CN101724877B - Electroplating method - Google Patents
Electroplating method Download PDFInfo
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- CN101724877B CN101724877B CN200810224585XA CN200810224585A CN101724877B CN 101724877 B CN101724877 B CN 101724877B CN 200810224585X A CN200810224585X A CN 200810224585XA CN 200810224585 A CN200810224585 A CN 200810224585A CN 101724877 B CN101724877 B CN 101724877B
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Abstract
The invention relates to an electroplating method which comprises the following steps of: providing a substrate, on which surface a seed crystal layer is formed; executing an electrolysis operation by taking the substrate as an anode in a tank bearing a liquid with the pH value of 5-9; and putting the substrate subjected to the electrolysis operation in an electroplating solution, and executing the electroplating operation by taking the substrate as a cathode. The electroplating method can reduce holes and/or disconnections in the electroplating process.
Description
Technical field
The present invention relates to technical field of manufacturing semiconductors, particularly a kind of electro-plating method.
Background technology
In the traditional technology, use electroplating technology usually and form the interconnecting metal layer (like copper) between device and external circuit.The step of utilizing traditional technology to carry out electroplating operations comprises step 11: as shown in Figure 1, substrate 10 is provided, and said substrate 10 surfaces are formed with crystal seed layer 20; Step 12: as shown in Figure 2, said substrate 10 is placed electroplating solution 30, be negative electrode with said substrate 10, carry out electroplating operations.
The ultimate principle that forms electrolytic coating is: the substrate 10 that the surface is had crystal seed layer 20 is immersed in the electroplating solution 30, and said substrate 10 is connected to external power with crystal seed layer 20 as electronegative flat board or cathodic electricity.Solid metal (like copper) piece is immersed in the electroplating solution 30 and constitutes positively charged anode.In the electroplating process, the metals ion in the electroplating solution is reduced into atoms metal on crystal seed layer 20 surfaces, simultaneously in metal anode generation oxidizing reaction, with the balance cathodic current.
Yet; Actual production is found; Shown in Fig. 3-5; Use in the electrolytic coating 40 that above-mentioned technology forms and be prone to form defectives 42 such as hole and/or consequent broken string, the existence of described hole and/or broken string will influence metal interconnected effect, and the generation that how to reduce described hole and/or broken string becomes those skilled in the art's problem demanding prompt solution.
On October 4th, 2006, the notification number of bulletin was to disclose a kind of electro-plating method in the Chinese patent of " CN1277958C "; Switch galvanized negative electrode inserts the dead time of millisecond magnitude with anode and in the centre method through the brief loop cycle that adopts the millisecond magnitude; So that the current density of capacity to be provided when the depositing metal layers in through hole; Improve electroplating effect, reduce the generation of electroplating hole.
But when using above-mentioned circulation means and improving electroplating effect, crucial improvement means are to shorten loop cycle and dead time, and obviously, the enforcement of above-mentioned electro-plating method depends on the circulation electroplating device, and the scope of application is narrower.
Summary of the invention
The invention provides a kind of electro-plating method, can in electroplating process, reduce the generation of hole and/or broken string.
A kind of electro-plating method provided by the invention comprises:
Substrate is provided, and said substrate surface is formed with crystal seed layer;
In carrying the groove of liquid that pH value is 5-9, be anode with said substrate, carry out electrolysis procedure, be attached to the particulate on the said crystal seed layer with removal;
The said substrate of the said electrolysis procedure of experience is placed electroplating solution, is negative electrode with said substrate, carries out electroplating operations.
Compared with prior art, technique scheme has the following advantages:
The electro-plating method that technique scheme provides; Through before carrying out electroplating operations; Carry out electrolysis procedure in advance; Be attached to the particulate on the said crystal seed layer to remove in the timed interval that forms said crystal seed layer and beginning electroplating process, then, strengthen the surface smoothness that is immersed in the crystal seed layer in the said electroplating solution; Reduce that said particulate adheres to the place because the generation of the discontinuous and consequent plating hole of the electrolytic coating phenomenon that the existence of said particulate causes, and needn't depend on the circulation electroplating device.
