110', and a metal body layer 108', respectively, as Figure 1C shown. In the etching process, the first barrier material 106 serves as an etch stop layer to protect the underlying magnetoresistance 104 from etching damage. The patterning process also includes removing the patterned photoresist layer 114 by an ashing process. Then, please refer to Figure 1D , a wet etching process is used to remove the portion of the first barrier material 106 not covered by the metal body layer 108' to form a lower barrier layer 106'.

[0057] It should be noted that the adhesion between the first barrier material 106 and the magnetoresistance 104 is greater than the adhesion between the magnetoresistance 104 and the dielectric layer of the substrate 102. Therefore, during the ashing of the photoresist layer 114 ( Figure 1C ), the deformation stress generated by the high temperature in the first barrier material 106 tends to locally crack from the pattern edge of the magnetoresistance 104 (e.g., region A) to release the stress, which causes the pattern edge of the magnetoresistance 104 to be locally lifted by the cracked first barrier material 106 and separated from the dielectric layer of the substrate 102. Thus, during the subsequent wet etching process for removing the first barrier material 106 ( Figure 1D) Local peeling (e.g., in region A) occurs at the pattern edge of the magnetoresistive element 104, thereby reducing the manufacturing yield of the magnetoresistive device and compromising the reliability of the magnetoresistive device.

[0058] Figure 2 FIG. 4 is a cross-sectional schematic view of a magnetoresistive device 200 according to another example, in which components identical to those in the foregoing Figures 1A - 1D example are denoted by the same reference numerals and their descriptions are omitted. Figure 2 The magnetoresistive device 200 shown is different from the foregoing Figure 1D magnetoresistive device 100 in that the magnetoresistive device 200 includes a tantalum (Ta) adhesion layer 202. The adhesion layer 202 is formed between the magnetoresistive element 104 and the substrate 102 and is configured to increase the adhesion between the magnetoresistive element 104 and the dielectric layer of the substrate 102, which can prevent the first barrier material 106 from cracking at the pattern edge of the magnetoresistive element 104. Therefore, during the wet etching process as described in Figure 1D , local peeling does not occur at the pattern edge (e.g., region A) of the magnetoresistive element 104.

[0059] In Figure 2 the example, if tantalum atoms of the adhesion layer 202 diffuse into the magnetoresistive element 104, the magnetoresistance ratio (MR%) of the magnetoresistive element 104 will be reduced. Therefore, after the adhesion layer 202 and the magnetoresistive element 104 are formed, the process temperature is limited to below 300°C. For example, in Figures 1A - 1D the example, the chemical vapor deposition (CVD) process temperature for forming the antireflection coating 112 is in the range of about 300°C to about 400°C. However, in Figure 2 the example, the chemical vapor deposition (CVD) process temperature for forming the antireflection coating 112 is limited to the range of about 250°C to about 300°C. The chemical vapor deposition (CVD) at a lower temperature has a lower deposition rate and poorer thickness uniformity, and results in more undesired particle manifestations, thereby reducing the production efficiency and production yield of the magnetoresistive device 200. In addition, the process temperature limitation below 300°C causes the magnetoresistive element 104 to be unable to improve the magnetoresistance ratio (MR%) through subsequent high-temperature annealing.

[0060] Figures 3A - 1 to 3I - 1 FIGS. 5A-5D are cross-sectional schematic views showing a magnetoresistive device including a stress relief structure at various different process stages according to some embodiments; Figures 3A - 2 to 3I - 2 FIGS. 6A-6D are top views showing the magnetoresistive device at various different process stages according to some embodiments, in which Figures 3A - 1 to 3I - 1 are respectively along Figures 3A - 2 to 3I - 2The line I-I in [the figure] is extracted. In some embodiments, without using a tantalum-containing adhesion layer, by forming a stress release structure to cover the side surface of the magnetoresistive element, the stress applied to the magnetoresistive element is released, which avoids local cracking at the pattern edge of the magnetoresistive element, and further avoids the problem of local peeling at the pattern edge of the magnetoresistive element.

