Silsesquioxane resins

Silsesquioxane resin

The present invention relates to silsesquioxane resins for anti-reflective coatings.

In the photolithography process, exposing the photoresist to UV light is an important step to obtain high-resolution images. With the continuous demand of the semiconductor industry for smaller feature sizes, 193nm optical lithography etching has now emerged as the technology for manufacturing devices with characteristics less than 100nm. The use of this shorter wavelength light requires a bottom anti-reflective coating (BARC) to reduce the reflection on the substrate and slow the oscillating curing of the photoresist by absorbing the light passing through the photoresist. Commercially available anti-reflective coatings are composed of both organic and inorganic materials. Generally, the inorganic ARC with good corrosion resistance is mainly based on CVD and suffers from the limitation of the integration disadvantage of extreme shape. On the other hand, the organic ARC material is applied by spin coating and has excellent filling and planarization characteristics, but it is not The etching selectivity of organic photoresist is very poor. Therefore, there is a great need for a material that can provide the combined advantages of organic and inorganic ARC.

In this regard, we have recently discovered that silsesquioxane resins based on specific phenyl hydrides exhibit excellent anti-reflective coating properties against 193nm light. Although the bottom anti-reflective coating (BARC) material can effectively reduce the reflection of activating radiation, it has been extremely challenging to remove the BARC material without damaging the upper photoresist and/or the lower substrate. The typical method of removing BARC is by plasma etching. However, plasma etching often results in thinning of the photoresist layer. Therefore, the pattern on the photoresist can be destroyed or not transferred to the substrate layer. Plasma etching can also damage the substrate and affect the performance of the final device. Moreover, the additional etching step for removing the BARC material will increase the cost of the photolithographic etching operation and the complexity of the process. Therefore, it is desirable to have an anti-reflective coating material that can be removed by a method other than plasma etching.

The present invention relates to a silsesquioxane resin that can be used as an anti-reflective coating for photolithography etching. The present invention relates more specifically to silsesquioxane materials containing carboxyl groups. Silsesquioxane resins with carboxyl functional groups form excellent spin-coated films and are resistant to organic solvents, such as PGMEA and 2-heptene, but are soluble in developers when cured at 250°C or below. In addition, the Si-rich ARC made from the silsesquioxane resin with carboxyl functional groups exhibits excellent dry etching resistance.

The present invention relates to a carboxy-functional silsesquioxane resin that can be used in anti-reflective coatings, wherein the silsesquioxane resin contains the following units:

(Ph(CH₂)_rSiO_(3-x)/2(OR')_x)_m

(HSiO_(3-x)/2(OR')_x)_n

(MeSiO_(3-x)/2(OR')_x)_o

(RSiO_(3-x)/2(OR')_x)_p

(R¹SiO_(3-x)/2(OR')_x)_q

Wherein Ph is a phenyl group, Me is a methyl group; R'is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; R is selected from a carboxylic acid group, a carboxylic acid-forming group or a mixture thereof; and R¹It is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl generating groups, aryl sulfonate groups, and reactive or curable organic functional groups; and the value of r The value of x is 0, 1, 2, 3, or 4; the value of x is 0, 1 or 2; the value of m in the resin is 0 to 0.95; the value of n is 0.05 to 0.95; the value of o is 0 to 0.95; The value of p is 0.05 to 0.5; the value of q is 0 to 0.95; and<img file="TW201024924A_D0001.tif" />. When these resins are used in anti-reflective coatings, their cured films exhibit excellent solvent resistance (for example, PGMEA) and can be removed by various methods including etching, wet development, wet stripping and other methods.

The silsesquioxane resin that can be used to form anti-reflective coatings contains the following units:

