Glass through hole metallization method

Abstract

The invention relates to the field of semiconductor packaging, in particular to a glass through hole metallization method which comprises the following steps: providing a glass substrate which is provided with a first surface and a second surface which are opposite to each other, and performing laser irradiation to denature glass in a first surface area in which a glass through hole and a first alignment mark need to be manufactured so as to form a denatured area; removing the denatured glass in the denaturation area to form a glass blind hole and a first alignment mark; a mask with a through hole and a second alignment mark is manufactured, the through hole corresponds to the glass blind hole, and the second alignment mark corresponds to the first alignment mark; performing alignment overlay on the glass substrate and the mask to enable the through hole and the glass blind hole to form a channel; filling the channel with conductive slurry, removing the mask, after curing, carrying out planarization processing on the first surface of the glass substrate, and carrying out thinning and planarization processing on the second surface, so that two ends of the glass blind hole are exposed from the first surface and the second surface respectively to form a glass through hole, rapid, simple, high-precision and low-cost conductive filling of the glass through hole is realized.

Description

Technical Field

[0001] The invention relates to the field of semiconductor packaging, and in particular to a method for metallizing a through-glass via. Background Art

[0002] With the development of the electronics field, industries such as AI, 5G, and high-performance computing have increasingly higher requirements for chip computing power. In order to meet the computing power requirements, it is necessary to continuously reduce the line width spacing to increase the transistor density per unit area of ​​the microchip, but due to the limitations of Moore's Law, it is impossible to continuously increase the transistor density. However, through bonding, through-silicon vias, and through-glass vias interconnection technologies, multiple chips can be integrated in the vertical direction, greatly improving the system integration and meeting the increasing computing power requirements. Compared with silicon-based substrates, glass substrates have better electrical properties and lower parasitic capacitance, which is more conducive to the transmission of high-frequency signals. At the same time, glass substrates have excellent optical properties, and different functions can be achieved by adjusting the composition of glass, and their applications are wide. The common process for filling glass through holes is electroplating copper technology. Specifically, due to the insulation of the glass substrate, it is necessary to magnetron sputter the glass substrate in advance to deposit a seed layer on its surface and the inner wall of the hole for subsequent electroplating and conduction. During the subsequent electroplating process, current is applied to the glass substrate to make it a plating cathode, and then its surface is contacted with the electroplating solution. The copper ions in the plating solution absorb electrons to form copper and attach to the seed layer until the glass through hole is filled with copper metal. This process requires the formation of a seed layer in advance, which is costly, takes a long time to process, has many factors affecting the process, is prone to defects, and will cause a series of chemical pollution problems. Therefore, it is urgent to provide a method for metallizing glass through holes. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention provides a method for through-glass via metallization, which adopts a mask vacuum printing technology, and after high-precision alignment through alignment marks, liquid conductive paste is accurately introduced into the glass blind hole through the aligned mask, and then pressure vacuum annealing treatment is used to solidify the conductive paste in the glass blind hole to form a dense conductive filling, and finally a glass through hole is formed by flattening treatment and back thinning, thereby realizing fast, simple, high-precision and low-cost conductive filling of the glass through hole.

[0004] To this end, the present invention provides a method for through-glass via metallization, comprising the following steps:

[0005] Providing a glass substrate, the glass substrate having a first surface and a second surface opposite to each other, and causing the glass of a first surface area where a through-glass hole and a first alignment mark are to be formed to be denatured by laser irradiation to form a denatured area;

[0006] Removing the denatured glass in the denatured area to form a glass blind hole and a first alignment mark;

[0007] Manufacturing a mask, wherein the mask has a through hole and a second alignment mark, wherein the through hole corresponds to the glass blind hole, and the second alignment mark corresponds to the first alignment mark;

[0008] Aligning and overlaying the glass substrate and the mask so that the through hole and the glass blind hole form a channel;

[0009] Filling the channel with a conductive paste, removing the mask, curing the conductive paste, and planarizing the first surface of the glass substrate;

[0010] The second surface of the glass substrate is thinned and planarized so that two ends of the glass blind hole are exposed from the first surface and the second surface respectively to form the glass through hole.

