A kind of by interconnected method of bottom-up filling realization through hole and products thereof
Technical field
The invention belongs to the semiconductor packaging field, more specifically, relate to a kind of by interconnected method of bottom-up filling realization through hole and products thereof.
Background technology
In the past few decades, integrated circuit processing technique is being followed Moore's Law and is being remained development at a high speed, the performance of chip has obtained greatly promoting, power consumption and cost also descend significantly, but the development of Electronic Encapsulating Technology is but relatively slow, become gradually one of bottleneck of restriction semiconductor technology evolves, traditional two-dimentional integrated form can't satisfy the industries such as consumer electronics, Aero-Space to speed and the more and more higher requirement of volume of integrated circuit, so three-dimensional integration technology is subject to increasing the attention and research.In numerous three-dimensional integration technologies, interconnecting silicon through holes technology (TSV) is a kind of novel solution, and it is by making the through hole of Z-direction at silicon chip, and the filled conductive material is realized the interconnection between the different chips in the through hole.The interconnection technique of this vertical direction can reduce the length of interconnection line between the chip, thereby can solve the delay problem between the chip, dwindle chip area, improve integration density, the limitation that surmounts Planar integration allows microelectronic industry continue to develop according to Moore's Law.
One of key of TSV technology is that the filling of through hole realizes signal of telecommunication interconnection.Usually adopt the mode of electroplating to carry out filling through hole in the prior art, wherein a kind of the electroplates in hole mode is sputtering seed layer on through-hole wall, then electroplates; This electro-plating method is owing to being that whole through hole is electroplated in the vertical simultaneously, need special electroplating device, and electroplating velocity is slow, require high to electroplate liquid, coating at silicon chip surface is thicker, and can exist the through hole upper and lower port to seal first, causes copper post inside that hole, the defective such as hollow are arranged, reduce simultaneously electrical property and the sealing of chip, affect device lifetime.
Another kind of the electroplates in hole mode is bottom-up electroplating technology, and to be copper begin deposition from an end of TSV through hole to electroplating process, along upwards growth of through hole, finally fills whole through hole.Bottom-up electro-plating method generally need to provide a through hole, adopts auxiliary disk as electroplating cathode, or utilizes the characteristic of electroplating cross growth at disk one face closure silicon through hole, realizes thus bottom-up plating.Electroplate with conformal and to compare, bottom-up plating does not need special installation, and speed is fast, and to electroplate liquid require lowly, the coating of silicon chip surface also can be controlled.But the method Seed Layer is made generally needs extra processing step, as make auxiliary disk, auxiliary disk ephemeral key closes; Or need to carry out in advance at the electroplated disk back side Seed Layer and fill, electroplate; Therefore exist technological process long, the defectives such as inefficiency.
Summary of the invention
Above defective or Improvement requirement for prior art, the invention provides a kind of by interconnected method of bottom-up filling realization through hole and products thereof, its purpose is to study also corresponding adjusting process step by growth mechanism and process to the filling through hole material, can so that control, low-cost, high efficiency mode carries out the electroplates in hole process, and obtains the better through hole interconnect architecture of filling effect product.
According to one aspect of the present invention, provide a kind of and realized the interconnected method of through hole by bottom-up filling, it is characterized in that, the method comprises the following steps:
(a) a surface processing at substrate makes blind hole, and so that the degree of depth of blind hole is not less than its diameter;
(b) on processing makes the whole substrate surface of blind hole, grow successively insulating barrier, barrier layer and Seed Layer;
(c) on the surface of described Seed Layer, be coated with photoresist and fill and lead up blind hole, then photoresist is carried out exposure and development treatment, so that photoresist is only residual on the Seed Layer surface that is in the blind hole bottom;
(d) Seed Layer not covered by photoresist on the substrate is carried out Transformatin, in this process, the Seed Layer of blind hole bottom is unaffected owing to the protection that is subjected to residual photoresist;
(e) remove the residual photoresist in blind hole bottom, expose the Seed Layer of its bottom;
(f) filled conductive material in the blind hole in this process, as boot media, utilizes electric conducting material growth variation between Seed Layer and the barrier layer in blind hole to finish bottom-up growth with the Seed Layer of blind hole bottom;
(g) reduction processing is carried out on another surface of the undressed blind hole of substrate, until blind hole is formed through hole, is finished thus the interconnected process of through hole and obtain required through hole interconnect architecture product.