Description of drawings
Fig. 1-Fig. 2 is for electroplating the diagrammatic cross-section of flow process in the explanation prior art;
Fig. 3 is for experiencing the structural representation of the defective that forms behind the electroplating operations in the explanation prior art;
Fig. 4-Fig. 5 is for experiencing the sample picture of the defective that forms behind the electroplating operations in the prior art;
Fig. 6 is the schematic flow sheet of the execution electroplating operations of explanation first embodiment of the invention;
Fig. 7-Fig. 9 is the diagrammatic cross-section of the plating flow process of explanation first embodiment of the invention;
The polarization curve synoptic diagram of Figure 10 voltage during for definite execution electrolysis and the electroplating operations of the explanation embodiment of the invention;
Figure 11 uses the preferred embodiment of the present invention for explanation and contrasts synoptic diagram with the defects detection result who uses prior art;
Figure 12 uses the preferred embodiment of the present invention for explanation and contrasts synoptic diagram with the electrical detection result who uses prior art.
Embodiment
Although below with reference to accompanying drawings the present invention is described in more detail, wherein represented the preferred embodiments of the present invention, be to be understood that those skilled in the art can revise the present invention described here and still realize advantageous effects of the present invention.Therefore, following description is appreciated that broad to those skilled in the art, and not as limitation of the present invention.
For clear, whole characteristics of practical embodiments are not described.In following description, be not described in detail known function and structure, because they can make the present invention because unnecessary details and confusion.Will be understood that in the exploitation of any practical embodiments, must make a large amount of implementation details, for example, change into another embodiment by an embodiment according to relevant system or relevant commercial restriction to realize pioneer's specific objective.In addition, will be understood that this development possibly be complicated and time-consuming, but only be routine work to those skilled in the art.
In the following passage, with way of example the present invention is described more specifically with reference to accompanying drawing.Will be clearer according to description and claims advantage of the present invention and characteristic.What need explanation is, accompanying drawing all adopts the form of simplifying very much and all uses non-ratio accurately, only in order to convenient, the purpose of the aid illustration embodiment of the invention lucidly.
As shown in Figure 6, as the first embodiment of the present invention, the step of carrying out electroplating operations comprises step 601: substrate is provided, and said substrate surface is formed with crystal seed layer; Step 602: in carrying the groove of liquid that pH value is 5-9, be anode, carry out electrolysis procedure with said substrate; Step 603: the said substrate that will experience said electrolysis procedure places electroplating solution, is negative electrode with said substrate, carries out electroplating operations.
Particularly; On the substrate definition device active region and accomplish shallow trench isolation from, then form grid structure and source region and drain region after; And then (be before-metal medium layer, PMD), continuation forms the first layer through hole (via) and groove (trench) in said first interlayer dielectric layer to deposit first interlayer dielectric layer; Behind the crystal seed layer of diapire that forms said through hole of covering and groove and sidewall, can form substrate 100.Can expand ground, behind deposition N-1 interlayer dielectric layer, continue to form N-1 layer through hole and groove, behind the crystal seed layer of diapire that forms said through hole of covering and groove and sidewall, still can form substrate 100.Obviously, the number N of said interlayer dielectric layer can be any natural number, and as 1,3,5,7 or 9 etc., the concrete number of said interlayer dielectric layer is confirmed according to product requirement.Said before-metal medium layer covers said grid structure and source region and drain region and fills up the linear slit that is positioned between said grid structure; Said grid structure comprises the side wall and the gate oxide of grid, all around gate.Said grid structure also can comprise the blocking layer that covers said grid and side wall.Said substrate comprises but is not limited to comprise the silicon materials of element, and for example the silicon of monocrystalline, polycrystalline or non-crystal structure or SiGe (SiGe) also can be silicon-on-insulators (SOI).It is as shown in Figure 7 that the surface that forms has the said substrate 100 of crystal seed layer 120.
In the step that forms said through hole and groove with form between the step of said crystal seed layer 120, also comprise: form and cover said through hole and the bottom of groove and the adhesive linkage of sidewall.Said adhesive linkage is in order to strengthen said crystal seed layer 120 and said through hole and the bottom of groove and the degree of engagement of sidewall, to reduce owing to the increase that engages the bad contact resistance that causes of effect.Said adhesive linkage can comprise the rhythmo structure of TaN/Ta or TiN/Ti.Said adhesive linkage chemical vapor deposition method capable of using obtains.
