The semiconductor integrated circuit (IC) industry has experienced rapid growth. Continuing advances in semiconductor manufacturing processes have resulted in integrated circuits (“ICs”) having semiconductor devices with finer features and/or higher degrees of integration. Functional density (i.e., the number of interconnected devices per IC chip area) has generally increased while feature size (i.e., the smallest component that can be created using a fabrication process) has decreased. This scaling-down process generally has generally provided benefits by increasing production efficiency and lowering associated costs.
Advanced IC packaging technologies have been developed to further reduce density and/or improve performance of ICs, which are incorporated into many electronic devices. For example, IC packaging has evolved, such that multiple ICs may be vertically stacked in so-called three-dimensional (“3D”) packages, or 2.5D packages (which use an interposer). Through via (also referred to as through-silicon via (TSV)) is one technique for electrically and/or physically connecting stacked ICs. Such techniques sometimes implement protective structures and/or shielding structures, such as guard rings, to improve TSV reliability and integrity. Design improvements in protective structures and/or shielding structures are needed.
The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. Dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The present disclosure relates generally to integrated circuit (IC) packaging, and more particularly, to guard rings for through vias.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first feature and the second feature are formed in direct contact and may also include embodiments in which additional features may be formed between the first feature and the second feature, such that the first feature and the second feature may not be in direct contact. In addition, spatially relative terms, for example, “lower,” “upper,” “horizontal,” “vertical,” “above,” “over,” “below,” “beneath,” “up,” “down,” “top,” “bottom,” etc. as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of the present disclosure of one features relationship to another feature. The spatially relative terms are intended to cover different orientations of the device including the features. Furthermore, when a number or a range of numbers is described with “about,” “approximate,” “substantially,” and the like, the term is intended to encompass numbers that are within a reasonable range considering variations that inherently arise during manufacturing as understood by one of ordinary skill in the art. For example, the number or range of numbers encompasses a reasonable range including the number described, such as within +/−10% of the number described, based on known manufacturing tolerances associated with manufacturing a feature having a characteristic associated with the number. For example, a material layer having a thickness of “about 5 nm” can encompass a dimension range from 4.5 nm to 5.5 nm where manufacturing tolerances associated with depositing the material layer are known to be +/−10% by one of ordinary skill in the art. In another example, two features described as having “substantially the same” dimension and/or “substantially” oriented in a particular direction and/or configuration (e.g., “substantially parallel”) encompasses dimension differences between the two features and/or slight orientation variances of the two features from the exact specified orientation that may arise inherently, but not intentionally, from manufacturing tolerances associated with fabricating the two features. Still further, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations described herein.
Advanced IC packaging technologies have been developed to further reduce density and/or improve performance of integrated circuits (ICs), which are incorporated into many electronic devices. For example, IC packaging has evolved, such that multiple ICs may be vertically stacked in three-dimensional (“3D”) packages or 2.5D packages (e.g., packages that implement an interposer). Through via (also referred to as through-silicon via (TSV)) is one technique for electrically and/or physically connecting stacked ICs. For example, where a first chip is stacked vertically over a second chip, a TSV may be formed that extends vertically through the first chip to the second chip, where the TSV electrically and/or physically connects a first conductive structure (e.g., first wiring) of the first chip to a second conductive structure (e.g., second wiring) of the second chip. The TSV is a conductive structure, such as a copper structure, and may extend through an entirety of the first chip to the second chip.
A guard ring is often formed around the TSV to protect the TSV, improve TSV performance, improve TSV structural stability, shield and/or reduce TSV-induced noise that can negatively impact the first chip and/or the second chip, or combinations thereof. The guard ring may be formed when forming a back-end-of-line (BEOL) structure of the first chip, such as first wiring of the first chip. The first wiring may be disposed over and connected to a first device substrate of the first chip and facilitate operation and/or electrical communication of devices and/or structures of the first device substrate. The TSV may be formed after forming the BEOL structure, for example, by etching through a dielectric layer of the BEOL structure in an area defined by the guard ring and through the first device substrate to form a TSV trench that exposes the second chip and filling the TSV trench with a conductive material. The TSV trench may expose a BEOL structure of the second chip, which may be disposed over and connected to a second device substrate of the second chip and facilitate operation and/or electrical communication of devices and/or structures of the second device substrate.
The present disclosure proposes a guard ring design that optimizes a spacing between a guard ring and a TSV and optimizes overlap between adjacent metal layers of the guard ring, adjacent levels of the metal layers of the guard ring, adjacent groups of metal layers of the guard ring, or combinations thereof to reduce and/or eliminate defects that may arise during formation of the TSV. In some embodiments, a distance between a guard ring and a TSV is about 0.2 μm to about 0.5 μm. In some embodiments, a ratio of an inner diameter (or an inner width) of a guard ring to a diameter (or width) of a TSV is greater than zero and less than about two. In some embodiments, overlap between adjacent metal layers of a guard ring is less than about 10 nm. In some embodiments, overlap between adjacent levels of the metal layers of a guard ring is less than about 10 nm. In some embodiments, overlap between adjacent groups of metal layers of a guard ring is less than about 10 nm. In some embodiments, overlap decreases from a top to a bottom of a guard ring. For example, a guard ring can include a first group of metal layers, a second group of metal layers, and a third group of metal layers. The second group of metal layers is between the first group of metal layers and the third group of metal layers, the first group of metal layers is a topmost group of metal layers of the guard ring, and the third group of metal layers is a bottommost group of metal layers of the guard ring. Overlap between adjacent metal layers in the first group of metal layers is greater than overlap between adjacent metal layers in the second group of metal layers, which is greater than overlap between adjacent metal layers in the third group of metal layers. The first group of metal layers, the second group of metal layers, and third group of metal layers each include at least two metal layers. In some embodiments, the first group of metal layers form a portion of a BEOL structure having a first pitch, the second group of metal layers form a portion of the BEOL structure having a second pitch, and the third group of metal layers form a portion of the BEOL structure having a third pitch. The first pitch, the second pitch, and the third pitch are different. Details of the proposed guard ring design and/or fabrication thereof are described herein. Different embodiments may have different advantages, and no particular advantage is required of any embodiment.
