Thin-layer resistance (TFR) module with a TFR element formed in a metal cup structure

Abstract

A thin-film resistive (TFR) module comprises a metal cup structure, a dielectric region, a TFR element, and a pair of TFR heads electrically connected to the TFR element. The metal cup structure includes a laterally extending metal cup base and multiple metal cup sidewalls extending upwards from the base. The dielectric liner region is formed within an opening defined by the metal cup structure. The TFR element is formed within an opening defined by the dielectric liner region, and is insulated from the metal cup structure by the dielectric liner region.

Description

RELATED PATENT APPLICATION

[0001] This application claims priority to commonly owned U.S. Provisional Patent Application No. 63 / 338,121, filed May 4, 2022, the entire contents of which are hereby incorporated by reference for all purposes. TECHNICAL FIELD

[0002] The present disclosure relates to thin film resistor (TFR) modules formed in integrated circuit (IC) devices, and more particularly to a TFR module including a TFR element formed in a metal can structure. BACKGROUND

[0003] As more and more functions are packed into single semiconductor chips, there is a growing need to incorporate a large number of passive components, such as resistors, into the corresponding integrated circuits. Some resistors can be manufactured by ion implantation and diffusion, such as poly resistors. However, such resistors typically exhibit large variations in resistance and can also have resistance values ​​that change drastically with temperature. A new technique for constructing integrated resistors, so-called thin-film resistors (TFRs), generally improves the performance of integrated resistors. TFRs are often formed from SiCr (silicon-20 chromium), SiCCr (silicon silicon carbide chromium), TaN (tantalum nitride), NiCr (nickel chromium), AINiCr (aluminum-doped nickel chromium), or TiNiCr (titanium nickel chromium).

[0004] The construction of a TFR module in an integrated circuit typically requires several additional photomask layers (masks), e.g., compared to the background / base manufacturing process for the corresponding IC device. As used herein, a "TFR module" may include a TFR element (e.g., a TFR film element), TFR heads, and certain associated structures, e.g., conductive contacts that provide electrical contact to the TFR heads. For example, the construction of a typical TFR module may include three additional mask layers for the manufacturing process: (1) a first additional mask layer to form the TFR heads, a second additional mask layer to form the TFR element, and a third additional mask layer to provide vias for the TFR heads. Each additional mask layer increases the cost of the respective manufacturing process.

[0005] There is a need for improved TFR modules for integrated circuits and their construction methods. For example, TFR modules must be constructed with fewer or no additional mask layers, e.g., compared to an IC manufacturing process, to reduce costs and manufacturing time. Another example is the need for a TFR module with an improved temperature coefficient of thermal conductivity (TCR) in some applications. SUMMARY

[0006] A TFR module may include a TFR element formed within a metal can structure. The TFR element may be spaced apart from (and insulated from) the metal can structure by a dielectric region. The metal can structure may include a laterally extending metal can bottom and a plurality of metal can sidewalls extending upwardly from the laterally extending metal can bottom. The dielectric liner region may be formed within an opening defined by the metal can structure, and the TFR element may be formed within an opening defined by the dielectric liner region, such that the TFR element is insulated from the metal can structure by the dielectric liner region.

[0007] The TFR element may include a laterally extending TFR element base and a plurality of TFR element sidewalls (e.g., one or two pairs of sidewalls) extending upwardly from the laterally extending TFR element base. A pair of TFR heads may each be electrically connected to a pair of TFR element sidewalls, e.g., to a first pair of TFR element sidewalls extending upwardly from a first pair of opposite sides of the laterally extending TFR element base. In some examples, a second pair of TFR element sidewalls (e.g., extending laterally between the pair of TFR heads) may be reduced, e.g., by removing at least a portion of the vertical height of the second pair of TFR element sidewalls.Reducing the sidewall pair extending laterally between the two TFR heads can reduce the variability of the TCR (Temperature Coefficient of Resistance) of the TFR module (here referred to as “TFR TCR”), e.g., by reducing the dependence of the TFR TCR on the lateral width of the TFR element.

[0008] In some examples, the TFR module may optionally include a metal cup structure contact electrically connected to the metal cup structure and spaced from the pair of TFR heads. The contact of the metal cup structure and the TFR heads may be formed in a common metal layer, e.g., an aluminum interconnect layer. In some examples, the contact with the metal cup structure defines a closed perimeter (in a horizontal plane) extending around the pair of TFR heads. In some examples, the contact of the metal cup structure may be electrically grounded, which may reduce noise that may affect the operation of the TFR module.

[0009] In some examples, the TFR module may be constructed without adding further photomask operations to the background / base manufacturing process for the IC device in question. In some examples, the TFR module may be constructed simultaneously with elements of an IC component structure, e.g., interconnect elements or structures for contacting a transistor component or other active element. For example, the metal can structure may be formed simultaneously with interconnect vias or IC component contacts, e.g., by depositing tungsten or another conformal metal into corresponding openings formed in a dielectric region.Another example is that the TFR heads (and the optional metal interconnect structure contact) can be formed in a metallic interconnect element, thus utilizing the existing photomask operations of the background / base manufacturing process for the IC device in question.

[0010] In some examples, the TFR module can be constructed at any depth within an IC device. For example, the TFR module can be constructed between any two metal interconnect layers, between an active region and a metal-1 interconnect layer, or between a shallow trench isolation (STI) field oxide region and a metal-1 interconnect layer.

[0011] One aspect provides a TFR including a metal can structure having (a) a laterally extending insulator can base and (b) a plurality of metal can sidewalls extending upwardly from the laterally extending metal can base; a dielectric liner region formed in an opening defined by the metal cup structure; a TFR element formed in an opening defined by the dielectric liner region, the TFR element being insulated from the metal can structure by the dielectric liner region; and a pair of TFR heads electrically connected to the TFR element.

[0012] In some examples, the TFR element includes (a) a laterally extending TFR element base and (b) a plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base.

[0013] In some examples, the plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base include (a) a first pair of TFR element sidewalls extending upwardly from a first pair of opposing sides of the laterally extending TFR element base, and (b) a second pair of TFR element sidewalls extending upwardly from a second pair of opposing sides of the laterally extending TFR element base. The vertical height of the first pair of TFR element sidewalls may be greater than the vertical height of a portion of the second pair of TFR element sidewalls.

