Background technology
Along with the unicircuit characteristic dimension to 65 nanometers and even meticulousr structural development, filling to slit (Seam), particularly the filling in slit with high aspect ratio is had higher requirement, the depth-to-width ratio in slit has reached 4: 1 even higher in the part of devices, and this is a great challenge for fill process.
High density plasma CVD (HDPCVD) is because can be under than the low deposition temperature, prepares the film that can fill (being defined as the degree of depth in slit and the ratio of the width) slit that has high aspect ratio, and is widely used in current actual production.
Usually, except that reactant gases, also need suitably feed buffer gas in the HDPCVD reaction chamber,, thereby increase the deposit reaction uniformity in order to the concentration of diluting reaction gas.Existing buffer gas is generally helium (He) or argon gas (Ar), along with the increase of integrated circuit (IC)-components dense degree, the film of deposit is more and more thinner, causes for obtaining uniform deposit effect, degree of uniformity requirement to reaction is more and more higher, promptly requires the size of particles of buffer gas more and more littler.Therefore, after the characteristic dimension of integrated circuit (IC)-components is reduced to below 90 nanometers, adopt helium (He) and hydrogen (H usually
2) mixed gas as buffer gas.
Yet actual production is found, uses helium (He) and hydrogen (H
2) mixed gas during as buffer gas, easily form the deposit particle on the deposition film surface, after this deposit particle carried out composition analysis, as can be known, this deposit particle is identical with the deposition film material, and thus, this deposit particle is considered to deposit usually and is reflected at silicon chip surface top upper zone and takes place to cause, be that deposition material just falls in the deposition film after forming the deposit particle, form the deposition film particle defects.This particle defects may be removed in follow-up cleaning process or process of lapping, forms cavity or pin hole on the deposition film surface then.
This cavity or pin hole comprise the influence that integrated circuit (IC)-components may cause: the cavity or the pin hole that are arranged in shallow channel isolation area, if in subsequent process, there is the electro-conductive material particulate to fall into, easily cause the shallow channel isolation area isolated failure, then increase the shallow channel isolation area leakage current, when serious even cause integrated circuit (IC)-components and lost efficacy; Cavity in the interlayer dielectric layer or pin hole easily cause between through hole interconnecting, and influence the integrated circuit (IC)-components electric property then.Thus, the generation that how to suppress surface particle in the HDPCVD process becomes those skilled in the art's problem demanding prompt solution.
Application number all provides a kind of method that reduces particulate in the Chinese patent application of " 200310122688.2 " and " 01110196.2 ", and the former pollutes in order to the particulate matter that reduces in the low-pressure chemical vapor phase deposition process; The latter pollutes in order to the particulate matter due to the minimizing plasma etch process.Two kinds of methods all are by in time detaching byproduct of reaction, avoiding it to drop in wafer surface, with the generation of minimizing wafer surface particulate, and the not fundamentally generation of inhibited reaction thing particulate.
Consider, use current technology, just after changing the buffer gas composition that feeds in the reaction chamber, just produced the surface particle defective, and the change of buffer gas composition just changes to helium (He) and hydrogen (H with original helium (He)
2) mixed gas, again because hydrogen has higher relatively activity, therefore, the feeding process of hydrogen and feeding time are controlled will be to the material impact that produces of HDPCVD reaction.Thus, by the control feeding process of hydrogen and feeding time to improve the HDPCVD reaction uniformity, become a direction of the process modification of the generation that suppresses the HDPCVD particle defects.
Summary of the invention
The invention provides a kind of high-density plasma chemical vapor deposition method, can in deposition process, suppress the generation of particle defects, and then improve the unicircuit electrical property.
A kind of high-density plasma chemical vapor deposition method provided by the invention carries out the deposit reaction by feed deposited gas in reaction chamber; Described deposited gas comprises first reactant gases, second reactant gases, helium and hydrogen, and described second reactant gases and helium had fed in the described reaction chamber before deposit reaction beginning; Described hydrogen feeds reaction chamber after described first reactant gases.
