CN111834235A - Through hole filling method and structure - Google Patents
Through hole filling method and structure Download PDFInfo
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- CN111834235A CN111834235A CN202010736473.3A CN202010736473A CN111834235A CN 111834235 A CN111834235 A CN 111834235A CN 202010736473 A CN202010736473 A CN 202010736473A CN 111834235 A CN111834235 A CN 111834235A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
- H01L21/486—Via connections through the substrate with or without pins
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
- H01L23/498—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers
- H01L23/49827—Via connections through the substrates, e.g. pins going through the substrate, coaxial cables
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
- H01L23/498—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers
- H01L23/49866—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers characterised by the materials
- H01L23/49894—Materials of the insulating layers or coatings
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
Abstract
The invention provides a through hole filling method and a structure, wherein the method comprises the following steps: filling the through hole with photoresist to form a filler body; removing the photoresist on the surface of the substrate, wherein the filler bodies in the through holes are inwards sunken; exposing and punching the filler body to form a standard hole, wherein the aperture of the standard hole is smaller than that of the through hole; curing the filler body; performing metal deposition to form a transition structure, wherein the transition structure covers the side wall of the standard hole, the surface of the substrate and the outer surface of the solidified colloid; forming an electroplating metal layer by a metal electroplating process, and filling the standard hole; the structure formed by the method avoids the problems of cavities, excessively thick surface coating and the like of the holes with large aperture, high depth-to-width ratio, high yield, low cost and good realizability.
Description
Technical Field
The invention relates to the technical field of semiconductor packaging, in particular to a through hole filling method and a through hole filling structure.
Background
In the manufacture of substrates (e.g., organic, glass, or ceramic substrates), it is often necessary to perform via processing on thick substrates and to plate the metal to achieve interconnection of the electrical properties of the upper and lower surfaces. The small-aperture holes are subjected to full-aperture electroplating in an electroplating mode, so that a filling effect with good performance can be obtained, and for the holes with large aperture (more than or equal to 50um) and high aspect ratio, the problems of cavities, excessively thick surface coatings and the like are easy to occur if a similar process is adopted, so that the yield is low, the cost is high, and the realizability is poor. Therefore, the method is usually realized by a process of depositing thin-wall metal and then plugging the hole or a process of depositing only thin-wall metal and not filling the hole. Unfilled vias do not allow vertical via stacking and are limited in high frequency signal transmission applications. In addition, as the thick substrate drilling technology is usually used in modes of sand blasting, laser drilling or mechanical drilling, the roughness of the formed hole wall is large and local defects exist, which causes the problems of uneven deposition thickness and poor continuity in the implementation process of a hole (metal) filling process after thin-wall metal deposition, and even if the process technology of sidewall treatment cleaning and the like is introduced, the problems of hole expansion, upper and lower surface damage, low controllability, thermal mismatch (because of different CTE of materials among layers, expansion or contraction with different proportions can be generated when the materials are heated, stress is generated among the materials, even cracking is generated) and the like which reduce the reliability are caused.
Disclosure of Invention
The invention aims to provide a through hole filling method and a through hole filling structure, which are used for solving the problem of low through hole filling yield on the conventional through hole substrate with large aperture and high depth-to-width ratio.
In order to solve the above technical problem, the present invention provides a method for filling a through hole, including:
filling the through hole with photoresist to form a filler body;
removing the photoresist on the surface of the substrate, wherein the filler bodies in the through holes are inwards sunken;
exposing and punching the filler body to form a standard hole, wherein the aperture of the standard hole is smaller than that of the through hole;
curing the filler body;
performing metal deposition to form a transition structure, wherein the transition structure covers the side wall of the standard hole, the surface of the substrate and the outer surface of the solidified colloid;
forming an electroplating metal layer by a metal electroplating process, and filling the standard hole; and
and removing the transition structure and the electroplated metal layer on the upper surface and the lower surface of the substrate.
