阅读说明：本技术 气密性完全填充的金属化的贯穿孔通孔 (Hermetically completely filled metallized through-hole vias ) 是由 P·马宗达 C·A·欧克洛 朴娥英 S·C·波拉德 N·K·塞巴晏 于 2020-01-22 设计创作，主要内容包括：根据各个实施方式,一种制品包括玻璃或玻璃陶瓷基材,其具有第一主表面以及与第一主表面相对的第二主表面；以及在轴向方向上穿过基材而从第一主表面延伸轴向长度L到达第二主表面的通孔,所述通孔限定了内表面；以及第一轴向部分、第三轴向部分和沿着轴向方向设置在第一轴向部分与第三轴向部分之间的第二轴向部分。所述制品还包括至少设置在第一轴向部分和/或第三轴向部分中的内表面上的氦气气密性粘附层；以及设置在通孔内的金属连接件,其中,所述金属连接件粘附于氦气气密性粘附层。所述金属连接件在通孔的轴向长度L内完全填充通孔,所述通孔具有小于或等于30μm的最大直径Φ-(最大),以及轴向长度L,并且所述最大直径Φ-(最大)满足方程：(According to various embodiments, an article includes a glass or glass-ceramic substrate having a first major surface and a second major surface opposite the first major surface; and a through hole extending in an axial direction through the substrate from the first major surface to the second major surface for an axial length L, the through hole defining an inner surface; and a first axial portion, a third axial portion, and a second axial portion disposed between the first axial portion and the third axial portion along the axial direction. The article further comprises an inner surface disposed at least in the first axial portion and/or the third axial portionA helium gas tight adhesion layer on the face; and a metal connector disposed within the through hole, wherein the metal connector is adhered to the helium gas-tight adhesion layer. The metal connection completely fills the through-hole within the axial length L of the through-hole, the through-hole having a maximum diameter Φ less than or equal to 30 μm Maximum of And an axial length L, and the maximum diameter Φ Maximum of Satisfies the equation:)

1. An article of manufacture, comprising:

a glass or glass-ceramic substrate having a first major surface and a second major surface opposite the first major surface, and a through-hole extending in an axial direction through the substrate from the first major surface to the second major surface by an axial length L, the through-hole defining:

an inner surface; and

a first axial portion, a third axial portion, and a second axial portion disposed between the first axial portion and the third axial portion along the axial direction;

a helium gas tight adhesion layer provided on at least the inner surface in the first axial portion and/or the third axial portion; and

a metal connection member disposed within the through hole, wherein the metal connection member is adhered to the helium gas-tight adhesion layer,

wherein:

the metal connecting piece completely fills the through hole within the axial length L of the through hole;

the through-hole has a maximum diameter phi of less than or equal to 30 [ mu ] m_{Maximum of}(ii) a And is

Axial length L and maximum diameter phi_{Maximum of}Satisfies the equation:

2. the article of claim 1, wherein the helium gas tight adhesion layer comprises one or more of: ti, TiN, Ta, TaN, Cr, Ni and metal oxides.

3. The article of claim 1 or claim 2, wherein the metal connector consists essentially of copper.

4. The article of any one of the preceding claims, wherein a metal connector hermetically seals the through-hole.

5. The article of any one of the preceding claims, wherein the through-hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the third diameter is less than the first diameter and the second diameter.

6. The article of claim 5, wherein a helium gas tight adhesion layer is disposed on an inner surface in the first axial section, the second axial section, and the third axial section.

7. The article of claim 6, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 27 μm.

8. The article of claim 5, wherein a helium gas tight adhesion layer is disposed on the inner surface in the first axial section and/or the third axial section, and wherein the helium gas tight adhesion layer is not disposed on the inner surface in the second axial section.

9. The article of claim 8, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 25 μm.

10. The article of any of claims 1-4, wherein the through-hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the first diameter is greater than the second diameter and the third diameter, and wherein the third diameter is greater than the second diameter.

11. The article of claim 10, wherein a helium gas tight adhesion layer is disposed on an inner surface in the first axial section, the second axial section, and the third axial section.

12. The article of claim 11, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 19 μm.

13. The article of claim 10, wherein a helium gas tight adhesion layer is disposed on the inner surface in the first axial section and/or the third axial section, and wherein the helium gas tight adhesion layer is not disposed on the inner surface in the second axial section.

14. The article of claim 13, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 17 μm.

15. The article of any of claims 1-4, wherein the through-hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the first diameter is equal to the second diameter and the third diameter.

16. The article of claim 15, wherein a helium gas tight adhesion layer is disposed on an inner surface in the first axial section, the second axial section, and the third axial section.

17. The article of claim 15, wherein a helium gas tight adhesion layer is disposed on the inner surface in the first axial section and/or the third axial section, and wherein the helium gas tight adhesion layer is not disposed on the inner surface in the second axial section.

18. The article of claim 17, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 25 μm.

19. The article of any one of the preceding claims, wherein the through-hole has an axial length L greater than or equal to 150 μm and less than or equal to 500 μm.

20. The article of any one of the preceding claims, wherein the axial length L and the maximum diameter Φ_{Maximum of}Satisfies the equation:

21. the article of any one of the preceding claims, wherein the article is crack free and has less than 10 before and after heating to a temperature of 450 ℃ and cooling to a temperature of 23 ℃^-5Helium permeability of atm cc/s.

22. The article of any one of the preceding claims, wherein the substrate comprises at least 90 wt.% silica.

23. A method of making a glass article, the method comprising:

depositing a helium gas-tight adhesion layer on a portion of an inner surface of a through-hole extending through a glass or glass-ceramic substrate, the substrate having a first major surface and a second major surface opposite the first major surface, and the through-hole extending through the substrate in an axial direction from the first major surface to the second major surface, the through-hole comprising a first axial portion, a third axial portion, and a second axial portion disposed between the first axial portion and the third axial portion, wherein the helium gas-tight adhesion layer is deposited at least on the inner surface of the through-hole in the first axial portion and/or the third axial portion;

depositing metal connections on the first, second and third axial portions of the through-hole to completely fill the through-hole, wherein:

the metal connecting piece completely fills the through hole within the axial length L of the through hole in the axial direction;

the tubeThe pores have a maximum diameter phi of less than 30 mu m_{Maximum of}(ii) a And is

Axial length L and maximum diameter phi_{Maximum of}Satisfies the equation:

24. the method of claim 23, wherein the helium gas tight adhesion layer comprises one or more of: ti, TiN, Ta, TaN, Cr, Ni and metal oxides.