[0014] In some examples, the plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base include a pair of TFR element sidewalls extending upwardly from two opposite sides of the laterally extending TFR element base.

[0015] In some examples, the TFR module includes at least one metal cup structure contact laterally spaced from the pair of TFR heads and electrically connected to the metal cup structure, wherein the at least one metal cup structure contact and the pair of TFR heads are formed in a common metal layer.

[0016] In some examples, the at least one contact of the metal cup structure defines a closed circular circumference in a horizontal plane.

[0017] In some examples, the TFR element includes (a) a laterally extending TFR element base and (b) a pair of TFR element sidewalls extending upwardly from the laterally extending TFR element base, and the pair of TFR heads are electrically connected to the pair of TFR element sidewalls and thereby electrically connected to the TFR element.

[0018] In some examples, the dielectric region of the liner comprises silicon oxide or silicon nitride.

[0019] Another aspect provides a device including an integrated circuit (IC) structure and a TFR module. The IC structure includes a lower IC structure element, at least one IC structure contact formed in a dielectric region and electrically connected to the lower IC structure element, and an upper IC structure element formed in a metal layer and electrically connected to the at least one IC structure contact.The TFR module includes a metal can structure formed in the dielectric region, the metal can structure having (a) a laterally extending metal can base and (b) a plurality of metal can sidewalls extending upwardly from the laterally extending metal can base, a dielectric liner region formed in an opening defined by the metal cup structure, a TFR element formed in an opening defined by the dielectric liner region, the TFR element being insulated from the metal cup structure by the dielectric liner region, and a pair of TFR heads formed in the metal layer and electrically connected to the TFR element. The metal can structure and the at least one IC structure contact may be formed from a common conformal metal deposition (e.g., comprising tungsten).

[0020] In some examples, the TFR element includes (a) a laterally extending TFR element base and (b) a plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base.

[0021] In some examples, the plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base include (a) a first pair of TFR element sidewalls extending upwardly from a first pair of opposing sides of the laterally extending TFR element base, and (b) a second pair of TFR element sidewalls extending upwardly from a second pair of opposing sides of the laterally extending TFR element base. The vertical height of the first pair of TFR element sidewalls may be greater than the vertical height of a portion of the second pair of TFR element sidewalls.

[0022] In some examples, the plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base include a pair of TFR element sidewalls extending upwardly from two opposite sides of the laterally extending TFR element base.

[0023] In some examples, the metal cup structure is formed on a TFR module base formed in a metal interconnect layer.

[0024] In some examples, the metal cup structure is formed on a salicided polysilicon structure.

[0025] In some examples, the metal cup structure is formed on a shallow trench isolation (STI) field oxide layer.

[0026] Another aspect provides a method of manufacturing a TFR module. The method includes forming a well opening in a dielectric region; depositing a conformal metal over the dielectric region and extending into the well opening to form a metal cup structure in the well opening; depositing a dielectric liner over the conformal metal and extending into an opening defined by the metal cup structure; depositing a TFR layer over the dielectric liner extending downward into an opening defined by the dielectric liner to form a cup structure for a TFR element; and performing a planarization process to remove upper portions of the conformal metal, the dielectric liner, and the TFR layer.A remaining portion of the TFR layer defines a TFR element disposed within the metal cup structure and including (a) a laterally extending TFR element base and (b) a plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base. The TFR element is electrically isolated from the metal cup structure by the dielectric liner. The method also includes forming a pair of TFR heads electrically connected to the TFR element.

[0027] In some examples, a remaining portion of the dielectric liner after the planarization process defines a dielectric liner region separating the TFR element from the metal can structure.

[0028] In some examples, the method includes applying a TFR cap layer over the TFR layer extending downward into an opening defined by the TFR element cup structure, wherein the planarization process removes a top portion of the TFR cap layer, with a remaining portion of the TFR cap layer defining a TFR cap region over the TFR element.

[0029] In some examples, the plurality of TFR element sidewalls includes a pair of TFR element sidewalls extending upwardly from a first pair of opposing sides of the laterally extending TFR element base, and the method includes forming the pair of TFR heads in a metal layer over the TFR element, wherein the pair of TFR heads are electrically connected to the pair of TFR element sidewalls.

[0030] In some examples, the plurality of TFR element sidewalls includes (a) a first pair of TFR element sidewalls extending upwardly from a first pair of opposite sides of the laterally extending TFR element base, and (b) a second pair of TFR element sidewalls extending upwardly from a second pair of opposite sides of the laterally extending TFR element base, and the method includes removing at least a partial height of the second pair of TFR element sidewalls and forming the pair of TFR heads electrically connected to the first pair of TFR element sidewalls.

[0031] In some examples, the method includes performing a metal etch to both (a) remove at least a partial height of the second pair of TFR element sidewalls and (b) form the pair of TFR heads electrically connected to the first pair of TFR element sidewalls.

[0032] In some examples, the method includes forming a metal layer including (a) the pair of TFR heads electrically connected to the TFR element, and (b) at least one contact of the metal cup structure laterally spaced from the pair of TFR heads and electrically connected to the metal cup structure.

[0033] In some examples, the method includes simultaneously forming the well opening and a via opening in the dielectric region, depositing the conformal metal over the dielectric region and extending into the well opening to connect the metal can structure in the well opening and extending into the via opening to form an interconnect via in the via opening, and forming a metal layer including (a) the pair of TFR heads electrically connected to the TFR element and (b) an interconnect element electrically connected to the via opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Exemplary aspects of the present disclosure are described below in conjunction with the figures: Fig. 1A is a top view and the Fig. 1B and Fig. 1C are two side cross-sectional views of an exemplary TFR module; Fig. 2A is a plan view and Fig. Figure 2B is a side cross-sectional view showing an example IC structure incorporating the example TFR module of the Fig. 1A-1C and includes an example connection structure that can be formed simultaneously according to an example; and the Fig. 3A-3J show an exemplary method for forming the Fig. 2A-2B, including the exemplary TFR module and the exemplary interconnect structure; and Fig. 4 is a side sectional view showing an exemplary IC structure including an exemplary TFR module and an exemplary interconnect structure formed on a silicided polysilicon layer; Fig. 5 is a side cross-sectional view showing an exemplary IC structure incorporating an exemplary TFR module constructed in a pre-metallic dielectric (PMD) region between a field oxide and a metal 1 layer; Fig. 6 is a side cross-sectional view showing an exemplary IC structure including an exemplary TFR module constructed in a PMD region between an active region and a metal 1 layer; and Fig. 7A is a top-down view and Fig. 7B and Fig. 7C are two side cross-sectional views of an exemplary TFR module; it should be understood that the reference numerals for each illustrated element that appears in multiple different figures have the same meaning in all figures, and that mention or discussion of an illustrated element in the context of a particular figure also applies to any other figure in which the same illustrated element is shown. DETAILED DESCRIPTION