(Ph(CH₂)_rSiO_(3-x)/2(OR')_x)_m

(HSiO_(3-x)/2(OR')_x)_n

(MeSiO_(3-x)/2(OR')_x)_o

(RSiO_(3-x)/2(OR')_x)_p

(R¹SiO_(3-x)/2(OR')_x)_q

Wherein Ph is a phenyl group, Me is a methyl group; R'is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; R is selected from a carboxylic acid group, a carboxylic acid-forming group or a mixture thereof; and R¹It is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl generating groups, aryl sulfonate groups, and reactive or curable organic functional groups; and the value of r The value of x is 0, 1, 2, 3, or 4; the value of x is 0, 1 or 2; the value of m in the resin is 0 to 0.90; the value of n is 0.05 to 0.99; the value of o is 0 to 0.95; The value of p is 0.01 to 0.5; the value of q is 0 to 0.5; and<img file="TW201024924A_D0002.tif" />. The value of m is typically 0.05 to 0.25, or 0.05 to 0.15. Typically, the value of n is 0.15 to 0.80, or 0.2 to 0.75. The value of o is typically 0.25 to 0.80, or 0.4 to 0.75. The value of p is typically 0.015 to 0.35, or 0.025 to 0.25. The value of q is typically 0 to 0.15, or 0 to 0.1.

R'is independently a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. Examples of R'can be H, methyl, ethyl, propyl, isopropyl and butyl.

In the resin, R is a carboxylic acid group, a carboxylic acid-forming group, or a mixture thereof. Examples of carboxylic acid groups are as in the general formula: R²C(O)OH, where R²It is selected from alkylene groups having 1 to 10 carbon atoms. Examples of groups forming carboxylic acids are as in the general formula: -R²C(O)OR³, Where R²Is selected from alkylene groups having 1 to 10 carbon atoms, and R³Department of protecting group. The protecting group is an organic group or silyl group which is cleaved under acidic conditions to produce a corresponding carboxylic acid group. Examples of protecting groups can be, but are not limited to, tertiary butyl, trimethylsilyl, acid anhydride, methylthiomethyl, benzyloxymethyl, benzhydryl, p-methoxybenzyl, and others. Many protecting groups are described in "Protective Groups in Organic Synthesis" by Greene and Wuts, 3rd edition, pages 369-453.

R¹It is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl generating groups, aryl sulfonate groups, and reactive or curable organic functional groups. The substituted phenyl group contains at least one HO-, MeO-, Me-, Et-, Cl- and/or other substituents. The ester group can be any organic substituent containing at least one ester functionality. Examples of ester groups useful herein are -(CH₂)₂-OC(O)Me and -(CH₂)₂-C(O)-OMe. The polyether group is an organic substituent containing a hydrocarbon unit connected by an oxygen atom, which is represented by, but not limited to, the following structure: -(CH₂)_a[O(CH₂)_b]_cOR⁴, Where a=2 to 12; b=2 to 6; c=2 to 200; R⁴=H, alkyl, or other organic groups. An example of a polyether group useful in this article is -(CH₂)₃-(OCH₂CH₂)_c-OMe, -(CH₂)₃-(OCH₂CH₂)_c-OH and -(CH₂)₃-(OCH₂CH₂)₇-OAc and -(CH₂)₃-(OCH₂CH₂)_c-OC(O)Me. The general formula of sulfhydryl is HS(CH₂)_d-, where the value of d is 1 to 18, such as mercaptopropyl, mercaptoethyl, and mercaptomethyl. The general formula of aryl sulfonate group is R⁵O-SO₂-Ph-(CH₂)_r-, where R⁵It is a hydrogen atom, an aliphatic group, or an aromatic group, and the value of r is 0, 1, 2, 3, or 4. Examples of arylsulfonate groups are. But not limited to HO-SO₂-Ph-(CH₂)_r-Or (CH₃)₂CHO-SO₂-Ph-(CH₂)_r-. Examples of reactive or curable organic functional groups are, but not limited to, alkenyl groups such as vinyl and allyl; epoxy groups such as glycidoxypropyl and epoxycyclohexyl, acrylate groups such as methyl Propyleneoxypropyl, propyleneoxypropyl, and others.

Typical methods used to make silsesquioxane resins include the hydrolysis and condensation polymerization of appropriate halogen or alkoxysilanes. One example is the hydrolysis and condensation polymerization of mixtures of phenyltrichlorosilane, trichlorosilane, carboxylic acid-containing or carboxylic acid-forming group silane, methyltrichlorosilane, and other organofunctional trichlorosilanes as appropriate. If the hydrolysis or polycondensation is incomplete by this method, the residual -OH and/or -OR' may still remain in the silsesquioxane resin. If the total amount of units containing -OR' groups in the silsesquioxane resin exceeds 40 mol%, the resin may be gelled and unstable. Typical upper silsesquioxane resins contain 6 to 38 mol% of units containing -OR' groups, or less than 5 mol%. Or less than 1 mole%.