25. The method of claim 23 or claim 24, wherein the metal connection consists essentially of copper.

26. The method of any of claims 23-25, wherein a metal connector hermetically seals the through-hole.

27. The method of any of claims 23-26, wherein depositing a metal connection comprises depositing a metal connection using electroplating.

28. The method of any of claims 23-27, wherein depositing a helium gas tight adhesion layer comprises: a helium gas-tight adhesion layer is deposited on the inner surfaces of the through holes in the first, second and third axial portions.

29. The method of any of claims 23-27, wherein depositing a helium gas tight adhesion layer comprises: a helium gas-tight adhesion layer is deposited on the inner surfaces of the through holes in the first and third axial portions, and wherein no helium gas-tight adhesion layer is deposited on the inner surfaces in the second axial portion.

30. The method of any of claims 23-29, wherein the substrate comprises at least 90 wt.% silica.

Technical Field

The present description relates generally to vias in glass and glass-ceramic substrates, and more particularly to hermetically sealed, fully filled, metallized vias in glass and glass-ceramic substrates.

Background

Glass and glass ceramic substrates with vias are desirable for many applications, including use in interposers, as electrical interfaces, RF filters, and RF switches. Glass substrates have become an attractive alternative to silicon and fiber reinforced polymers for these applications.

It is desirable to fill such vias with a conductor. Currently, copper is the most desirable material for such conductors. However, copper does not adhere well to glass. In particular, for some applications, a hermetic seal between copper and glass is desired. Such seals are difficult to obtain because copper does not adhere well to glass and has a large mismatch due to the thermal expansion coefficients of many conductive materials (e.g., copper) and many desirable glass and glass ceramic substrate compositions. Furthermore, when copper adheres to glass, the large thermal expansion coefficient mismatch of copper and glass causes radial and/or circumferential cracking of the glass when the glass article is subjected to high temperature processing. Radial cracks form during heating because the free expansion of copper is limited by the matrix glass, resulting in high stress build-up that leads to the formation of radial cracks. On the other hand, circumferential cracks are formed during cooling. The free shrinkage of copper is limited by the glass matrix, leading to stress build-up and the formation of circumferential cracks.

While conformal coatings with cavities within the conductor material may reduce stress buildup and the formation of circumferential cracks, such cavities may be contaminated with corrosive materials during post-processing or use, resulting in degradation of the conductor material.

Therefore, there is a need for alternative methods for metallizing hermetically sealed through-glass vias.

Disclosure of Invention

According to a first aspect, an article includes a glass or glass-ceramic substrate having a first major surface and a second major surface opposite the first major surface; and a through hole extending in an axial direction through the substrate from the first major surface to the second major surface for an axial length L, the through hole defining an inner surface; and a first axial portion, a third axial portion, and a second axial portion disposed between the first axial portion and the third axial portion along the axial direction. The article further comprises a helium gas tight adhesion layer disposed on at least the inner surface in the first axial portion and/or the third axial portion; and a metal connector disposed within the through hole, wherein the metal connector is adhered to the helium gas-tight adhesion layer. The metal connection completely fills the through-hole within the axial length L of the through-hole, the through-hole having a maximum diameter Φ less than or equal to 30 μm_{Maximum of}And axial length L and maximum diameterΦ_{Maximum of}Satisfies the equation:

according to a 2 nd aspect, an article comprises the article of the 1 st aspect, wherein the helium gas tight adhesion layer comprises Ti, TiN, Ta, TaN, Cr, Ni, and a metal oxide.

According to a 3 rd aspect, an article comprises the article of the 1 st or 2 nd aspect, wherein the metal connection consists essentially of copper.

According to a 4 th aspect, an article comprises the article according to any of the preceding aspects, wherein the metal connection hermetically seals the through hole.

According to a 5 th aspect, an article comprises the article according to any of the preceding aspects, wherein the through hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the third diameter is smaller than the first diameter and the second diameter.

According to a 6 th aspect, an article comprises the article of the 5 th aspect, wherein a helium gas tight adhesion layer is provided on an inner surface in the first, second and third axial portions.

According to aspect 7, an article comprises the article according to aspect 6, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 27 μm.

According to an 8 th aspect, an article comprises the article according to the 5 th aspect, wherein a helium gas tight adhesion layer is provided on the inner surface in the first axial portion and/or the third axial portion, and wherein the adhesion layer is not provided on the inner surface in the second axial portion.

According to a 9 th aspect, an article comprises the article according to the 8 th aspect, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 25 μm.

According to a 10 th aspect, an article comprises the article of any of aspects 1-4, wherein the through hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the first diameter is greater than the second diameter and the third diameter, and wherein the third diameter is greater than the second diameter.

According to an 11 th aspect, an article comprises the article of the 10 th aspect, wherein a helium gas tight adhesion layer is provided on an inner surface in the first axial section, the second axial section and the third axial section.

According to a 12 th aspect, an article comprises the article according to the 11 th aspect, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 19 μm.

According to a 13 th aspect, an article comprises the article according to the 10 th aspect, wherein the helium gas tight adhesive layer is provided on the inner surface in the first axial portion and/or the third axial portion, and wherein the helium gas tight adhesive layer is not provided on the inner surface in the second axial portion.

According to a 14 th aspect, an article comprises the article according to the 13 th aspect, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 17 μm.

According to a 15 th aspect, an article comprises the article according to any of the 1 st to 4 th aspects, wherein the through hole has a first diameter at the first major surface, a second diameter at the second major surface, and a third diameter in the second axial portion, and wherein the first diameter is equal to the second diameter and the third diameter.

According to a 16 th aspect, an article comprises the article of the 15 th aspect, wherein a helium gas tight adhesion layer is provided on an inner surface in the first axial section, the second axial section and the third axial section.

According to a 17 th aspect, an article comprises the article according to the 15 th aspect, wherein the helium gas tight adhesive layer is provided on the inner surface in the first axial portion and/or the third axial portion, and wherein the helium gas tight adhesive layer is not provided on the inner surface in the second axial portion.

According to an 18 th aspect, an article comprises the article according to the 17 th aspect, wherein the maximum diameter Φ_{Maximum of}Less than or equal to 25 μm.

According to a 19 th aspect, an article comprises the article according to any preceding aspect, wherein the through-hole has an axial length L greater than or equal to 150 μm and less than or equal to 500 μm.