[0011] In order to solve the deficiencies in the prior art, the present invention uses a mask plate to directly fill the glass blind hole with metal, and then thins it to form a through hole, so there is no need to first sputter and deposit a seed layer to make it conductive, which reduces the process flow. At the same time, it can replace the wet electroplating process, and there is no need to use expensive electroplating solution, so the processing cost can be reduced, and there is no chemical pollution caused by a series of subsequent scrapping of the plating solution. In addition, the type of conductive slurry is not particularly limited, and its characteristics (such as resistivity, CTE, etc.) can be adjusted by adjusting the type of conductive nanoparticles in the conductive slurry and the ratio of various substances, so it can meet different needs and has a wider range of applications.

[0012] According to an embodiment of the present invention, the aperture of the glass blind hole is smaller than the aperture of the through hole, thereby preventing the glass blind hole from being unable to be filled after the mask is shifted.

[0013] According to an embodiment of the present invention, the diameter of the glass blind hole is 10 μm-100 μm.

[0014] According to an embodiment of the present invention, the diameter of the through hole is 15 μm-105 μm.

[0015] According to an embodiment of the present invention, the shapes of the first alignment mark and the second alignment mark are at least one of a cross mark and a circular mark.

[0016] According to an embodiment of the present invention, the shapes of the first alignment mark and the second alignment mark are a combination of a cross mark and a circle mark;

[0017] wherein the cross mark in the first alignment mark has a first horizontal axis and a first vertical axis, the lengths of the first horizontal axis and the first vertical axis are equal, and the widths of the first horizontal axis and the first vertical axis are equal;

[0018] The cross mark in the second alignment mark has a second horizontal axis and a second vertical axis, the lengths of the second horizontal axis and the second vertical axis are equal, and the widths of the second horizontal axis and the second vertical axis are equal;

[0019] The length of the first horizontal axis is smaller than the length of the second horizontal axis, and the width of the first horizontal axis is smaller than the width of the second horizontal axis;

[0020] The diameter of the circular mark in the first alignment mark is smaller than the diameter of the circular mark in the second alignment mark.

[0021] According to an embodiment of the present invention, the glass substrate and the mask are aligned and overlaid so that the through hole and the glass blind hole form a channel, including: identifying the first alignment mark of the glass substrate and the second alignment mark of the mask by an optical system, and adjusting the position of the glass substrate by an alignment system so that the first alignment mark and the second alignment mark are aligned. In this way, high-precision alignment can be achieved, avoiding the phenomenon of no filling and non-conductivity in the hole caused by mask offset.

[0022] According to an embodiment of the present invention, the optical system comprises a high-power microscope;

[0023] The alignment system includes a moving device, which is used to fix and move the glass substrate. Thus, the alignment accuracy can be within ±1 μm.

[0024] According to an embodiment of the present invention, the conductive paste is filled under a vacuum degree of 20 Pa-30 Pa. Thus, the generation of voids during the conductive paste filling is avoided.

[0025] According to an embodiment of the present invention, the curing conditions of the conductive paste include: controlling the oxygen content of the system to be 0ppm-10ppm, the curing temperature to be 200℃-300℃, and the pressure of the system to be 5kg / cm 2 -8kg / cm 2 The conductive paste is cured under pressure and vacuum conditions for 30-40 minutes, and then cured under vacuum conditions for 30-40 minutes, with a vacuum degree of 60-80 Torr. This avoids oxidation of the conductive paste. At the same time, the conductive paste in the hole can be densified through pressure and vacuum annealing curing treatment, avoiding the generation of bubbles in the hole during annealing.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 A schematic diagram showing the formation of a denatured zone by laser irradiation of a glass substrate in the present invention is shown;

[0029] Figure 2 A schematic diagram showing the process of removing the denatured region to form a glass blind hole and a first alignment mark in the present invention is shown;

[0030] Figure 3 A schematic diagram of the mask preparation process in the present invention is shown;

[0031] Figure 4 A schematic diagram showing the alignment and overlaying of the mask and the glass substrate in the present invention is shown;

[0032] Figure 5 A schematic diagram showing the filling of the conductive paste in the present invention;

[0033] Figure 6 A schematic diagram showing the removal of the mask and the curing of the conductive paste in the present invention is shown;

[0034] Figure 7 A schematic diagram showing a planarization process for a first surface of a glass substrate in the present invention is shown;

[0035] Figure 8 A schematic diagram showing the thinning and planarization treatment of the second surface of the glass substrate in the present invention is shown.