The weight average molecular weight (Mw) of silsesquioxane resin is between 500 and 200,000, or between 500 and 100,000, or between 700 and 30,000. It is detected by RI and polymerized Styrene standard gel permeation chromatography determination.

The method for preparing silicone resin includes (A) containing HSiX in an organic solvent₃With RSiX₃, And depending on the situation MeSiX₃, Ph(CH₂)_rSiX₃, And R¹SiX₃The mixture of silane reactants reacts with (B) water, where X is a hydrolyzable group and is independently selected from Cl, Br, CH₃CO₂-, alkoxy-OR', or other hydrolyzable groups. Examples of silanes useful herein can be, but not limited to, HSi(OEt)₃, HSiCl₃, PhCH₂CH₂SiCl₃, And PhSiCl₃, MeSi(OMe)₃, MeSiCl₃, R¹SiCl₃With R¹Si(OMe₃)₃, Where R¹As defined above, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group. There are typically 0 to 90 mol%, or 5 to 25 mol% of Ph(CH₂)_rSiX₃, 5 to 99 mol%, or 15 to 80 mol%, HSiX₃, 0 to 95 mol%, or 25 to 80 mol% MeSiX₃, 1 to 95 mol%, or 1.5 to 35 mol% of RSiX₃, And 0 to 50 mol%, or 0 to 15 mol% of R¹SiX₃, But the condition is that the sum of the reactants is equal to 100 mol%.

Examples of carboxyl functional silanes that can be used to prepare silsesquioxane resins can be, but not limited to,

(MeO)₃Si-(CH₂)₂-COO^tBu

(MeO)₃Si-(CH₂)_d-(OCH₂CH₂)_e-COO^tBu

(MeO)₃Si-(CH₂)₂-COO-SiMe₃

(MeO)₃Si-(CH₂)_d-(OCH₂CH₂)_e-COO-SiMe₃

<chemistry general="n"><img file="TW201024924A_D0003.tif" /></chemistry>

<chemistry general="n"><img file="TW201024924A_D0004.tif" /></chemistry>

Among them, Me is methyl,^tBu is the tertiary butyl group, the value of m is 2 or 3, and the value of n is 1-10.

The amount of water in the reaction is typically 0.5 to 2 moles of water per mole of X groups in the silane reactant, or 0.5 to 1.5 moles of water per mole of X groups in the silane reactant.

The time to form a silsesquioxane resin is affected by many factors, such as temperature, the type and amount of silane reactants, and the amount of catalyst (if any). The reaction is preferably carried out for a time substantially sufficient for the hydrolysis reaction of all X groups. Typically, the reaction time is between several minutes to several hours, or 10 minutes to 1 hour. The reaction to produce the silsesquioxane resin can be carried out at any temperature, as long as the temperature does not cause significant gelation or initiate the curing of the silsesquioxane resin. The temperature at which the reaction is carried out is typically between 25°C and up to the reflux temperature of the reaction mixture. The reaction is typically performed by heating under reflux for 10 minutes to 1 hour.

The reaction step includes two steps of hydrolysis and condensation polymerization of the silane component. In order to promote the reaction completely, a catalyst can be used. The catalyst can be alkali or acid such as mineral acid. Available mineral acids include, but are not limited to, HCl, HF, HBr, HNO₃, And H₂SO₄, Especially HCl. The benefit of HCl or other volatile acids is that the volatile acid can be easily removed from the composition by steam stripping after the reaction is completed. The amount of catalyst can be determined by its characteristics. The amount of catalyst is typically 0.05% to 1% by weight based on the weight of (A) + (B).