According to a 20 th aspect, an article comprises an article according to any preceding aspect, wherein the axial length L and the maximum diameter Φ_{Maximum of}Satisfies the equation:

according to a 21 st aspect, an article comprises the article according to any preceding aspect, wherein the article is crack free and has less than 10 before and after heating to a temperature of 450 ℃ and cooling to a temperature of 23 ℃^-5Helium permeability of atm cc/s.

An article according to claim 22 comprising the article of any preceding aspect, wherein the substrate comprises at least 90 wt% silica.

According to a 23 th aspect, a method of making a glass article comprises: depositing a helium gas-tight adhesion layer on a portion of an inner surface of a through-hole extending through a glass or glass-ceramic substrate, the substrate having a first major surface and a second major surface opposite the first major surface, and the through-hole extending through the substrate in an axial direction from the first major surface to the second major surface, the through-hole comprising a first axial portion, a third axial portion, and a second axial portion disposed between the first axial portion and the third axial portion, wherein the helium gas-tight adhesion layer is deposited at least on the inner surface of the through-hole in the first axial portion and/or the third axial portion; and depositing a metal connection on the first, second and third axial portions of the through-hole up toCompletely filling the via. The metal connection completely fills the through-hole in the axial direction within the axial length L of the through-hole, the through-hole having a maximum diameter Φ less than or equal to 30 μm_{Maximum of}And axial length L and maximum diameter phi_{Maximum of}Satisfies the equation:

according to a 24 th aspect, a method comprises the method of the 23 th aspect, wherein the helium gas tight adhesion layer comprises one or more of Ti, TiN, Ta, TaN, Cr, Ni and a metal oxide.

According to a 25 th aspect, a method comprises the method according to the 23 th or 24 th aspect, wherein the metal connection consists essentially of copper.

According to a 26 th aspect, a method comprises the method according to any one of the 23 th to 25 th aspects, wherein the metal connection hermetically seals the through hole.

According to an eighth aspect, a method comprises the method according to any of the aspects of the 23-26, wherein depositing a metal connection comprises depositing a metal connection using electroplating.

According to a 28 th aspect, a method comprises the method according to any one of the 23 th to 27 th aspects, wherein depositing a helium gas tight adhesion layer comprises: a helium gas tight adhesion layer is deposited on the inner surfaces of the through holes in the first, second and third axial portions.

According to a 29 th aspect, a method comprises the method according to any one of the 23 th to 27 th aspects, wherein depositing a helium gas tight adhesion layer comprises: a helium gas tight adhesion layer is deposited on the inner surface of the through hole in the first axial section and/or the third axial section, and wherein the helium gas tight adhesion layer is not deposited on the inner surface in the second axial section.

According to a 30 th aspect, a method comprises the method according to any one of the 23 th to 29 th aspects, wherein the substrate comprises at least 90% by weight silica.

Drawings

FIG. 1 shows a perspective view of a substrate having a through-hole;

FIG. 2 shows a cross-sectional view of the via taken along line 2-2' of FIG. 1, the via having a necked configuration and being partially bonded;

FIG. 3 shows a cross-sectional view of the via taken along line 2-2' of FIG. 1, the via having a necked configuration and being fully bonded;

FIG. 4 shows a cross-sectional view of the through-hole of FIG. 1 taken along line 2-2' having a tapered configuration and being partially bonded;

FIG. 5 shows a cross-sectional view of the through-hole taken along line 2-2' of FIG. 1, the through-hole having a tapered configuration and being fully bonded;

FIG. 6 shows a cross-sectional view of the through-hole of FIG. 1 taken along line 2-2' thereof, the through-hole having a cylindrical configuration and being partially bonded;

FIG. 7 shows a cross-sectional view of the through-hole of FIG. 1 taken along line 2-2' thereof, the through-hole having a cylindrical configuration and being fully bonded;

FIG. 8 shows a flow chart of a process of fabricating a via;

FIG. 9 shows the configuration of vias with copper conformal coatings for modeling;

FIG. 10A is a graph of stress-strain relationship for a modeled elastic perfect plastic material as described herein;

FIG. 10B is a graph of temperature dependent yield stress for copper modeled as described herein;

FIG. 11 is a plot of modeled first maximum principal stress and modeled maximum radial stress (y-axis) for various copper coating thicknesses (x-axis);

FIG. 12 is a graph of modeled first maximum principal stresses (y-axis) for various via diameters (x-axis) for a fully filled, partially bonded via; and

FIG. 13 is a graph of modeled first maximum principal stresses (y-axis) for various via diameters (x-axis) for a fully filled, fully bonded via.

Detailed Description

Unless specifically stated otherwise, any methods described herein should not be construed as requiring that their steps be performed in a particular order, or that any apparatus be specifically oriented. Accordingly, if a method claim does not actually recite an order to be followed by its steps, or any apparatus claim does not actually recite an order or orientation to individual components, or no further limitation to a specific order is explicitly stated in the claims or specification, or a specific order or orientation is recited to components of an apparatus, then no order or orientation should be inferred, in any respect. This applies to any possible non-expressive basis for interpretation, including: a logical problem related to the arrangement of steps, a flow of operations, an order of components, or an orientation of components; obvious meaning derived from grammatical organization or punctuation, and quantity or type of implementation described in the specification.

As used herein, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "an" element includes aspects having two or more such elements, unless the context clearly indicates otherwise. Also, the word "or" should be construed as inclusive (e.g., "x or y" means one or both of x or y) when used without "either" following the word "or" (or other similar language indicating that "or" is expressly intended as exclusive, e.g., only one of x or y, etc.).

The term "and/or" should also be construed as inclusive (e.g., "x and/or y" means one or both of x or y). Where "and/or" is used as a connection of a group of three or more items, the group should be interpreted as including only one item, all items together, or any combination or number of items. Also, terms used in the specification and claims, such as having, including, containing, and comprising, are to be understood as being synonymous with the terms including and comprising.

As used herein, the term "about" means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller as desired, such as to reflect tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term "about" is used to describe a numerical value or an end-point of a range, the disclosure should be understood to include the specific numerical value or end-point referred to. Whether or not the numerical values or endpoints of ranges in the specification are listed as "about," the numerical values or endpoints of ranges are intended to include both embodiments: one modified with "about" and the other not modified with "about". It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

The disclosed ranges are to be understood to encompass any and all subranges or individual values encompassed within each range and support is provided for claims that recite those subranges or individual values. For example, a stated range of 1 to 10 should be understood as any and all subranges between the minimum value of 1 and the maximum value of 10 or individual values therebetween (including and/or excluding endpoints), and support is provided for claims describing these subranges or individual values; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, etc.) or any value from 1 to 10 (e.g., 3, 5.8, 9.9994, etc.).