[0036] Reference numerals:

[0037] Glass substrate 1, first surface 11, second surface 12, modified area 2 for forming glass blind hole, modified area 3 for forming first alignment mark, first longitudinal axis width d1, first transverse axis length d2, glass blind hole 4, mask 5, through hole 6, second alignment mark 7, second longitudinal axis width d3, second transverse axis length d4, conductive paste 8. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0039] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0040] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0041] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0042] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0043] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0044] In the prior art, when the conventional electroplating technology is used to fill the through-glass holes with conductivity, since the glass substrate and the side walls are not conductive, it is necessary to perform magnetron sputtering metallization on both sides of the glass substrate and in the hole in advance, which has high process difficulty and cost. Moreover, when the depth-to-width ratio of the through-glass hole is relatively high, it is easy to cause incomplete metal coverage in the hole, and voids will appear after subsequent electroplating, affecting reliability. At the same time, the hole wall metal grows at a slower rate, the processing time of the single-chip substrate is longer, and the processing efficiency is lower. In addition, when the through-glass hole is conductively filled, a corresponding electroplating solution is required as a metal source, and the cost and maintenance cost of the electroplating solution are high, and it has certain pollution.

[0045] To this end, the present invention provides a method for through-glass via metallization, comprising the following steps:

[0046] (1) A glass substrate is provided, wherein the glass substrate has a first surface and a second surface opposite to each other, and the glass of the first surface area where the glass through hole and the first alignment mark are to be formed is denatured by laser irradiation to form a denatured area. Figure 1 .

[0047] Among them, the laser is irradiated and propagated on the surface of the glass substrate. During the short irradiation process, higher energy is transmitted into the glass, causing thermal damage in the local area and changing its density, thereby producing a modified area that is sensitive to subsequent etching.

[0048] According to a specific embodiment of the present invention, the type of laser is not particularly limited, and those skilled in the art may make a reasonable selection according to actual needs. As some specific examples, picosecond infrared laser may be selected.

[0049] According to a specific embodiment of the present invention, the shape of the first alignment mark is not particularly limited, and those skilled in the art can make a reasonable selection according to actual needs. As some specific examples, a cross mark and / or a circular mark can be selected, preferably a combination of a cross mark and a circular mark, wherein the number of the cross mark and the circular mark is not particularly limited, and those skilled in the art can select according to actual needs. As some specific examples, it can be one or more, for example, the first alignment mark includes a cross mark and multiple circular marks, wherein the circular marks are evenly arranged around the cross mark, including but not limited to Figure 1 Preferably, the cross mark in the first alignment mark has a first horizontal axis and a first vertical axis, the lengths d2 of the first horizontal axis and the first vertical axis are equal, and the widths d1 of the first horizontal axis and the first vertical axis are equal.

[0050] According to a specific embodiment of the present invention, the number of the first alignment marks and glass through holes is not particularly limited, and those skilled in the art may select them according to actual needs. As some specific examples, they may be one or more, preferably multiple.

[0051] According to a specific embodiment of the present invention, the distribution of the first alignment marks can also be selected according to actual needs, for example, evenly distributed around the glass substrate.

[0052] According to a specific embodiment of the present invention, the arrangement of the through-glass holes may also be selected according to actual needs, for example, multiple through-glass holes may be evenly arranged.

[0053] (2) removing the denatured glass in the denatured area to form a glass blind hole and a first alignment mark. Figure 1-2 .

[0054] Since the etching rate of the modified area is higher than that of the unmodified area, the glass blind hole and the first alignment mark can be formed in one step in this step.