[0035] The Fig. 1A-1C show an example of a TFR module 100 according to the present disclosure. In particular, Fig. 1A a top view of the TFR module 100, Fig. Figure 1B shows a first lateral cross-sectional view through the Fig. 1A shown section line 1B-1B and Fig. Figure 1C shows a second side cross-sectional view through the Fig. 1A, section line 1C-1C. As shown, the TFR module 100 includes a metal can structure 102, a dielectric liner region 104 formed in an opening defined by the metal can structure 102, a TFR element 106 formed in an opening defined by the dielectric liner region 104, and a pair of TFR heads 108a and 108b electrically connected to the TFR element 106. The metal cup structure 102 includes a laterally extending metal can base 110 and a plurality of metal can sidewalls 112a-112d extending upwardly from the laterally extending metal cup base 110. As shown in Fig. 1A, the side walls 112a-112d of the metal cup define a closed rectangular perimeter in the xy plane.

[0036] The TFR element 106 is physically separated from the metal can structure 102 by the dielectric region 104, thereby electrically isolating the TFR element 106 from the metal can structure 102. In some examples, the dielectric region 104 comprises silicon oxide or silicon nitride.

[0037] A TFR capping layer region 120 may be formed over the TFR element 106. The TFR capping layer region 120 may comprise silicon nitride, silicon oxide, or another suitable material to protect the underlying TFR element 106 from certain manufacturing processes, e.g., a chemical mechanical planarization (CMP) process (e.g., as described below with reference to the Fig. 3F and Fig. 3G) and / or a metal etching process (e.g. as described below with reference to Fig. 3H-3J explained).

[0038] In the illustrated example, the TFR element 106 includes a laterally extending TFR element base 116 and a plurality of TFR element sidewalls 118 that extend upwardly from the laterally extending TFR element base, for example, from opposite lateral sides of the laterally extending TFR element base. In some examples, the TFR element 106 includes (a) a first pair of TFR element sidewalls 118a and 118c that extend upwardly from a first pair of opposite sides of the laterally extending TFR element base 116, and (b) a second pair of TFR element sidewalls 118b and 118d that extend upwardly from a second pair of opposite sides of the laterally extending TFR element base 116, wherein the second pair of opposite sides are orthogonal to the first pair of opposite sides. In some examples, the second pair of TFR element sidewalls 118b and 118d may be reduced, e.g.,B. to improve the TCR performance of the TFR module 100, as described below. As used herein, "lowering" the second pair of TFR element sidewalls 118b and 118d may include at least partially or completely removing a vertical height (in the z-direction) of each TFR element sidewall 118b and 118d along at least a partial lateral length (in the x-direction) of each TFR element sidewall 118b and 118d. As explained below, in some examples, the TFR element sidewalls 118b and 118d may each include a partial section aligned below the TFR heads 108a and 108b, in . Fig. 1A as TFR element sidewall portions 118b' and 118d', which may remain intact after an etch that partially or completely removes the other portions of the TFR element sidewalls 118b and 118d (i.e., portions of the TFR element sidewalls 118b and 118d that are not aligned below the TFR head 108a or 108b).

[0039] In some examples, the second pair of TFR element sidewalls 118b and 118d may be partially removed, e.g., by a metal etching process, such that a vertical height of the second pair of TFR element sidewalls 118b and 118d (e.g., excluding the TFR element sidewall portions 118b' and 118d') is less than a vertical height (z-direction) of the first pair of TFR element sidewalls 118a and 118c. In other examples, the second pair of TFR element sidewalls 118b and 118d (e.g., with the exception of the TFR element sidewall portions 118b' and 118d') may be completely removed, e.g., by an etching process, such that the TFR element 106 includes only the first pair of TFR element sidewalls 118a and 118c (and, in some examples, the unremoved TFR element sidewall portions 118b' and 118d'). Fig. 1A and 1C together show an example of (optionally) vertically shortened TFR element sidewalls 118b and 118d, indicated by dashed lines, although in other examples the TFR element sidewalls 118b and 118d may be completely removed, as described above.

[0040] In some examples, the sidewalls of the TFR elements 118b and 118d may be reduced, e.g., as described above, by a metal etching process used to form the TFR heads 108a and 108b (and the optional metal can structure contacts 134 discussed further below).

[0041] As previously mentioned, reducing the second pair of TFR element sidewalls 118b and 118d can improve the TCR performance of the TFR module 100. It is known that ribs or other protrusions extending from a TFR element, e.g., between the two TFR heads, can provide undesirable effects on the TCR of the respective TFR module. For example, laterally extending sidewalls 118b and 118d extending upward from the TFR element 116 can affect the TCR of the TFR module 100 depending on the lateral width of the TFR element 106 in the y-direction. Thus, in some examples, reducing the second pair of TFR element sidewalls 118b and 118d may reduce variability in the TCR of the TFR module 100, e.g., by reducing the dependence of the TCR on the width of the TFR element 106 in the y-direction.

[0042] As in the Fig. 1A and 1B, the pair of TFR heads 108a and 108b may be formed on the respective top surfaces of the pair of TFR element sidewalls 118a and 118c such that the TFR heads 108a and 108b are electrically connected to the TFR element sidewalls 118a and 118c and thus electrically connected to the TFR element 106.