Glass and glass ceramic substrate with through-holes

Glass and glass ceramic substrates with through-holes are desirable for a variety of applications. For example, a 3D interposer with Through Package (TPV) interconnects that connect logic devices on one side of the interposer and memory on the other side of the interposer is desirable for high bandwidth devices. Existing substrates are formed either from organic materials or from silicon. However, the organic interposer has a problem of poor dimensional stability, while the silicon wafer is expensive and has a problem of high dielectric loss. Glass and glass-ceramics can be excellent substrate materials due to their relatively low dielectric constants, their thermal stability, and low cost. Glass or glass ceramic substrates with Through Glass Vias (TGVs) have some applications. These vias typically need to be completely filled or conformally filled with a conductive metal (e.g., copper) to form an electrical pathway. Copper is a particularly desirable conductive metal, but it does not adhere well to glass and copper has a large coefficient of thermal expansion mismatch with many substrate compositions. The large mismatch in thermal expansion coefficients of copper and glass can lead to radial and/or circumferential cracking of the glass when the glass article is subjected to high temperature processing. Accordingly, various embodiments described herein have vias that are limited in diameter below a critical threshold, thereby enabling the vias to be completely filled with copper without causing cracking of the substrate when subjected to high temperature processes.

Fig. 1 shows an article comprising a substrate 100, schematically depicted in partial perspective view. The substrate 100 includes a first major surface 102 and a second major surface 104 opposite the first major surface 102. A plurality of through-holes 110 extend through the body of the substrate 100 from the first major surface 102 to the second major surface 104. The metal connector 150 fills the through-hole 110. It is understood that any number of vias 110 may extend through the substrate 100 in any arrangement. The coordinate mark 101 shows the direction of the axial dimension z, which is perpendicular to the plane of the first main surface 102 and the second main surface 104. Unless otherwise specified, the "length" of the through-hole or metal connection is in the axial dimension z. The thickness t of the substrate 100, sometimes referred to herein as the axial length L, can be any suitable thickness in the axial dimension, depending on the application.

In various embodiments, substrate 100 may comprise any suitable glass or glass-ceramic substrate. In some embodiments, high silica glass or glass ceramic substrates are desirable for certain applications due to their dielectric properties. For example, a glass or glass-ceramic material having a silica content of 50 mole%, 55 mole%, 60 mole%, 65 mole%, 70 mole%, 75 mole%, 80 mole%, 85 mole%, 90 mole%, 95 mole%, or 100 mole%, or any range (including endpoints) having any two of these values as endpoints, can be used. Glass or glass-ceramic materials having a silica content of 50 to 100 mole%, or 75 to 100 mole%, may be used. In a specific embodiment, the substrate comprises at least 90% by weight silica.

For substrates having the dimensions described herein, it is particularly difficult to obtain a hermetically sealed via in high silica glass with a copper metal connector for at least two reasons. First, copper does not adhere well to glass. Second, the CTE mismatch between copper and high silica glass is particularly large, which can cause cracking of the substrate when the substrate is subjected to thermal cycling. Despite these reasons, the articles and methods described herein achieve a hermetic seal by providing an excellent stress relief mechanism.

Fig. 2-7 show an article comprising a substrate 100, schematically depicted as a cross-sectional view of fig. 1 along line 2-2'. Fig. 2-7 show the substrate 100, coordinate mark 101, first major surface 102, second major surface 104, via 110, and metal connector 150 of fig. 1. The inner surface 114 of the through bore 110 is divided into a first axial portion 116, a second axial portion 118, and a third axial portion 120. In the first and third axial portions 116, 120, a helium gas tight adhesion layer 122 is provided on the inner surface 114 of the through hole 110. In an embodiment, a helium gas tight adhesion layer 122 is provided on the inner surface 114 of the through hole 110 along the entire perimeter of at least one of the first axial portion 116 and/or the third axial portion 120. Thus, while fig. 2-7 depict the helium gas-tight adhesion layer 120 as being located in at least the first axial portion 116 and the third axial portion 120, it is contemplated that in other embodiments, the helium gas-tight adhesion layer 122 may be located in the first axial portion 116 and not in the third axial portion 120, or in the third axial portion 120 and not in the first axial portion 116. In some embodiments, such as the embodiments shown in fig. 2, 4 and 6, the helium gas tight adhesion layer 122 is not present in the second axial portion 118. Such embodiments are referred to as "partial bonding". However, in other embodiments, such as the embodiment shown in fig. 3, 5 and 7, the helium gas-tight adhesion layer 122 is present in the second axial portion 118 and extends along the entire axial length from the first major surface 102 to the second major surface 103. Such an embodiment is referred to as "fully bonded". In the partially bonded embodiment, the helium gas tight adhesion layer 122 is not present in the second axial portion 118, and therefore, the metal connector 150 is less strongly bonded to the inner surface 114 along the second axial portion 118.

The phrase "helium gas tight adhesion layer" as used herein means less than 10^-5a permeability of atm cc/s, which provides a hermetic adhesion layer to helium gas, measured using a vacuum-based helium leak detection test system by adhering the metal connector 150 to the inner surface 114 of the via 110. In some embodiments, the adhesion layer is less than 10 deg.f^-8The permeability of atm cc/s provides hermeticity to helium. Suitable helium gas-tight adhesion layer materials include metals such as titanium (Ti), chromium (Cr), tantalum (Ta), vanadium (V), nickel (Ni), tungsten (W), or metal oxides such as zinc oxide, tungsten oxide, and manganese oxide, or nitrides such as titanium nitride (TiN) and tantalum nitride (TaN). In various embodiments, the helium gas-tight adhesion layer comprises one or more of: ti, TiN, Ta, TaN, Cr, Ni and metal oxides. The helium gas-tight adhesion layer has a thickness of 1nm or more and 500nm or less. For example, in some embodiments, the helium gas tight adhesion layer has a thickness of about 100 nm.