In
Device substrate 102 can include various passive microelectronic devices and active microelectronic devices, such as resistors, capacitors, inductors, diodes, p-type FETs (PFETs), n-type FETs (NFETs), metal-oxide semiconductor (MOS) FETs (MOSFETs), complementary MOS (CMOS) transistors, bipolar junction transistors (BJTs), laterally diffused MOS (LDMOS) transistors, high voltage transistors, high frequency transistors, other suitable components, or combinations thereof. The various microelectronic devices can be configured to provide functionally distinct regions of an IC, such as a logic region (i.e., a core region), a memory region, an analog region, a peripheral region (e.g., an input/output (I/O) region), a dummy region, other suitable region, or combinations thereof. The logic region may be configured with standard cells, each of which can provide a logic device and/or a logic function, such as an inverter, an AND gate, an NAND gate, an OR gate, an NOR gate, a NOT gate, an XOR gate, an XNOR gate, other suitable logic device, or combinations thereof. The memory region may be configured with memory cells, each of which can provide a storage device and/or storage function, such as flash memory, non-volatile random-access memory (NVRAM), static random-access memory (SRAM), dynamic random-access memory (DRAM), other volatile memory, other non-volatile memory, other suitable memory, or combinations thereof. In some embodiments, memory cells and/or logic cells include transistors and interconnect structures that combine to provide storage devices/functions and logic devices/functions, respectively.
A multi-layer interconnect (MLI) feature 110 is disposed over side 104 of device substrate 102. MLI feature 110 electrically connects various devices (e.g., transistors) and/or components of device substrate 102 and/or various devices (e.g., a memory device disposed within MLI feature 110) and/or components of MLI feature 110, such that the various devices and/or components can operate as specified by design requirements. MLI feature 110 includes a combination of dielectric layers and electrically conductive layers (e.g., patterned metal layers) configured to form interconnect (routing) structures. The conductive layers form vertical interconnect structures, such as device-level contacts and/or vias, and/or horizontal interconnect structures, such as conductive lines. Vertical interconnect structures typically connect horizontal interconnect structures in different layers/levels (or different planes) of MLI feature 110. During operation, the interconnect structures can route electrical signals between devices and/or components of device substrate 102 and/or MLI feature 110 and/or distribute electrical signals (for example, clock signals, voltage signals, and/or ground signals) to the devices and/or the device components of device substrate 102 and/or MLI feature 110. Though MLI feature 110 is depicted with a given number of dielectric layers and metal layers, the present disclosure contemplates MLI feature 110 having more or less dielectric layers and/or metal layers.
MLI feature 110 can include circuitry fabricated on and/or over side 104 by back end-of-line (BEOL) processing and thus can also be referred to as a BEOL structure. MLI feature 110 includes an n level interconnect layer, an (n+x) level interconnect layer, and intermediate interconnect layer(s) therebetween (i.e., an (n+1) level interconnect layer, an (n+2) level interconnect layer, and so on), where n is an integer greater than or equal to 1 and x is an integer greater than or equal to 1. Each of n level interconnect layer to (n+x) level interconnect layer includes a respective metallization layer and a respective via layer. For example, n level interconnect layer includes a respective n via layer (denoted as Vn) and a respective n metallization layer (denoted as Mn) over n via layer, (n+1) level interconnect layer includes a respective (n+1) via layer (denoted as Vn+1) and a respective (n+1) metallization layer (denoted as Mn+1) over (n+1) via layer, and so on for the intermediate layers to (n+x) level interconnect layer, which includes a respective (n+x) via layer (denoted as Vn+1) and an (n+x) metallization layer (denoted as Mn+1) over (n+x) via layer. In the depicted embodiment, n equals 1, x equals 9, and MLI feature 110 includes ten interconnect layers, such as a 1st level interconnect layer including a V1 layer and an M1 layer, a 2nd level interconnect layer including a V2 layer and an M2 layer, and so on to a 10th level interconnect layer including a V10 layer and an M10 layer. Each via layer physically and/or electrically connects an underlying metallization layer and an overlying metallization layer, an underlying device-level contact layer (e.g., a middle end-of-line (MEOL) interconnect layer, such as an M0 layer) and an overlying metallization layer, an underlying device feature (e.g., a gate electrode of a gate or a source/drain) and an overlying metallization layer, or an underlying metallization layer and an overlying top contact layer. For example, V2 layer is between, physically connected, and electrically connected to M1 layer and M2 layer. In another example, V1 layer is between, physically connected, and electrically connected to M1 layer and an underlying device-level contact layer and/or an underlying device feature. In some embodiments, the metallization layers and the via layers are further electrically connected to device substrate 102. For example, a first combination of metallization layers and via layers are electrically connected to a gate of a transistor of device substrate 102 and a second combination of metallization layers and via layers are electrically connected to a source/drain of the transistor, such that voltages can be applied to the gate and/or the source/drain.