As further preferably, in step (a), process by deep reaction ion etching, laser ablation or wet etching and to make blind hole; The quantity of described blind hole is one or more, and wherein the blind hole aperture is between 1 micron~1000 microns, and the degree of depth is between 10 microns~1000 microns, and the degree of depth of blind hole is 1~50 times of its diameter.
As further preferably, in step (b), the material of described insulating barrier is selected from mixture or the complex of silicon dioxide, silicon nitride, alundum (Al2O3), polyimides, Parylene, polyphenyl and cyclobutane or photoresist and above-mentioned material, and preferably adopts the mode of thermal oxidation, physical vapor deposition or chemical vapor deposition to form; Described barrier layer is the double-deck barrier layer of titanium barrier layer, titanium-tungsten, the double-deck barrier layer of titanium-titanium nitride or the double-deck barrier layer of tantalum-tantalum nitride, and preferably adopts the mode of atomic layer deposition, physical vapor deposition or chemical vapor deposition to form; Described Seed Layer is that the materials such as copper or gold consist of, and preferably adopts the mode of chemical plating, electrochemistry grafting, atomic layer deposition, physical vapor deposition or chemical vapor deposition to form.
As further preferably, in step (c), when the surface-coated photoresist that is deposited with Seed Layer to substrate and after filling and leading up blind hole, its integral body put in the vacuum environment to carry out vacuumize processing, discharge thus the inner residual bubble of blind hole so that photoresist obtains fully filling in blind hole.
As further preferably, described photoresist is positive photoresist or negative photoresist, and the vacuum degree of vacuum environment is set to-0.3MPa~0.05MPa.
As further preferably, in step (c), by laser, electron beam or ion beam mode photoresist is carried out exposure, after exposure, photoresist is carried out the heating firmly treatment, then be soaked in the developer solution or by spray developing liquid and carry out development treatment.
As further preferably, in step (c), residual photoresist thickness is set to less than 1/2 of blind hole depth value on the Seed Layer surface of blind hole bottom.
As further preferably, in step (d), remove Seed Layer not covered by photoresist on the substrate by methods such as wet etching, dry etchings.
As further preferably, in step (e), the mode that preferably adopts acetone to soak removes the residual photoresist in blind hole bottom.
As further preferably, in step (f), described packing material is selected from copper, gold, silver or its mixture, and fill method is preferentially selected plating.
As further preferably, in step (g) afterwards, also comprise the step of removing dry film, pad, the rerouting of line layer and/or making salient point.
As further preferably, described substrate is selected from the compound semiconductors such as the element semiconductors such as silicon, germanium or GaAs, InP, gallium nitride.
According to another aspect of the present invention, also provide corresponding through hole interconnect architecture product.
In general, according to above technical scheme of the present invention compared with prior art, mainly possess following technical characterstic:
1, study by growth mechanism and process to the filling through hole material, there is very large growth variation in packing material in Seed Layer and barrier layer; And through after the present invention's processing, Seed Layer only exists in the blind hole bottom, impel the growth rate of blind hole underfill will be much larger than the growth rate of blind hole sidewall, packing material will be take the Seed Layer of blind hole bottom as boot media, from the beginning deposit of blind hole bottom, and realize bottom-up high speed, high-quality filling;
2, be a kind of bottom-up filling mode owing to what realize, during plating solution composition required to electroplate low than general conformal; Simultaneously, can strengthen electroplating current, improve electroplating efficiency, and needn't worry to cause inside the situations such as defective to occur because the blind hole opening seals first;
3, the surface of substrate is electroplated the rear surface and can not produced coating, thereby when post-processed, do not need the CMP(chemico-mechanical polishing owing to there not being the existence of Seed Layer) etc. processing, can reduce process costs;
4, according to manufacture method of the present invention be convenient to control, filling quality is high, and can simplify the processing step of through hole interconnect architecture, reduce process costs, thereby be particularly useful for large batch of suitability for industrialized production purposes.