[0061] According to some embodiments, a substrate 302 is provided, as Figure 3A - 1 shown. In some embodiments, the substrate 302 includes a semiconductor substrate 303, active elements 304 disposed on the semiconductor substrate 303, and a multi-layer interconnection structure 305. In some embodiments, the semiconductor substrate 303 may be a silicon substrate, a silicon germanium (SiGe) substrate, a compound semiconductor substrate, a silicon on insulator (SOI) substrate, or a similar substrate. In some embodiments, the active elements 304 are logic circuits, such as transistors. In some embodiments, the multi-layer interconnection structure 305 includes a dielectric layer 310 (such as an inter-metal dielectric layer and / or an inter-layer dielectric layer), and conductive components surrounded by the dielectric layer 310 (for example, contact plugs 308 and / or via holes 314 providing vertical electrical wiring, and conductive lines 312 providing horizontal electrical wiring).

[0062] According to some embodiments, a magnetoresistive material 316 is formed on the dielectric layer 310 of the substrate 302, as Figure 3A - 1 shown. In some embodiments, the magnetoresistive material 316 includes or is nickel iron (NiFe), cobalt iron (CoFe), cobalt iron boron (CoFeB), copper (Cu), platinum manganese (PtMn), iridium manganese (IrMn), ruthenium (Ru), or similar materials, the aforementioned multi-layers, the aforementioned combinations, or other stacks suitable for forming anisotropic magnetoresistance (AMR) or giant magnetoresistance (GMR). In some embodiments, the magnetoresistive material 316 is formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), other suitable deposition techniques, or the aforementioned combinations. In some embodiments, there is no tantalum-containing adhesion layer between the dielectric layer 310 and the magnetoresistive material 316.

[0063] According to some embodiments, a protective material 318 is formed on the magnetoresistive material 316, as Figure 3A - 1 and Figure 3A - 2 shown. In some embodiments, the protective material 318 includes or is titanium tungsten (TiW), titanium (Ti), titanium nitride (TiN), or the aforementioned combinations. In some embodiments, the protective material 318 is formed by physical vapor deposition (PVD), atomic layer deposition (ALD), other suitable deposition techniques, or the aforementioned combinations. In some embodiments, the thickness of the protective material 318 ranges from about to about In one embodiment, the protective material 318 is formed of titanium tungsten (TiW), wherein the weight ratio of titanium to tungsten is about 1:9.

[0064] According to some embodiments, a patterning process is performed on the protective material 318 and the magnetoresistive material 316 to form a protective layer 319A, 319B, and magnetoresistances 317A, 317B, respectively, as Figure 3B - 1 and Figure 3B - 2 shown. According to some embodiments, the side surface of the protective layer 319A is aligned above the side surface of the magnetoresistance 317A, and the side surface of the protective layer 319B is aligned above the side surface of the magnetoresistance 317B. In some embodiments, the patterning process includes a photolithography process and an etching process. For example, a mask element (e.g., photoresist) is formed on the protective material 318 ( Figure 3A - 1 ), and then the portions of the protective material 318 and the magnetoresistive material 316 that are not covered by the mask element are etched away until the dielectric layer 310 of the substrate 302 is exposed. The etching process can be dry etching, such as ion beam etch (IBE), reactive ion etch (RIE), or other suitable etching techniques. According to some embodiments, the multi-layer interconnect structure 305 couples the active element 304 to the magnetoresistance 317A and / or the magnetoresistance 317B, and / or an electrical connection structure (not shown) below the magnetoresistances 317A and 317B.