MLI feature 110 includes a dielectric layer 115 having metal lines 116, vias 118, other conductive features, or combinations thereof disposed therein. Each of Mn metallization layer to Mn+x metallization layer includes a patterned metal layer (i.e., a group of metal lines 116 arranged in a desired pattern) in a respective portion of dielectric layer 115. Each of Vn via layer to Vn+x via layer includes a patterned metal layer (i.e., a group of vias 118 arranged in a desired pattern) in a respective portion of dielectric layer 115. Dielectric layer 115 includes a dielectric material, such as silicon oxide, tetraethylorthosilicate (TEOS) oxide, phosphosilicate glass (PSG), boron-doped silicate glass (BSG), boron-doped PSG (BPSG), low-k dielectric material (having, for example, a dielectric constant that is less than a dielectric constant of silicon oxide (e.g., k<3.9)), other suitable dielectric material, or combinations thereof. Exemplary low-k dielectric materials include fluorosilicate glass (FSG), carbon-doped oxide, Black Diamond® (Applied Materials of Santa Clara, Calif.), xerogel, aerogel, amorphous fluorinated carbon, parylene, benzocyclobutene (BCB), SILK (Dow Chemical, Midland, Mich.), polyimide, other low-k dielectric material, or combinations thereof. In some embodiments, dielectric layer 115 includes a low-k dielectric material, such as carbon-doped oxide, or an extreme low-k dielectric material (e.g., k≤2.5), such as porous carbon-doped oxide.
Dielectric layer 115 can have a multilayer structure. For example, dielectric layer 115 includes at least one interlevel dielectric (ILD) layer, at least one contact etch stop layer (CESL) disposed between respective ILD layers, and at least one CESL disposed between a respective ILD layer and device substrate 102. In such embodiments, a material of the CESL is different than a material of the ILD layer. For example, where the ILD layer includes a low-k dielectric material, the CESL can include silicon and nitrogen (e.g., silicon nitride, silicon oxynitride, silicon carbonitride, or combinations thereof) or other suitable dielectric material. The ILD layer and/or the CESL may have a multilayer structure having multiple dielectric materials. In some embodiments, each of n level interconnect layer to (n+x) level interconnect layer includes a respective ILD layer and/or a respective CESL of dielectric layer 115, and respective metal lines 116 and vias 118 are in the respective ILD layer and/or the respective CESL. In some embodiments, each of Mn layer to Mn+x layer includes a respective ILD layer and/or a respective CESL of dielectric layer 115, where respective metal lines 116 are in the respective ILD layer and/or the respective CESL. In some embodiments, each of Vn layer to Vn+x layer includes a respective ILD layer and/or a respective CESL of dielectric layer 115, where respective vias 118 are in the respective ILD layer and/or the respective CESL.
A top contact (TC) layer is disposed over MLI feature 110, and in the depicted embodiment, are disposed over a topmost metallization layer of MLI feature 110 (i.e., M10 layer). TC layer includes patterned metal layers (i.e., a group of contacts 120 and a contact 122 arranged in a desired pattern (e.g., a contact layer) and a group of vias 124 arranged in a desired pattern (e.g., a via layer)) in a respective portion of dielectric layer 115. The via layer (e.g., vias 124) physically and/or electrically connects the contact layer (e.g., contacts 120 and contact 122) to MLI feature 110 (e.g., metal lines 116 of Mn+x layer). Contacts 120 and/or contact 122 may facilitate electrical connection of MLI feature 110 and/or device substrate 102 to external circuitry and thus may be referred to as external contacts. In some embodiments, contacts 120 and/or contact 122 are under-bump metallization (UBM) structures. In some embodiments, dielectric layer 115 includes at least one passivation layer. For example, dielectric layer 115 may include a passivation layer disposed over a topmost metallization layer of MLI feature 110, such as M10 layer. In such embodiments, TC layer may include the passivation layer, where contacts 120, contact 122, and vias 124 are disposed in the passivation layer. The passivation layer includes a material that is different than a dielectric material of an underlying ILD layer of MLI feature 110. In some embodiments, the passivation layer includes polyimide, undoped silicate glass (USG), silicon oxide, silicon nitride, other suitable passivation material, or combinations thereof. In some embodiments, a dielectric constant of a dielectric material of the passivation layer is greater than a dielectric constant of a topmost ILD layer of MLI feature 110. The passivation layer may have a multilayer structure having multiple dielectric materials. For example, the passivation layer can include a silicon nitride layer and a USG layer.
Metal lines 116, vias 118, contacts 120, contact 122, and vias 124 include a metal material, including for example, aluminum, copper, titanium, tantalum, tungsten, ruthenium, cobalt, iridium, palladium, platinum, nickel, tin, gold, silver, other suitable metals, alloys thereof, silicides thereof, or combinations thereof. In some embodiments, metal lines 116, vias 118, contacts 120, contact 122, vias 124, or combinations thereof include a bulk metal layer (also referred to as a metal fill layer, a conductive plug, a metal plug, or combinations thereof). In some embodiments, metal lines 116, vias 118, contacts 120, contact 122, vias 124, or combinations thereof include a barrier layer, an adhesion layer, and/or other suitable layer disposed between the bulk metal layer and dielectric layer 115. The barrier layer can include titanium, titanium alloy (e.g., TiN), tantalum, tantalum alloy (e.g., TaN), other suitable barrier material (e.g., a material that can prevent diffusion of metal constituents from metal lines 116, vias 118, contacts 120, contact 122, vias 124, or combinations thereof into dielectric layer 115), or combinations thereof. In some embodiments, metal lines 116, vias 118, contacts 120, contact 122, vias 124, or combinations thereof include different metal materials. For example, lower metal lines 116 and/or vias 118 of MLI feature 110 include tungsten, ruthenium, cobalt, or combinations thereof, while higher metal lines 116 and/or vias 118 of MLI feature 100 include copper. In some embodiments, metal lines 116, vias 118, contacts 120, contact 122, vias 124, or combinations thereof include the same metal materials.