[0043] In some examples, the metal cup structure 102 is formed over a liner (or "adhesive layer") 124, which may comprise, for example, TiN with a thickness in the range of 50Å-200Å. In some examples, the metal cup structure 102 (including the adhesive layer 124) is formed on a TFR module base 130. As shown in the Fig. 3A-3J, the base of the TFR module 130 may include a metal element formed in a metal interconnect layer. In other examples, e.g., as shown in Fig. 4, the TFR module base 130 may comprise a silicided polysilicon structure including a polysilicon region with a layer or region of metal silicide formed thereon. In other examples, e.g., as shown in Fig. 5 below, the base of the TFR module 130 may be formed on a shallow trench oxide (STI) layer.

[0044] In some examples, the TFR module 100 includes at least one metal cup structure contact 134 electrically connected to the metal cup structure 102 and laterally spaced from the pair of TFR heads 108a and 108b. In some examples, the metal cup structure contact 134 and the pair of TFR heads 108a and 108b are formed in a common (i.e., the same) metal layer, e.g., a metal interconnect layer comprising aluminum or another suitable metal.

[0045] In the illustrated example, e.g. as in Fig. 1A, the TFR element 106 includes a metallic cup structure contact 134 that defines a closed rectangular perimeter (in the horizontal xy plane) extending around the pair of TFR heads 108a and 108b. In some examples, e.g., as in Fig. 1B, the metal can structure contact 134 may be grounded by suitable conductive elements connected to the metal can structure contact 134, thereby reducing noise that may affect the operation of the TFR module 100.

[0046] In some examples, the TFR module 100 may be constructed without adding additional photomask operations to the integrated circuit manufacturing process, as explained in more detail below.

[0047] The Fig. 2A and Fig. 2B show an exemplary IC device 200 that implements the Fig. 1A-1B and an exemplary IC structure 202 formed concurrently according to an example. In particular, Fig. 2A is a top view of the exemplary IC device 200, and Fig. 2B shows a side cross-sectional view of the exemplary IC device 200 through the Fig. 2A shown section line 2B-2B.

[0048] As mentioned above, the TFR module 100 can be constructed without adding additional photomask operations to the background / base manufacturing process for forming the IC structure 202.

[0049] As mentioned above, the TFR module 100 includes a metal cup structure 102, a dielectric liner region 104, a TFR element 106 formed within the metal cup structure 102 and insulated from the metal cup structure 102 by the dielectric liner region 104, a pair of TFR heads 108a and 108b, and optionally a metal cup structure contact 134. A TFR cap layer region 120 may be formed over the TFR element 106. The metal cup structure 102 includes a laterally extending metal cup base 110 and a plurality of metal cup sidewalls 112a-112d extending upwardly from the laterally extending metal cup base 110 and defining a closed rectangular perimeter in the xy plane. As already mentioned, the metal cup structure 102 may be formed over a liner 124 comprising, for example, TiN, and may be formed on a TFR module base 130 or other suitable structure (e.g.on an STI field oxide layer).

[0050] The TFR element 106 includes a laterally extending TFR element base 116 and a plurality of TFR element sidewalls 118 extending upwardly from the laterally extending TFR element base. As described above, the TFR element 106 includes the first pair of TFR element sidewalls 118a and 118c extending upwardly from the first pair of opposite sides of the laterally extending TFR element base 116, and may optionally include the second pair of TFR element sidewalls 118b and 118d extending upwardly from the second pair of opposite sides of the laterally extending TFR element base 116, wherein the second pair of opposite sides are orthogonal to the first pair of opposite sides. As described above, in some examples, the second pair of TFR element sidewalls 118b and 118d may be reduced (e.g.,by partially or completely removing the height of the TFR element side walls 118b and 118d), which can reduce the variability of the TFR TCR.

[0051] As in Fig. 2B, the IC structure 202 may include a lower IC structure element 204 formed in the lower metal layer M x is formed, at least one IC structure contact 206 which is electrically connected to the lower IC structure element 204, and an upper IC structure element 210 which is formed in the upper metal layer M x+1 formed and electrically connected to the at least one IC structure contact 206. In this example, the lower IC structure element 204 has a lower connection element 204 formed in the lower metal layer M x is formed, the at least one IC structure contact 206 has vias 206 which are formed in the via layer V xare formed (e.g., by depositing a conformal via material, e.g., tungsten, into the respective via openings) and are electrically connected to the lower connecting element 204, and the upper IC structure element 210 has an upper connecting element 210 formed in the upper metal layer M x+1 formed and electrically connected to the vias 206.

[0052] Both the lower connecting element 204 and the upper connecting element 210 may comprise a wire or other lateral elongated structure or a discrete pad (e.g., having a rectangular or substantially rectangular shape in plan view) or any other suitable shape and structure.

[0053] The lower connecting element 204 and the base of the TFR module 130 can be simultaneously formed in the lower metal layer M xThe upper connecting element 210, the TFR heads 108a and 108b and the (optional) metal cup structure contact 134 can be formed simultaneously in the upper metal layer M x+1 The metal cup structure 102, the dielectric liner region 104, the TFR element 106 and the TFR cap layer 120 can be formed in the via layer Vx between the lower metal layer Mx and the upper metal layer M x+1 be formed, e.g. using a Damascene process, as described below with regard to the Fig. 3A-3H. As explained below in Fig. 3B, the vias 206 and the metal can structure 102 may be formed simultaneously by depositing a conformal via material, e.g., tungsten, into the corresponding openings in the dielectric region 122.

[0054] As used herein, a “metal layer”, e.g. in connection with the lower metal layer M xand the upper metal layer M x+1 , any metallic or metallized layer or layers, including (a) a metallic interconnect layer containing, for example, copper, aluminum, or another metal applied by a subtractive patterning process (e.g., applying, patterning, and etching a metal layer) or applied by a damascene process, or (b) a silicided polysilicon layer containing, for example, a number of polysilicon regions each having a layer or region of metal silicide formed thereon. In some examples, the lower metal layer M x be a silicided polysilicon layer and the upper metal layer M x+1 may have a first metallic interconnect layer, often referred to as Metal-1. In such examples, x=0, so that the lower metal layer M x = M0 and the upper metal layer M x+1= M1 (ie metal-1).

