Articles and methods of forming vias in substrates
11114309 · 2021-09-07
Assignee
Inventors
Cpc classification
B23K26/53
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/31
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T428/24273
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T428/24322
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B05D2203/30
PERFORMING OPERATIONS; TRANSPORTING
B32B3/26
PERFORMING OPERATIONS; TRANSPORTING
B05D3/107
PERFORMING OPERATIONS; TRANSPORTING
H01L21/3081
ELECTRICITY
B05D1/60
PERFORMING OPERATIONS; TRANSPORTING
B32B3/266
PERFORMING OPERATIONS; TRANSPORTING
H01L21/486
ELECTRICITY
B32B33/00
PERFORMING OPERATIONS; TRANSPORTING
C03C15/00
CHEMISTRY; METALLURGY
B32B17/06
PERFORMING OPERATIONS; TRANSPORTING
B23K2103/50
PERFORMING OPERATIONS; TRANSPORTING
International classification
B32B3/26
PERFORMING OPERATIONS; TRANSPORTING
H01L21/311
ELECTRICITY
H01L21/48
ELECTRICITY
B05D5/00
PERFORMING OPERATIONS; TRANSPORTING
B05D3/00
PERFORMING OPERATIONS; TRANSPORTING
C03C23/00
CHEMISTRY; METALLURGY
B05D1/00
PERFORMING OPERATIONS; TRANSPORTING
C03C15/00
CHEMISTRY; METALLURGY
B32B33/00
PERFORMING OPERATIONS; TRANSPORTING
H01L23/498
ELECTRICITY
Abstract
Methods of forming vias in substrates having at least one damage region extending from a first surface etching the at least one damage region of the substrate to form a via in the substrate, wherein the via extends through the thickness T of the substrate while the first surface of the substrate is masked. The mask is removed from the first surface of the substrate after etching and upon removal of the mask the first surface of the substrate has a surface roughness (Rq) of about less than 1.0 nm.
Claims
1. An article comprising: a substrate comprising a first surface and a second surface separated by a thickness T; at least one damage region within the substrate and extending from the first surface; and a first film layer disposed on an undamaged region of the first surface of the substrate, the first film layer selected from a group consisting of diphenylsilicon, phenylsilicon, methylphenylsilicon, and diamond-like carbon (DLC), wherein the first film layer is configured to be removed via oxidation from the first surface of the substrate without increasing a surface roughness (Rq) of the first surface of the substrate beyond Van der Waal bonding capability with an additional surface.
2. The article of claim 1, wherein the substrate is a glass, ceramic, or glass-ceramic.
3. The article of claim 1, wherein the first film layer is configured to be removed from the first surface of the substrate such that the first surface of the substrate has a surface roughness (Rq) of less than about 1.0 nm upon removal of the first film layer.
4. The article of claim 3, wherein the first film layer is configured to be removed from the first surface of the substrate such that the surface roughness (Rq) of the first surface of the substrate is less than about 0.3 nm.
5. The article of claim 3, wherein the first film layer is configured to be removed from the first surface of the substrate such that the surface roughness (Rq) of the first surface of the substrate is not substantially increased from a surface roughness (Rq) of the first surface of the substrate measured prior to application of the first film layer.
6. The article of claim 5, wherein the first film layer is configured to be removed from the first surface of the substrate such that the surface roughness (Rq) of the first surface of the substrate decreases from a surface roughness (Rq) of the first surface of the substrate measured after application of the first film layer.
7. The article of claim 1, further comprising a second film layer disposed on the undamaged region of the second surface of the substrate, the second film layer selected from a group consisting of diphenylsilicon, phenylsilicon, methylphenylsilicon, and diamond-like carbon (DLC).
8. The article of claim 7, wherein the second film layer is configured to be removed via oxidation from the second surface of the substrate without increasing a surface roughness (Rq) of the second surface of the substrate beyond Van de Waal bonding capability with an additional surface.