Each metallization layer is a patterned metal layer having metal lines 116, where the patterned metal layer has a corresponding pitch. Metallization layers of MLI feature 110 can thus be grouped by their respective pitches. A pitch of a patterned metal layer generally refers to a sum of a width of metal lines (e.g., metal lines 116) of the patterned metal layer and a spacing between directly adjacent metal lines of the patterned metal layer (i.e., a lateral distance between edges of directly adjacent metal lines 116 of the patterned metal layer). In some embodiments, a pitch of the patterned metal layer is a lateral distance between centers of directly adjacent metal lines 116 of the patterned metal layer. In
A through substrate via (TSV) 130 (also referred to as a through silicon via or a through semiconductor via) is disposed in dielectric layer 115. TSV 130 is physically and/or electrically connected to TC layer (e.g., a respective via 124 physically and electrically connects TSV to contact 122, which is connected to a guard ring 140). TSV 130 extends from contact 122, through dielectric layer 115, and through device substrate 102. In
TSV 130 includes a conductive material, including for example, aluminum, copper, titanium, tantalum, tungsten, ruthenium, cobalt, iridium, palladium, platinum, nickel, tin, gold, silver, other suitable metals, alloys thereof, silicides thereof, or combinations thereof. In some embodiments, TSV 130 includes a bulk metal layer (also referred to as a metal fill layer, a conductive plug, a metal plug, or combinations thereof) and a barrier layer, where the barrier layer is disposed between the bulk metal layer and dielectric layer 115. The barrier layer can include titanium, titanium alloy (e.g., TiN), tantalum, tantalum alloy (e.g., TaN), other suitable barrier material (e.g., a material that can prevent diffusion of metal constituents from TSV 130 into dielectric layer 115), or combinations thereof. In some embodiments, the bulk metal layer is a copper plug or a tungsten plug, and the barrier layer is a metal nitride layer (e.g., TaN layer or TiN layer). In some embodiments, the bulk metal layer includes a seed layer between the barrier layer and the metal plug. The seed layer can include copper, tungsten, other suitable metals (such as those described herein), alloys thereof, or combinations thereof. In some embodiments, TSV 130 includes a dielectric liner between the bulk metal layer or the barrier layer and dielectric layer 115. The dielectric liner includes silicon oxide, silicon nitride, other suitable dielectric material, or combinations thereof. The bulk metal layer, the barrier layer, the seed layer, the dielectric liner, or combinations thereof may have a multilayer structure. In some embodiments, TSV 130 includes polysilicon (e.g., the metal plug is a polysilicon plug).
Guard ring 140 is disposed in dielectric layer 115 and around TSV 130. Guard ring 140 extends through dielectric layer 115 from TC layer to side 104 of device substrate 102. Guard ring 140 is separated from TSV 130 by dielectric layer 115. Guard ring 140 has a dimension Db, such as a width or a diameter, along the x-direction. From a top view (
Guard ring 140 is physically and/or electrically connected to TC layer (e.g., vias 124 physically and electrically connect guard ring 140 to contact 122). Guard ring 140 may be physically and/or electrically connected to device substrate 102. For example, an MEOL layer (i.e., device-level contacts and/or vias) can physically and/or electrically connect guard ring 140 to device substrate 102, such as to a doped region (e.g., an n-well and/or a p-well) in device substrate 102. In some embodiments, guard ring 140 is electrically connected to a voltage. In some embodiments, guard ring 140 is electrically connected to an electrical ground. In some embodiments, guard ring 140 is configured to electrically insulate TSV 130 from MLI feature 110, device substrate 102, other device features and/or device components, or combinations thereof. In some embodiments, guard ring 140 absorbs thermal stress and/or mechanical stress from, within, and/or around TSV 130. In some embodiments, guard ring 140 reduces thermal stress and/or mechanical stress from, within, and/or around TSV 130. Such stresses can result from TSV 130, device substrate 102, and/or dielectric layer 115 having different coefficients of thermal expansion (CTE). Such stresses may result during and/or after fabrication of TSV 130. In some embodiments, guard ring 140 reduces or eliminates cracks at an interface of TSV 130 and device substrate 102 (e.g., at metal/semiconductor interfaces), which may arise from the stresses described herein. In some embodiments, guard ring 140 provides structural support, integrity, reinforcement, or combinations thereof for TSV 130.