[0055] The Fig. 3A-3J show an exemplary method for forming the Fig. 2, which includes an example TFR module 100 and an example interconnect structure 202. In other examples, the interconnect structure 202 may be optional, such that the TFR module 100 may be formed without the elements of the interconnect structure 202 by the process described below.

[0056] As in Fig. 3A, the lower connecting element 204 and the base of the TFR module 130 are in the lower metal layer M x In this example, the lower metal layer M x have a metallic connecting layer, wherein the lower connecting element 204 and the TFR module base 130 are each formed as metal elements (e.g., aluminum elements). In another example, e.g., as in Fig. 4, the lower metal layer M x have a silicided polysilicon layer, wherein the lower interconnect element 204 and the TFR module base 130 each have a silicide region formed on a corresponding polysilicon structure.

[0057] The dielectric region 122 (e.g., an Inter Metal Dielectrics (IMD) region or a Poly Metal Dielectrics (PMD) region) is formed over the lower interconnect element 204 and the TFR module base 130, wherein the lower interconnect element 204 and the TFR module base 130 are formed in the lower metal layer M x The dielectric region 122 may include one or more dielectric materials, e.g., silicon oxide, PSG (phosphosilicate glass), or FSG (fluorine-doped glass), or a combination thereof.

[0058] Via layer openings 300, including interconnect vias 302 and a well opening 304, may be patterned (using a photomask) and etched into the dielectric region 122. The via layer openings 300 may be formed using a plasma etching process or other suitable etching process, followed by resist stripping or other suitable process to remove the remaining portions of the photoresist material. The etching process for forming the via layer openings 300 may be a selective etch that ends on the lower interconnect element 204 and the TFR module base 130 (e.g., made of aluminum or another metal). Thus, the TFR module base 130 may serve as an etch stop for the formation of the well opening 304.

[0059] Interconnect via openings 302 may be via openings having a width (or diameter or critical dimension (CD)) W via both in the x-direction and in the y-direction in the range of, for example, 0.1-0.5 um.

[0060] In contrast, the tub opening 304 can have a much larger width in the x-direction (W tub_x ) and / or y-direction (W tub_y ) than the interconnect via openings 302. The shape and dimensions of the well opening 304 may be selected based on various parameters, e.g., for effective manufacturing of the TFR module 100 (e.g., effective formation of the metal cup structure 102, the dielectric liner region 104, the TFR element 106, and the TFR cap layer region 120 in the well opening 304) and / or for the desired performance characteristics of the resulting TFR module 100. In one example, e.g., as shown in Fig. 3A, the tub opening 304 may have a square or rectangular shape in plan view.

[0061] As already mentioned, the width of the tub opening 304 in the x-direction (W tub_x ), y-direction (W tub_y ) or in both the x and y directions (W tub_x and W tub_y ) be significantly larger than the width W via of the interconnect via openings 302 in the x-direction, y-direction, or both the x- and y-direction. In some examples, for example, the width W tub_x and W tub_y the tub opening 304 is at least twice as large as the width W via of the interconnect via openings 302. In certain examples, the widths W tub_x and W tub_y the tub opening 304 is at least five times as large or at least ten times as large as the width W via the interconnect via openings 302. In some examples, W tub_x and Wtub_y each in the range of 1-100 µm.

[0062] Furthermore, the tub opening 304 can be formed in both the x- and y-directions with a height-to-width ratio of less than or equal to 1.0, e.g., to enable effective filling of the tub opening 304 with conformal materials. The tub opening 304 can, for example, be formed with an aspect ratio H tub / W tub_x and H tub / W tub_y in the range of 0.01-1.0, e.g. in the range of 0.1-1.0. In some examples, the aspect ratios H tub / W tub_x and H tub / W tub_y less than or equal to 1.0, e.g., to effectively fill the well opening 304 with various materials to form the molding structure 102, the dielectric liner region 104, the TFR element 106, and the TFR cap layer 120 in the well opening 304. The well opening 304 may, for example, have an aspect ratio H tub / Wtub_x or H tub / W tub_y in the range of 0.1-1.0 or in particular in the range of 0.5-1.0.

[0063] Next, as in Fig. 3B, the liner 124, comprising, for example, TiN with a thickness in the range of 50Å-200Å, is applied to the structure and extends into the respective via layer openings 300. A conformal metal 310 is applied to the metal layer 124 and extends into the respective via layer openings 300 to (a) fill the interconnect via openings 302 and form corresponding vias 206 and (b) form the metal cup structure 102, which includes a laterally extending metal cup base 110 and metal cup sidewalls 112a-112d that extend upwardly from the lateral peripheral edges of the laterally extending metal cup base 110 and define a closed rectangular perimeter in the xy plane. The sidewalls 112a and 112c of the metal cup are shown in the cross-sectional view of Fig. 3B, while the side walls 112b and 112d of the metal cup are outside the plane of the Fig. 3B and are therefore not shown.

[0064] In one example, the conformal metal 310 comprises tungsten deposited to a thickness in the range of 1000Å-5000Å. In other examples, the conformal metal 310 may comprise Co, TiN, or another conformal metal. The conformal metal 310 may be deposited by conformal chemical vapor deposition (CVD) or another suitable vapor deposition process.

[0065] Next, as in Fig. 3C, a dielectric liner 320 is applied to the conformal metal 310 and extends into an opening 322 defined by the cup-shaped molding structure 102 to form the cup-shaped dielectric region 104 in the opening 322. In some examples, the dielectric liner 320 comprises silicon oxide, silicon nitride, or other conformal dielectric material and may have a thickness T DL in the range of 2000Å-5000Å. In some examples, the dielectric liner 320 may be deposited using a plasma-enhanced chemical vapor deposition (PECVD) process.

[0066] Next, as in Fig. 3D, a TFR layer (or film) 330 is deposited over the dielectric liner 320 and extends downward into an opening 332 through the cup-shaped region of the dielectric liner 104 to form a cup-shaped TFR layer structure 334 including (a) a laterally extending TFR element base 116 and (b) TFR element sidewalls 118a-118d extending upward from the laterally extending TFR element base 116. In this example, the TFR element sidewalls 118a-118d extend upward from the respective lateral peripheral edges of the laterally extending TFR element base 116. In some examples, the TFR layer 330 comprises SiCCr, SiCr, NiCr, TaN, TiN, or another TFR material and may be deposited, for example, by physical vapor deposition (PVD) with a thickness in the range of 50Å-1000Å.In some examples, such a TFR layer 330 may provide a sheet resistance of about 1 kΩ / square, e.g., for use in analog applications.