Said crystal seed layer 120 physical vapor deposition (PVD) technologies capable of using form.When the interconnection material of filling said through hole and groove was metallic copper, said crystal seed layer was a copper.In the practice, said crystal seed layer 120 is in order to being connected to external power as electronegative flat board or cathodic electricity when forming electrolytic coating, is reduced and the metallic copper atom that forms to carry by the metal copper ion in the electroplating solution.
But actual production is found, is prone to form hole and/or consequent broken string in the electrolytic coating that on above-mentioned crystal seed layer 120, forms.
Contriver of the present invention thinks after analyzing that the reason that forms hole and/or broken string is: in the practice, between said crystal seed layer 120 of formation and beginning electroplating process, always exist certain time interval; In the said timed interval, to put the particulate that exists in the environment of said substrate and be prone under electrostatic adsorption, be attached on the said crystal seed layer 120, the particulate that adheres to will reduce the surface smoothness of said crystal seed layer 120; Then, when being immersed in said crystal seed layer 120 in the electroplating solution, at the adhesion of particles place; Be prone to cause the disappearance of said electrolytic coating; That is, be prone to cause the electrolytic coating that forms discontinuous, produce the generation of electroplating hole and/or broken string phenomenon thus.
Thus, contriver of the present invention proposes, and before carrying out electroplating operations, removes and is attached to the particulate on the said crystal seed layer 120, becomes the direction that reduces the generation of electroplating hole and/or broken string phenomenon.
Particularly; Through before carrying out electroplating operations; Carry out electrolysis procedure in advance, be attached to the particulate on the said crystal seed layer 120 with removal, then; Strengthen the surface smoothness be immersed in the crystal seed layer 120 in the said electroplating solution, reduce that said particulate adheres to the place because the generation of discontinuous and consequent plating hole of electrolytic coating that the existence of said particulate causes and/or broken string phenomenon.
As shown in Figure 8, when carrying out said electrolysis procedure, need said substrate 100 is placed the groove of load bearing fluid 140, the pH value of said liquid 140 can be 5-9, as 5,6,7,8,9; Particularly, said liquid 140 can be a kind of in sulfuric acid and/or hydrochloric acid soln, ammoniacal liquor or the deionized water of dilution.Said liquid 140 is as the ionogen of said electrolysis procedure, and said substrate 100 is an anode, and negative electrode can be the solid copper billet that is immersed in the said liquid 140.After applying voltage; Said particulate is under the effect of reversed electric field power (with carrying out electroplating operations Comparatively speaking); Electrostatic adsorption is destroyed, because the weakening or eliminate of said electrostatic adsorption, and; Substrate 100 with said crystal seed layer 120 when carrying out said electrolysis procedure, be inverted (the said liquid of the faces towards surface of said crystal seed layer 120) in said liquid 140 (for electroplating operations; Said liquid 140 is electroplating solution) in, make said particulate will break away from said crystal seed layer 120, and get in the said liquid 140.
Then, as shown in Figure 9, the said substrate of experiencing said electrolysis procedure is placed electroplating solution 160, be negative electrode with said substrate 100, carry out electroplating operations.The method of carrying out said electroplating operations can adopt any traditional technology, repeats no more at this.
As other embodiment of the present invention, when carrying out said electrolysis procedure, said pH value is that the liquid of 5-9 is in the mobile equilibrium.The said liquid that is in flow state will produce certain impact to the particulate that adheres to, be beneficial to the electrostatic adsorption that destroys between itself and crystal seed layer, be easy to increase the speed that said particulate breaks away from said crystal seed layer.In addition, the said liquid that is in the mobile equilibrium also is easy to get rid of the impurity that comprises in it, is beneficial to the carrying out of said electrolysis procedure.
Particularly, said pH value is that the liquid of 5-9 can be electroplating solution.At this moment, the step of execution electroplating operations is: at first, substrate is provided, said substrate surface is formed with crystal seed layer; Subsequently, said substrate being placed electroplating solution, is anode with said substrate, carries out electrolysis procedure; Again, in said electroplating solution, be negative electrode, carry out electroplating operations with said substrate.