9. The article of claim 1, wherein the first film is DLC and the DLC is a hydrogenated amorphous carbon.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The embodiments set forth in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
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DETAILED DESCRIPTION
(9) Referring generally to the figures, embodiments of articles and methods of creating vias in substrates provided herein allow for the preservation of surface roughness (Rq) of substrates so that the substrates may be removably bonded to carriers for further processing. Reference will now be made in detail to various embodiments of articles and methods of forming vias in substrates, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. It is noted that the embodiments illustrated in the figures are not to scale and that relative sizes and widths were selected for illustrative purposes only.
(10) Embodiments preserve a pre-etch surface roughness of a substrate by utilizing mask layers during etching processes for via formation. By preserving the low surface roughness of the substrate during via formation, the substrate may be removably bonded to a carrier for further processing. After processing, the substrate may be removed from the carrier, such that the carrier may be reused for processing further substrates. Various embodiments of articles and methods for via formation are described in detail below.
(11)
(12)
(13) Referring to
(14) Referring now to
(15) Referring to block 11 of
(16) In another example, the at least one damage region 120 may not be a hole through the thickness T of the substrate 110 but rather a line of laser-induced damage formed by a pulsed laser. The pulsed laser may form the damage line by non-linear multi-photon absorption, for example. The rate of material removal within the line of laser-induced damage defining the at least one damage region 120 is faster than the rate of material removal outside of the at least one damage region 120 during the etching process. Exemplary ways for performing the laser damage creation and subsequent etching are disclosed in U.S. Pat. No. 9,278,886 and U.S. Pub. No. 2015/0166395, each of which is hereby incorporated by reference in its entirety.
(17) At block 12 of the flowchart 10 of
(18) The first and second masks 150a, 150b may be a variety of materials. For example, and without limitation, the mask may be made from diphenylsilicon, phenylsilicon, methylphenylsilicon, and diamond-like carbon (DLC). In some embodiments, the diamond-like carbon may be hydrogenated amorphous carbon. Such hydrogenated amorphous carbon films may be formed by depositing a hydrocarbon precursor compound such as compounds of formula C.sub.nH.sub.y, wherein n is 1 to 6 and y is 2 to 14. In some examples, n is 1 to 4 and y is 2 to 10. The hydrocarbon compounds can be linear or branched. In some examples, the coating layer formed by depositing a hydrocarbon precursor compound has a combined carbon and hydrogen content of at least 80 weight percent, at least 85 weight percent, at least 90 weight percent, or at least 95 weight percent. In some examples, the precursor compound is deposited to form the coating layer has a combined carbon and hydrogen content of at least 80 weight percent, at least 85 weight percent, at least 90 weight percent, at least 95 weight percent, at least 98 weight percent, at least 99 weight percent, or greater than 99.5 weight percent.
(19) Examples of hydrocarbon precursor compounds include alkanes. An alkane can include methane, ethane, propane, butane, pentane and hexane. In some examples, the hydrocarbon precursor compounds include at least one carbon-carbon double bond, for example, an alkene. An alkene can include ethylene, propylene, butylene, pentene and hexane. The carbon-carbon double bond in the alkene can be present at various positions in the compound, for instance, but-1-ene or but-2-ene. In yet other examples, the hydrocarbon precursor compounds includes at least one carbon-carbon triple bond, for example, an alkyne. An alkyne can include ethyne, propyne, butyne, pentyne and hexyne. In some examples, the carbon-carbon triple bond in the alkyne is present at various positions in the compound, for instance, 1-butyne or 2-butyne.
(20) It is contemplated that the first and second masks 150a, 150b may all be the same material. In other embodiments, the first and second masks 150a, 150b may be different materials. In embodiments wherein the mask material is diphenylsilicon, a diphenylsilicon film may be applied to at least one of the first and second surfaces 112, 114 of the substrate 110. Wherein the diphenylsilicon film is applied to both of the first and second surfaces 112, 114 there is a first diphenylsilicon film layer and a second diphenylsilicon film layer. Furthermore, though not shown, the diphenylsilicon film may be applied to edge surfaces of the substrate 110. The film may be applied by vapor deposition, for example. By way of example and not limitation, diphenylsilicon film is formed from diphenylsilane and hydrogen by chemical vapor deposition, preferably plasma enhanced chemical vapor deposition. Diphenylsilicon is a highly effective masking material and is resistant to acid erosion. As such, diphenylsilicon can withstand contact with hydrofluoric-mineral acid mixtures commonly used in etching processes. Furthermore, diphenylsilicon may be readily removed from glass surfaces without creating excessive surface roughness (Rq).