[0065] According to some embodiments, a dielectric material 320 is conformally formed on the substrate 302, the magnetoresistances 317A, 317B, and the protective layers 319A, 319B, as Figure 3C - 1 and Figure 3C - 2 shown. According to some embodiments, the dielectric material 320 laterally extends conformally along the upper surface of the dielectric layer 310, the side surfaces of the magnetoresistances 317A, 317B, and the side surfaces and upper surfaces of the protective layers 319A, 319B. In some embodiments, the dielectric material 320 includes or is silicon oxide, silicon nitride, silicon oxynitride, a combination of the foregoing, or other suitable dielectric materials. In some embodiments, the dielectric material 320 is formed by chemical vapor deposition (CVD) (e.g., low-temperature chemical vapor deposition), physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable deposition techniques. In some embodiments, the thickness of the dielectric material 320 ranges from about to about

[0066] According to some embodiments, an etching process is performed on the dielectric material 320 until the upper surfaces of the protective layers 319A, 319B, and the upper surface of the dielectric layer 310 are exposed, as Figure 3D - 1 and Figure 3D - 2As shown. The etching process can be dry etching, such as ion beam etching (IBE), reactive ion etching (RIE), or other suitable etching techniques. In some embodiments, the etching process is a maskless etching process, that is, during the etching process, no mask element is formed on the dielectric material 320.

[0067] According to some embodiments, after the etching process, the remaining dielectric material 320 forms stress release structures 321A, 321B. According to some embodiments, the stress release structure 321A and the stress release structure 321B each laterally extend in a closed loop manner to surround the side surfaces of the magnetoresistive element 317A and the magnetoresistive element 317B. According to some embodiments, the stress release structures 321A, 321B completely cover the side surfaces of the magnetoresistive elements 317A, 317B. That is, in some embodiments, the stress release structures 321A, 321B extend upward beyond the upper surfaces of the magnetoresistive elements 317A, 317B to at least partially cover the side surfaces of the protective layers 319A, 319B. According to some embodiments, the stress release structures 321A, 321B face the inner surfaces of the magnetoresistive elements 317A, 317B and abut against the magnetoresistive elements 317A, 317B and the protective layers 319A, 319B.

[0068] According to some embodiments, the stress release structures 321A, 321B are configured to transfer the stress applied to the magnetoresistive elements 317A, 317B by the material layers (such as the protective layers 319A, 319B, and subsequent formed material layers) above the magnetoresistive elements 317A, 317B to the stress release structures 321A, 321B, thereby releasing the stress applied to the magnetoresistive elements 317A, 317B. Thus, the stress release structure avoids the problems of local cracking and subsequent peeling at the edges of the magnetoresistive pattern by covering the interface between the magnetoresistive element and the protective layer at the edges.

[0069] According to some embodiments, a first barrier material 322 is formed on the substrate 302, the stress release structures 321A, 321B, and the protective layers 319A, 319B, as Figure 3E - 1 shown. According to some embodiments, the first barrier material 322 conformally extends along the upper surface of the dielectric layer 310, the outer surfaces of the stress release structures 321A, 321B, and the upper surfaces (and if there are exposed side surfaces) of the protective layers 319A, 319B. In some embodiments, the first barrier material 322 comprises or is titanium tungsten (TiW), titanium nitride (TiN), titanium (Ti), tantalum nitride (TaN), tantalum (Ta), combinations of the foregoing, or other suitable barrier materials. In some embodiments, the first barrier material 322 is formed by physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable deposition techniques. In some embodiments, the thickness of the first barrier material 322 ranges from about to about

[0070] According to some embodiments, a metal body material 324 is formed over the first barrier material 322, as Figure 3E - 1 shown. In some embodiments, the metal body material 324 comprises or is aluminum copper (AlCu), aluminum silicon copper (AlSiCu), a combination of the foregoing, or other suitable metal materials. In some embodiments, the metal body material 324 is formed by physical vapor deposition (PVD), atomic layer deposition (ALD), electroplating, or other suitable deposition techniques. In some embodiments, the thickness of the metal body material 324 ranges from about to about therein.

[0071] According to some embodiments, a second barrier material 326 is formed over the metal body material 324, as Figure 3E - 1 and Figure 3E - 2 shown. In some embodiments, the second barrier material 326 comprises or is titanium nitride (TiN), titanium (Ti), tantalum nitride (TiN), tantalum (Ta), a combination of the foregoing, or other suitable barrier materials. In some embodiments, the second barrier material 326 is formed by physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable deposition techniques. In some embodiments, the thickness of the second barrier material 326 ranges from about to about

[0072] According to some embodiments, a patterning process 1000 is performed on the second barrier material 326 and the metal body material 324. The patterning process 1000 includes a lithography process to form a mask element 328 (e.g., photoresist) over the upper surface of the second barrier material 326, as Figure 3F - 1 and Figure 3F - 2 shown. According to some embodiments, the pattern of the mask element 328 corresponds to the pattern of the electrical connection structure to be subsequently formed over the magnetoresistances 317A, 317B. In some embodiments, an anti-reflection coating (ARC) may be formed over the upper surface of the second barrier material 326 before forming the mask element 328.