Optionally, in the through hole filling method, filling the through hole with photoresist to form the filler body includes:
pressing the diaphragm-shaped photoresist into the through hole;
or filling the through hole with liquid photoresist, then drying the photoresist,
wherein, when the photoresist is filled, vacuum decompression filling is adopted.
Optionally, in the via filling method, removing the photoresist on the substrate surface includes:
adopting a developing solution or a solvent to wipe the photoresist on the surface of the substrate, wherein the substrate prevents the photoresist in the through hole from being removed;
or the photoresist on the surface of the substrate is soaked in a developing solution or a solvent, and the photoresist in the through hole is kept under the action of the surface tension of the solution;
after the photoresist on the surface of the substrate is removed, the filler body forms an inward concave shape in the through hole, so that the length of the side wall of the standard hole is smaller than that of the side wall of the through hole;
and after the photoresist on the surface of the substrate is removed, part of the side wall of the through hole is exposed.
Optionally, in the through hole filling method, curing the filler body includes:
heating and curing, carrying out UV curing on the filler body, or injecting ions into the filler body for curing;
and carrying out plasma cleaning, and carrying out optimized cleaning on residual impurities.
Optionally, in the through hole filling method, performing exposure and punching on the filler body includes:
carrying out one-time front exposure and one-time back exposure by adopting a large well depth exposure machine, or carrying out multiple pulse exposure by adopting the large well depth exposure machine and then developing to form a standard hole;
the well depth of the large well depth exposure machine is not less than 150 microns, and the light spot is not more than 20 microns;
the aperture of the standard hole is not more than 20 microns, and the aspect ratio of the standard hole is not less than 15: 1.
Optionally, in the via filling method, forming the transition structure includes:
applying bias voltage to the substrate to perform metal sputtering on the seed layer of the adhesion layer, wherein the material of the transition structure comprises one or more of chromium, copper, titanium, gold and silver;
the transition structure covers all exposed surfaces.
Optionally, in the via filling method, filling the standard hole by a metal plating process includes:
and electroplating metal until the standard hole is completely filled to form a metal electroplated layer, wherein the metal electroplated layer covers the side wall of the standard hole and the transition structure to form a metal filler body.
Optionally, in the through hole filling method, the transition structure and the electroplated metal layer on the upper and lower surfaces of the substrate are removed by chemical mechanical polishing, an outer layer supported by the photoresist is formed in the through hole, and an inner layer is completely filled with metal and the upper and lower surfaces of the inner layer are covered by metal to form the dumbbell-shaped conductive transfer structure.
The present invention also provides a via filling structure, comprising:
a substrate having one or more through-holes extending through a top surface and a bottom surface of the substrate;
a photoresist support structure disposed within the via, the photoresist support structure filling the via, the photoresist support structure having a top surface and a bottom surface, the top surface of the photoresist support structure being recessed inwardly of the substrate relative to the top surface of the substrate, and the bottom surface of the photoresist support structure being recessed inwardly of the substrate relative to the bottom surface of the substrate;
a standard hole through the photoresist support structure;
a transition structure covering the top and bottom surfaces of the photoresist support structure and the sidewalls of the standard hole; and
a metal layer filling the standard hole, covering the transition structure, and at least partially or completely filling a recessed portion of the photoresist support structure relative to the substrate.
Optionally, in the through hole filling structure, the top surface of the photoresist support structure is recessed towards the inside of the substrate relative to the top surface of the substrate, and the bottom surface of the photoresist support structure is recessed towards the inside of the substrate relative to the bottom surface of the substrate, so that at least part of the side wall of the through hole is exposed, and the height of the exposed side wall of the through hole is in the range of 0 to the thickness of the substrate.
Optionally, in the through hole filling structure, an outer layer photoresist support structure is formed in the through hole as a support, the inner layer is completely filled with metal, and the upper surface and the lower surface of the inner layer are both covered with metal to form a dumbbell-shaped conductive switching structure.