Description of drawings
Fig. 1 is achieved in accordance with the invention by bottom-up filling and realizes the interconnected process flow diagram of through hole;
Fig. 2 a is the structural representation that processes blind hole on the substrate be used to being presented at;
Fig. 2 b is be used to the structural representation of deposition insulating layer, barrier layer and Seed Layer successively on the surface that is presented at substrate and is processed with blind hole;
Fig. 2 c is be used to coating photoresist on the surface that is presented at substrate and is deposited with Seed Layer and the structural representation after filling and leading up blind hole;
Fig. 2 d is for showing the structural representation after photoresist execution exposure and the development treatment;
Fig. 2 e is for showing take blind hole bottom photoresist as protection mechanism, removing the structural representation of the Seed Layer that comes out in the blind hole;
Fig. 2 f is the structural representation of removing the residual photoresist of blind hole for showing;
Fig. 2 g contains the structural representation that the blind hole of Seed Layer is filled for showing to the bottom.
In institute's drawings attached, identical Reference numeral is used for representing identical element or structure, wherein:
1-substrate 2-insulating barrier 3-barrier layer 4-Seed Layer 5-photoresist 6-electric conducting material
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.In addition, below in each execution mode of described the present invention involved technical characterictic just can mutually not make up as long as consist of each other conflict.
Fig. 1 realizes the interconnected process flow diagram of through hole according to of the present invention by bottom-up filling.As shown in fig. 1, mainly comprise the following steps: according to the interconnected method of realization through hole of the present invention
At first, shown in Fig. 2 a, a surface (being shown as upper surface among the figure) processing on substrate 1 makes blind hole, and so that the degree of depth of blind hole is not less than its diameter.Substrate can be selected semi-conducting material, such as compound semiconductors such as the element semiconductors such as silicon, germanium or GaAs, InP, gallium nitride.On two surfaces of substrate semiconductor device, multilayer electricity interlinkage layer or the micro-sensor structure that completes can be arranged, can also comprise pad or passivation layer.Processing makes a plurality of blind holes on the surface of substrate 1, and the diameter of blind hole does not wait from 1 micron to 1000 microns, and its cross section generally is circular or square; The degree of depth of blind hole is not less than its diameter, is preferably set in the present invention 1 times to 50 times of its diameter.Above-mentioned blind hole can be processed by deep reaction ion etching (DRIE), laser ablation or wet etching and be made.
Then, shown in Fig. 2 b, make on the whole substrate surface of blind hole successively deposition insulating layer 2, barrier layer 3 and Seed Layer 4 in processing, be formed with successively thus insulating barrier, barrier layer and the Seed Layer of layer structure at other positions of substrate surface of blind hole bottom, blind hole sidewall and undressed blind hole.The material of insulating barrier 2 is selected from mixture or the complex of silicon dioxide, silicon nitride, alundum (Al2O3), polyimides, Parylene, polyphenyl and cyclobutane or photoresist and above-mentioned material, and preferably adopts the mode of thermal oxidation, physical vapor deposition (PVD) or chemical vapor deposition (CVD) to form.Barrier layer 3 is titanium barrier layer, the double-deck barrier layer of titanium-tungsten (Ti-W), the double-deck barrier layer of titanium-titanium nitride (Ti-TiN) or the double-deck barrier layer of tantalum-tantalum nitride (Ta-TaN), and preferably adopts the modes such as atomic layer deposition (ALD), physical vapor deposition (PVD) or chemical vapor deposition (CVD) to form; Seed Layer 4 is that copper (Cu) or gold materials such as (Au) consist of, and preferably adopts the mode of chemical plating, electrochemistry grafting, atomic layer deposition (ALD), physical vapor deposition (PVD) or chemical vapor deposition (CVD) to form.