[0067] In some examples, the TCR of the TFR layer may be modified or "tuned" to a value closer to zero, e.g., to a value in the range of -100 ppm / °C to +100 ppm / °C, in the range of -50 ppm / °C to +50 ppm / °C, or in the range of -10 ppm / °C to +10 ppm / °C, to thereby reduce the temperature sensitivity of the performance of the final TFR module 100. In examples where the TFR element 106 is built in a PMD region prior to forming a Metal 1 layer (e.g., in the Fig. 4-6), the TFR layer 330 may be annealed (bringing the TCR value of the TFR layer 330 closer to zero) by heating the TFR layer 330 in a temperature-controlled process at an elevated temperature, e.g., in the range of 250°C to 600°C.

[0068] Next, as in Fig. 3E, a TFR cap layer 340 is applied over the TFR layer 330, extending into and filling an opening 342 defined by the cup-shaped TFR layer structure 334. In some examples, the TFR cap layer 340 may comprise silicon nitride, silicon oxide, or another suitable material to protect the underlying TFR layer 330 (in particular, the cup-shaped TFR layer structure 334) during subsequent processes, e.g., during the CMP process, which is described further below with reference to FIG. Fig. 3F and Fig. 3G, and during metal etching, which is discussed below with reference to the Fig. 3H-3J is discussed.

[0069] Next, as in the Fig. 3F and Fig. 3G, a planarization process, e.g., a chemical mechanical planarization (CMP) process, is performed to remove upper portions of the TFR cap layer 340, the TFR layer 330, the dielectric liner 320, the conformal metal 310, and the liner 124. Fig. Figure 3F shows a top view of the resulting structure after the planarization process, and Fig. Figure 3G shows a lateral cross-section through the Fig. Line 3G-3G shown in Figure 3F. The planarization process forms a planarized upper surface 350 of the via layer V x The dielectric liner 320 can protect portions of the underlying TFR layer, including the laterally extending TFR element base 116, from the planarization process. A portion of the dielectric liner 320 remaining after the planarization process defines the dielectric liner region 120.

[0070] Next, as in the Fig. 3H, Fig. 31 and Fig. 3J, an upper metal layer (M x+1 -layer) on the planarized upper surface 350 of the via layer V x trained. Fig. Figure 3H shows a top view of the resulting structure after forming the top metal layer, Fig. Figure 3I shows a side cross-sectional view through line 3I-3I in Fig. 3H and Fig. Figure 3I shows a side cross-sectional view through line 3J-3J in Fig. 3H. In the upper metal layer M x+1Various metal elements 360 may be formed, including (a) the upper interconnect element 210, which is electrically connected (e.g., by direct contact) to the interconnect vias 206, (b) the TFR heads 108a and 108b, which are electrically connected (e.g., by direct contact) to the TFR element sidewalls 118a and 118c, respectively, and (c) the optional metal cup structure contact 134, which is electrically connected (e.g., by direct contact) to the metal cup structure 102 and optionally connected to ground. The upper metal layer M x+1 may contain aluminum or other suitable metal.

[0071] In some examples, the metal elements 360 may be formed by depositing a metal (e.g., aluminum) on the planarized top surface 350, forming and patterning a photomask over the deposited metal, and performing a metal etch to remove portions of the deposited metal not covered by the patterned photomask. In some examples, the metal etch may extend over the top metal layer M x+1continue beyond (downward) to reduce the sidewalls of the TFR elements 118b and 118d, e.g., by removing at least a portion of the vertical height of the sidewalls of the TFR elements 118b and 118d that are not protected by the overlying TFR heads 108a and 108b. In some examples, these unprotected portions of the TFR element sidewalls 118b and 118d (i.e., not aligned below the TFR head 108a or 108b) are partially removed by the metal etching, leaving vertically shortened TFR element sidewalls 118b and 118d, e.g., as in Fig. 3.) In other examples, the unprotected portions of the TFR element sidewalls 118b and 118d are completely removed by the metal etch, so that the resulting TFR element 106 includes only a pair of TFR element sidewalls 118a and 118c extending upward from the laterally extending TFR element base 116, and in some examples, protected portions of the TFR element sidewalls 118b' and 118d' (i.e., portions of the TFR element sidewalls 118b and 118d aligned below the TFR heads 108a and 108b). The dielectric liner region 120 may protect the underlying, laterally extending TFR element base 116 from etching.

[0072] As mentioned above with regard to the Fig. 1A-1C, reducing the second pair of TFR element sidewalls 118b and 118d can improve the TCR performance of the TFR element 106, e.g., by reducing its dependence on the width of the TFR element 106 in the y-direction. Thus, the TCR performance of the TFR module 100 can be improved by both (a) performing an anneal, as discussed above with respect to Fig. 3D, and (b) the second pair of TFR element sidewalls 118b and 118d is reduced, e.g., during the metal etching required to form the upper metal layer M x+1 is used.

[0073] The optional metal cup structure contact 134 may be laterally spaced from the pair of TFR heads 108a and 108b. As shown in Fig. As shown in Figure 3I, the contact of the metal cup structure 134 may be spaced from the pair of TFR heads 108a and 108b by a minimum lateral distance (or "critical dimension" - CD) sufficient to avoid electrical short circuits, considering dimensional deviations resulting from typical process variations. In some examples, the dielectric liner 320 is deposited with a sufficient thickness (e.g., 2500Å-5000Å) to have a defined minimum lateral width W DL The minimum lateral width W DL may be selected such that the contact 134 of the metal can structure (in contact with the underlying metal can sidewalls 112a-112d) is spaced at least the minimum lateral distance CD from the TFR heads 108a and 108b (respectively in contact with the underlying TFR element sidewalls 118a and 118c).