Optionally, in the through hole filling structure, the through hole is a cylinder, a cuboid, a waist drum body, a truncated cone body or a polygonal column body,
the upper surface and the lower surface of the metal layer are of a circular truncated cone or square truncated cone structure, and the middle of the metal layer is a cylinder, a cuboid, a waist drum body, a circular truncated cone body or a polygonal column body.
According to the through hole filling method and the through hole filling structure, the through hole is filled with the photoresist, the standard hole with the smaller diameter is formed by punching on the filling body, the standard hole can be completely filled in the subsequent metal deposition and metal electroplating process, the filling effect with good performance is obtained, the problems that a hole with a large aperture, a high depth-to-width ratio and the like and a surface coating layer is too thick are avoided, the yield is high, the cost is low, and the realizability is good.
The invention adopts a photosensitive material and a photoetching method to form a precise fine structure. Unlike other filling materials which are used as dielectric layers at the same time, the organic filling (photosensitive material) is only present in the holes in the structure. Except for metal in the holes, the upper surface and the lower surface of the substrate have no other structures, and the original characteristics (such as hardness, flatness, dielectric constant and the like) of the original substrate material can be ensured after grinding. Compared with a thin-wall metal interconnection mode, a metal interconnection structure with full hole filling and large-diameter through holes is provided. The structure is a large-aperture vertical stack of holes, providing a solution to the requirements of large current and high frequency signal transmission, especially for substrates with high density hole arrays. The liquid medicine consumption of the whole metal filling with large aperture is reduced, the subsequent surface layer thick metal removing process is improved, and the cost is reduced. The invention can realize the uniform hole formation and stable filling of the hole patterns on the same substrate or different substrates. A method for converting the model into an operable stable process model is provided for adapting to various individual design problems, so that the process cost is reduced, and the yield is improved. The components of the filler material can be prepared according to the performances of the outer-layer substrate and the inner metal, play a role in buffering and releasing the thermal mismatch caused by the stretching effect between the metal and the substrate, and are suitable for processing high-reliability requirements and multilayer re-wiring layers.
Drawings
FIG. 1 is a schematic structural diagram of a via filling structure according to an embodiment of the present invention;
FIGS. 2-8 are schematic diagrams illustrating a process of a via filling method according to an embodiment of the invention;
shown in the figure: 1-a substrate; 2-a through hole; 4-filler body/support structure; 5-partial sidewall/undercut region of the via; 6-a concave structure; 7-standard/laser holes; 8-transition structure; 9-metal plating/metal filler body.
Detailed Description
The through hole filling method and structure proposed by the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Furthermore, features from different embodiments of the invention may be combined with each other, unless otherwise indicated. For example, a feature of the second embodiment may be substituted for a corresponding or functionally equivalent or similar feature of the first embodiment, and the resulting embodiments are likewise within the scope of the disclosure or recitation of the present application.
The core idea of the invention is to provide a through hole filling method and structure to meet the technical problem of metal filling and metallization of through holes of multilayer wiring circuit boards such as glass, ceramics or substrates; meanwhile, a solution is provided for realizing one-time all filling on the same substrate with different apertures.
In order to realize the above idea, the present invention provides a method and a structure for filling a through hole, as shown in fig. 2 to 8, including: forming one or more through-holes 2 on a substrate 1; filling the through hole 2 with photoresist to form a filler body 4; removing the photoresist on the surface of the substrate 1; exposing and punching the filler body 4 to form a standard hole 7, wherein the aperture of the standard hole 7 is smaller than that of the through hole 2; curing and cleaning the filler body 4 to form a cured filler body; carrying out deposition of a transition layer to form a transition structure 8; the standard holes 7 are filled by a metal plating process.