A ratio of dimension Db to dimension DTSV is configured to optimize a spacing S (also referred to as a distance) along the x-direction between guard ring 140 and TSV 130. In some embodiments, the ratio of dimension Db to dimension DTSV is greater than zero and less than about two (i.e., 2>Db/DTSV>0). A Db/DTSV ratio that is equal to zero provides a spacing S equal to zero (i.e., no spacing is between guard ring 140 and TSV 130, and guard ring 140 may be physically connected to TSV 130), which negates a purpose and/or a function of guard ring 140. For example, when guard ring 140 is merely an extension of TSV 130 (and forms a portion thereof), guard ring 140 cannot protect TSV 130 as intended. For example, guard ring 140 cannot provide electrical insulation; reduce or eliminate stress from, within, and/or around TSV 130; reduce or eliminate cracking; provide structural integrity; or combinations thereof. A Db/DTSV ratio that is greater than two provides a spacing between guard ring 140 and TSV 130 that is too large, and guard ring 140 cannot protect TSV 130 as intended. For example, when guard ring 140 is spaced too far from TSV 130, guard ring 140 cannot sufficiently absorb and/or reduce stresses from, within, and/or around TSV 130. Stresses may then concentrate on TSV 130, which can degrade performance and/or structural integrity of TSV 130. In some embodiments, spacing S is about 20 nm to about 50 nm. A spacing S that is greater than 50 nm is too large and prevents guard ring 140 from sufficiently protecting TSV 130 (e.g., guard ring 140 cannot adequately absorb and/or reduce stresses from, within, and/or around TSV 130). A spacing S that is less than 20 nm is too small and can result in a connection between guard ring 140 and TSV 130, which may destroy a shielding function of guard ring 140.
Guard ring 140 is fabricated in conjunction with MLI feature 110, and guard ring 140 may be considered a portion of MLI feature 110. For example, guard ring 140 includes a stack of interconnect structures, where the interconnect structures are vertically stacked along the z-direction (or along a thickness direction of TSV 130). Each interconnect structure includes a respective metal line 116 and a respective via 118. In
Overlap in guard ring 140 is controlled to optimize spacing S between guard ring 140 and TSV 130 and/or reduce and/or eliminate defects that may arise during fabrication of TSV 130. Overlap (overlay) generally refers to a distance one layer (or structure) is shifted laterally relative to another layer (or structure). For example, in
In
In
In some embodiments, interconnect structures, metal lines 116, vias 118, or combinations thereof of guard ring 140 can be divided into groups, and each group can be assigned different overlay OVL tolerances, so long as each allowable overlay OVL tolerance is less than about 10 nm. In
In some embodiments, overlap OVLa is between any two interconnect structures and/or metal lines 116 of set 140a. In some embodiments, overlap OVLa is between directly adjacent interconnect structures and/or metal lines 116 of set 140a. In some embodiments, overlap OVLa is between a bottommost interconnect structure of set 140a (e.g., a interconnect structure) and/or metal line 116 thereof and a contact and/or a via of an underlying MEOL layer. In some embodiments, overlap OVLa is between a topmost interconnect structure of set 140a (e.g., (a+6) interconnect structure) and/or metal line 116 thereof and a bottommost interconnect structure of set 140b (e.g., (a+7) interconnect structure) and/or metal line 116 thereof. In some embodiments, overlap OVLb is between any two interconnect structures and/or metal lines 116 of set 140b. In some embodiments, overlap OVLb is between directly adjacent interconnect structures and/or metal lines 116 of set 140b. In some embodiments, overlap OVLb is between a bottommost interconnect structure of set 140b (e.g., (a+7) interconnect structure) and/or metal line 116 thereof and a topmost interconnect structure of set 140a (e.g., (a+6) interconnect structure) and/or metal line 116 thereof. In some embodiments, overlap OVLb is between a topmost interconnect structure of set 140b (e.g., (a+8) interconnect structure) and/or metal line 116 thereof and a bottommost interconnect structure of set 140c (e.g., (a+b) interconnect structure) and/or metal line 116 thereof. In some embodiments, overlap OVLc is between any two interconnect structures and/or metal lines 116 of set 140c. In some embodiments, overlap OVLc is between directly adjacent interconnect structures and/or metal lines 116 of set 140c. In some embodiments, overlap OVLc is between a bottommost interconnect structure of set 140c (e.g., (a+b) interconnect structure) and/or metal line 116 thereof and a topmost interconnect structure of set 140b (e.g., (a+8) interconnect structure) and/or metal line 116 thereof. In some embodiments, overlap OVLc is between a topmost interconnect structure of set 140c (e.g., (a+b) interconnect structure) and/or metal line 116 thereof and contacts 124 of TC layer.
As noted above, each interconnect structure of guard ring 140 (e.g., (a+1) interconnect structure) has a respective metal line 116 and a respective via 118. In
In some embodiments, metal lines 116 of guard ring 140 have the same width. In some embodiments, metal lines 116 of guard ring 140 have different widths (e.g., different widths W1) and sidewalls of metal lines 116 forming inner sidewall 142 are substantially vertically aligned (i.e., overlap OVL is less than about 10 nm). In some embodiments, width of metal lines 116 of guard ring 140 increases along height H of guard ring 140 (i.e., as a distance from side 104 of device substrate 102 increases). For example, width W1 of metal lines 116 increases from a first width to a second width. In such embodiments, width W1 of metal line 116 of a interconnect structure may be equal to the first width, width W1 of metal line 116 of (a+b) interconnect structure may be equal to the second width, and width W1 of metal lines 116 of intermediate interconnect structures may be between the first width and the second width. In some embodiments, metal lines 116 of interconnect structures of a same set of guard ring 140 have the same width, but the sets have different widths and sidewalls of metal lines 116 forming inner sidewall 142 are substantially vertically aligned (i.e., overlap OVL is less than about 10 nm). For example, width W1 of metal lines 116 of set 140a may be equal to a first width, width W1 of metal lines 116 of set 140b may be equal to a second width, and width W1 of metal lines 116 of set 140c may be equal to a third width, where the first width, the second width, and the third width are different. In some embodiments, the third width is greater than the second width, and the second width is greater than the third width. In some embodiments, metal lines 116 of interconnect structures of a same set of guard ring 140 have different widths, and sidewalls of metal lines 116 of the set forming inner sidewall 142 are substantially vertically aligned (i.e., overlap OVL is less than about 10 nm). For example, width W1 of metal lines 116 of set 140a are different but TSV-facing sidewalls of metal lines 116 of set 140a have overlap OVLa.