[0055] According to a specific embodiment of the present invention, the removal method includes but is not limited to chemical etching. Specifically, the glass substrate obtained in step (1) can be placed in an alkaline solution for chemical etching. The alkaline solution can be potassium hydroxide, and its concentration can be determined according to actual conditions. As some specific examples, its concentration can be 6mol / L-10mol / L. The etching temperature can be 80℃-110℃, such as 80℃, 90℃, 100℃, 110℃, etc., and the etching time can be 5h-10h, such as 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0056] According to a specific embodiment of the present invention, the cross-sectional shape of the glass blind hole is not particularly limited, and can be rectangular, conical, or other geometric shapes, preferably conical. In subsequent processes, through holes can be formed by thinning, which avoids the double-sided sputtering step.

[0057] (3) Making a mask, wherein the mask has a through hole and a second alignment mark, wherein the through hole corresponds to the glass blind hole, and the second alignment mark corresponds to the first alignment mark. Figure 3 .

[0058] According to a specific embodiment of the present invention, the aperture of the glass blind hole 4 is smaller than the aperture of the through hole 6. Thus, it is prevented that the glass blind hole cannot be filled after the mask is shifted.

[0059] Specifically, the aperture of the glass blind hole is 10μm-100μm, which can be selected according to actual needs. As some specific examples, the aperture of the glass blind hole can be 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc.

[0060] Specifically, the aperture of the through hole is 15μm-105μm, which can be selected according to actual needs. As some specific examples, the aperture of the through hole can be 15μm, 25μm, 35μm, 45μm, 55μm, 65μm, 75μm, 85μm, 95μm, 105μm, etc.

[0061] According to a specific embodiment of the present invention, the shape of the second alignment mark is not particularly limited, and those skilled in the art may make a reasonable selection according to actual needs. As some specific examples, a cross mark and / or a circular mark may be selected, preferably a combination of a cross mark and a circular mark, including but not limited to Figure 3 Preferably, the cross mark in the second alignment mark has a second horizontal axis and a second vertical axis, the lengths d4 of the second horizontal axis and the second vertical axis are equal, and the widths d3 of the second horizontal axis and the second vertical axis are equal.

[0062] According to a specific embodiment of the present invention, the length of the first horizontal axis is smaller than the length of the second horizontal axis, the width of the first horizontal axis is smaller than the width of the second horizontal axis, and the diameter of the circular mark in the first alignment mark is smaller than the diameter of the circular mark in the second alignment mark, thereby preventing the glass blind hole from being unable to be filled after the mask is offset.

[0063] Specifically, the width of the first horizontal axis in the first alignment mark can be selected to be 20μm, the length of the first horizontal axis can be selected to be 190μm, and the diameter of the circular mark can be selected to be 20μm; the width of the second horizontal axis in the second alignment mark can be selected to be 25μm, the length of the first horizontal axis can be selected to be 200μm, and the diameter of the circular mark can be selected to be 25μm.

[0064] According to a specific embodiment of the present invention, the material of the mask can be reasonably selected according to actual needs. As some specific examples, different metal materials can be selected, such as Cr, Al, Fe, etc.

[0065] According to a specific embodiment of the present invention, the method for preparing the mask is not particularly limited, and those skilled in the art may make a reasonable selection according to actual needs. As some specific examples, the mask may be prepared by photolithography technology. Figure 3 That is, a photoresist is spin-coated on a metal substrate, and after curing, a laser direct writing lithography machine is used to transfer a second alignment mark and a through-hole pattern corresponding to the first alignment mark onto the photoresist, and after developing and curing, RIE (reactive ion etching) is used to etch out a corresponding pattern, and then the photoresist is removed to obtain the mask. The mask can be cleaned and reused.

[0066] (4) Aligning and overlaying the glass substrate and the mask so that the through hole and the glass blind hole form a channel. Figure 4 .

[0067] According to a specific embodiment of the present invention, this step may specifically include: identifying a first alignment mark of the glass substrate and a second alignment mark of the mask by an optical system, and adjusting the position of the glass substrate by an alignment system so that the first alignment mark and the second alignment mark are aligned.