In the scheme, a photosensitive material and a photoetching method are selected to form an accurate fine structure. Unlike other filling materials which are used as dielectric layers at the same time, the organic filling (photosensitive material) is only present in the holes in the structure. Except for metal in the holes, the upper surface and the lower surface of the substrate have no other structures, and the original characteristics (such as hardness, flatness, dielectric constant and the like) of the original substrate material can be ensured after grinding. Compared with a thin-wall metal interconnection mode, a metal interconnection structure with full hole filling and large-diameter through holes is provided. The structure provides a solution for the requirements of large-aperture vertical stack holes, large-current and high-frequency signal transmission and the like, in particular to a substrate with a high-density hole array. The liquid medicine consumption of the whole metal filling with large aperture is reduced, the subsequent surface layer thick metal removing process is improved, and the cost is reduced. The technology can realize that holes with different sizes on the same substrate or different substrates form a uniform hole pattern size capable of being stably filled. A method for converting the model into an operable stable process model is provided for adapting to various individual design problems, so that the process cost is reduced, and the yield is improved. The components of the filler material can be prepared according to the performances of the outer-layer substrate and the inner metal, play a role in buffering and releasing the thermal mismatch caused by the stretching effect between the metal and the substrate, and are suitable for processing high-adaptability requirements and multilayer re-wiring layers.
In an embodiment of the present invention, as shown in fig. 2, a plurality of through holes 2 may be formed on a substrate 1 through a dry or wet etching process, laser drilling, or the like. The substrate 1 may comprise a wide variety of semiconductor materials such as silicon, germanium, gallium arsenide, indium phosphide, and the like. Alternatively, the substrate 1 may also be made of an electrically non-conductive material, such as a glass, plastic, ceramic or sapphire wafer. The through holes 2 may be the same or different through holes.
In the method for filling a large-aperture high-aspect-ratio through hole, as shown in fig. 3, filling the through hole 2 with photoresist to form a filler 4 includes: pressing a diaphragm-shaped photoresist (dry film) into the through hole 2; or filling the through hole with liquid photoresist, and then drying the photoresist. When the photoresist is filled, vacuum decompression filling can be adopted to fill the through holes, so that a better filling effect is ensured, and the pressure of the vacuum film pressing machine is 0.3 hPa.
Further, in the method for filling a large-aperture high-aspect-ratio through hole, removing the photoresist on the surface of the substrate 1 includes: as shown in fig. 4, the photoresist or the dry film on the surface of the substrate is wiped with a developing solution or a solvent, and the substrate blocks the photoresist or the dry film in the through hole from being removed; or soaking the photoresist or the dry film on the surface of the substrate in a developing solution or a solvent, wherein the photoresist or the dry film in the through hole is kept under the action of the surface tension of the solution; after the photoresist 4 on the surface of the substrate 1 is removed, the filler body 4 forms an inward concave structure 6 in the through hole, so that the length of the side wall of the standard hole is smaller than that of the side wall of the through hole; after the photoresist 4 on the surface of the substrate 1 is removed, part of the side wall 5 of the through hole is exposed. The length of the partial side wall 5 is in the range of 0 to the base thickness.
In the embodiment of the present invention, as shown in fig. 5, exposure punching is performed on the filler body 4, including: carrying out one-time front exposure and one-time back exposure by adopting a large well depth exposure machine, or carrying out multiple pulse exposure by adopting the large well depth exposure machine and then developing to form a standard hole 7; the well depth of the large well depth exposure machine is not less than 150 microns, and the light spot is not more than 20 microns; the aperture of the standard hole 7 is not more than 20 microns, the aspect ratio of the standard hole is not less than 15:1, and the standard hole can be cylindrical or waist drum-shaped.
In the embodiment of the present invention, the filler body 4 is cured and then cleaned, including: according to the performance of the adopted photoresist or dry film, proper temperature is selected for heating and curing, the filler body 4 is subjected to UV curing, or ions are injected into the filler body 4 for curing; plasma cleaning is carried out, and residual impurities are optimally cleaned
Next, as shown in fig. 6, forming the transition structure 8 includes: applying bias voltage to the substrate to perform metal sputtering on the seed layer of the adhesion layer, wherein the material of the transition structure 8 comprises one or more of chromium, copper, titanium, gold and silver; the transition structure 8 covers the sidewalls and all exposed surfaces of the standard hole 7, including the recessed structure 6, the exposed portion of the sidewalls 5 of the through hole, and the upper surface of the substrate 1.