[0073] According to some embodiments, the patterning process 1000 further includes an etching process 1100 on the second barrier material 326 and the metal body material 324 until the upper surface of the first barrier material 322 is exposed, as Figure 3G - 1 and Figure 3G - 2As shown. According to some embodiments, in the etching process 1100, the first barrier material 322 serves as an etch stop layer to protect the underlying magnetoresistances 317A, 317B from being damaged by the etching. In some embodiments, the etching process 1100 can be dry etching, such as ion beam etch (IBE), reactive ion etch (RIE), or other suitable etching techniques.

[0074] According to some embodiments, the etching process 1100 removes the portions of the second barrier material 326 and the metal body material 324 that are not covered by the masking element 328, such that the mask pattern 328 is transferred into the second barrier material 326 and the metal body material 324. According to some embodiments, the remaining second barrier material 326 and metal body material 324 are respectively referred to as the upper barrier layers 327A, 327B and the metal body layers 325A, 325B, where the metal body layer 325B is not shown in Figure 3G - 1 and Figure 3G - 2 . According to some embodiments, the upper barrier layer 327A and the metal body layer 325A correspond to the magnetoresistance 319A, and the upper barrier layer 327B and the metal body layer 325B correspond to the magnetoresistance 319B. According to some embodiments, the upper barrier layer 327A is aligned above the metal body layer 325A, and the upper barrier layer 327B is aligned above the metal body layer 325B.

[0075] According to some embodiments, the patterning process 1000 further includes removing the masking element 328 (e.g., photoresist) using an ashing process, thereby exposing the upper barrier layers 327A, 327B.

[0076] According to some embodiments, using the metal body layers 325A, 325B as an etch mask, a wet etching process 1200 is performed on the first barrier material 322 and the protective layers 319A, 319B until the upper surfaces of the magnetoresistances 317A and 317B and the upper surface of the dielectric layer 310 are exposed, as Figure 3H - 1 and Figure 3H - 2 shown. According to some embodiments, the inner surfaces of the stress release structures 321A, 321B facing the magnetoresistances 317A, 318B are also partially exposed. According to some embodiments, the wet etching process 1200 uses a solution containing hydrogen peroxide (H2O2) to avoid damaging the magnetoresistances 317A and 317B.

[0077] According to some embodiments, the wet etching process 1200 removes portions of the first barrier material 322 and the protective layers 319A, 319B that are not covered by the metal body layers 325A, 325B. According to some embodiments, the remaining first barrier material 322 is referred to as the lower barrier layers 323A and 323B, and the remaining protective layers 319A, 319B are labeled as protective layers 319A', 319B', where the lower barrier layer 323B and the protective layer 319B' are not shown in Figure 3H - 1 and Figure 3H - 2 . According to some embodiments, the lower barrier layer 323A is aligned under the metal body layer 325A, and the lower barrier layer 323B is aligned under the metal body layer 325B. According to some embodiments, the upper barrier layer 327A, the metal body layer 325A, and the lower barrier layer 323A combine to form an electrical connection structure 330A on the magnetoresistive element 317A, and the upper barrier layer 327B, the metal body layer 325B, and the lower barrier layer 323B combine to form an electrical connection structure 330B on the magnetoresistive element 317B.