Generally speaking, the silane reactant is insoluble or slightly soluble in water. Considering this aspect, the reaction is carried out in an organic solvent. The organic solvent is present in any amount sufficient to dissolve the silane reactant. Typically, the organic solvent is present in an amount of 1 to 99% by weight, or 70 to 90% by weight of the weight of (A)+(B). Examples of usable organic solvents are, for example, but not limited to, saturated aliphatics such as n-pentane, hexane, n-heptane and isooctane; cycloaliphatics such as cyclopentane and cyclohexane; aromatics such as benzene, toluene, Xylene, trimethylbenzene; ethers such as tetrahydrofuran, two<img file="TW201024924A_D0005.tif" />Alkanes, ethylene glycol diethyl ether, ethylene glycol dimethyl ether; ketones such as methyl isobutyl ketone (MIBK) and cyclohexanone; halogen-substituted alkanes such as trichloroethane; halogenated aromatics such as Bromobenzene and chlorobenzene; esters such as propylene glycol monomethyl ether acetate (PGMEA), isobutyl isobutyrate and propyl propionate. Examples of usable silicone solvents are, but not limited to, cyclic silicones such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. A single solvent or a mixture of solvents can be used.

In the method for manufacturing silsesquioxane resin, after the reaction is completed, volatiles can be removed from the silsesquioxane resin solution under reduced pressure. These volatiles include alcohol by-products, excess water, catalysts, hydrochloric acid (via the chlorosilane route) and solvents. Methods for removing volatiles are known in the art and include, for example, distillation or stripping under reduced pressure.

After the completion of the reaction, the catalyst may be removed as appropriate. The method of removing the catalyst is well known in the art and may include neutralization, steam stripping, water washing, or a combination thereof. The catalyst may negatively affect the shelf life of the silsesquioxane resin, especially when it is in solution, so it is recommended to remove it.

In order to increase the molecular weight of the silsesquioxane resin and/or improve the storage stability of the silsesquioxane resin, the reaction can be carried out by heating between 40°C and the reflux temperature of the solvent for an extended period of time ( "Bodying step"). This concentration step can be performed after the reaction step or as part of the reaction step. Typically, the concentration step is performed for a period of 10 minutes to 6 hours, or 20 minutes to 3 hours.

After the reaction for producing the silsesquioxane resin, many optional steps can be performed according to the situation to obtain the silsesquioxane resin in the desired form. For example, the silsesquioxane resin in solid form can be recovered by removing the solvent. The method of removing the solvent is not important and there are several methods well known in the art (for example, distillation under heating and/or vacuum). Once the silsesquioxane resin in solid form is recovered, the resin may be re-dissolved in the same or other solvents for special purposes as appropriate. Alternatively, if a different solvent is required for the final product instead of the solvent used in the reaction, the solvent exchange can be performed, for example, by adding a second solvent and removing the first solvent by distillation. In addition, the resin concentration in the solvent can be adjusted by removing some solvents or adding an additional amount of solvents.

Another method of making silsesquioxane resins involves grafting the corresponding carboxyl-containing units onto the starting silsesquioxane resin. The method of grafting the corresponding carboxyl-containing unit to the starting silsesquioxane resin is to graft the carboxyl-containing olefin to the Si-H silsesquioxane resin in the presence of a transition metal catalyst. superior.

The carboxyl-containing olefins that can be used herein include double bonds and carboxyl-containing groups -C(O)OR³Of organic molecules, where R³Department as above. Examples of carboxyl-containing groups are carboxylic acid (R³=H), carboxylic acid anhydride or carboxylic acid ester. When the carboxylate group is a carboxylate group, it has a protected organic group that is cleaved under reaction conditions to produce the corresponding carboxylic acid.

The carboxyl-containing olefins that can be used herein include, but are not limited to, CH₂=CH-(CH₂)_g-COOR³, Where R³Can be^tBu, SiMe₃, Si^tBuMe₂, Or CPh₃; And g=0 to 8;

CH₂=CH-(CH₂)_g-COO-CH₂-OMe

Where g=0 to 8;

CH₂=CH-(CH₂)_g-(OCH₂CH₂) n-COOR³

Where R³Can be^tBu, SiMe₃, Si^tBuMe₂, Or CPh₃; And g=0 to 8; n=1 to 10;

<chemistry general="n"><img file="TW201024924A_D0006.tif" /></chemistry>

In this article, the SiH-containing silsesquioxane resin that can be used to manufacture silsesquioxane resin contains the unit:

(Ph(CH₂)_rSiO_(3-x)/2(OR')_x)_m

(HSiO_(3-x)/2(OR')_x)_n"