In an embodiment of the present invention, in the method for filling a large-aperture high-aspect-ratio through hole, as shown in fig. 7, filling the standard hole 7 by a metal plating process includes: and electroplating metal until the standard hole is completely filled to form a metal electroplated layer 9, wherein the thickness of the metal electroplated layer 9 is 10-20 microns, and the metal electroplated layer 9 covers the side wall of the standard hole 7 and the transition structure 8 to form a metal filler body 9.
In another embodiment of the present invention, in the method for filling a large-aperture high-aspect-ratio through hole, the aperture of the through hole 2 is larger than 50 μm, the filler body 4 is in the shape of one or more of a cylinder, a cuboid, a waist drum, a truncated cone and a polygonal cylinder, and the metal filler body 9 is in the shape of one or more of a cylinder, a cuboid, a waist drum, a truncated cone and a polygonal cylinder. In the method for filling a large aperture high aspect ratio through hole, as shown in fig. 8, the method further includes: after the standard hole 7 is filled through a metal electroplating process, the surface of the substrate 1 is chemically or mechanically polished, the electroplated metal layer 9 and the transition structure 8 on the top surface of the substrate are removed, and only the electroplated metal layer 9 and the transition structure 8 inside the through hole are reserved, so that an outer layer is formed inside the through hole and supported by photoresist, and an inner layer is completely filled with metal and the upper surface and the lower surface of the inner layer are both covered by metal to form a dumbbell-shaped conductive switching structure as a conductive through hole structure.
The embodiment also provides a large-aperture high-aspect-ratio through hole filling structure formed by the method. As shown in fig. 1, the main body of the structure has four parts: the substrate 1 with the through hole 2 structure clings to the inner wall of the through hole 2 and forms a supporting structure 4 which is provided with a through hole with a diameter smaller than that of the through hole 2 of the substrate and is inwards concave towards the middle layer of the substrate along the radial direction, and a transition structure 8 which wraps the supporting structure 4 and partial side walls of the through hole 2 can be used for realizing the functions of blocking, adhering and the like, for example, the combination of one or more metals such as Cr/Cu/Ni/Au and the like, and dumbbell-shaped metal electroplated layers 9 which fill the upper end and the lower end of the residual through hole structure and are larger than the middle part can be. The substrate 1 may comprise a wide variety of semiconductor materials such as silicon, germanium, gallium arsenide, indium phosphide, and the like. Alternatively, the substrate 1 may also be made of an electrically non-conductive material, such as a glass, plastic, ceramic or sapphire wafer. The support structure 4 may be formed of a dry film or a photoresist. The support structure 4 is recessed into the via interior at the top and bottom of the via 2 and exposes a portion of the via sidewall 5.
The upper surface of the metal plating layer 9 is flush with the upper surface of the substrate 1 or one of the structures is slightly sunken (the size is between 0 and the thickness of the substrate/2), and the lower surface of the metal plating layer 9 is flush with the lower surface of the substrate 1 or one of the structures is slightly sunken (the size is between 0 and the thickness of the substrate). Therefore, the outer layer is formed in the through hole and supported by the supporting structure, the inner layer is completely filled with metal, and the upper surface and the lower surface of the inner layer are both covered by metal to form a dumbbell-shaped conductive switching structure which is used as a conductive through hole structure.
The through hole 2 on the substrate 1 can be in various shapes such as a cylinder, a cuboid, a waist drum shape, a round table shape, a polygonal column and the like, the upper end and the lower end of the metal plating layer 9 can be in structures such as a round table or a square table and the like, and the middle can be in various shapes such as a cylinder, a cuboid, a waist drum shape, a round table shape, a polygonal column and the like.
The material and processing method of the transition structure 8 can be the same as or different from those of the metal plating layer 9.
The dimension 11 in the transition structure 8 ranges from 0 to the aperture; dimension 12 ranges from 0 to the substrate thickness.