Described first reactant gases comprises the mixed gas of silane, silane and phosphuret-(t)ed hydrogen composition or the mixed gas of silane and silicon fluoride composition; Described second reactant gases comprises a kind of or its combination in the gas materials such as ozone, oxygen, nitrous oxide, carbonic acid gas; The concentration ratio scope of helium and hydrogen is 1: 2~2: 1 in the described reaction chamber; The concentration ratio of helium and hydrogen is 4: 3 in the described reaction chamber; Be less than or equal to 1/10th of described deposit duration of the reaction the pitch time of described hydrogen and described first reactant gases feeding reaction chamber; Be less than or equal to 5 seconds the pitch time that described hydrogen and described first reactant gases feed reaction chamber; Described hydrogen and described first reactant gases feed reaction chamber simultaneously; The starting stage flow of described hydrogen after feeding reaction chamber progressively increases; The time that progressively increase process of described hydrogen flowing quantity continues is less than or equal to 1/10th of described deposit duration of the reaction; The time that progressively increase process of described hydrogen flowing quantity continues is less than or equal to 3 seconds.
Compared with prior art, the present invention has the following advantages:
1. by the feeding time of control hydrogen, the feeding time that is about to hydrogen is controlled at after the feeding of first reactant gases, controls reaction process then, has suppressed the generation of particle defects;
2. by the feeding process of control hydrogen, promptly control hydrogen and make its slow feeding, make reaction chamber to replenish buffer gas reposefully, make the deposit reaction process can carry out more evenly;
3. by suppressing the generation of particle defects, can reduce the generation of deposited film surface hole or pin hole, and then improve the shallow channel isolation area leakage current, and the short circuit between the minimizing through hole, optimize the integrated circuit (IC)-components performance.
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 extensive instruction for those skilled in the art, and not as limitation of the present invention.
For clear, whole features of practical embodiments are not described.In the 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 developer's specific objective.In addition, will be understood that this development may be complicated and time-consuming, but only be routine work for those skilled in the art with advantage of the present invention.
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 following explanation and claims advantages and features of the invention.It should be noted that accompanying drawing all adopts very the form of simplifying and all uses non-ratio accurately, only in order to convenient, the purpose of the aid illustration embodiment of the invention lucidly.
Using method provided by the invention carries out the step of high-density plasma chemical vapor deposition and mainly comprises: at first, feeding time of hydrogen is controlled at after first reactant gases feeds, with the control reaction process, suppresses the generation of particle defects; Then, control hydrogen makes its slow feeding, makes reaction chamber to replenish buffer gas reposefully, makes the deposit reaction process can carry out more evenly; At last, proceed the subsequent deposition process.
As embodiments of the invention, method provided by the invention is applied in the filling process of shallow channel isolation area oxide compound.
Deposit shallow channel isolation area oxide material is generally silicon-dioxide (SiO
2), required reactant gases comprises first reactant gases and second reactant gases, and described first reactant gases comprises silane (SiH
4), described second reactant gases comprises oxygen (O
2), nitrous oxide (N
2O) or carbonic acid gas (CO
2); Be the degree of uniformity that intensified response is carried out, also need feed the mixed gas of helium and hydrogen as buffer gas.
In the actual production process, for satisfying processing requirement, should keep helium 40 in described second reactant gases 20 and the buffer gas at finite concentration in the reaction chamber at any time, and 30 carrying out for the deposit reaction of the hydrogen in described first reactant gases 10 and the buffer gas feed.The concentration ratio scope of buffer gas helium 40 and hydrogen 30 is 1: 2~2: 1 in the reaction chamber, is preferably 4: 3.
Fig. 1 feeds time sequential synoptic diagram for the reactant gases of the existing method of explanation, as shown in Figure 1, state with all gases in the height curve representation reaction process, high-order curve representation gas has fed reaction chamber, low level curve representation gas does not also feed reaction chamber, the time that on behalf of the deposit reaction, the transverse axis of curve carry out.