[0074] In the Fig. 3H-3I, the contact of the metal cup structure 134 defines a closed rectangular perimeter (in the horizontal xy plane) that extends around the TFR heads 108a and 108b (e.g., completely around them). In some examples, as in Fig. 3I, the contact 134 of the metal can structure may be grounded by suitable conductive elements connected to the contact 134 of the metal can structure, thereby reducing noise that may affect the operation of the TFR module 100.

[0075] Fig. 4 is a side cross-sectional view of an IC device 400 including a TFR module 402 and an exemplary interconnect structure 404 formed on a lower metal layer Mo comprising a silicided polysilicon layer. The TFR module 402 may include a metal can structure 102, a dielectric liner region 104, a TFR element 106 formed within the metal can structure 102 and insulated from the metal can structure 102 by the dielectric liner region 104, a pair of TFR heads 108a and 108b, and optionally a metal can structure contact 134. A TFR cap layer region 120 may be formed over the TFR element 106. The metal can structure 102 may be formed over the liner 124 and formed on a TFR module base 406.

[0076] In this example, a lower interconnect element 408 of the interconnect structure 404 and the TFR module base 406 may each include a metal silicide region formed on a corresponding polysilicon region. Specifically, the lower interconnect element 408 may include a first metal silicide region 422a formed on a first polysilicon region 420a, and the TFR module base 406 may include a second metal silicide region 422b formed on a second polysilicon region 420b. In some examples, regions 422a and 422b may include metal silicides such as titanium silicide, cobalt silicide, or nickel silicide.In this example, the metal can structure 102, the dielectric liner region 104, the TFR element 106, and the TFR cap layer 120 may be formed in a via layer (or contact layer) V0 that includes a pre-metal dielectric (PMD) region 422, and the top interconnect element 210, the TFR heads 108a and 108b, and the (optional) metal can structure contact 134 may be formed simultaneously in a metal 1 (M1) interconnect layer, e.g., made of aluminum. In some examples, the PMD region 422 may include silicon oxide, phosphosilicate glass (PSG), or borophosphosilicate glass (BPSG).

[0077] In another embodiment, the TFR module 402 may be formed on a non-silicided region of polysilicon. With reference to Fig. 4, for example, the second metal silicide region 422b may be omitted and the metal cup structure 102 of the TFR module 402 may be formed directly on the polysilicon region 420b.

[0078] Fig. 5 is a side cross-sectional view showing another exemplary IC device 500 including an exemplary TFR module 502 and an exemplary IC structure 504 formed between (a) a lower layer L including an active region 508 and an STI field oxide region 510, and (b) a metal 1 layer M1. The active region 508 may include a doped silicon region formed adjacent to the field oxide region 510 over a silicon substrate 512.

[0079] The exemplary IC structure 504 includes a lower IC structure element 520, at least one IC structure contact 506 electrically connected to the lower IC structure element 520, and an upper IC structure element 210 formed in the Metal 1 layer M1 and electrically connected to the at least one IC structure contact 506. In this example, the lower IC structure element 520 comprises a silicided polysilicon element formed on the active area 508, the at least one IC structure contact 506 comprises vertically extending contacts 506 electrically connected to the underlying silicided polysilicon element 520, and the upper IC structure element 210 comprises an interconnect element 210 formed in the Metal 1 layer M1 and electrically connected to the vertically extending contacts 506. The vertically extending contacts 506 are formed in a PMD region 514, which, for example,Silicon oxide, PSG, or BPSG, as described above with respect to the vias 206. The silicided polysilicon element 520 may include a region 524 of metal silicide (e.g., titanium silicide, cobalt silicide, or nickel silicide) formed on a polysilicon region 522, e.g., a polygate of a transistor.

[0080] The TFR module 502 may include a metal cup structure 102, a dielectric liner region 104, a TFR element 106 formed within the metal cup structure 102 and insulated from the metal cup structure 102 by the dielectric liner region 104, a pair of TFR heads 108a and 108b electrically connected to the TFR element 106, and optionally a metal cup structure contact 134 electrically connected to the metal cup structure 102. A TFR cap layer region 120 may be formed over the TFR element 106. The metal cup structure 102 may be formed over the liner 124.

[0081] As shown, the metal cup structure 102 (and the liner 124) can be formed directly on the region of STI field oxide 510 such that the region of STI field oxide 510 defines a TFR module base 540.

[0082] In some examples, an optional etch stop layer 530, e.g., comprising silicon nitride with a thickness in the range of 250Å-750Å, may be formed over the STI field oxide region 510 and extend over the silicided polysilicon element 520. The optional etch stop layer 530 may control the depth of an etch used to form corresponding openings in the PMD region 514 for forming the vertically extending contacts 506 and the metal cup structure 102. In some examples, the vertically extending contacts 506 and the metal cup structure 102 may be formed simultaneously by depositing tungsten or another conformal metal in the respective openings in the PMD region 514, optionally over a liner 124.

[0083] Fig. 6 is a side cross-sectional view showing an example IC device 600 including the example TFR module 502 and the example IC structure 504 of the example IC device 500 described above. However, in this example, the TFR module 502 is formed on an active region 602, e.g., a doped silicon region adjacent to the STI field oxide region 510. In some examples, the active region 602 is silicided, with an optional metal silicide region 604 (e.g., comprising titanium silicide, cobalt silicide, or nickel silicide) formed on the active region 602, and the metal can structure 102 of the TFR module 502 formed on the metal silicide region 604. In other examples, the active region 602 is not silicided, and the metal can structure 102 is formed directly on the active region 602 (e.g., doped silicon region), which thus defines the base of the TFR module.