(21) In embodiments, the mask material is hydrogenated amorphous carbon a hydrogenated amorphous carbon film may be applied to at least one of the first and second surfaces 112, 114 of the substrate 110. Wherein the hydrogenated amorphous carbon film is applied to both of the first and second surfaces 112, 114 there is a first hydrogenated amorphous carbon film layer and a second hydrogenated amorphous carbon film layer. The hydrogenated amorphous carbon may be deposited by chemical vapor deposition (CVD) techniques, and like methods. Specific examples of CVD techniques include CVD, low pressure CVD, atmospheric pressure CVD, Plasma Enhanced CVD (PECVD), atmospheric plasma CVD, atomic layer deposition (ALD), plasma ALD, and chemical beam epitaxy. In another example, the coating layer can be deposited by a pyrolytic torch at temperatures above 600° C., above 800° C., or above 1,000° C., including any ranges and subranges therebetween. A gas mixture for forming the coating layer, which contains the hydrocarbon compound, may also comprise a controlled amount of another compound, for example, a carrier gas or working gas. The other compound can include air, oxygen, nitrous oxide, carbon dioxide, water vapor, or hydrogen peroxide, and/or one or more an inert gas, for example, helium, neon, argon, krypton, xenon.
(22) One of the biggest challenges of any selective etching process in which a mask is used is mask removal. The mask material must be tough enough to resist etching, but also must be readily removable without damaging the substrate. Polymer masks, such as photoresist, usually involve soaking the masked substrate in hot solvents with mechanical agitation. Often, inorganic masks are removed by plasma etching. For example, PECVD deposited silicon carbine (SiC) is generally removed with a fluorine containing plasma. However, under such a process, the substrate is also etched during removal, thus increasing the surface roughness (Rq) of the substrate. Diphenylsilicon is unique to traditional masking materials in that it is particularly susceptible to oxidation. During oxidation, the organic groups are pyrolized and removed and the silicon is oxidized to form silicon dioxide. This process allows for the surface roughness of the substrate to be substantially preserved. As shown in Example 3 below, hydrogentated amorphous carbons may also be oxidized to remove the mask. It is contemplated that other plasma polymer films and materials may have substantially similar benefits to diphenylsilicon. For example, and not a limitation, phenylsilicon, methylphenylsilicon, and diamond-like carbon (DLC).
(23) Referring to block 13 of the flowchart 10 of
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(25) After the at least one via 124 has been opened to a desired diameter, the first and second masks 150a, 150b may be removed from the substrate 110 (block 14 of
(26) After the via 124 has been etched, the substrate 110 may be subjected to additional processing steps for acquiring additional interposer properties.
(27) However, the challenge of using Van der Waals surface bonding techniques for bonding substrates is that the roughness of the surfaces' being bonded together impacts the ability of the surfaces to be bonded. As a non-limiting example, surface roughness (Rq) greater than about 1.0 nm may substantially prevent spontaneous bonding or result in weak bonding of the substrate 110 to the carrier 200. Weak bonding may permit liquids from one or more processes to infiltrate between the substrate 110 and the carrier 200, thereby leading to de-lamination or to process contamination as residue from one process may impact later processes.
(28) The carrier 200 may be of any suitable material, such as glass, for example. The carrier 200 need not be glass, but instead may be ceramic, glass-ceramic, or metal, for example. If made of glass, the carrier 200 may be of any suitable composition including, but not limited to, aluminosilicate, borosilicate, aluminoborosilicate, soda lime silicate, and may be either alkali containing or alkali-free depending upon its ultimate application. The carrier 200 may have any suitable thickness. Additionally, the carrier 200 may be made of one layer, as shown, or multiple layers (including multiple thin sheets) that are bonded together (e.g., by lamination). Furthermore, the coefficient of thermal expansion of the carrier 200 may be substantially matched with that of the substrate 110 to prevent warping of the substrate 110 or decoupling of the substrate 110 from the carrier 200 during processing at elevated temperatures. The surface roughness (Rq) of the substrate 110 is additive to the surface roughness of the carrier 200. Therefore, it is generally recommended that the carrier 200 have a surface roughness (Rq) less than or equal to 0.6 nm.