[0068] Specifically, the optical system includes a high-power microscope, and the alignment system includes a moving device, and the moving device is used to fix and move the glass substrate. That is, the glass substrate is fixed on the sample stage, the metal mask is fixed on the corresponding clamping device, the alignment mark on the mask is observed through the high-power microscope, and the direction position of the glass substrate is adjusted through the moving device, so that the first alignment mark and the second alignment mark are aligned, and the alignment accuracy can reach within ±1μm, so as to achieve high-precision hole filling and avoid the phenomenon of no filling and non-conductivity in the hole caused by mask offset.

[0069] Specifically, the high-power microscope may be disposed above the mask to facilitate observation of the alignment marks on the mask.

[0070] According to a specific embodiment of the present invention, this step further includes contacting and fixing the glass substrate and the metal mask, wherein the two can be brought into contact by using N2 pressure.

[0071] (5) Filling the channel with a conductive paste, removing the mask, curing the conductive paste, and planarizing the first surface of the glass substrate. Figure 5-7 .

[0072] According to a specific embodiment of the present invention, the conductive paste refers to a paste made by dispersing conductive nanoparticles (such as copper, silver, gold and graphite, etc.) in an organic adhesive such as epoxy resin, which can form electrodes and conductive circuits by printing and other methods, and the dispersed conductive nanoparticles can conduct electricity after contacting each other after annealing and curing. Its composition can be reasonably selected according to actual needs, for example, the type and ratio of conductive nanoparticles in the conductive paste can be adjusted according to different characteristics (resistivity, CTE, etc.) to meet different needs.

[0073] According to a specific embodiment of the present invention, the filling of the conductive paste is preferably performed under vacuum conditions, for example, the conductive paste is filled while the cavity is maintained at 20Pa-30Pa to avoid bubbles during filling and after curing.

[0074] According to a specific embodiment of the present invention, the filling of the conductive paste can be specifically as follows: injecting the conductive paste onto the mask plate, and using a PFA scraper to squeeze the conductive paste into the channel, and performing a vacuum treatment at the same time, so that the conductive paste is completely filled into the channel. PFA is a fluorine-containing polymer material with excellent strength, heat resistance, corrosion resistance and weather resistance, and extremely high purity. It can be used for wafer clamping, transmission, etc., and no external pollution will be introduced during the production process.

[0075] According to a specific embodiment of the present invention, the curing conditions of the conductive paste are preferably: the oxygen content of the control system is 0ppm-10ppm, the curing temperature is 200℃-300℃, and the pressure of the control system is 5kg / cm 2 -8kg / cm 2 The conductive paste is cured under pressure and vacuum conditions for 30-40 minutes, and then cured under vacuum conditions for 30-40 minutes, with a vacuum degree of 60-80 Torr. This avoids oxidation of the conductive paste. At the same time, through pressure and vacuum annealing and curing treatment, the conductive paste in the hole can be densified, avoiding the generation of voids in the hole.

[0076] Specifically, the filled glass substrate can be placed in a pressure vacuum oven for baking, and the oxygen content needs to be kept below 10ppm during baking, such as 0ppm, 1ppm, 2ppm, 3ppm, 4ppm, 5ppm, 6ppm, 7ppm, 8ppm, 9ppm, 10ppm, etc., to prevent oxidation of the conductive paste. The baking temperature is 200℃-300℃, such as 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, etc.

[0077] Specifically, the curing of the conductive paste can be divided into two stages: a pressurization stage and a vacuum stage. In the pressurization stage, the system pressure is controlled to be 5 kg / cm 2 -8kg / cm2 Curing is carried out under the following conditions, and the curing time may be 30min-40min. At this stage, the conductive slurry filled in the channel can be densified. In the vacuum stage, the vacuum degree of the system is controlled to be below 80Torr, for example, 60Torr-80Torr, and the time may be 30min-40min. At this stage, the gas generated during baking can be extracted to prevent bubbles from appearing inside the hole during annealing.

[0078] According to a specific embodiment of the present invention, the planarization treatment may be performed by mechanical polishing or the like, and specifically may be: chemical mechanical polishing is performed on the glass substrate after annealing to remove excess conductive slurry on the surface and improve the flatness of the substrate.