As the liquid that carries above-mentioned electrolysis procedure, can simplify technology with said electroplating solution, reduce the kind of chemical required in the processing procedure, reduce the number of times that said substrate is passed between the groove that carries different solutions, can reduce the generation of waste product; Obviously, when carrying out said electrolysis procedure, said electroplating solution also preferably is in the mobile equilibrium.The said electroplating solution that is in flow state is easy to increase the speed that said particulate breaks away from said crystal seed layer, and, also be easy to get rid of the impurity that comprises in it, be beneficial to the carrying out of said electroplating operations.
When the interconnecting metal of filling said through hole and groove was copper (that is, said electrolytic coating is a copper), said crystal seed layer also was a copper, and said crystal seed layer adopts physical gas-phase deposition to form; Said electroplating solution is a copper sulfate; Particularly, in the practice, need from production, be beneficial to the Cl that electroplating reaction carries out common also including in the said electroplating solution
-And H
+Deng, that is, said electroplating solution can be the acidic solution of copper sulfate.
In addition, in order to make that said crystal seed layer receives few damage of trying one's best when utilizing said electrolysis procedure to remove particulate, executive condition that can preferred said electrolysis procedure.
Particularly, as the preferred embodiments of the present invention, before carrying out said electrolysis procedure, also comprise: the polarization curve of confirming said electroplating operations.To confirm the variation tendency of electrode reaction.Said polarization curve can obtain when utilizing traditional technology to carry out electroplating operations, specifically can use any existing method, repeats no more at this.
Be example with the copper electroplating operations, shown in figure 10, along with the variation (polarity that comprises cathode and anode transforms and the electrically variation of size) of voltage, its polarization curve is divided into depletion region ab, cut-off region bc, linear section cd and saturation region de.In the practice, carry out the voltage of said electroplating operations and in the linear section of said polarization curve, choose, both be beneficial to the speed that improves electroplating reaction, also be beneficial to the quality of improvement via the electrolytic coating of electroplating reaction formation.
In addition, can know, when carrying out said electrolysis procedure, compare when carrying out said electroplating operations that polarity is opposite, and (when carrying out said electroplating operations, substrate/crystal seed layer is a negative electrode by aforementioned analysis; When carrying out said electrolysis procedure, substrate/crystal seed layer is an anode); And when carrying out said electroplating operations, required voltage value can be the arbitrary value among its polarization curve internal linear district cd, still; In polar phase inverse time; The voltage of the absolute value of corresponding said voltage value is in the depletion region ab in the said polarization curve, that is, and and when carrying out said electrolysis procedure with this voltage that is in the depletion region ab in the said polarization curve; The reverse plating that will cause established seed layer material (being copper) (promptly; Because polar changes, said crystal seed layer becomes anode by negative electrode, and electrode reaction is by the Cu in the electroplating solution
2+Get electronics and generate Cu, become the Cu betatopic and become Cu
2+), the copper behind the betatopic will get in the electroplating solution, in other words, will cause the consume of said crystal seed layer.Therefore, the voltage of carrying out said electrolysis procedure is preferably in the cut-off region of said polarization curve and chooses.
As an example, be example with the copper plating, in the practice, carry out the voltage of said electroplating operations and elect 0.5V as, this 0.5V is that copper is electroplated the arbitrary value among the polarization curve internal linear district cd; And the voltage range that cut-off region bc is corresponding in the said polarization curve be-0.3V～0.3V, the span of carrying out the voltage of said electrolysis procedure be (0V, 0.3V], be preferably [0.1V, 0.3V], like 0.1V, 0.2V or 0.3V.
What need explanation is, the span of carrying out the voltage of said electrolysis procedure can be also that [0.3V 0V), is preferably [0.1V;-0.3V], as-0.1V ,-0.2V or-0.3V, at this moment; Said electrolysis procedure is reverse electroplating operations, just level of response is had restriction, and is weak slightly.In addition, when carrying out said reverse electroplating operations, required electroplating solution can be merely the liquid that pH value is 5-9, is 5,6,7,8 or 9 like pH value; Particularly, said liquid can be a kind of in sulfuric acid and/or hydrochloric acid soln, ammoniacal liquor or the deionized water of dilution.
In addition, the time length of carrying out said electrolysis procedure is 1 second-10 seconds, and is concrete as 1 second, 3 seconds, 5 seconds, 8 seconds or 10 seconds.This be because: the time length is too short, is prone to weaken particle removing effect, promptly weakens the effect of improving described hole and/or disconnection defect; Time length is oversize, and it is liquid or the electroplating solution erosion of 5-9 that said crystal seed layer is prone to by said pH value, then, and the electric property of the wafer that obtains after the subsequent operations of influence experience.