In some embodiments, for example, in partially bonded embodiments, the axial length of the first axial portion 116 or the third axial portion 120 may be referred to as the "adhesion length" because this length is the length of the through-hole 110 along which the metal connector 150 adheres securely to the substrate 100. In some such embodiments, the adhesion length is greater than or equal to 5 μm and less than or equal to 148 μm. The adhesion length may be greater than or equal to 10 μm and less than or equal to 135 μm, greater than or equal to 10 μm and less than or equal to 130 μm, greater than or equal to 10 μm and less than or equal to 125 μm, greater than or equal to 10 μm and less than or equal to 120 μm, greater than or equal to 10 μm and less than or equal to 115 μm, greater than or equal to 15 μm and less than or equal to 140 μm, greater than or equal to 15 μm and less than or equal to 135 μm, greater than or equal to 15 μm and less than or equal to 130 μm, greater than or equal to 15 μm and less than or equal to 125 μm, greater than or equal to 15 μm and less than or equal to 120 μm, greater than or equal to 20 μm and less than or equal to 140 μm, greater than or equal to 20 μm and less than or equal to 135 μm, greater than or equal to 20 μm and less than or equal to 130 μm, greater than or equal to 20 μm and less than or equal to 125 μm, greater than or equal to 25 μm and less than or equal to 140 μm, greater than or equal to 25 μm and less than or equal to 135 μm, greater than or equal to 25 μm and less than or equal to 130 μm, greater than or equal to 130 μm and less than or equal to 140 μm, greater than or equal to 30 μm and less than or equal to 35 μm, or greater than or equal to 35 μm and less than or equal to 140 μm. In some embodiments, the adhesion length is greater than or equal to 40 μm and less than or equal to 140 μm, greater than or equal to 40 μm and less than or equal to 130 μm, greater than or equal to 40 μm and less than or equal to 120 μm, greater than or equal to 40 μm and less than or equal to 110 μm, greater than or equal to 40 μm and less than or equal to 100 μm, greater than or equal to 40 μm and less than or equal to 90 μm, greater than or equal to 40 μm and less than or equal to 80 μm, greater than or equal to 40 μm and less than or equal to 70 μm, or greater than or equal to 40 μm and less than or equal to 60 μm. For example, the adhesion length may be about 40 μm, 50 μm, 60 μm, or 70 μm. It is contemplated that other attachment lengths may be used in various embodiments.

The through-hole 110 has a through-hole length 130 in the axial direction, which is sometimes referred to herein as the axial length L of the through-hole 110. In fully bonded embodiments, the adhesion length may be equal to the via length 130. The through-hole 110 has a first diameter 132a at the first major surface 102, a second diameter 132b at the second major surface 104, and a third diameter 132c in the second axial portion 118.

As shown in fig. 2-7, the metal connector 150 completely fills the through-hole 110 from the first major surface 102 to the second major surface 104 over the axial length L of the through-hole 110, thereby eliminating the possibility of contamination within the cavity in the metal connector 150. The metal connector may be formed of any suitable metal. In some embodiments, copper may be a desirable metal due to its particularly high electrical conductivity. Gold, silver and other conductive metals, as well as alloys of conductive metals, may also be used. In an embodiment, the metal connection comprises copper. In some embodiments, the metal connector consists essentially of copper. The metal connector 150 adhered inside the through-hole 110 hermetically seals the through-hole 110.

Shape of through hole

In the embodiments described herein, the through-hole 110 may have any of various shapes. In the embodiment shown in fig. 2 and 3, the through-hole 110 has a tapered inner surface 114 that tapers or narrows from a first diameter 132a at the first major surface 102 and a second diameter 132b at the second major surface 104 to a waist 125, the waist 125 having a waist diameter equal to the third diameter 132 c. This configuration is referred to herein as a fully filled necked via, or FPV. As used herein, the "waist" of a through-hole refers to the portion of the through-hole of variable diameter having the smallest diameter. In these embodiments, the diameter of the through-hole 110 may vary depending on the axial position. The overall "diameter" of the through-hole 110 is the maximum diameter Φ_{Maximum of}. Unless otherwise specified, "through hole diameter" refers to the maximum diameter. When the through-hole 110 is not circular, the "diameter" of the through-hole 110 is the diameter of a circle having the same sectional area as the through-hole 110 in a plane perpendicular to the axial direction.

The through bore waist 125 has a minimum diameter along the axial length of the through bore. As a percentage of the first diameter, the diameter of the through-hole waist may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any range having any two of these values as endpoints, inclusive. As a percentage of the second diameter, the diameter of the through-hole waist may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any range having any two of these values as endpoints, inclusive. The diameter of the through-hole waist may be 75% or less of the first diameter, and the diameter of the through-hole waist may be 75% or less of the second diameter. The diameter of the through-hole waist may be 20% to 50% or less of the first diameter, and the diameter of the through-hole waist may be 20% to 50% or less of the second diameter. In various embodiments, the third diameter 132c, or via waist, is greater than or equal to 10 μm and less than or equal to 30 μm. The third diameter 132c may be greater than or equal to 20 μm and less than or equal to 30 μm, or greater than or equal to 22 μm and less than or equal to 27 μm. For example, the third diameter 132c may be 10 μm, 15 μm, 20 μm, 22 μm, 25 μm, 27 μm, or 30 μm. In various embodiments, the ratio of the third diameter 132c to the first diameter 132a is less than or equal to 1:6, less than or equal to 1:5, less than or equal to 1:4, less than or equal to 1:3, or less than or equal to 1:2, and/or the ratio of the third diameter 132c to the second diameter 132b is less than or equal to 1:6, less than or equal to 1:5, less than or equal to 1:4, less than or equal to 1:3, or less than or equal to 1: 2.

The through-holes 110 optionally have rounded corners 124 at the inner edges to reduce stress concentrations, including at the through-hole waist 125. As used herein, "rounded corners" refer to rounded corners along the interior corners of the via 110. Such rounded corners may be used at any edge of the via shape. Rounded fillet 124 may have any suitable diameter, e.g., 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or any range having any two of these values as endpoints, inclusive. Other diameters may be used.

The through-hole 110 has an inner surface 114, the inner surface 114 having two different slopes, and a slope variation at the rounded corner 124. The through-hole 110 may have a single bevel, two bevels as shown in fig. 2, or a more complex shape from each of the first and second major surfaces 102, 104 to the waist 125. One or more of the bevels may be perpendicular to the first and second major surfaces 102, 104, as shown in fig. 2.

In the embodiment shown in fig. 4 and 5, the through-hole 110 has a tapered inner surface 114 that tapers or narrows from a first diameter 132a at the first major surface 102 to a second diameter 132b at the second major surface 104. The through bore 110 also includes a third diameter 132c within the second axial portion that is smaller than the first diameter 132a and larger than the second diameter 132 b. Thus, the first diameter 132a is greater than the second diameter 132b and the third diameter 132c, and the third diameter 132c is greater than the second diameter 132 b. This configuration is referred to herein as a fully filled tapered via, or FTV. In such embodiments, the first diameter 132a is the maximum via diameter Φ_{Maximum of}。

In the embodiment shown in fig. 6 and 7, the through-hole 110 has an inner surface 114 perpendicular to the first and second major surfaces 102, 104. The through hole has a first diameter 132a at the first main surface 102, a second diameter 132b at the second main surface 104, and a third diameter 132c in the second axial portion, the third diameter 132c being equal to the first diameter 132a and the second diameter 132 b. This configuration is referred to herein as a fully filled cylindrical via, or FCV. In such embodiments, the diameter of the through-hole 110 is constant with axial position.