[0079] (6) The second surface of the glass substrate is thinned and flattened so that two ends of the glass blind hole are exposed from the first surface and the second surface respectively to form the glass through hole. Figure 8 .

[0080] According to a specific embodiment of the present invention, the thinning process may be performed by mechanical polishing or the like, and specifically may be: thinning and chemically mechanically polishing the second surface of the glass substrate to expose the metal layer on the second surface to form a through-glass hole.

[0081] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0082] Example 1

[0083] A method for through-glass via metallization comprises the following steps:

[0084] (1) Laser modification: Picosecond infrared laser is used to irradiate and propagate on the surface of the glass substrate to produce a modified area that is sensitive to chemical etching. The glass blind hole and alignment mark patterns are processed simultaneously. The size of the glass blind hole is 10μm-100μm. The cross alignment mark in the alignment mark is 20μm wide and 190μm long, and is distributed around the glass substrate.

[0085] (2) Chemical etching: The laser-processed glass substrate is immersed in a 6-mol / L-10-mol / L KOH solution at 80-110°C for 5-10 hours. Since the chemical etching rate of the modified area is higher than that of the unmodified area, glass blind holes and alignment marks can be formed in this step.

[0086] (3) Mask fabrication: Spin-coat photoresist on a Cr metal substrate, soft-bake and solidify the photoresist, transfer the corresponding alignment marks and through-hole patterns onto the photoresist using a laser direct-write lithography machine, develop and bake and solidify, use RIE etching to fabricate the corresponding patterns, and remove the photoresist; wherein the cross alignment mark in the mask is 25 μm wide and 200 μm long, and is distributed around the metal mask; the through-hole diameter in the mask is designed to be 5 μm larger than the glass through-hole diameter;

[0087] (4) Alignment of substrate and mask: Fix the glass substrate on the sample stage and the metal mask on the corresponding fixture. Observe the alignment mark of the mask through a high-power microscope on the top of the mask, adjust the position of the glass substrate in the XYθ direction, and align the two. The alignment accuracy can reach within ±1μm. After alignment, use N2 pressure to push the glass substrate towards the metal mask so that the two are in contact and fixed;

[0088] (5) Conductive slurry filling: Inject the conductive slurry onto the metal mask through the pipeline, and use a PFA scraper to squeeze the conductive slurry into the corresponding mask through-holes. At the same time, evacuate the cavity to keep the vacuum degree below 30Pa, and the conductive slurry can be further filled into the glass blind hole;

[0089] (6) Baking and curing: The filled glass substrate is placed in a pressure vacuum oven for baking. The oxygen content needs to be kept below 10 ppm during baking. The baking temperature is 200°C-300°C and the baking time is 60 minutes, of which the pressurization stage is 30 minutes and the pressure is maintained at 5 kg / cm 2 -8kg / cm 2 , densify the conductive paste filled in the blind hole, the vacuum stage is 30 minutes, and the vacuum degree needs to be kept below 80Torr;

[0090] (7) Surface flattening: chemically and mechanically polish the annealed glass substrate to remove excess conductive slurry on the surface and improve the flatness of the substrate;

[0091] (8) Substrate thinning: The back side of the substrate is thinned and chemically mechanically polished to expose the back metal layer and form a glass through hole.

[0092] Example 2

[0093] A method for through-glass via metallization comprises the following steps:

[0094] (1) Laser modification: Picosecond infrared laser is used to irradiate and propagate on the surface of the glass substrate to produce a modified area that is sensitive to chemical etching. The glass blind holes and alignment mark patterns are processed simultaneously. The size of the glass blind holes is 10μm-100μm. The circular alignment marks in the alignment marks have a diameter of 20μm and are distributed around the glass substrate.

[0095] (2) Chemical etching: The laser-processed glass substrate is immersed in a 6-mol / L-10-mol / L KOH solution at 80-110°C for 5-10 hours. Since the chemical etching rate of the modified area is higher than that of the unmodified area, glass blind holes and alignment marks can be formed in this step.