The invention utilizes the photosensitive material to carry out hole type transformation by a photoetching mode, thereby realizing the purpose of solving the full hole filling on the hole substrate containing large aperture and high aspect ratio so as to meet the technical problem of metallization of metal filling of through holes of multilayer circuit boards such as glass, ceramics or substrates. Meanwhile, a solution is provided for realizing one-time all filling on the same substrate with different apertures.
According to the method and the structure for filling the large-aperture high-aspect-ratio through hole, the through hole is filled with the photoresist, the standard hole with the smaller aperture is formed in the filling body by punching, the standard hole can be completely filled in the subsequent metal deposition and metal electroplating processes, the filling effect with good performance is obtained, the problems that the large-aperture high-aspect-ratio hole is hollow, the surface coating is too thick and the like are solved, the yield is high, the cost is low, and the realizability is good.
The manufacturing method comprises the following steps: flat panel with hole array: 1 is a substrate; 2 are through holes with different sizes); laminating the film-shaped photoresist (dry film), or filling the through hole with liquid photoresist. The photoresist filling can adopt vacuum decompression filling to ensure better filling effect. Vacuum pressure reduction is realized by a vacuum film pressing machine, the pressure reaches 0.3hPa, and the pressure is 0.6 MPa.
And removing the surface dry film or the photoresist. Because the colloid in the through hole is protected by the glass, the dry film or the photoresist in the through hole cannot be removed by the developing solution or the solvent, and the dry film or the photoresist in the through hole is remained.
The large-well deep exposure machine carries out single exposure on the front surface and the back surface once respectively or pulse multiple exposure and then develops, and at least a high-gradient straight through hole or a waist-drum-shaped through hole with the aperture being less than or equal to 20um and the depth-to-width ratio being more than or equal to 15:1 can be formed. The exposure machine with the well depth of more than or equal to 150um and the light spot of less than or equal to 20um can form the pattern exposure with the aperture of 20 and the depth-to-width ratio of 15: 1.
And (3) curing, namely selecting the temperature suitable for filling the colloid in the hole to perform heating curing or UV curing, performing plasma cleaning, and optimally cleaning the roughness and residual impurities in the hole. Because the exposure and development parameters are consistent, all original holes of the substrate are converted into small holes with uniform shapes and high aspect ratios.
And (4) depositing metal. And applying bias voltage to carry out seed layer metal sputtering. The metal sputtering of the seed layer of the adhesion layer is carried out by applying bias, for example, a Cr layer is laminated with Cu, a Ti layer is laminated with Cu, a Cr layer is laminated with Au, etc. (8 is sputtering layer metal). Forming a thin metal layer coated on the outer side of the structure.
And finishing the small hole electroplating. And forming a plated metal layer with a certain thickness on the upper surface and the lower surface, wherein the hole is completely filled with the through hole, and the metal completely covers the hole. And (5) performing chemical mechanical polishing to form the conductive through hole filled with complete metal.
The photoresist and dry film used in the present invention are preferably positive photoresist or dry film, and negative photoresist and dry film can also be used. The CTE (coefficient of thermal expansion) of the photoresist and the dry film is better between the plating metal and the base material. The through hole is filled with the dry film or the liquid photoresist, the surface photoresist or the dry film is removed by the developing solution, and in the removing process, the photoresist at the hole opening of the through hole is partially removed to form a small-size recess at the hole opening. And photoetching the dry film plugged into the hole to form a small hole with a high depth-to-width ratio, and curing the residual photoresist to be used as a part of substrate material. And then filling by adopting a small-aperture through hole filling process. And finally, polishing to form a conductive through hole structure supporting the upper surface and the lower surface of the multilayer trepanning.