Described first reactant gases 10 usually need be through an air balance (divert) step before feeding reaction chamber, be and guarantee that described first reactant gases 10 has stable flow rate and empties the impurity that feeds in the pipeline when reality feeds reaction chamber, starting stage can be discharged by being arranged near the discharge line in place, reaction chamber gas inlet by first reactant gases 10 that source of the gas discharges, can feed in the reaction chamber beginning deposition process behind the stability of flow.
In the existing method, hydrogen 30 is released from corresponding source of the gas simultaneously with first reactant gases 10, and hydrogen 30 need not the said flow equilibrium step, promptly at hydrogen 30 and first reactant gases 10 from the d/d starting stage of corresponding source of the gas, first reactant gases 10 needs experience said flow equilibrium step, and hydrogen 30 is directly fed reaction chamber.In the curve shown in Figure 1, the a section time length is the required time of air balance step of first reactant gases, as mentioned above, at this section in the period, with described first reactant gases of low level curve representation 10 feeding states, with the feeding state of described second reactant gases 20 of high-order curve representation and buffer gas helium 40 and hydrogen 30.The time that on behalf of deposition process, the b section time length carry out is with the state of each gas in the high-order curve representation reaction chamber.
As embodiments of the invention, be to suppress the generation of particle defects, the time that hydrogen 30 is fed reaction chambers is controlled at first reactant gases 10 and feeds after the reaction chambers, with the control reaction process; Promptly behind first reactant gases, 10 experience said flow equilibrium steps,, it is fed reaction chamber again from source of the gas release hydrogen 30.Fig. 2 feeds time sequential synoptic diagram for the reactant gases of explanation the inventive method first embodiment, as shown in Figure 2, the a section time length is the required time of air balance step of first reactant gases 10, at this section in the period, with the feeding state of hydrogen 30 in described first reactant gases 10 of low level curve representation and the buffer gas, with the feeding state of helium 40 in described second reactant gases 20 of high-order curve representation and the buffer gas.
The described time that hydrogen 30 is fed reaction chamber is controlled at first reactant gases 10 and feeds after the reaction chamber, comprises that control hydrogen interval certain hour after first reactant gases 10 of stability of flow feeds reaction chamber feeds in the reaction chamber again.
Be less than or equal to 1/10th of deposit duration of the reaction the pitch time that first reactant gases 10 of described hydrogen 30 and stability of flow feeds reaction chambers.Described deposit duration of the reaction is determined according to processing condition and product requirement.As embodiments of the invention, described deposit duration of the reaction scope is: 50~200 seconds (s) is less than or equal to 5s the pitch time that first reactant gases 10 of described hydrogen 30 and stability of flow feeds reaction chambers.
Subsequently, in reaction chamber, feed hydrogen 30, and the feeding process of control hydrogen, make reaction chamber can replenish buffer gas reposefully, and then make the deposit reaction process can carry out more evenly.The time that on behalf of deposition process, the b section time length carry out is with the state of each gas in the high-order curve representation reaction chamber.
The method of the feeding process of described control hydrogen 30 is for progressively increasing the flow of hydrogen in the starting stage that feeds hydrogen 30.Shown in hydrogen b section curve leading portion among Fig. 2.The time that described hydrogen flowing quantity increase process gradually continues is less than or equal to 1/10th of deposit duration of the reaction.As embodiments of the invention, described deposit duration of the reaction scope is: 50~200 seconds (s) is less than or equal to 3s the pitch time that first reactant gases 10 of described hydrogen 30 and stability of flow feeds reaction chambers.
At last, proceed the subsequent deposition process.
As the second embodiment of the present invention, Fig. 3 feeds time sequential synoptic diagram for the reactant gases of explanation the inventive method second embodiment, as shown in Figure 3, the feeding time of control hydrogen 30, first reactant gases 10 of stability of flow feeds simultaneously after making it and experiencing the air balance step; Subsequently, hydrogen 30 directly can be fed to set flow.The a section time length is the required time of air balance step of first reactant gases 10, at this section in the period, with the feeding state of hydrogen 30 in described first reactant gases 10 of low level curve representation and the buffer gas, with the feeding state of helium 40 in described second reactant gases 20 of high-order curve representation and the buffer gas.The time that on behalf of deposition process, the b section time length carry out is with the state of each gas in the high-order curve representation reaction chamber.