[0078] According to some embodiments, the electrical connection structure 330A (or 330B) is configured to change the direction of current flow in the magnetoresistive element 317A (or 317B) between the electrical connection structures 330A (or 330B), such that the magnetoresistance value responds linearly to changes in an applied magnetic field. According to some embodiments, the extending direction of the electrical connection structures 330A, 330B and the extending direction of the magnetoresistive elements 317A, 317B may form an angle of about 45 degrees. According to some embodiments, the electrical connection structures 330A, 330B extend laterally beyond the outer surfaces of the stress relief structures 321A, 321B facing away from the magnetoresistive elements 317A, 317B. That is, the electrical connection structures 330A, 330B partially cover the outer surfaces of the stress relief structures 321A, 321B.

[0079] According to some embodiments, by covering the interfaces at the edges between the magnetoresistive elements and the protective layers, the stress relief structures 321A, 321B release the stress applied to the magnetoresistive elements 317A, 317B, thereby avoiding local cracking at the pattern edges of the magnetoresistive elements 317A, 317B. Thus, during the wet etching process 1200, problems such as local peeling at the pattern edges of the magnetoresistive elements as described in the previous Figures 1A - 1D example are avoided.

[0080] According to some embodiments, a passivation layer 332 is formed to cover the dielectric layer 310 and the electrical connection structures 330A, 330B, as shown in Figure 3I - 1 and Figure 3I - 2As shown. Next, an opening 334 is formed through the passivation layer 332 to expose the upper surface of the upper barrier layer 327A of the electrical connection structure 330A, thereby fabricating the magnetoresistive device 300. In some embodiments, the passivation layer 330 comprises or is silicon oxide, silicon nitride, silicon oxynitride, or a combination of the foregoing. In some embodiments, the passivation layer 330 is formed by chemical vapor deposition (CVD).

[0081] According to some embodiments, since there is no tantalum-containing adhesion layer between the magnetoresistances 317A, 318B and the dielectric layer 310, the chemical vapor deposition (CVD) for forming the passivation layer 332 can be performed at a relatively high temperature, such as in the range of about 400 °C to about 450 °C. Performing chemical vapor deposition at a higher temperature to form the passivation layer 332 not only results in a higher deposition rate and better thickness uniformity, but also has fewer undesirable particle manifestations, thereby improving the production efficiency and production yield of the magnetoresistive device.

[0082] In addition, according to some embodiments, after the opening 334 for forming the passivation layer 332, a high-temperature annealing can be performed on the magnetoresistive device 300, such as an annealing temperature in the range of 350 °C to about 450 °C, to improve the characteristics of the magnetoresistances 317A, 318B, such as including increasing the magnetoresistance ratio (MR%) and reducing the sheet resistance (Rsq).

[0083] Figures 4A - 1 to 4H - 1 is a cross-sectional schematic diagram showing a magnetoresistive device including a stress relief structure at various different process stages according to some embodiments; Figures 4A - 2 to 4H - 2 is a top view schematic diagram showing a magnetoresistive device at various different process stages according to some embodiments, wherein Figures 4A - 1 to 4H - 1 are respectively taken along Figures 4A - 2 to 4H - 2 the line I-I in.

[0084] Figures 4A - 1 to 4H - 2 The magnetoresistive device of the embodiment of Figures 3A - 1 to 3I - 2 is substantially similar to the magnetoresistive device of the embodiment of Figures 4A - 1 to 4H - 2 except for the stress relief structure. Figures 3A - 1 to 3I - 2 Components identical to those in the foregoing

[0085] After forming the protective layers 319A, 319B and the magnetoresistances 317A, 317B, a dielectric material 420 is formed over the substrate 302, the magnetoresistances 317A, 317B, and the protective layers 319A, 319B, as shown in Figure 4A - 1 and Figure 4A - 2As shown. In some embodiments, the dielectric material 420 comprises or is silicon oxide, silicon nitride, silicon oxynitride, a combination of the foregoing, or other suitable dielectric materials. In some embodiments, the dielectric material 420 is formed by chemical vapor deposition (CVD) (e.g., low temperature chemical vapor deposition), physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable deposition techniques. In some embodiments, the thickness of the dielectric material 420 ranges from about to about

[0086] According to some embodiments, the dielectric material 420 includes a flat portion 424 extending over the dielectric layer 305, and protrusions 422A, 422B corresponding to and covering the magnetoresistances 317A, 317B. According to some embodiments, the protrusions 422A, 422B protrude above the flat portion 424.