The through-hole 110 may have any suitable through-hole length 130, or axial length L. By way of non-limiting example, the thickness of the substrate 100 (and the via length 130) may be 150 μm, 180 μm, 240 μm, 300 μm, 360 μm, 420 μm, 480 μm, 500 μm, or any range having any two of these values as endpoints, including endpoints. In some embodiments, the thickness t and via length are 150 μm to 500 μm, or 200 μm to 360 μm.

The through-hole 110 may have any suitable first, second, and third diameters 132a, 132b, 132 c. As non-limiting examples, these diameters may be 5 μm, 10 μm, 13 μm, 15 μm, 17 μm, 19 μm, 20 μm, 21 μm, 22 μm, 24 μm, 25 μm, 27 μm, 30 μm, or any range having any two of these values as endpoints, inclusive. In some embodiments, the via diameter can be greater than or equal to 1 μm and less than or equal to 30 μm, greater than or equal to 1 μm and less than or equal to 25 μm, greater than or equal to 1 μm and less than or equal to 19 μm, or greater than or equal to 1 μm and less than or equal to 17 μm. As will be described in more detail below, in various embodiments, the maximum diameter Φ of the via 110 depends on the via shape and whether the metal connections are partially or fully bonded_{Maximum of}Less than or equal to 30 μm, less than or equal to 27 μm,less than or equal to 25 μm, less than or equal to 24 μm, less than or equal to 22 μm, less than or equal to 21 μm, less than or equal to 19 μm, even less than 17 μm, less than or equal to 15 μm, or even less than 13 μm, in order to reduce stress and prevent cracking of the substrate.

In some embodiments, the vias 110 are fully filled, fully bonded cylindrical vias, and the maximum diameter Φ_{Maximum of}Less than or equal to 30 μm, less than or equal to 27 μm, or less than or equal to 24 μm. In other embodiments, the vias 110 are fully filled, partially bonded cylindrical vias and have a maximum diameter Φ_{Maximum of}Less than or equal to 25 μm, less than or equal to 22 μm, or less than or equal to 19 μm. In other embodiments, the via 110 is a fully filled, fully bonded tapered via, and has a maximum diameter Φ_{Maximum of}Less than or equal to 19 μm, less than or equal to 17 μm, or even less than or equal to 15 μm. In other embodiments, the via 110 is a fully filled, partially bonded tapered via, and has a maximum diameter Φ_{Maximum of}Less than or equal to 17 μm, less than or equal to 15 μm, or less than or equal to 13 μm. In other embodiments, the via 110 is a fully filled, fully bonded necked via with a maximum diameter Φ_{Maximum of}Less than or equal to 27 μm, less than or equal to 24 μm, or less than or equal to 21 μm. In other embodiments, the via 110 is a fully filled, partially bonded necked via with a maximum diameter Φ_{Maximum of}Less than or equal to 25 μm, less than or equal to 22 μm, or less than or equal to 19 μm.

The axial lengths of the first, second and third axial portions may have any suitable length. In various embodiments, the length is selected to achieve a combination of low maximum principal stress and helium gas tightness. In some embodiments, the lengths of the first and third axial portions are independently selected from 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% of the length of the through-hole, or any range having any two of these values as endpoints, including endpoints. The length of the second axial portion is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98% of the length of the through-hole, or any range having any two of these values as endpoints, including endpoints. The length of the first and third axial portions may be 2% to 40% of the length of the through hole, while the length of the second axial portion is 20% to 96% of the length of the through hole.

In various embodiments, the via is a high aspect ratio via, wherein the via length is 150 μm to 500 μm and the via diameter is 1 μm to 30 μm. As used herein, "aspect ratio" refers to the ratio of the average thickness of the glass substrate to the average diameter of the through-hole. By "high aspect ratio" is meant an aspect ratio greater than 3.

In various embodiments described herein, the through-hole 110 has an axial length L and a maximum diameter Φ_{Maximum of}And they satisfy the following equations:

in some embodiments, the through-hole 110 has an axial length L and a maximum diameter Φ_{Maximum of}And they satisfy the following equations:

although conventionally, the aspect ratio (L/phi)_{Maximum of}) Used as a critical parameter, but has been found to be L/(Φ)_{Maximum of})^1/2More than may be associated with the difficulties associated with electroless and electroplating of through-via vias. For example, it can be shown that two through-glass via geometries of the same aspect ratio can have different L/(Φ)_{Maximum of})^1/2Value, and L/(Φ)_{Maximum of})^1/2Higher value through-glass vias are more difficult to metallize. Without being bound by theory, it is believed that the compounds are due to autocatalytic reasons (in the absence ofIn the case of electro-plating) or charge transfer reactions (in the case of electroplating) cause reactions on the sidewalls that result in depletion of copper ions, the diffusion of copper ions to the center of the via needs to be sufficiently fast. Theoretical analysis of the diffusion reaction equation for the system shows the diffusion/reaction ratio and L/(Φ)_{Maximum of})^1/2And (4) in proportion. Specifically, L/(Φ)_{Maximum of})^1/2The higher the value of (a), the greater the difficulty of metallization without defects being formed in the via due to copper depletion.

Manufacturing method

The through-glass vias having a tapered shape may be fabricated by any suitable method. One method is to form a damage trace in the substrate 100 using a laser and then perform etching. Exemplary methods are described in U.S. patent No. 9,656,909 and U.S. patent application serial No. 62/588,615, which are incorporated herein by reference in their entirety. Another method is to modify the photosensitive glass with a laser and then etch it.

Fig. 8 shows a flow chart illustrating a process for metallizing through-glass vias. In step 810, a helium gas tight adhesion layer is deposited on the inner surface of the through hole in at least the first axial portion and the third axial portion. In a subsequent step 820, a metal connection is deposited within the through hole such that the metal connection is adhered to the helium gas-tight adhesion layer at least in the first and third axial portions.