In some embodiments, vias 118 of guard ring 140 have the same width. In some embodiments, vias 118 of guard ring 140 have different widths (e.g., different widths W2) so long as sidewalls of metal lines 116 forming inner sidewall 142 are substantially vertically aligned (i.e., overlap OVL is less than about 10 nm). In such embodiments, sidewalls of metal lines 142 forming outer sidewall 144 of guard ring 140 may not be vertically aligned and/or may have overlay greater than 10 nm. In such embodiments, guard ring 140 may have a substantially vertical inner sidewall, but an outer sidewall having a non-uniform profile (e.g., stair profile, tapered profile, zig-zag profile, or other suitable profile). In some embodiments, width W2 of vias 118 can vary as described above with reference to width W1 of metal lines 116 (e.g., increase or decrease along height H, vary based on a set to which vias 118 belong, etc.). In some embodiments, thickness t1 is greater than thickness t2. In some embodiments, thickness t1 is less than thickness t2. In some embodiments, thickness t1 is equal to thickness t2. In some embodiments, metal lines 116 of guard ring 140 have the same thickness. In some embodiments, metal lines 116 of guard ring 140 have different thicknesses (e.g., different thicknesses t1). In some embodiments, vias 118 of guard ring 140 have the same thickness. In some embodiments, vias 118 of guard ring 140 have different thicknesses (e.g., different thicknesses t2). In some embodiments, thickness t1 of metal lines 116 can vary as described above with references to width W1 of metal lines 116 (e.g., increase or decrease along height H, vary based on a set to which metal lines 116 belong, etc.). In some embodiments, thickness t2 of vias 118 can vary as described above with references to width W1 of metal lines 116 (e.g., increase or decrease along height H, vary based on a set to which vias 118 belong, etc.).
In some embodiments, widths and/or thicknesses of metal lines 116 of guard ring 140 are different than widths and/or thicknesses, respectively, of metal lines 116 of the interconnect layers of MLI feature 110. In some embodiments, widths and/or thicknesses of vias 118 of guard ring 140 are different than widths and/or thicknesses, respectively, of vias 118 of the interconnect layers of MLI feature 110. In some embodiments, widths and/or thicknesses of metal lines 116 of guard ring 140 are the same as widths and/or thicknesses, respectively, of metal lines 116 of the interconnect layers of MLI feature 110. In some embodiments, widths and/or thicknesses of vias 118 of guard ring 140 are the same as widths and/or thicknesses, respectively, of vias 118 of the interconnect layers of MLI feature 110. In some embodiments, conductive materials of metal lines 116 and/or vias 118 of guard ring 140 are different than conductive materials of metal lines 116 and/or vias 118, respectively, of the interconnect layers of MLI feature 110. In some embodiments, conductive materials of metal lines 116 and/or vias 118 of guard ring 140 are the same as conductive materials of metal lines 116 and/or vias 118, respectively, of the interconnect layers of MLI feature 110.
Semiconductor structure 100 may be attached (bonded) to another semiconductor structure to form an IC package or portion thereof. For example, in
In some embodiments, semiconductor structure 100 and semiconductor structure 180 are chips that include at least one functional IC, such as an IC configured to perform a logic function, a memory function, a digital function, an analog function, a mixed signal function, a radio frequency (RF) function, an input/output (I/O) function, a communications function, a power management function, other function, or combinations thereof. In such embodiments, TSV 130 vertically physically and/or electrically connects chips. In some embodiments, semiconductor structure 100 and semiconductor structure 180 are chips that provide the same function (e.g., central processing unit (CPU)). In some embodiments, semiconductor structure 100 and semiconductor structure 180 are chips that provide different functions (e.g., CPU and graphics processing unit (GPU), respectively). In some embodiments, semiconductor structure 100 and/or semiconductor structure 180 is a system-on-chip (SoC), which generally refers to a single chip or monolithic die having multiple functions. In such embodiments, TSV 130 vertically physically and/or electrically connects SoCs. In some embodiments, the SoC is a single chip having an entire system, such as a computer system, fabricated thereon.
In some embodiments, semiconductor structure 100 is a portion of a chip-on-wafer-on-substrate (CoWoS) package, an integrated-fan-out (InFO) package, a system on integrated chip (SoIC) package, other three-dimensional integrated circuit (3DIC) package, or a hybrid package that implements a combination of multichip packaging technologies. In some embodiments, TSV 130 of semiconductor structure 100 is physically and/or electrically connected to a package substrate, an interposer, a redistribution layer (RDL), a printed circuit board (PCB), a printed wiring board, other packaging structure and/or substrate, or combinations thereof. In some embodiments, TSV 130 of semiconductor structure 100 is physically and/or electrically connected to controlled collapse chip connections (C4 bonds) (e.g., solder bumps and/or solder balls) and/or microbumps (also referred to as microbonds, μbumps, and/or μbonds), which are physically and/or electrically connected to a packaging structure.