[0096] (3) Mask fabrication: Spin-coat photoresist on an Al metal substrate, soft-bake and solidify the photoresist, transfer the corresponding alignment marks and through-hole patterns onto the photoresist using a laser direct-write lithography machine, develop and bake and solidify, use RIE etching to fabricate the corresponding patterns, and remove the photoresist; wherein the circular alignment marks in the mask have a diameter of 25 μm and are distributed around the metal mask; the through-hole diameter in the mask is designed to be 5 μm larger than the glass through-hole diameter;

[0097] (4) Alignment of substrate and mask: Fix the glass substrate on the sample stage and the metal mask on the corresponding fixture. Observe the alignment mark of the mask through a high-power microscope on the top of the mask, adjust the position of the glass substrate in the XYθ direction, and align the two. The alignment accuracy can reach within ±1μm. After alignment, use N2 pressure to push the glass substrate towards the metal mask so that the two are in contact and fixed;

[0098] (5) Conductive slurry filling: Inject the conductive slurry onto the metal mask through the pipeline, and use a PFA scraper to squeeze the conductive slurry into the corresponding mask through-holes. At the same time, evacuate the cavity to keep the vacuum degree below 30Pa, and the conductive slurry can be further filled into the glass blind hole;

[0099] (6) Baking and curing: The filled glass substrate is placed in a pressure vacuum oven for baking. The oxygen content needs to be kept below 10 ppm during baking. The baking temperature is 200°C-300°C and the baking time is 60 minutes, of which the pressurization stage is 30 minutes and the pressure is maintained at 5 kg / cm 2 -8kg / cm 2 , densify the conductive paste filled in the blind hole, the vacuum stage is 30 minutes, and the vacuum degree needs to be kept below 80Torr;

[0100] (7) Surface flattening: chemically and mechanically polish the annealed glass substrate to remove excess conductive slurry on the surface and improve the flatness of the substrate;

[0101] (8) Substrate thinning: The back side of the substrate is thinned and chemically mechanically polished to expose the back metal layer and form a glass through hole.

[0102] Example 3

[0103] A method for through-glass via metallization comprises the following steps:

[0104] (1) Laser modification: Picosecond infrared laser is used to irradiate and propagate on the surface of the glass substrate to produce a modified area that is sensitive to chemical etching; the glass blind hole and alignment mark patterns are processed simultaneously, and the size of the glass blind hole is 10μm-100μm; the cross alignment mark in the alignment mark is 20μm wide and 190μm long, and the circular alignment mark is 20μm in diameter, which are distributed around the glass substrate;

[0105] (2) Chemical etching: The laser-processed glass substrate is immersed in a 6-mol / L-10-mol / L KOH solution at 80-110°C for 5-10 hours. Since the chemical etching rate of the modified area is higher than that of the unmodified area, glass blind holes and alignment marks can be formed in this step.

[0106] (3) Mask fabrication: Spin-coat photoresist on an Fe metal substrate, soft-bake and solidify the photoresist, transfer the corresponding alignment marks and through-hole patterns onto the photoresist using a laser direct-write photolithography machine, develop and bake and solidify, use RIE etching to fabricate the corresponding patterns, and remove the photoresist; wherein the cross alignment mark in the mask is 25 μm wide and 200 μm long, and the circular alignment mark is 25 μm in diameter, which are distributed around the metal mask; the through-hole diameter in the mask is designed to be 5 μm larger than the glass through-hole diameter;

[0107] (4) Alignment of substrate and mask: Fix the glass substrate on the sample stage and the metal mask on the corresponding fixture. Observe the alignment mark of the mask through a high-power microscope on the top of the mask, adjust the position of the glass substrate in the XYθ direction, and align the two. The alignment accuracy can reach within ±1μm. After alignment, use N2 pressure to push the glass substrate towards the metal mask so that the two are in contact and fixed;

[0108] (5) Conductive slurry filling: Inject the conductive slurry onto the metal mask through the pipeline, and use a PFA scraper to squeeze the conductive slurry into the corresponding mask through-holes. At the same time, evacuate the cavity to keep the vacuum degree below 30Pa, and the conductive slurry can be further filled into the glass blind hole;

