KR101178620B1 - Slurry and additive composition for high planarity slurry composition for relatively weak layer - Google Patents

Abstract

As an additive in the slurry composition containing anionic surfactant as a dispersing agent, Amphoteric surfactant; And a pH adjusting agent, wherein the high leveling flattening slurry composition additive includes a high leveling flattening slurry composition additive, wherein the film to be polished is 1.2 times or more compared to plasma enhanced tetra-ethyl ortho silicate (PE TEOS) in chemical mechanical polishing (CMP). A slurry composition is disclosed.

Description

High level polishing flattening slurry and additive composition for insulating materials with weak mechanical properties {SLURRY AND ADDITIVE COMPOSITION FOR HIGH PLANARITY SLURRY COMPOSITION FOR RELATIVELY WEAK LAYER}

The present invention relates to a slurry composition used in a process of rapidly polishing and planarizing a patterned wafer having an uneven portion having a large step with respect to an insulating film having low mechanical properties in a semiconductor device manufacturing technology, and an additive included in the slurry composition.

As semiconductor devices become finer and more dense, finer pattern formation techniques are used. Accordingly, the surface structure of the semiconductor devices becomes more complicated and the level of the surface films becomes larger. In the manufacture of semiconductor devices, a CMP process is used as a planarization technique for removing a step in a specific film formed on a substrate, a process and wiring for planarization of an interlayer insulating film and an insulating film for shallow trench isolation (STI), contact plugs, As a process for forming a metal conductive film such as a via contact or the like, a CMP process is frequently used. The CMP process is a technique of planarizing the surface by chemically and mechanically removing the uneven surface of the wafer while supplying a slurry to these contact sites while the surface of the wafer to be polished is brought into contact with the polishing pad.

The CMP process is a complex process, and there are various evaluation indices. In particular, important factors that determine the performance of the CMP process include polishing speed, planarization of the polishing surface, and scratches. Variables influencing these characteristics include CMP process conditions, a kind of slurry which is a main consumable material, and a kind of polishing pad, and it is known that the influence of the slurry is particularly great when the high-difference insulating film is planarized. Conventionally, a technique for implementing a polishing selectivity for a high step part by mixing a slurry composition and a functional additive composition immediately before a CMP process has been developed and applied.

When the step is quickly removed in the high step planarization CMP process, and the step is removed and the slurry is applied with a function that the grinding speed is reduced sharply and the grinding is hardly performed, the thickness of the film can be reduced in the deposition process, which is the previous step. As a result, raw material can be reduced, and productivity can be improved by shortening the process time. In order to impart this function, functional additive prescription is required, and when added directly to the slurry to achieve the function, the dispersion stability and aging stability of the slurry may be deteriorated, which may cause defects such as scratches.

Therefore, there is a need for a slurry and an additive composition having a high step removal rate and a slow removal rate after the step removal, which has an automatic stop function.

In the prior art, PE TEOS and HDP films are mainly used as an insulating film in the interlayer separation (ILD) and device isolation (STI) processes, and thus, slurry and additives having automatic polishing stop function for PE TEOS and HDP films. The composition is being applied. However, as the device technology is advanced and process refinement is progressing, the film quality used in the past is being replaced. Accordingly, there is a need for a slurry and additive composition having a high step leveling and automatic polishing stop function applicable to the film quality being replaced. Do.

In the present invention, the slurry additive composition for PE TEOS, HDP film quality, which is conventionally used, is not applied to the film properties with relatively low mechanical properties such as BPSG, PSG or SOD (Spin-On-Dielectric), and Poly Si. The present inventors have developed a slurry and additive composition having high step planarization and automatic polishing stop function for a film having a weak mechanical property.

As an additive in the slurry composition containing anionic surfactant as a dispersing agent, Amphoteric surfactant; And a pH adjusting agent, wherein the film to be polished is 1.2 times or more compared to plasma enhanced tetra-ethyl ortho silicate (PE TEOS) in chemical mechanical polishing (CMP).

The amphoteric surfactant contains betaine, in particular cocamidopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine (2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine), alkyl amido betaine, alkylamide propyl betaine, alkyl betaine, alkyl dimethyl amine beta Phosphorus (alkyl dimethyl amine betaine), amidosulfobetaine, alkyldimethyl betaine, apricotamidopropyl betaine, coco amido betaine, coco beta Phosphorus (coco betaine), cocoamidopropyl betaine, cocodimethylbetaine, cocodimethylbetaine, lauryl betaine, laurylamiidopropyl betaine, witt Germanamidopro Betaine (wheatgermamidopropyl betaine), isostearamidopropyl betaine, myristamidopropyl betaine, palmitamidopropyl betaine, and undecylamidopropyl betaine undecylenamidopropyl betaine) at least one selected from the group consisting of 0.5 to 1 parts by weight based on 100 parts by weight of the total additive.