Then, as shown in Fig. 2 c and 2d, Seed Layer 4 whole surface on for example be coated with photoresist 5 and fill and lead up blind hole by the spin coating mode, then photoresist is carried out exposure and development treatment, so that photoresist is only residual on the surface of the Some Species sublayer that is in the blind hole bottom and cover Seed Layer.In this process, according to a preferred embodiment of the present invention, can be in coating after photoresist fill and lead up blind hole, its integral body put to carry out in the vacuum environment vacuumize processing, can discharge thus the inner residual bubble of blind hole and make photoresist in blind hole, obtain the fully effect of filling.Described photoresist 5 is photo-sensitive characteristics, can be negative photoresist or positive photoresist; The vacuum degree of vacuum environment is set to-0.3MPa~0.05MPa.Expose with specific equipment such as mask aligner, or carry out with laser, electron beam or ion beam.After the exposure, preferably can select to heat with hot plate, baking oven or infrared mode and be applied to on-chip photoresist 5, carry out the post bake step to improve photoetching quality.Developing refers to that the substrate 1 that will scribble photoresist 5 is soaked in the developer solution, or passes through the method for spray developing liquid, removes a part of photoresist, thereby forms required figure.According to another preferred implementation of the present invention, in above-mentioned steps, behind photoresist 5 exposure imagings, only at blind hole bottom residual fraction photoresist, come out in the most of zone of blind hole, its one-tenth-value thickness 1/10 of residual photoresist is set to less than 1/2 of blind hole depth value in this way.
Then, shown in Fig. 2 e, the photoresist 5 bottom blind hole with the technique of wet etching or dry etching, is removed the Seed Layer 4 that comes out as mask.Because the protective effect of photoresist 5 will be subjected to the impact of etching technics by the Seed Layer 4 of photoresist 5 overlay areas.Seed Layer 4 can be copper, gold etc.The thickness of Seed Layer is preferably between 10 nanometers to 10 micron.
Then, shown in Fig. 2 f, can for example adopt chemical mode to remove residual photoresist 5 in the blind hole, and expose the Seed Layer of its bottom, the preferred mode that adopts acetone to soak in this process.
Then, shown in Fig. 2 g, fill up electric conducting material 6 in blind hole, filling generally is to adopt to electroplate or the method for chemical plating, and the material of filling generally is copper, also can be the mixture of the material such as gold, silver or other metals, alloy.Although the barrier layer 3 on the blind hole sidewall also is with conductivity, but owing to there not being Seed Layer to cover, packing material 6 growth rates on it will be much smaller than the growth rate at bottom seed layer 4 places, packing material 6 will be take the Seed Layer 4 of via bottoms as boot media, begin deposition from the blind hole bottom, realize bottom-up high speed, high-quality plating filling.At last, reduction processing is carried out on another surface of the undressed blind hole of substrate, until blind hole is formed through hole, obtained thus required through hole interconnect architecture product.
In sum, only keep the Seed Layer of deposit among the present invention at through hole, utilize the growth variation of blind hole packing material on Seed Layer and barrier layer, take the Seed Layer of via bottoms as boot media, realize bottom-up growth; In addition, the surface of substrate is electroplated the rear surface and can not produced coating, thereby when post-processed, do not need the techniques such as CMP owing to there not being the existence of Seed Layer.Correspondingly, can simplify the manufacture craft that the bottom-up plating of through hole is filled according to manufacture craft of the present invention, reduce the process costs that the through hole interconnect architecture is made, possess simultaneously be convenient to control, the filling quality advantages of higher, thereby be particularly useful for large batch of suitability for industrialized production purposes.
Those skilled in the art will readily understand; the above only is preferred embodiment of the present invention; not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., all should be included within protection scope of the present invention.