(MeSiO_(3-x)/2(OR')_x)_o

(R¹SiO_(3-x)/2(OR')_x)_q

Wherein Ph is a phenyl group, Me is a methyl group; R'is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; and R¹It is selected from substituted phenyl groups, ester groups, polyether groups, mercapto groups, sulfur-containing organic functional groups, hydroxyl generating groups, aryl sulfonate groups, and reactive or curable organic functional groups; and The value of x is 0, 1, 2, 3, or 4; the value of x is 0, 1, or 2; the value of m in the resin is 0 to 0.90; the value of n" is 0.10 to 1; the value of o is 0 to 0.95; the value of q is 0 to 0.5; and<img file="TW201024924A_D0007.tif" />。

The value of m is typically 0.05 to 0.25, or 0.5 to 0.15. Typically, the value of n is 0.165 to 0.95, or 0.10 to 0.3. The value of o is typically 0.25 to 0.80, or 0.25 to 0.75. The value of q is typically 0 to 0.15, or 0 to 0.1.

The carboxylate olefin is reacted with Si-H-containing silsesquioxane resin in the presence of a transition metal catalyst. Usable transition metal catalysts can be selected from various hydrosilation catalysts known to promote the reaction of vinyl functional groups with silicon-bonded hydrogen atoms. Suitable transition metal catalysts may include platinum-containing and rhodium-containing compounds and complexes. Platinum catalysts such as platinum acetylpyruvate or chloroplatinic acid are representative catalysts of these compounds and are suitable for use. A typical transition metal catalyst is the chloroplatinic acid complex of divinyltetramethyldisiloxane, which is diluted in polydimethylsiloxane capped with dimethylvinylsiloxy.

The amount of carboxylate olefin to the Si-H silsesquioxane resin is typically such that the final resin contains 5 to 99 mol% (HSiO_(3-x)/2(OR')_x) And 1 to 50 mole% of (RSiO_(3-x)/2(OR')_x), or 15 to 80 mole% (HSiO_(3-x)/2(OR')_x) And 1.5 to 35 mol% (RSiO_(3-x)/2(OR')_x), or 20 to 75 mol% (HSiO_(3-x)/2(OR')_x) And 2.5 to 25 mol% (RSiO_(3-x)/2(OR')_x). The amount of transition metal catalyst used is typically to provide 2 ppm, or 5 to 200 ppm of transition metal (such as Pt), based on the total weight of the carboxylate olefin and the Si-H-containing silsesquioxane. .

The present invention also relates to an anti-reflective coating (ARC) composition, which comprises: (i) a silsesquioxane resin, which comprises the following units:

(Ph(CH₂)_rSiO_(3-x)/2(OR')_x)_m

(HSiO_(3-x)/2(OR')_x)_n

(MeSiO_(3-x)/2(OR')_x)_o

(RSiO_(3-x)/2(OR')_x)_p

(R¹SiO_(3-x)/2(OR')_x)_q

Wherein Ph is a phenyl group, Me is a methyl group; R'is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; R is selected from a carboxylic acid group, a carboxylic acid-forming group or a mixture thereof; and R¹It is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl generating groups, aromatic sulfonate ester groups, and reactive or curable organic functional groups; and The value of x is 0, 1, 2, 3, or 4; the value of x is 0, 1 or 2; the value of m in the resin is &gt;0 to 0.90; the value of n is 0.05 to 0.99; the value of o is 0 to 0.95; the value of p is 0.01 to 0.5; the value of q is 0 to 0.5; and<img file="TW201024924A_D0008.tif" />;and

(ii) Solvent

The usable solvent (ii) includes, but is not limited to, 1-methoxy-2-propanol, ethyl propylene glycol monomethyl ethyl acetate γ-butyrolactone, and cyclohexanone. The ARC composition typically includes 10 to 99.9% by weight, or 80 to 95% by weight of the solvent based on the total weight of the ARC composition.

The anti-reflective coating composition is formed by mixing the silsesquioxane resin with a solvent and any other additives as appropriate.

Instance

The following examples illustrate embodiments of the present invention. Those skilled in the art should understand that the techniques disclosed in the following examples refer to the techniques disclosed by the inventor to enable the implementation of the present invention to proceed well. However, considering the present invention, those skilled in the art in view of the present disclosure should be able to understand that various changes can be made without departing from the spirit of the present invention and still obtain the same or similar results. All percentages are weight %. The structures given in Examples 1 to 6 are based on the theoretical structures of the reactants.