[0084] Fig. 7A is a plan view and Fig. 7B and Fig. 7C are two side cross-sectional views of an exemplary TFR module 700. In particular, Fig. 7A is a plan view of the TFR module 700, Fig. Figure 7B shows a first lateral cross-sectional view through the Fig. 7A shown section line 7B-7B and Fig. Figure 7C shows a second side cross-sectional view through the Fig.7A. As shown, the TFR module 700 includes (a) a metal can structure 102 having a laterally extending metal can base 110 and a plurality of metal can sidewalls 112a-112d extending upwardly from the laterally extending metal can base 110, (b) a dielectric liner region 104 formed in an opening defined by the metal cup structure 102, (c) a TFR element 106 formed in an opening defined by the dielectric liner region 104, the dielectric liner region 104 isolating the TFR element 106 from the metal can structure 102, and the pair of TFR heads 108a and 108b electrically connected to the TFR element 106. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 338,121

[0001]

Claims

[1] Thin film resistor (TFR) module comprising: a metal cup structure including (a) a laterally extending metal cup base and (b) a plurality of metal cup sidewalls extending upwardly from the laterally extending metal cup base; a dielectric liner region formed in an opening defined by the metal cup structure; a TFR element formed in an opening defined by the dielectric liner region, the TFR element being insulated from the metal can structure by the dielectric liner region; and a pair of TFR heads electrically connected to the TFR element. [2] The TFR module of claim 1, wherein the TFR element includes (a) a laterally extending TFR element base and (b) a plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base. [3] The TFR module of claim 2, wherein the plurality of laterally extending TFR element sidewalls include: a first pair of TFR element sidewalls extending upwardly from a first pair of opposite sides of the laterally extending TFR element base; and a second pair of TFR element sidewalls extending upwardly from a second pair of opposite sides of the laterally extending TFR element base; wherein a vertical height of the first pair of TFR element sidewalls is greater than a vertical height of a portion of the second pair of TFR element sidewalls. [4] The TFR module of claim 2, wherein the plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base includes a pair of TFR element sidewalls extending upwardly from two opposite sides of the laterally extending TFR element base. [5] The TFR module of claim 1, comprising at least one metal can structure contact laterally spaced from the pair of TFR heads and electrically connected to the metal can structure; wherein the at least one metal can structure contact and the pair of TFR heads are formed in a common metal layer. [6] The TFR module of claim 5, wherein the at least one metal cup structural contact defines a closed perimeter in a horizontal plane. [7] TFR module according to claim 1, wherein: the TFR element includes (a) a laterally extending TFR element base and (b) a pair of TFR element sidewalls extending upwardly from the laterally extending TFR element base; and the pair of TFR heads are electrically connected to the pair of TFR element sidewalls and thereby electrically connected to the TFR element. [8] The TFR module of claim 1, wherein the dielectric region of the liner comprises silicon oxide or silicon nitride. [9] Device comprising: an integrated circuit (IC) structure comprising: a lower IC structural element; and at least one IC structural contact formed in a dielectric region, the IC structural contact being electrically connected to the lower IC structural element; and an upper IC structural element formed in a metal layer, the upper IC structural element being electrically connected to the at least one IC structural contact; and one of the thin film resistor (TFR) modules according to claims 1 to 8, where: the metal cup structure is formed in the dielectric region; the metal cup structure and the at least one IC structure contact are formed from a conformal metal; and the pair of TFR heads is formed in the metal layer. [10] The device of claim 9, wherein the metal cup structure is formed on a TFR module base formed in a metal interconnect layer. [11] The device of any one of claims 9 to 10, wherein the metal cup structure is formed on a salicided polysilicon structure. [12] The device of any one of claims 9 to 11, wherein the metal cup structure is formed on a shallow trench isolation (STI) oxide layer. [13] Method comprising: Forming a well opening in a dielectric region; Applying a conformal metal over the dielectric region and extending into the well opening to form a metal cup structure in the well opening; Applying a dielectric liner over the conformal metal and extending into an opening defined by the metal cup structure; Applying a thin film resistor (TFR) layer over the dielectric liner extending downward into an opening defined by the dielectric liner to form a TFR element cup structure; Performing a planarization process to remove upper portions of the conformal metal, the dielectric liner, and the TFR layer, wherein a remaining portion of the TFR layer defines a TFR element disposed within the metal can structure and including (a) a laterally extending TFR element base and (b) a plurality of TFR element sidewalls extending upwardly from the laterally extending TFR element base; wherein the TFR element is electrically insulated from the metal cup structure by the dielectric liner; and Forming a pair of TFR heads electrically connected to the TFR element. [14] The method of claim 13, wherein after the planarization process, a remaining portion of the dielectric liner defines a dielectric liner region separating the TFR element from the metal can structure. [15] The method of any one of claims 13 to 14, comprising applying a TFR cap layer over the TFR layer extending downward into an opening defined by the TFR element cup structure; wherein the planarization process removes an upper portion of the TFR cap layer, a remaining portion of the TFR cap layer defining a TFR cap layer region over the TFR element. [16] A method according to any one of claims 13 to 15, wherein: the plurality of TFR element sidewalls comprise a pair of TFR element sidewalls extending upwardly from a first pair of opposite sides of the laterally extending TFR element base; and the method comprises forming the pair of TFR heads in a metal layer over the TFR element, wherein the pair of TFR heads are electrically connected to the pair of TFR element sidewalls. [17] A method according to any one of claims 13 to 16, wherein: the multiple TFR element side walls include: a first pair of TFR element sidewalls extending upwardly from a first pair of opposite sides of the laterally extending TFR element base; and a second pair of TFR element sidewalls extending upwardly from a second pair of opposite sides of the laterally extending TFR element base; and the procedure has: Removing at least a partial height of the second pair of TFR element side walls; and Forming the pair of TFR heads electrically connected to the first pair of TFR element sidewalls. [18] The method of claim 17, comprising performing a metal etch to both (a) remove at least a partial height of the second pair of TFR element sidewalls and (b) form the pair of TFR heads electrically connected to the first pair of TFR element sidewalls. [19] The method of any one of claims 13 to 18, comprising forming a metal layer having (a) the pair of TFR heads electrically connected to the TFR element and (b) at least one metal can structure contact laterally spaced from the pair of TFR heads and electrically connected to the metal can structure. [20] A method according to any one of claims 13 to 19, comprising: simultaneously forming the well opening and a connecting via opening in the dielectric region; Applying the conformal metal over the dielectric region and extending into the well opening to form a metal cup structure in the well opening and extending into the interconnect via opening to form an interconnect via in the interconnect via opening; and Forming a metal layer having (a) the pair of TFR heads electrically connected to the TFR element and (b) an interconnect element electrically connected to the interconnect via. [21] A device or thin film resistor (TFR) module formed by any of the methods according to claims 13 to 20.

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