In chemical mechanical polishing (CMP), the polishing target film to which the slurry composition is applied is at least one selected from the group consisting of BPSG (Borophospho Silicate Glass), PSG, Spin on Dielectric (SOD), and Poly Si film quality.

The slurry composition comprises at least one abrasive selected from the group consisting of ceria, colloidal silica, fumed silica and zirconia.

The pH adjusting agent is triethylamine, triethanolamine, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, ammonium hydroxide (NH4OH), potassium hydroxide (KOH) at least one selected from the group consisting of polyacrylic acid, carboxylic acid, formic acid, acetic acid, propionic acid, valeric acid, enanthic acid, oxalic acid, malonic acid, succinic acid and malic acid.

It provides a high leveling planarization slurry composition comprising the additive.

According to the present invention, it is excellent in chemical passivation during pattern wafer polishing of high step uneven portions in a process in which a material with weak mechanical properties is deposited, and has excellent step removal ability against excessive film quality of mechanical polishing, and automatically stops polishing after planarization. Excellent function can achieve flattening. In addition, it is excellent in the role of lubricants to prevent defects due to mechanical polishing, it is possible to achieve high quality polishing with excellent cleaning effect after CMP. In addition, it is possible to have excellent passivation with a low content of input, and thus shows an excellent effect on preventing scratches and defects generated when an excessive amount of surfactant is added.

In the process of flattening the high step uneven portion by using the slurry composition, the initial polishing convex portion is subjected to strong physical pressure, so that the polishing function of the abrasive particles acts strongly, so that the polishing proceeds quickly, but the concave portion that is under pressure is not polished. Since the automatic polishing stop function adsorbed on the surface forms a film on the surface of the polished film, the polishing is suppressed, so that the polishing rate is significantly lowered. As polishing continues, the steps between the concave and convex parts become smaller, and the steps become extinct. At this time, the polishing speed is significantly lower because the function of the polishing suppression film formed on the polished film is larger than the physical polishing action due to pressure. do.

As the metal oxide abrasive grains included in the slurry composition, ceria, colloidal silica, fumed silica, zirconia, and the like are used. Ceria has lower hardness than silica particles, but due to the chemical polishing mechanism in which Si-O-Ce bonds are formed between Si and Ce atoms, the polishing rate of silicon-containing surfaces such as glass or semiconductor substrates is very high. It is advantageous.

The content of the abrasive particles is important to ensure a sufficient step removal rate, and the use rate may vary depending on the desired polishing rate since the polishing rate at the same content varies depending on the type of particles. In the case of ceria, the content of the abrasive particles is used at 0.1 to 20% by weight, preferably 0.5 to 5% by weight. If the content is too small, the step removal rate tends to be too slow. If the content is too high, a larger amount of the automatic polishing stop function is required to implement the automatic polishing stop function and the viscosity of the abrasive may be difficult to handle.

In the case of ceria particles, the particle diameter in the dispersion is preferably 50 to 500 nm in size considering the scratch and polishing rate. If the average particle diameter of the ceria particles is too large, there is a fear that polishing defects such as scratches may occur on the surface of the semiconductor substrate. If the average particle diameter is too small, the polishing rate may be lowered, and since the ratio of the surface area per unit volume is large, it is easily affected by the surface state, and agglomeration occurs due to conditions such as pH or additive concentration, and polishing defects such as scratches on the semiconductor surface are caused. May cause.

Anionic surfactants can be used as a dispersant in the slurry composition, and the anionic surfactants act as dispersants by electrostatic dispersion. When anionic surfactant is used as a dispersant, an additive is used to secure dispersion stability.

According to an embodiment of the present invention, as an additive of a slurry composition comprising an anionic surfactant as a dispersant, it includes an amphoteric surfactant and a pH adjusting agent, and the film to be polished is in CMP (Chemical Mechanical Polishing) It provides a high level flattening slurry composition additive that is 1.2 times or more than PE TEOS (plasma enhanced tetra-ethyl ortho silicate). Slurry compositions comprising such additives exhibit particularly good polishing speeds and automatic stop functions for BPSG membranes. As the semiconductor design rules become very fine, insulation materials with relatively weak mechanical properties are employed in the deposition process applied to STI device isolation. Therefore, mechanical strength is weaker than that of existing films in the subsequent CMP process. The material is polished. In this case, it is necessary to strengthen the chemical polishing, in which the mechanical polishing of the polished film is predominantly applied during the chemical mechanical polishing (CMP) process, thereby achieving a function according to the process characteristics.