[0087] According to some embodiments, a photoresist material 440 is formed over the dielectric material 420 in its entirety, as Figure 4B - 1 and Figure 4B - 2 shown.

[0088] According to some embodiments, the photoresist material 440 is etched back until the protrusions 422A, 422B of the dielectric material 420 are exposed, as Figure 4C - 1 and Figure 4C - 2 shown. According to some embodiments, after the etch-back process, the remaining photoresist material 440 remains over the flat portion 424 of the dielectric material 420 and is labeled as photoresist material 440'.

[0089] According to some embodiments, an etching process is performed on the dielectric material 420 and the photoresist material 440' until the upper surfaces of the protective layers 319A, 319B are exposed, as Figure 4D - 1 and Figure 4D - 2 shown. According to some embodiments, after the etching process, the remaining dielectric material 420 forms a stress relief structure 421. In some embodiments, the etching process can be dry etching, such as ion beam etching (IBE), reactive ion etching (RIE), or other suitable etching techniques.

[0090] In some embodiments, during the etching process, the photoresist material 440' is completely depleted. According to some embodiments, due to the etch selectivity between the dielectric material 420 and the photoresist material 440', the flat portion 424 of the dielectric material 420 remains on the upper surface of the dielectric layer 310, thereby forming a flat portion 424' of the stress relief structure 421. Furthermore, the etching process removes the protrusions 424A, 424B of the dielectric material 420 above the protective layers 319A, 319B, thereby forming protrusions 426A and 426B of the stress relief structure 421.

[0091] According to some embodiments, the protrusions 426A and 426B protrude above the flat portion 424'. According to some embodiments, the protrusions 426A and 426B each extend laterally in a closed annular manner to surround the side surfaces of the magnetoresistances 317A and 317B. According to some embodiments, the protrusions 426A and 426B completely cover the side surfaces of the magnetoresistances 317A and 317B. That is, the protrusions 426A and 426B extend upward beyond the upper surfaces of the magnetoresistances 317A and 317B to at least partially cover the side surfaces of the protective layers 319A and 319B. According to some embodiments, the protrusions 426A and 426B face the inner surfaces of the magnetoresistances 317A and 317B and abut against the magnetoresistances 317A and 317B and the protective layers 319A and 319B. According to some embodiments, the flat portion 424 extends over the dielectric layer 310 and extends between the protrusion 426A and the protrusion 426B.

[0092] According to some embodiments, a first barrier material 322, a metal body material 324, and a second barrier material 326 are sequentially formed over the stress relief structure 421 and the protective layers 319A and 319B, as Figure 4E - 1 and Figure 4E - 2 shown.

[0093] According to some embodiments, the second barrier material 326 and the metal body material 324 are subjected to the patterning process 1000 as described above with respect to Figures 3F - 1 to 3G - 2 to form the upper barrier layers 327A and 327B and the metal body layers 325A and 325B, as Figure 4F - 1 and Figure 4F - 2 shown. Among them, the metal body layer 325B is not shown in Figure 4F - 1 and Figure 4F - 2 . According to some embodiments, after the ashing process of the patterning process 1000, the upper barrier layers 327A and 327B are exposed.

[0094] According to some embodiments, using the metal body layers 325A and 325B as etch masks, the first barrier material 322 and the protective layers 319A and 319B are subjected to the wet etching process 1200 as described above with respect to Figure 3H - 1 and Figure 3H - 2 until the upper surfaces of the magnetoresistances 317A and 317B and the stress relief structure 421 are exposed, as Figure 4G - 1 and Figure 4G - 2 shown. According to some embodiments, the protrusions 426A and 426B of the stress relief structure 421 facing the side surfaces of the magnetoresistances 317A and 317B are also partially exposed.