As embodiments of the invention, method provided by the invention can be applicable in the deposition process of interlayer dielectric layer (IMD/ILD).
The inter-level dielectric layer material is generally silicon-dioxide (SiO
2), fluorine silex glass (FSG) or phosphorosilicate glass (PSG) etc., required reactant gases comprises first reactant gases and second reactant gases, described first reactant gases comprises silane (SiH
4), silane (SiH
4) and phosphuret-(t)ed hydrogen (PH
3) mixed gas or the silicon fluoride (SiF that form
4) mixed gas formed, described second reactant gases comprises ozone (O
3), oxygen (O
2), nitrous oxide (N
2O), carbonic acid gas (CO
2) etc.; Be the degree of uniformity that intensified response is carried out, also need feed the mixed gas of helium and hydrogen as buffer gas.
As the third embodiment of the present invention, described hydrogen interval certain hour after the silane of stability of flow feeds reaction chamber feeds in the reaction chamber again.
Be less than or equal to 1/10th of deposit duration of the reaction the pitch time of the silane feeding reaction chamber of described hydrogen and stability of flow.Described deposit duration of the reaction is determined according to processing condition and product requirement.As embodiments of the invention, described deposit duration of the reaction scope is: 50~200 seconds (s) is less than or equal to 5s the pitch time that first reactant gases 10 of described hydrogen 30 and stability of flow feeds reaction chambers.
The method of the feeding process of described control hydrogen is for progressively increasing the flow of hydrogen in the starting stage that feeds hydrogen.The time that the described hydrogen flowing quantity process that continues to increase continues is less than or equal to 1/10th of deposit duration of the reaction.As embodiments of the invention, described deposit duration of the reaction scope is: 50~200 seconds (s) is less than or equal to 3s the pitch time that first reactant gases 10 of described hydrogen 30 and stability of flow feeds reaction chambers.
Obviously, the feeding time and the feeding process of control hydrogen, first reactant gases 10 of stability of flow feeds simultaneously after promptly adopting described hydrogen and experiencing the air balance step; And described hydrogen feeds reaction chamber to set the direct mode that feeds of flow, can be used as the fourth embodiment of the present invention.
Simultaneously, first reactant gases 10 of stability of flow feeds simultaneously after described hydrogen and the experience air balance step; And feed hydrogen in the mode that progressively increases flow, can be used as the fifth embodiment of the present invention; In addition, described hydrogen after first reactant gases 10 of stability of flow feeds reaction chambers at interval certain hour feed in the reaction chamber again, and described hydrogen feeds reaction chamber in the mode of setting flow and directly feeding, and can be used as the sixth embodiment of the present invention.
What need emphasize is, the concrete technology that relates in the described HDPCVD process can adopt any traditional method, and the technical scheme that relates under any circumstance all is not considered integral part of the present invention, does not repeat them here.
Adopt the inventive method, by the feeding time of control hydrogen, the feeding time that is about to hydrogen is controlled at after the feeding of first reactant gases, controls reaction process then, has suppressed the generation of particle defects; By the feeding process of control hydrogen, promptly control hydrogen and make its slow feeding, make reaction chamber to replenish buffer gas reposefully, make the deposit reaction process can carry out more evenly; By suppressing the generation of particle defects, can reduce the generation of deposited film surface hole or pin hole, and then improve the shallow channel isolation area leakage current, and the short circuit between the minimizing through hole, optimize the integrated circuit (IC)-components performance.
Although the present invention has been described and has enough described embodiment in detail although describe by the embodiment at this, the applicant does not wish 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, can depart from these details and do not break away from the spirit and scope of the total inventive concept of applicant.