In the existing method, no matter the substrate is exposed and filled by CMP after being completely filled, or colloid is directly used as an upper surface dielectric layer and a lower surface dielectric layer, copper columns of the formed structure within the height range of the substrate are all cylinders or spindle bodies close to the cylinders (the structure of the copper columns depends on the hole type of the original substrate). The metal electroplated layer in the structure of the invention is in a dumbbell-shaped structure: the structure has the advantages that only metal (copper) is exposed outside except the base body (glass) from top to bottom, so that the application range of the structure is improved (such as the fields of medical treatment, high-energy detection and the like which have special requirements on background base materials and bare leakage materials), as shown in figure 1 (8 and 9 in figure 1 are both metal, the colloid filling part is completely coated by the metal and the base, and the colloid in the existing structure is bare leaked on the outer surface). The biggest difference between the method and the prior method is that the structure formed by the method is completely different from the structure formed by the method, and the complete coating of the colloid and the complete exposure of the front side and the back side of the colloid cause the difference of the limiting conditions of the colloid in use and subsequent process processing.
The invention is different from the traditional photoetching process, and the key point is that a step of developing process is carried out before the exposure of the photosensitive material, and the process aims to ensure that the substrate can be exposed without subsequent CMP grinding and corrosion and the full metal covering at the hole opening is formed. The invention avoids the defects that the CMP process is needed, the uneven surface structure is possibly formed due to different materials, the colloid needs to be exposed, and the process and time cost are increased in the prior method; the defect that the colloid on the surface directly solidified in the prior method can not be removed in a developing mode is also avoided.
Meanwhile, the invention does not need to be patterned, can form the required pattern structure by direct full exposure without the requirement on alignment precision, saves the manufacturing cost and the process time of the mask and has high yield of the process.
The method is directly suitable for filling the through hole, and avoids the defect that the structure needing CMP in the prior art needs to ensure at least one flat surface, so the prior method is only limited to blind hole processing if the process complexity is not improved.
The existing photoetching process is generally limited to pattern photoetching with a low depth-to-width ratio, and a special photosensitive material (such as SU-8) is required to be used for the high depth-to-width ratio structure.
In summary, the above embodiments have described the method for filling a large aperture high aspect ratio through hole and the different configurations of the structure in detail, and it is needless to say that the present invention includes but is not limited to the configurations listed in the above embodiments, and any modifications based on the configurations provided by the above embodiments are within the scope of the present invention. One skilled in the art can take the contents of the above embodiments to take a counter-measure.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (12)
1. A via filling method, comprising:
filling the through hole with photoresist to form a filler body;
removing the photoresist on the surface of the substrate, wherein the filler bodies in the through holes are inwards sunken;
exposing and punching the filler body to form a standard hole, wherein the aperture of the standard hole is smaller than that of the through hole;
curing the filler body;
performing metal deposition to form a transition structure, wherein the transition structure covers the side wall of the standard hole, the surface of the substrate and the outer surface of the solidified colloid;
forming an electroplating metal layer by a metal electroplating process, and filling the standard hole; and
and removing the transition structure and the electroplated metal layer on the upper surface and the lower surface of the substrate.
2. The via filling method of claim 1, wherein filling the via hole with the photoresist and forming the filler body comprises:
pressing the diaphragm-shaped photoresist into the through hole;
or filling the through hole with liquid photoresist, then drying the photoresist,
wherein, when the photoresist is filled, vacuum decompression filling is adopted.
3. The via filling method of claim 2, wherein removing the photoresist on the substrate surface comprises:
adopting a developing solution or a solvent to wipe the photoresist on the surface of the substrate, wherein the substrate prevents the photoresist in the through hole from being removed;
or the photoresist on the surface of the substrate is soaked in a developing solution or a solvent, and the photoresist in the through hole is kept under the action of the surface tension of the solution;
after the photoresist on the surface of the substrate is removed, the filler body forms an inward concave shape in the through hole, so that the length of the side wall of the standard hole is smaller than that of the side wall of the through hole;
and after the photoresist on the surface of the substrate is removed, part of the side wall of the through hole is exposed.
4. The via filling method of claim 1, wherein curing the filler body comprises:
heating and curing, carrying out UV curing on the filler body, or injecting ions into the filler body for curing;
and carrying out plasma cleaning, and carrying out optimized cleaning on residual impurities.