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BEOL overlap control, such as described herein, is implemented to ensure that any overlap between vertically stacked conductive layers (or levels) is less than about 10 nm. BEOL overlap control may also be implemented to optimize inner dimension Db. For example, parameters of patterning processes described herein, such as those implemented to form guard ring 140 and/or MLI feature 110, are tuned to ensure overlap between openings in patterned overlying layers and conductive features in patterned underlying layers is less than about 10 nm. In some embodiments, maintaining overlap less than about 10 nm can improve uniformity of inner dimension Db along height H of guard ring 140. In some embodiments, maintaining overlap less than about 10 nm can improve uniformity of spacing S between guard ring 140 and subsequently formed TSV 130. In some embodiments, BEOL control and maintaining overlap less than about 10 nm improves process control of inner dimension Db and/or spacing S, which can reduce process defects during TSV trench formation (
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In some embodiments, depositing the portion of dielectric layer 115 includes depositing an ILD layer. In some embodiments, depositing the portion of dielectric layer 115 includes depositing a CESL. Dielectric layer 115, CESL, ILD layer, or combinations thereof are formed by chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), high density plasma CVD (HDPCVD), flowable CVD (FCVD), physical vapor deposition (PVD), atomic layer deposition (ALD), metalorganic chemical vapor deposition (MOCVD), remote plasma CVD (RPCVD), low-pressure CVD (LPCVD), atomic layer CVD (ALCVD), atmospheric pressure CVD (APCVD), other suitable deposition methods, or combinations thereof.
In some embodiments, 1st level interconnect layer of MLI feature 110 and/or 1st interconnect structure of guard ring 140 are formed by a dual damascene process, which can involve depositing conductive material for via/metal line pairs at the same time. In such embodiments, vias 118 and metal lines 116 may share a barrier layer and a conductive plug, instead of each having a respective and distinct barrier layer and conductive plug (e.g., where a barrier layer of a respective metal line 116 separates a conductive plug of the respective metal line 116 from a conductive plug of its corresponding, respective via 118). In some embodiments, the dual damascene process includes performing a patterning process to form interconnect openings that extend through dielectric layer 115 to expose underlying conductive features. The patterning process can include a first lithography step and a first etch step to form trench openings of the interconnect openings (which correspond with and define metal lines 116) in dielectric layer 115 and a second lithography step and a second etch step to form via openings of the interconnect openings (which correspond with and define vias 118) in dielectric layer 115. The first lithography/first etch step and the second lithography/second etch step can be performed in any order (e.g., trench first via last or via first trench last). The first etch step and the second etch step are each configured to selectively remove dielectric layer 115 with respect to a patterned mask layer. The first etch step and the second etch step may be a dry etching process, a wet etching process, other suitable etching process, or combinations thereof.
After performing the patterning process, the dual damascene process can include performing a first deposition process to form a barrier material over dielectric layer 115 that partially fills the interconnect openings and performing a second deposition process to form a bulk conductive material over the barrier material, where the bulk conductive material fills remainders of the interconnect openings. In such embodiments, the barrier material and the bulk conductive material are disposed in the interconnect openings and over a top surface of dielectric layer 115. The first deposition process and the second deposition process can include CVD, PVD, ALD, HDPCVD, MOCVD, RPCVD, PECVD, LPCVD, ALCVD, APCVD, PEALD, electroplating, electroless plating, other suitable deposition methods, or combinations thereof. A CMP process and/or other planarization process is then performed to remove excess bulk conductive material and barrier material from over the top surface of dielectric layer 115, resulting in the patterned via layer (e.g., vias 118) and the patterned metal layer (e.g., metal lines 116) of 1st level interconnect layer of MLI feature 110 and corresponding 1st interconnect structure of guard ring 140. The CMP process planarizes top surfaces of dielectric layer 115 and vias 118 and/or metal lines 116. The barrier material and the bulk conductive material may fill the trench openings and the via openings of the interconnect openings without interruption, such that barrier layers and conductive plugs of metal lines 116 and vias 118 may each extend continuously from metal lines 116 to respective vias 118 without interruption.
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In some embodiments, for a given level interconnect layer, metal lines 116 and vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer are formed simultaneously with metal lines 116 and vias 118, respectively, of the given level interconnect layer. For example, openings in dielectric layer 115 for vias 118 of V1 layer and vias 118 of 1st interconnect structure of guard ring 140 are formed by the same patterning process and the openings are filled with conductive material by the same deposition process. In another example, openings in dielectric layer 115 for metal lines 116 of M1 layer and metal lines 116 of 1st interconnect structure of guard ring 140 are formed by the same patterning process, and the openings are filled with conductive material by the same deposition process.
In some embodiments, for a given level interconnect layer, metal lines 116 and vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer are formed at least partially simultaneously with metal lines 116 and vias 118, respectively, of the given level interconnect layer. For example, openings in dielectric layer 115 for vias 118 of V1 layer and vias 118 of 1st interconnect structure of guard ring 140 are formed by the same patterning process, and the openings are filled with conductive material by different deposition processes. In another example, openings in dielectric layer 115 of metal lines 116 of M1 layer and metal lines 116 of 1st interconnect structure of guard ring 140 are formed by the same patterning process, and the openings are filled with conductive material by different deposition processes. In another example, openings for vias 118 of V1 layer and vias 118 of Pt interconnect structure of guard ring 140 are filled with conductive material by the same deposition process, and the openings are formed in dielectric layer 115 by different patterning processes. In another example, openings for metal lines 116 of M1 layer and metal lines 116 of 1st interconnect structure of guard ring 140 are filled with conductive material by the same deposition process, and the openings are formed in dielectric layer 115 by different patterning processes.