A helium gas tight adhesion layer may be deposited on the inner surfaces in the first and third axial sections (and optionally in the second axial section) by any suitable method. For example, the length of the first and third axial portions in the z-dimension can be easily controlled using line of sight deposition (e.g., sputtering) methods and adjusting the deposition angle. The substrate may be rotated during deposition to ensure that the adhesion length is constant around the entire perimeter of the through-hole inner surface.

Helium gas tight adhesion layers in the form of films formed of metals, metal oxides or metal nitrides can be applied to glass surfaces using many different methods such as sputtering, electron beam deposition, ion beam deposition, atomic layer deposition, chemical vapor deposition and solution coating.

The metal connections may be deposited by any suitable means. One suitable method for depositing copper (and other metals) is to deposit a catalyst (e.g., Pd) on a helium gas tight adhesion layer, then electrolessly deposit copper, followed by electroplating copper. In various embodiments, the electroplating process comprises: using an electroplating bath comprising a metal salt, a supporting electrolyte and an additive, and applying a current density of greater than or equal to 1.5mA/cm²And less than or equal to 5mA/cm²Or greater than or equal to 1.5mA/cm²And less than or equal to 2.5mA/cm²The current of (2). The metal salt may be a salt of a metal forming the metal connector, e.g., CuSO₄。

Another suitable method may include: a metal connection is deposited at the "bottom" of the via and metal deposition is continued so that metal material can continue to grow and fill the via until the metal material reaches the "top" of the via. This process is sometimes referred to as "bottom-up electrolytic plating".

Other suitable methods for depositing the metal connections include filling the vias with a metal paste, and sintering or Chemical Vapor Deposition (CVD). Suitable methods for depositing copper are further described in U.S. patent publication US2017-0287728 (see, e.g., paragraphs [0004] - [0005], which is incorporated herein by reference in its entirety.

Thermal cycling

Glass and glass ceramic substrates having filled vias are often subjected to thermal cycling. Such thermal cycling may occur during device operation, or during manufacturing steps subsequent to via filling. In some embodiments, for example, the glass substrate may be subjected to thermal cycling for annealing.

As noted above, there is a large mismatch between the Coefficient of Thermal Expansion (CTE) of copper and other metals and the CTE of many glass and glass-ceramic materials. Due to CTE mismatch, the metal bond expands more rapidly upon heating than the surrounding glass or glass-ceramic substrate. Similarly, upon cooling, the metal connector shrinks faster than the surrounding substrate. This difference in expansion and contraction creates stresses that can lead to various failure mechanisms, such as delamination or cracking. These failure mechanisms can cause loss of hermeticity and other problems.

Delamination is a failure mechanism. Delamination occurs when a conductive metal (e.g., copper) is desorbed from the interior of the via. When there is a weak bond between the conductor and the substrate, the stresses caused by thermal cycling can lead to delamination. Delamination can lead to loss of gas tightness because gases and liquids can penetrate the substrate along the interface between the delaminated metal connection and the inner surface of the via.

By forming a sufficiently strong bond between the substrate and the metal connection, delamination may be reduced or eliminated. A helium gas tight adhesion layer disposed between the substrate and the metal connector, and on the inner surface of the through hole, may be used to form this bond. As used herein, "adhesion layer" refers to any layer or surface treatment that allows the bond between the metal connector and the substrate to be strong enough to withstand thermal cycling from 23 ℃ to 450 ℃.

While delamination may be prevented by forming a strong bond between the metal connector and the substrate, this stronger bond prevents the metal connector from moving relative to the substrate during thermal cycling. As a result, thermal cycling causes stresses in the substrate that result in cracking and loss of gas tightness.

The two-dimensional (2D) plane strain solution of the elastic classical Lame problem for predicting stress fields in glass centers is as follows:

wherein σ_rAnd σ_θAre radial and circumferential stress, respectively, and ε_T＝(α_f-α_m) Δ T is the misfit strain due to the thermal load Δ T. Material properties α, E and v are CTE, young's modulus and poisson's ratio, and subscripts f and m represent via (fiber) and glass (matrix), respectively.

Failure can occur in both the heating and cooling portions of the thermal cycle. During heating, the maximum expansion mismatch is at the hottest temperature. Most of the stress in the substrate is compressive at higher temperatures because the metal connectors expand more than the substrate. The circumferential tensile stresses in the glass that predominate during heating are around the metal joint and can lead to radial cracking. Which can be extended to the next via. During cooling, the maximum shrinkage mismatch is at the lowest temperature. Most of the stress in the substrate is tensile stress at lower temperatures because the metal connector contracts more than the substrate. The radial stresses that predominate during cooling can lead to cracking. Radial stress is tensile stress in the glass near the surface, which can cause glass circumferential cracking (C-cracking). For heating and cooling, the presence of shear stress along the interface can induce interfacial failure by delamination.

Towards the end of the cooling portion of the thermal cycle, the metal connector 150 contracts more than the substrate 100 due to the difference in CTE. Since the metal link 150 adheres to the substrate 100, the contraction of the metal link 150 pulls on the substrate 100, thereby placing the substrate 100 in tensile stress. Without sufficient freedom to supply force relief, the tensile stress would cause microcracks in the substrate 100, which in turn may cause loss of hermeticity.

Various embodiments described herein may exhibit helium gas tightness and not crack after being subjected to thermal cycling. More specifically, in various embodiments, the article is free of cracks and has less than 10 ℃ before and after heating to a temperature of 450 ℃ and cooling to a temperature of 23 ℃^-5atm cc/s, or even less than 10^-8Helium permeability of atm cc/s. In various embodiments described herein, the maximum diameter Φ of the through-hole 110 is maintained_{Maximum of}Less than or equal to 30 μm provides helium gas tightness while enabling the substrate and metal connection to shrink at different rates without creating tensile stresses sufficient to create microcracks.

Modeling

The geometry of fig. 9 was used for modeling, where the inner surface of the through-hole was conformally coated with copper everywhere, but not with an axial length of 75 μm — 37.5 μm on each side of the waist, where the through-hole was always filled. The via length was 300 μm. The first diameter and the second diameter are each 50 μm. Starting from both surfaces, a diameter of 50 μm is maintained along the axial length by a distance of 50 μm. Starting at 50 μm from each surface, the through-hole tapers inwardly to a diameter of 20 μm at the waist 125, which waist 125 is half the length along the axial direction. On both the first and second main surfaces, there is a 20 μm thick copper overlay. It is expected that the modeling results will extend to other via and metal connector shapes that have cavities in the metal connector and have a second axial portion of weak bonding between the metal connector and the substrate.