5. The via filling method of claim 1, wherein performing exposure drilling on the filler body comprises:
carrying out one-time front exposure and one-time back exposure by adopting a large well depth exposure machine, or carrying out multiple pulse exposure by adopting the large well depth exposure machine and then developing to form a standard hole;
the well depth of the large well depth exposure machine is not less than 150 microns, and the light spot is not more than 20 microns;
the aperture of the standard hole is not more than 20 microns, and the aspect ratio of the standard hole is not less than 15: 1.
6. The via filling method of claim 1, wherein forming a transition structure comprises:
applying bias voltage to the substrate to perform metal sputtering on the seed layer of the adhesion layer, wherein the material of the transition structure comprises one or more of chromium, copper, titanium, gold and silver;
the transition structure covers all exposed surfaces.
7. The via filling method of claim 1, wherein filling the standard via by a metal plating process comprises:
and electroplating metal until the standard hole is completely filled to form a metal electroplated layer, wherein the metal electroplated layer covers the side wall of the standard hole and the transition structure to form a metal filler body.
8. The method for filling via holes according to claim 1, wherein the transition structure and the plated metal layer on the upper and lower surfaces of the substrate are removed by chemical mechanical polishing, and an outer layer is formed in the via hole with a photoresist as a support, and the inner layer is completely filled with metal and has upper and lower surfaces covered with metal to form a dumbbell-shaped conductive via structure.
9. A via fill structure, comprising:
a substrate having one or more through-holes extending through a top surface and a bottom surface of the substrate;
a photoresist support structure disposed within the via, the photoresist support structure filling the via, the photoresist support structure having a top surface and a bottom surface, the top surface of the photoresist support structure being recessed inwardly of the substrate relative to the top surface of the substrate, and the bottom surface of the photoresist support structure being recessed inwardly of the substrate relative to the bottom surface of the substrate;
a standard hole through the photoresist support structure;
a transition structure covering the top and bottom surfaces of the photoresist support structure and the sidewalls of the standard hole; and
an electroplated metal layer filling the standard hole, covering the transition structure, and at least partially or completely filling the recessed portion of the photoresist support structure relative to the substrate.
10. The via fill structure of claim 9, wherein a top surface of the photoresist support structure is recessed into the substrate interior relative to the top substrate surface and a bottom surface of the photoresist support structure is recessed into the substrate interior relative to the bottom substrate surface such that at least a portion of the via sidewalls are exposed, the height of the exposed via sidewalls being in the range of 0 a to the substrate thickness.
11. The via-fill structure of claim 10, wherein the outer photoresist support structure is formed as a support within the via, the inner layer is completely metal-filled and has top and bottom surfaces covered with metal to form a dumbbell-shaped conductive via structure.
12. The via filling structure of claim 10, wherein the via is a cylinder, a rectangular parallelepiped, a waist drum, a truncated cone, or a polygonal cylinder,
the upper surface and the lower surface of the electroplating metal layer are in a round table or square table structure, and the middle of the electroplating metal layer is a cylinder, a cuboid, a waist drum body, a round table body or a polygonal cylinder body.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2002141440A (en) * | 2000-11-01 | 2002-05-17 | Mitsui High Tec Inc | Method for manufacturing substrate |
| US20020111013A1 (en) * | 2001-02-15 | 2002-08-15 | Okada Lynn A. | Method for formation of single inlaid structures |
| TW200518292A (en) * | 2003-11-28 | 2005-06-01 | Hsuan Chi Kuang Tien Semiconductor Corp | Semiconductor chip-carrying substrate and its manufacturing method |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002141440A (en) * | 2000-11-01 | 2002-05-17 | Mitsui High Tec Inc | Method for manufacturing substrate |
| US20020111013A1 (en) * | 2001-02-15 | 2002-08-15 | Okada Lynn A. | Method for formation of single inlaid structures |
| TW200518292A (en) * | 2003-11-28 | 2005-06-01 | Hsuan Chi Kuang Tien Semiconductor Corp | Semiconductor chip-carrying substrate and its manufacturing method |
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