[0095] According to some embodiments, after the wet etching process 1200, the remaining first barrier materials 322 are referred to as lower barrier layers 323A and 323B, and the remaining protective layers 319A, 319B are labeled as protective layers 319A, 319B', where the lower barrier layer 323B and the protective layer 319B' are not shown in Figure 4G - 1 and Figure 4G - 2 . According to some embodiments, the upper barrier layer 327A, the metal body layer 325A, and the lower barrier layer 323A combine to form an electrical connection structure 330A on the magnetoresistive element 317A, and the upper barrier layer 327B, the metal body layer 325B, and the lower barrier layer 323B combine to form an electrical connection structure 330B on the magnetoresistive element 317B. According to some embodiments, the electrical connection structures 330A, 330B extend laterally beyond the protrusions 426A, 426B of the stress relief structure 421 and partially cover the upper surface of the flat portion 424' of the stress relief structure 421.

[0096] According to some embodiments, by covering the interfaces of the magnetoresistive elements and the protective layers at the edges, the protrusions 426A, 426B of the stress relief structure 421 release the stress applied to the magnetoresistive elements 317A, 317B, thus avoiding local cracking at the pattern edges of the magnetoresistive elements 317A, 317B. Thereby, during the wet etching process 1200, the problem of local peeling at the pattern edges of the magnetoresistive elements as described in the example of Figures 1A - 1D is avoided.

[0097] According to some embodiments, a passivation layer 332 is formed to cover the substrate 302 and the electrical connection structures 330A, 330B, as shown in Figure 4H - 1 and Figure 4H - 2 . Then, an opening 334 is formed through the passivation layer 332 to expose the upper surface of the upper barrier layer 337A of the electrical connection structure 330A, thereby fabricating the magnetoresistive device 400.

[0098] Figure 5A and Figure 5B are part of a magnetoresistive device according to some embodiments to illustrate some details of the stress relief structure.

[0099] According to some embodiments, in order to completely remove the magnetoresistive material 316 not covered by the masking element, the etching process ([[]] Figure 3B - 1 ) for forming the magnetoresistive elements 317A, 317B further etches the dielectric layer 310 of the substrate 302 to form a platform 510M, as shown in Figure 5A and Figure 5B . According to some embodiments, the aforementioned stress relief structure 321A (or 321B) covers and surrounds the side surface of the platform 510M, as shown in Figures 3A - 1 to 3I - 2 . According to some embodiments, the aforementioned regarding Figure 5A shown in the figure. According to some embodiments, the aforementioned regardingFigures 4A - 1 to 4H - 2 The protrusion 426A (or 426B) of the stress release structure 421 covers and surrounds the side surface of the platform 510M, as Figure 5B shown.

[0100] In summary, according to the embodiments of the present invention, by forming a stress release structure to cover the side surface of the magnetoresistive element, the stress applied to the magnetoresistive element is released, which avoids local cracking at the pattern edge of the magnetoresistive element, and further avoids the problem of local peeling at the pattern edge of the magnetoresistive element. Therefore, the manufacturing yield of the magnetoresistive device is improved.

[0101] In addition, according to the embodiments of the present invention, since there is no tantalum-containing adhesion layer between the magnetoresistive element and the underlying dielectric layer, the process temperature is not limited to below 300°C. Therefore, the magnetoresistive device can be annealed at a high temperature to improve the performance of the magnetoresistive device.

[0102] The above outlines multiple embodiments so that those skilled in the relevant art in the technical field to which the present invention pertains can better understand the viewpoints of the embodiments of the present invention. Those skilled in the relevant art in the technical field to which the present invention pertains should understand that they can design or modify other processes and structures based on the embodiments of the present invention to achieve the same purposes and / or advantages as the embodiments introduced herein. Those skilled in the relevant art in the technical field to which the present invention pertains should also understand that such equivalent processes and structures do not depart from the spirit and scope of the present invention, and they can make various changes, substitutions, and replacements without departing from the spirit and scope of the present invention.

Claims

1. A magnetoresistive device, characterized in that, Comprising: A magnetoresistive element disposed on a substrate; A stress release structure covering one side surface of the magnetoresistive element; An electrical connection structure disposed on the magnetoresistive element; And A passivation layer disposed on the electrical connection structure and the stress release structure.