BPSG is a glass based on silicon, phosphorus, boron and oxygen, and phosphorus and boron may be changed in the range of 0.1 to 20% by weight, respectively. BSG is a glass mainly containing silicon, boron and oxygen, and can change boron in the range of 0.1-20 weight%. PSG is a glass composed mainly of silicon, phosphorus and oxygen, and may change phosphorus in the range of 0.1 to 20% by weight.

The amphoteric surfactant included in the additive is betaine, specifically cocamidopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine (2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine), alkyl amido betaine, alkylamide propyl betaine, alkyl betaine, alkyl dimethyl amine beta Phosphorus (alkyl dimethyl amine betaine), amidosulfobetaine, alkyldimethyl betaine, apricotamidopropyl betaine, coco amido betaine, coco beta Phosphorus (coco betaine), cocoamidopropyl betaine, cocodimethylbetaine, cocodimethylbetaine, lauryl betaine, laurylamiidopropyl betaine, witgerma Midopropyl betaine, isostearamidopropyl betaine, myristamidopropyl betaine, palmitamidopropyl betaine, and undecylamidopropyl betaine One or more selected from the group consisting of phosphorus (undecylenamidopropyl betaine), it is contained in 0.5 to 1 parts by weight based on 100 parts by weight of the total additive.

The betaine is a compound represented by the following formula (1).

The cocamidopropyl betaine is a compound represented by the following formula (2).

Where

R is an alkyl group having 1 to 10 carbon atoms,

n is an integer of 1-5.

Amphoteric surfactants act as cationic surfactants in acidic atmospheres, nonionic surfactants in neutral atmospheres and anionic surfactants in basic atmospheres, depending on the pH range. In addition, when the anionic surfactant used as a dispersant and an amphoteric surfactant are used together as an additive, the automatic polishing stop function can be enhanced without chemical coagulation effect, and the existing slurry compositions are implemented in HDP or PE TEOS, especially in a BPSG membrane. Compared with one performance, it was implemented at the same level or higher. According to the type of insulating film, when the amphoteric surfactant having a strong automatic stop function was used for polishing HDP or PE TEOS, it showed an excellent effect on the performance efficiency compared to the dosage, and it was confirmed that the use of the additive was also effective on the HDP or PE TEOS film quality. .

Conventionally, high step polishing has been achieved using polyacrylic acids / amines, carboxylic acids / amines or gemini-type surfactants, but chemical passivation performance is poor for soft membranes such as BPSG, which have low mechanical strength. The use of strong adsorbents could potentially lead to defects in cleaning problems. In addition, amines used with carboxylic acids are known as influencing factors for wafer breakage, so it is urgent to apply alternative materials according to the adoption of soft film quality. Betaine-containing compounds, collectively referred to as "trialkylamino acids" in amphoteric surfactants, contain one amine group and one carboxyl group in their chemical structure, even when used as a single substance. It can create a pH atmosphere of the acidic region to exert, and can act as a cationic surfactant can exhibit excellent passivation performance for the surface of the surface to be polished.

In order to achieve the function by applying simultaneously to the ILD and STI process, it is possible to give a selective function by adding a pH adjuster as needed.The pH adjuster included in the additive as a basic pH adjuster triethylamine (triethylamine), triethanol One or more selected from the group consisting of amine (triehanolamine), 2-amino-2-methyl-1-propanol, ammonium hydroxide (NH 4 OH) and potassium hydroxide (KOH) Can be. Polyacrylic acid and carboxylic acid may be used as the acidic pH adjusting agent, and one selected from the group consisting of formic acid, acetic acid, propionic acid, valeric acid, enanthic acid, oxalic acid, malonic acid, succinic acid and malic acid The above can be used.

The present invention also provides a high step planarization slurry composition comprising the additive according to the present invention. In the case of polishing the semiconductor substrate using the slurry composition, the slurry composition is supplied to the polishing pad, the surface to be polished of the semiconductor device is brought into contact with the polishing pad, and the polishing of the silicon dioxide-based material layer is performed by relative movement therebetween. Polish the surface. As the polishing apparatus, a general polishing apparatus can be used. That is, the planarization process can be performed by holding the semiconductor device in the polishing head while supplying the abrasive from the abrasive supply pipe, making contact with the polishing pad attached to the surface of the polishing platen, and rotating the polishing head and the polishing plate relative to each other. . However, it is not limited to this apparatus. The polishing head can perform linear motion as well as rotation, and the polishing surface and the polishing pad can be about the same size or less than the semiconductor device. In this case, it is preferable to polish the whole surface of the semiconductor device by relatively moving the polishing head and the polishing platen. The polishing table and the polishing pad may be moved in one direction in a belt manner, not rotationally. As the polishing pad, a general nonwoven fabric, urethane foam, porous resin, nonporous resin, or the like can be used. In order to accelerate the supply of the abrasive to the surface of the polishing pad or to allow the abrasive to be stored in a certain amount, grooves such as lattice, concentricity, and spiral may be formed.