[0109] (6) Baking and curing: The filled glass substrate is placed in a pressure vacuum oven for baking. The oxygen content needs to be kept below 10 ppm during baking. The baking temperature is 200°C-300°C and the baking time is 60 minutes, of which the pressurization stage is 30 minutes and the pressure is maintained at 5 kg / cm 2 -8kg / cm 2 , densify the conductive paste filled in the blind hole, the vacuum stage is 30 minutes, and the vacuum degree needs to be kept below 80Torr;

[0110] (7) Surface flattening: chemically and mechanically polish the annealed glass substrate to remove excess conductive slurry on the surface and improve the flatness of the substrate;

[0111] (8) Substrate thinning: The back side of the substrate is thinned and chemically mechanically polished to expose the back metal layer and form a glass through hole.

[0112] It can be seen from Examples 1-3 that the method provided by the present invention can achieve fast, simple, high-precision and low-cost conductive filling of glass through holes, while achieving densification and solidification of the conductive paste to avoid the generation of voids.

[0113] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0114] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for through-glass via metallization, characterized in that: The following steps are involved: Providing a glass substrate, the glass substrate having a first surface and a second surface opposite to each other, and causing the glass of a first surface area where a through-glass hole and a first alignment mark are to be formed to be denatured by laser irradiation to form a denatured area; Removing the denatured glass in the denatured area to form a glass blind hole and a first alignment mark; Manufacturing a mask, wherein the mask has a through hole and a second alignment mark, wherein the through hole corresponds to the glass blind hole, and the second alignment mark corresponds to the first alignment mark; Aligning and overlaying the glass substrate and the mask so that the through hole and the glass blind hole form a channel; Filling the channel with a conductive paste, removing the mask, curing the conductive paste, and planarizing the first surface of the glass substrate; The second surface of the glass substrate is thinned and planarized so that two ends of the glass blind hole are exposed from the first surface and the second surface respectively to form the glass through hole.

2. The method according to claim 1, characterized in that The aperture of the glass blind hole is smaller than the aperture of the through hole.

3. The method according to claim 1, characterized in that The aperture of the glass blind hole is 10 μm-100 μm.

4. The method according to claim 1, characterized in that: The through hole has a diameter of 15 μm-105 μm.

5. The method according to claim 1, characterized in that The first alignment mark and the second alignment mark are in a shape of at least one of a cross mark and a circle mark.

6. The method according to claim 1, characterized in that The shapes of the first alignment mark and the second alignment mark are a combination of a cross mark and a circle mark; wherein the cross mark in the first alignment mark has a first horizontal axis and a first vertical axis, the lengths of the first horizontal axis and the first vertical axis are equal, and the widths of the first horizontal axis and the first vertical axis are equal; The cross mark in the second alignment mark has a second horizontal axis and a second vertical axis, the lengths of the second horizontal axis and the second vertical axis are equal, and the widths of the second horizontal axis and the second vertical axis are equal; The length of the first horizontal axis is smaller than the length of the second horizontal axis, and the width of the first horizontal axis is smaller than the width of the second horizontal axis; The diameter of the circular mark in the first alignment mark is smaller than the diameter of the circular mark in the second alignment mark.

7. The method according to claim 1, characterized in that The glass substrate and the mask are aligned and overlaid so that the through hole and the glass blind hole form a channel, including: identifying a first alignment mark of the glass substrate and a second alignment mark of the mask by an optical system, and adjusting the position of the glass substrate by an alignment system so that the first alignment mark and the second alignment mark are aligned.

8. The method according to claim 7, characterized in that The optical system includes a high-power microscope; The alignment system includes a moving device for fixing and moving the glass substrate.

9. The method according to claim 1, characterized in that: The conductive paste is filled under a vacuum degree of 20Pa-30Pa.

10. The method according to claim 1, characterized in that The curing conditions of the conductive paste include: controlling the oxygen content of the system to 0-10 ppm, the curing temperature to 200° C.-300° C., and the pressure of the system to 5 kg / cm 2 -8kg / cm 2 The curing is carried out under vacuum conditions for 30-40 minutes, and then cured under vacuum conditions for 30-40 minutes, with a vacuum degree of 60-80 Torr.

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