In some embodiments, for a given level interconnect layer, metal lines 116 and vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer are formed by different processes than metal lines 116 and vias 118, respectively, of the given level interconnect layer. For example, vias 118 of V1 layer are formed by a first set of processes (e.g., a first patterning process and a first deposition process) and vias 118 of 1st interconnect structure of guard ring 140 are formed by a second set of processes (e.g., a second patterning process and a second deposition process). In another example, metal lines 116 of M1 layer are formed by a first set of processes (e.g., a first patterning process and a first deposition process) and metal lines 116 of 1st interconnect structure of guard ring 140 are formed by a second set of processes (e.g., a second patterning process and a second deposition process).
In some embodiments, for a given level interconnect layer, metal lines 116 and/or vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer and metal lines 116 and/or vias 118, respectively, of the given level interconnect layer are formed by the same single damascene process. In some embodiments, for a given level interconnect layer, metal lines 116 and/or vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer and metal lines 116 and/or vias 118, respectively, of the given level interconnect layer are formed by different single damascene processes. In some embodiments, for a given level interconnect layer, metal lines 116 and vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer and metal lines 116 and vias 118 of the given level interconnect layer are formed by the same dual damascene process. In some embodiments, for a given level interconnect layer, metal lines 116 and vias 118 of an interconnect structure of guard ring 140 at the given level interconnect layer and metal lines 116 and vias 118 of the given level interconnect layer are formed by different dual damascene processes.
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In some embodiments, a Bosch process, such as depicted in
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The present disclosure provides for many different embodiments. An exemplary semiconductor structure includes a device substrate having a first side and a second side. A dielectric layer is disposed over the first side of the device substrate. A through via extends along a first direction through the dielectric layer and through the device substrate from the first side to the second side. A guard ring is disposed in the dielectric layer and around the through via. The guard ring includes metal layers stacked along the first direction. The metal layers include first sidewalls and second sidewall. The first sidewalls form an inner sidewall of the guard ring. An overlap between the first sidewalls of the metal layers is less than about 10 nm. The overlap is along a second direction different than the first direction. In some embodiments, a region defined by the inner sidewall of the guard ring has a first dimension along the second direction, the through via has a second dimension along the second direction, and a ratio of the first dimension to the second dimension is greater than zero and less than about two. In some embodiments, a spacing is between the through via and the inner sidewall of the guard ring, the spacing is along the second direction, and the spacing is about 20 nm to about 50 nm. In some embodiments, the inner sidewall is substantially vertical along the first direction.
In some embodiments, a first set of the metal layers has a first overlap, a second set of the metal layers has a second overlap different than the first overlap, and the first overlap and the second overlap are each less than about 10 nm. In some embodiments, the first set of the metal layers is between the second set of the metal layers and the first side of the device substrate, and the first overlap is less than the second overlap. In some embodiments, a third set of the metal layers has a third overlap that is different than the first overlap and the second overlap, the second set of the metal layers is between the third set of the metal layers and the first set of the metal layers, and the third overlap is greater than the second overlap.
In some embodiments, the semiconductor structure further includes a multilayer interconnect structure disposed in the dielectric layer. The multilayer interconnect structure includes a first set of metallization layers having a first pitch and a second set of metallization layers having a second pitch that is different than the first pitch. The first set of the metal layers are a portion of the first set of metallization layers and the second set of metal layers are a portion of the second set of metallization layers. In some embodiments, the first set of metallization layers is between the second set of metallization layers and the first side of the device substrate, and the first pitch is less than the second pitch.
An exemplary semiconductor arrangement includes a first semiconductor structure, a second semiconductor structure, and a conductive structure that extends through the first semiconductor structure to the second semiconductor structure. The conductive structure connects the first semiconductor structure and the second semiconductor structure. The semiconductor arrangement further includes a stack of interconnect structures that form a ring around the conductive structure. An overlap between the interconnect structures is less than about 10 nm. In some embodiments, the ring has an inner diameter, the conductive structure has a diameter, and a ratio of the inner diameter to the diameter is greater than zero and less than about two. In some embodiments, the overlap between the interconnect structures increases along a height of the stack of interconnect structures.
In some embodiments, the first semiconductor structure includes a first multilayer interconnect (MLI) feature over a first device substrate and a first top contact layer over the first MLI feature. In some embodiments, the second semiconductor structure includes a second MLI feature over a second device substrate and a second top contact layer over the second MLI feature. In some embodiments, the stack of interconnect structures is disposed in the first MLI feature and the conductive structure extends through the first MLI feature and the first device substrate to the second top contact layer. In some embodiments, the first MLI feature includes metallization layers disposed in a dielectric layer and a number of interconnect structures in the stack of interconnect structures is equal to a number of metallization layers of the first MLI feature. In some embodiments, the first MLI feature includes metallization layers disposed in a dielectric layer and a number of interconnect structures in the stack of interconnect structures is different than a number of metallization layers of the first MLI feature.
In some embodiments, the stack of interconnect structures includes a first interconnect structure disposed directly on a second interconnect structure. The first interconnect structure includes a first metal line disposed over a first via and the second interconnect structure includes a second metal line disposed over a second via. The overlap is between the first metal line and the second metal line. In some embodiments, the first metal line and the second metal line each have a first sidewall and a second sidewall. The first sidewall is proximate the conductive structure and the second sidewall is opposite the first sidewall. The overlap is between the first sidewall of the first metal line and the first sidewall of the second metal line. In some embodiments, the first sidewall of the first metal line is vertically aligned with the first sidewall of the second metal line.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This is a non-provisional application of and claims benefit of U.S. Provisional Patent Application Ser. No. 63/286,641, filed Dec. 7, 2021, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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63286641 | Dec 2021 | US |