Table 1 below shows the polishing rate and polishing selectivity of the convex and concave portions when the Gemini-type surfactant (additive 1) and polyacrylic acid (additive 2), which have been conventionally used as additives in PE TEOS and BPSG films, are used, respectively. It was.

number Membrane additive Convex Polishing Rate
(Å / min) Concave Polishing Rate
(Å / min) Polishing selection ratio Comparative Example 1 PE TEOS Additives1 1863 138 14 Comparative Example 2 Additive2 1753 152 12 Comparative Example 3 BPSG Additives1 3542 2010 2 Comparative Example 4 Additive2 4643 5690 One

Referring to Table 1, although the polishing selectivity was very high at 14 and 12 when the additives 1 and 2 were used in the PE TEOS film, the polishing selectivity was very low at 2 and 1 when used the same in BPSG film quality. It can be seen that the high step polishing selectivity to PE TEOS film quality does not apply to the BPSG film quality.

In Table 2 below, cocamidopropyl betaine (CAPB) and polyacrylic acid (polyacrylic acid, PAA, additive 2) according to one embodiment of the present invention as an additive for PE TEOS and BPSG membranes, respectively The polishing rate and polishing selectivity of the convex portions and the concave portions are shown.

number Polishing Film additive Convex Polishing Rate
(Å / min) Concave Polishing Rate
(Å / min) Polishing selectivity CAPB (part by weight) PAA (part by weight) Comparative Example 5 PE TEOS - One 1753 152 12 Comparative Example 6 BPSG 4643 5690 One Example 1 0.1 0.5 3131 3988 0.8 Example 2 0.2 2 1686 754 2.2 Example 3 0.3 0.5 2472 3300 0.7 Example 4 0.3 - 495 158 3 Example 5 0.4 0.5 1932 663 2.9 Example 6 0.5 - 1060 99 11 Example 7 One - 847 112 8

Referring to Table 2, when only polyacrylic acid without cocamidopropyl betaine was used for the PE TEOS and BPGS film quality, the polishing selectivity was significantly different to 12 for PE TEOS and 1 for BPGS (Comparative Example 5). And 6). The polishing selectivity was confirmed when the CAPB concentration was varied in the range of 0.1 to 1, when the PAA was mixed in different weight ratios. When comparing CAPB with 0.3 parts by weight and using PAA with 0.5 parts by weight (Example 3) and without PAA (Example 4), the polishing selectivity when using CAPB alone was 3 It was confirmed that the polishing selectivity was higher than that of using PAA together (polishing selectivity 0.7). When CAPB alone was used at 0.5 to 1 parts by weight, the polishing selectivity was very preferred, at least 8.

Claims (7)

As an additive in the slurry composition containing anionic surfactant as a dispersing agent,
Amphoteric surfactants; And
contains a pH adjuster,
The high-level flattening slurry composition additive, wherein the film to be polished is 1.2 times or more compared to plasma enhanced tetra-ethyl ortho silicate (PE TEOS) in chemical mechanical polishing (CMP).
The method of claim 1,
The amphoteric surfactant is cocamidopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine ), Alkyl amido betaine, alkylamide propyl betaine, alkyl betaine, alkyl dimethyl amine betaine, amidosulfobetaine ), Alkyldimethyl betaine, apricotamidopropyl betaine, coco amido betaine, coco betaine, cocoamidopropyl betaine ), Cocodimethylbetaine, lauryl betaine, laurylamiidopropyl betaine, wheatgermamidopropyl betaine, isostearic acid At least one selected from the group consisting of isostearamidopropyl betaine, myristamidopropyl betaine, palmitamidopropyl betaine, and undecylenamidopropyl betaine High level planarization slurry composition additive.
The method of claim 1,
The polishing target film is at least one selected from the group consisting of BPSG (Borophospho Silicate Glass), PSG (Phospho Silicate Glass), SOD (Spin on Dielectric), Poly Si (Polycrystalline silicone) film quality, high-level flattening slurry composition additive.
The method of claim 1,
Wherein the amphoteric surfactant is included in an amount of 0.5 to 1 parts by weight based on 100 parts by weight of the total additive.
The method of claim 1,
Wherein said slurry composition comprises at least one abrasive selected from the group consisting of ceria, colloidal silica, fumed silica, and zirconia.
The method of claim 1,
The pH adjusting agent is triethylamine, triethanolamine, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, ammonium hydroxide (NH4OH), potassium hydroxide (KOH) high level flattening, at least one selected from the group consisting of polyacrylic acid, carboxylic acid, formic acid, acetic acid, propionic acid, valeric acid, enanthic acid, oxalic acid, malonic acid, succinic acid and malic acid Slurry composition additives.
A high level flattening slurry composition comprising the additive of any one of claims 1 to 6.