(29) Referring to block 16 of
EXAMPLES
(30) The following Comparative Example and Examples 1 and 2 compare changes in surface roughness (Rq) as a result of acid etching and the removal of diphenylsilicon films. In each example, the glass samples were 0.7 mm thick and did not have damage regions. The surface roughness (Rq) of each sample was measured by a Veeco Dimension ICON AFM with the following parameters: 1 Hz, 512 scans/line, and 2 micron image size.
Comparative Example
(31) In this comparative example, the surface roughness (Rq) of an unmasked Eagle XG® glass sample was measured periodically while the glass sample was etched by a 6M hydrofluoric and 1.6M nitric acid mixture. It was established that surface roughness (Rq) greater than 1 nm is achieved in less than 10 minutes at room temperature with mechanical (non-ultrasonic) agitation. This amount of time corresponded to an etching depth of 40 μm. The results are tabulated in TABLE 1 below. It is noted that surface roughness's (Rq) in some instances of over 1.0 nm may lead to weak or ineffectual Van der Waals bonding.
(32) TABLE-US-00001 TABLE 1 Time 5 minutes 10 minutes 15 minutes Surface Roughness (Rq) 1.11 nm 1.67 nm 1.46 nm
Example 1
(33) In this example, the surface roughness (Rq) of an Eagle XG® glass sample was measured before application, after application, and after removal of a diphenylsilicon film. The diphensylsilicon film was deposited in an Applied Materials P5000 Universal Chemical Vapor Deposition (CVD) System with the following parameters: 390° C., volumetric flow rate of 500 sccm diphenylsilicane, volumetric flow rate of 600 sccm Hydrogen (H.sub.2), 9 torr, 210 mils. gap, 300 W RF, diphenylsilane bubbler at 80° C. The diphenylsilicon film had a thickness of 60 nm. The diphenylsilicon film was removed by a Gasonics L3510 photoresist stripper having the following parameters: 200° C., 1200 mT, 1000 sccm N2, 100 sccm O2, 900 W, 2.54 GHz, endpoint control with 30 sec. over-etch. The results, tabulated below in TABLE 2, illustrate the surface roughness (Rq) increasing only slightly, while still being well within the range required for Van der Waals bonding as described above. It is noted that the glass substrate was not subjected to acid etching in this example.
(34) TABLE-US-00002 TABLE 2 Status Before After Application Application After Removal Surface Roughness (Rq) 0.193 nm 0.298 nm 0.272 nm
Example 2
(35) In this example, the surface roughness (Rq) of an Eagle XG® glass sample was measured after application of the diphenylsilicon film, after 15 minutes of etching, and after removal of a diphenylsilicon film. As in example 1, the diphensylsilicon film was deposited in an Applied Materials P5000 Universal CVD System with the following parameters: 390° C., volumetric flow rate of 500 sccm diphenylsilicane, volumetric flow rate of 600 sccm Hydrogen (H.sub.2), 9 torr, 210 mils. gap, 300 W RF, diphenylsilane bubbler at 80° C. The diphenylsilicon film had a thickness of 60 nm. The etchant was a mixture of by a 3M hydrofluoric acid and 1M nitric acid and incorporated mechanical (non-ultrasonic) agitation. As in the above example, the diphenylsilicon film was removed by a Gasonics L3510 photoresist stripper having the following parameters: 200° C., 1200 mT, 1000 sccm N2, 100 sccm O2,900 W, 2.54 GHz, endpoint control with 30 sec. over-etch. The results, tabulated below in TABLE 3, illustrate the surface roughness (Rq) being well within the range required for Van der Waals bonding as described above. This example also illustrates diphenylsilicon's resistance to acid erosion as discussed herein.