2. The magnetoresistive device according to claim 1, characterized in that, The inner surface of the stress release structure facing the magnetoresistive element extends upward beyond the upper surface of the magnetoresistive element.

3. The magnetoresistive device according to claim 1, characterized in that, The electrical connection structure covers the outer surface of the stress release structure facing away from the magnetoresistive element.

4. The magnetoresistive device according to claim 1, characterized in that, The stress release structure extends in a closed loop manner to surround the magnetoresistive element.

5. The magnetoresistive device according to claim 1, characterized in that, The stress release structure comprises: A flat portion extending on a dielectric layer of the substrate; A protrusion protruding above the flat portion and abutting against the magnetoresistive element.

6. The magnetoresistive device according to claim 1, characterized in that, The electrical connection structure comprises: A lower barrier layer, a metal main body layer, and an upper barrier layer, stacked in sequence on the magnetoresistive element.

7. The magnetoresistive device according to claim 6, characterized in that, Further comprising: A protective layer disposed between the magnetoresistive element and the lower barrier layer.

8. The magnetoresistive device according to claim 7, characterized in that, One side surface of the protective layer is aligned with the side surface of the magnetoresistive element.

9. The magnetoresistive device according to claim 8, characterized in that, The stress release structure at least partially covers the side surface of the protective layer.

10. The magnetoresistive device according to claim 7, characterized in that, The protective layer is formed of titanium tungsten.

11. The magnetoresistive device according to claim 1, characterized in that, The stress release structure is formed of silicon oxide, silicon nitride, or silicon oxynitride.

12. The magnetoresistive device according to claim 1, characterized in that, The substrate includes a platform, and the stress release structure surrounds the platform.

13. A method for forming a magnetoresistive device, characterized in that, Comprising: Forming a magnetoresistive element on a substrate; Forming a dielectric material on the magnetoresistive element; Etching the dielectric material to form a stress release structure surrounding one side surface of the magnetoresistive element; Forming an electrical connection structure on the magnetoresistive element; And Forming a passivation layer covering the electrical connection structure and the stress release structure.

14. The method for forming a magnetoresistive device as claimed in claim 13, wherein: Etching the dielectric material until the upper surface of the substrate is exposed; The electrical connection structure extends laterally beyond the outer surface of the stress release structure facing away from the magnetoresistive element.

15. The method for forming a magnetoresistive device as claimed in claim 13, wherein, The dielectric material comprises: A flat portion extending on the substrate; and A protruding portion protruding above the flat portion and covering the magnetoresistive element.

16. The method for forming a magnetoresistive device as claimed in claim 15, wherein, Before etching the dielectric material, further comprising: Forming a photoresist material on the dielectric material; and Etching back the photoresist material to expose the protruding portion of the dielectric material and leaving the photoresist material on the flat portion; Wherein after etching the dielectric material, the flat portion remains on the substrate.

17. The method for forming a magnetoresistive device as claimed in claim 13, wherein, The step of forming the magnetoresistive element includes: Forming a magnetoresistive material on the substrate; Forming a protective material on the magnetoresistive material; and Performing a first patterning process on the protective material and the magnetoresistive material to form a protective layer and the magnetoresistive element respectively.

18. The method for forming a magnetoresistive device as claimed in claim 17, wherein, The step of forming the electrical connection structure includes: Depositing a first barrier material on the protective layer and the stress release structure; Depositing a metal main body material on the first barrier material; Depositing a second barrier material on the metal main body material; Performing a second patterning process on the second barrier material and the metal main body material to form an upper barrier layer and a metal main body layer respectively; and Using the metal main body layer as an etching mask to perform a wet etching process on the first barrier material to form a lower barrier layer.

19. The method for forming a magnetoresistive device as claimed in claim 18, wherein, The wet etching process removes a part of the protective layer, exposing the inner surface of the stress release structure facing the magnetoresistive element.

20. The method for forming a magnetoresistive device as claimed in claim 17, wherein, The first patterning process includes: patterning a dielectric layer of the substrate to form a platform, and the stress relief structure covers one side surface of the platform.

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