Be the improve effect of checking technique scheme to described hole and/or broken string; Contriver of the present invention is corresponding to have carried out described hole and/or disconnection defect detection with the substrate behind the execution electroplating operations of above-mentioned preferred version and the acquisition of application traditional scheme; Shown in figure 11; The result shows, use above-mentioned preferred version after, can make to be decreased to 1-5 by 20-100 at suprabasil described hole of a slice and/or disconnection defect 42.
In addition; Wafer acceptability test (WAT) has been carried out in (it is qualified to have detected) substrate that contriver's correspondence of the present invention obtains when carrying out electroplating operations with above-mentioned preferred version with the application traditional scheme, has specifically tested the contact resistance (Rc) of the through hole after filling, and the result shows; Compare when carrying out electroplating operations with the application traditional scheme; After using above-mentioned preferred version execution electroplating operations, the variation of the contact resistance of the through hole after the filling can be left in the basket, promptly; When the application technique scheme is improved described hole and/or broken string, can not produce detrimentally affect to the electric property of wafer.
What need stress is that not elsewhere specified step all can use conventional methods acquisition, and concrete processing parameter is confirmed according to product requirement and processing condition.
Although the present invention has been described and has enough described embodiment in detail although describe through the embodiment at this, the applicant does not hope by any way the scope of claims is limited on this details.Other to those skilled in the art advantage and improvement are conspicuous.Therefore, relative broad range the invention is not restricted to represent and the specific detail of describing, equipment and the method and the illustrative example of expression.Therefore, these details be can depart from and the spirit and the scope of the total inventive concept of applicant do not broken away from.
Claims (8)
1. an electro-plating method is characterized in that, comprising:
Substrate is provided, and said substrate surface is formed with crystal seed layer;
In carrying the groove of liquid that pH value is 5-9, be anode with said substrate, carry out electrolysis procedure, be attached to the particulate on the said crystal seed layer with removal;
The said substrate of the said electrolysis procedure of experience is placed electroplating solution, is negative electrode with said substrate, carries out electroplating operations; The voltage of voltage when carrying out said electrolysis procedure when carrying out said electroplating operations; Said pH value is that the liquid of 5-9 is electroplating solution.
2. electro-plating method according to claim 1 is characterized in that: said crystal seed layer adopts physical gas-phase deposition to form.
3. electro-plating method according to claim 1 is characterized in that: said seed layer material is a copper.
4. electro-plating method according to claim 3 is characterized in that: said electroplating solution is the acidic solution of copper sulfate.
5. electro-plating method according to claim 1 is characterized in that: when carrying out said electrolysis procedure, said pH value is that the liquid of 5-9 is in mobile equilibrium.
6. electro-plating method according to claim 1 is characterized in that, before carrying out said electrolysis procedure, also comprises: confirm the polarization curve of said electroplating operations, carry out the voltage of said electrolysis procedure and in the cut-off region of said polarization curve, choose.
7. electro-plating method according to claim 6 is characterized in that: the voltage of carrying out said electroplating operations is chosen in the linear section of said polarization curve.
8. electro-plating method according to claim 1 is characterized in that: the time length of carrying out said electrolysis procedure is 1-10 second.
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| CN200810224585XA CN101724877B (en) | 2008-10-21 | 2008-10-21 | Electroplating method |
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| CN200810224585XA CN101724877B (en) | 2008-10-21 | 2008-10-21 | Electroplating method |
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| CN101724877B true CN101724877B (en) | 2012-05-23 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1571121A (en) * | 2003-07-11 | 2005-01-26 | 中芯国际集成电路制造(上海)有限公司 | Copper electroplating method |
| CN1645570A (en) * | 2004-01-20 | 2005-07-27 | 台湾积体电路制造股份有限公司 | Method for removing particles from wafer surface |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1571121A (en) * | 2003-07-11 | 2005-01-26 | 中芯国际集成电路制造(上海)有限公司 | Copper electroplating method |
| CN1645570A (en) * | 2004-01-20 | 2005-07-27 | 台湾积体电路制造股份有限公司 | Method for removing particles from wafer surface |
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