In one process flow for fabricating a real device, the geometry of fig. 29 including the adhered copper cap exists when the most severe thermal cycling occurs. Thereafter, the copper cap is removed and further processing may occur. The geometry of fig. 9 is related to the thermal cycle modeled here.

The modeling is based on the following parameters of Ryu SK, Lu KH, Zhang X, Im JH, Ho PS, Huang R.Impact of near-surface thermal stresses on interface Reliability for 3-D interconnects, IEEE Transactions on Device and Materials Reliability, 3 months 2011; 11(1):35- ("Ryu") theory of acquisition. From Ryu, when a via is provided in a wafer, there is an analytical solution for predicting the stress of the via and the wafer surface. However, there is no closed-loop solution to predict the stress through the thickness. Therefore, modeling is required. For modeling, a single isolated hole in a finite plate is modeled. Two-dimensional axial symmetry is assumed and a sufficiently small grid size of 0.5 μm is used. Modeling was performed using ANSYS v.19 structural modeling software.

For modeling, it was assumed that the glass was elastic and that the properties of fused silica were as follows: e (Young's modulus) is 73 GPa; v (poisson's ratio) 0.17 and α (coefficient of thermal expansion) 0.55 ppm/deg.c. Copper is assumed to have elastic perfect plastic properties and to have a temperature dependent yield stress. Fig. 10A shows a graph 1000 illustrating the stress-strain relationship for an elastic perfect plastic material. Fig. 10B shows a graph 1010 illustrating temperature dependent copper yield stress. The elastic properties of the copper used for modeling were: e (Young's modulus) 121 GPa; v (poisson's ratio) 0.35 and α (coefficient of thermal expansion) 17 ppm/deg.c. It is also assumed that the system comprising copper vias and fused silica is in a stress-free state at 25 ℃. The modeling calculates the stress after thermal cycling from 25 ℃ to 400 ℃ and back down to 25 ℃.

If the glass cracks, it will first crack where the first principal stress is greatest (i.e., "maximum first principal stress"). Referring to fig. 9, the modeling shows the highest first principal stress at two points. First, along line 190, a short distance from the interface between the helium gas-tight adhesion layer 122 and the substrate 100, there is a high maximum principal stress on the surface of the substrate 100. The first point of this high stress corresponds to the failure mechanism observed in the sample-microcracks in the surface.

Second, there is a maximum principal stress at point 192. This point is the principal stress component that induces crack initiation and propagation. Fig. 11 shows a plot of modeled first maximum principal stress and maximum radial stress along line 190 for different copper wall thicknesses. As shown in fig. 11, the maximum values of both the radial stress and the first maximum principal stress increase exponentially with temperature. For coatings having a thickness greater than or equal to 12 μm, the first maximum principal stress and the maximum radial stress intersect or exceed a threshold (for the configuration shown in fig. 9, the threshold for the first maximum principal stress is 140MPa and the threshold for the maximum radial stress is 80 MPa).

Additional experiments examined the percentage of vias that had cracks for different copper coating thicknesses after the wafer was annealed to a maximum temperature of 400 c. The coating thickness is measured at the first or second major surface and groups are formed based on integers of the coating thickness measurements. In other words, the group "8 μm" includes coating thicknesses of 8.00 μm to 8.99 μm, the group "9 μm" includes coating thicknesses of 9.00 μm to 9.99 μm, and so on. Based on experimental data, cracking did not occur in the through-holes until the coating thickness was greater than or equal to 12 μm. Based on modeling and experimental data, it was determined that the threshold stress for crack formation corresponds to a maximum first principal stress of 140MPa and a radial stress of 80 MPa. Therefore, for values below this stress threshold, no cracks are expected to occur.

Using a critical threshold for maximum principal stress of 140MPa, modeling will be used to determine the desired crack-free via diameter in a fully filled configuration (e.g., the configurations shown in fig. 2-7). The same material inputs for the metallized conformal copper feature shown in fig. 9 were used to model a fully filled via feature. For the tapered configuration, a taper ratio of 5:3 (maximum diameter: minimum diameter) is used.

To account for the variability of stress calculations related to the mesh size used in the model, an error of ± 10% was applied. Therefore, a lower limit of 126MPa is used to determine the critical via diameter required to eliminate cracks in a fully filled via.

Fig. 12 is a graph showing predicted glass surface stress around a via for a partially bonded, fully filled via. For the configurations shown in fig. 2 and 6 (FPV and FCV, respectively), the lower limit of the critical stress threshold is reached at a diameter less than or equal to 25 μm. However, the configuration shown in FIG. 4 (FTV) reaches a critical stress threshold at a diameter of less than or equal to 17 μm. Thus, FCV and FPV via shape configurations can have maximum via diameter tolerances to provide a partially bonded crack-free, air-tight, completely filled via.

Fig. 13 is a graph showing predicted glass surface stresses around fully bonded and fully filled vias. Based on this modeling, the configuration (FPV) of FIG. 3 reached a critical stress threshold at a diameter of 27 μm or less, the configuration (FCV) shown in FIG. 7 reached a critical stress threshold at a diameter of 30 μm or less, and the configuration shown in FIG. 5 reached a critical stress threshold at a diameter of 19 μm or less. The results of modeling of different via configurations and bonding parameters are summarized in table 1.

Table 1:

as can be seen from the data presented in table 1, the fully bonded via configuration can support a larger diameter than the partially bonded via configuration. Without being bound by theory, it is believed that in a fully bonded configuration, there is a greater distribution of stress throughout the thickness of the glass, as opposed to a partially bonded configuration, where stress may be concentrated near the center and surface of the substrate. In addition, experiments conducted demonstrated that the fully bonded configuration exhibited the metal connection protruding more from the through hole surface than the partially bonded configuration.

Conclusion

As used herein, the phrase "consisting essentially of … …" limits the scope of the claims to the specified materials or steps, as well as "those that do not materially affect the basic and novel characteristics of the claimed invention".

Those skilled in the relevant art will recognize and appreciate that many changes can be made to the various embodiments described herein, while still obtaining the beneficial results. It will also be apparent that some of the desired benefits of this embodiment can be obtained by selecting some of the features without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Accordingly, it is to be understood that this disclosure is not limited to the particular compositions, articles, devices, and methods disclosed unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The features illustrated in the drawings are exemplary of selected embodiments of the present description and are not necessarily depicted to scale. These drawing features are examples and are not intended to be limiting.

Unless otherwise stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, where a method claim does not actually recite an order to be followed by its steps or it does not otherwise specifically imply that the steps are to be limited to a specific order in the claims or specification, it is not intended that any particular order be implied.