(36) TABLE-US-00003 TABLE 3 Status After After Application 15 Minute Etch After Removal Surface Roughness (Rq) 0.269 nm 0.259 nm 0.201 nm
Example 3
(37) In this example, 6 samples of Eagle XG® glass wafers having a 0.7 mm thickness, a diameter of 150 mm and no damage regions had an amorphous hydrogenated carbon film mask applied. The mask was deposited from ethylene and hydrogen in a Nextral NE500 reactive ion etcher under the conditions of 30 sccm ethylene, 70 sccm hydrogen, at a pressure of 60 mT, at a power of 800 W and a frequency of 13.56 MHz. The deposition time and thickness of the mask (as deposited) is listed in Table 4 below. The index of refraction of the mask was also measured (as deposited) at 632 nm. The thickness and index of refraction were measured using a N&K analyzer. After depositing the mask, the samples were etched for approximately 15 minutes at 23° C. in an etching solution of 10 wt % hydroflouric acid and 7 wt % nitric acid. The thickness of the mask and the index of refreaction at 632 nm was measured again after etching using a N&K analyzer and are listed in Table 4 below. The changes in thickness and index were within the range of experimental error. Next the mask was removed by a Gasonics L3510 photoresist stripper having the following parameters: 200° C., 1200 mT, 1000 sccm N2, 100 sccm O2,900 W, 2.54 GHz, endpoint control with 30 sec. over-etch. and the surface roughness (Rq) of each sample was measured by a Veeco Dimension ICON AFM with the following parameters: 1 Hz, 512 scans/line, and 2 micron image size. The results are listed in Table 4 below.
(38) As can be seen in Table 4, Sample 7 did not have a mask and was etched under the same conditions as the six samples with the mask. The surface roughness (Rq) of the unmasked Sample 7 was significantly higher 1.13 compared to 0.240 to 0.278. This demonstrates that the mask
(39) TABLE-US-00004 TABLE 4 Deposi- Refractive Refractive Rq tion Thickness Thickness Index at Index at (nm) Sam- Time (nm) as (nm) after 632 nm as 632 nm After ple (s) deposited etching deposited etching removal 1 30 22.86 23.78 1.809 1.791 0.278 2 59 33.52 32.85 2.001 2.013 0.241 3 89 46.02 46.14 2.066 2.065 0.267 4 160 76.93 76.63 2.119 2.119 0.257 5 178 80.81 80.39 2.120 2.119 0.240 6 237 110.80 110.90 2.118 2.120 0.248 7 0 0 0 0 1.13
(40) Other materials provided herein may be deposited on substrates using an Applied Materials P5000 Universal CVD System having similar parameters. For example, phenylsilicon films may deposited from organosilicon hydride precursors with a hydrogen carrier gas in an Applied Materials P5000 Universal CVD system from phenylsilane and hydrogen with the following conditions: 390° C., volumetric flow rate of 120 sccm phenylsilane, and volumetric flow rate of 600 sccm Hydrogen (H.sub.2), 9 Torr. pressure, 210 mils. gap, and 300 W 13.56 MHz RF. The phenylsilane ampoule may be at 30° C. The deposition rate may be nearly 1000 nm/min. Methylphenylsilicon films may deposited us a Applied Materials P5000 Universal CVD System with the following process conditions: 390° C., volumetric flow rate of 200 sccm methylphenylsilane, volumetric flow rate of 600 sccm Hydrogen (H.sub.2), 9 torr, 210 mils. gap, and 450 W RF. The methylphenylsilane ampoule may be at 80° C. Other precursors such as organosilicon halides would produce similar results.
(41) It should be understood that embodiments described herein provide for forming vias in substrates without substantially increasing the surface roughness (Rq) of the substrate. By preserving the low surface roughness of the substrate during via formation, the substrate may be removably bonded to a carrier for further processing. After processing, the substrate may be removed from the carrier, such that the carrier may be reused for processing further substrates. Furthermore, the through vias may be made substantially cylindrical because they may be etched from both ends.
(42) It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.