<b>Example 1</b>

T^(Ph)_0.10T^(H)_0.20T^(Me)_0.625T^(PSA)_0.075

A reactor was charged with 445.1g propylene glycol methyl ether acetate (PGMEA), 30.89g 3-(triethoxysilyl)propyl succinic anhydride (0.101mol), 28.62g phenyltrichlorosilane (0.135mol) ), 126.40g methyltrichlorosilane (0.864mol), and 36.65g trichlorosilane (0.271mol). Set the jacket temperature to 25°C. Stir the solution vigorously. Put 1080g PGMEA and 54.1g deionized water into a flask. Stir the mixture of PGMEA and water vigorously until all the water is dissolved in PGMEA. Then, the PGMEA/water solution was added to the reactor under nitrogen within 1 hour while the reactants were stirred vigorously. After the addition was completed, the mixture in the reactor was washed 3 times with DI water (2×571 g). Then 120 g of ethanol (EtOH) was added and the solution was stripped to obtain a clear PGMEA solution. The solution was diluted to 10% by weight by adding more PGMEA and then filtered through a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=11300, Mw/Mn=2.70.

<b>Example 2</b>

T^(Ph)_0.05T^(H)_0.50T^(Me)_0.425T^(PSA)_0.075

A reactor was charged with 672.5g propylene glycol methyl ether acetate (PGMEA), 11.42g 3-(triethoxysilyl)propyl succinic anhydride (0.038mol), 15.87g phenyltrichlorosilane (0.075mol) ), 95.29g methyltrichlorosilane (0.638mol), and 101.59g trichlorosilane (0.750mol). Set the jacket temperature to 25°C. Stir the solution vigorously. Put 1080g PGMEA and 59.4g deionized water into a flask. Stir the mixture of PGMEA and water vigorously until all the water is dissolved in PGMEA. Then, the PGMEA/water solution was added to the reactor under nitrogen within 1 hour while vigorously stirring the reactants. After the addition was completed, the mixture in the reactor was washed 3 times with DI water (2×500 g). Then EtOH (120 g) was added to strip the solution to obtain a clear PGMEA solution. The solution was diluted to 10% by weight by adding more PGMEA and then filtered through a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=44300, Mw/Mn=5.99.

<b>Example 3</b>

T^(PhEt)_0.07T^(H)_0.70T^(CH₂^CHMeCOOtBu)_0.₂₃

Add styrene (7.29g, 0.07mol) and tert-butyl methacrylate (32.71g, 0.23mol), then add platinum catalyst. The mixture was stirred and irradiated with a UV lamp at room temperature. After 18 hours, the volatiles were removed at 40°C to obtain the title resin viscous oil. The resin was dissolved in PGMEA to obtain a 10% by weight solution and the solution was filtered through a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=4890, Mw/Mn=2.44.

<b>Example 4</b>

T^(PhEt)_0.07T^(H)_0.74T^[(CH₂⁾₃^COOtBu]_0.19

Add styrene (3.65g, 0.035mol) and tert-butyl crotonate (17.0g, 0.115mol), then add platinum catalyst. The mixture was stirred and refluxed overnight. The volatiles were then removed at 40°C to obtain a viscous oil. The oil was dissolved in PGMEA to obtain a 10% by weight solution and the solution was filtered with a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=5730, Mw/Mn=2.21.

<b>Example 5</b>

T^(PhEt)_0.07T^(H)_0.70T^[(CH₂⁾₃^COOtBu]_0.23

Add styrene (3.65g, 0.035mol) and tertiary butyl crotonate (14.22g, 0.095 mol), then add platinum catalyst. Rotary evaporation at 40°C to obtain viscous oil. The oil was dissolved in PGMEA to obtain a 10% by weight solution and the solution was filtered through a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=15,300, Mw/Mn=2.78.

<b>Example 6</b>

T^(Ph)_0.1T^(H)_0.2T^(Me)_0.6T^((CH₂⁾₃^COOtBu)_0.1

With T(Ph)_0.1T(H)_0.3T(Me)_0.6Add tertiary butyl crotonate (3.26 g, 0.022 mol) to a flask of resin (20 g, 0.38 mol) in toluene, and then add platinum catalyst. The mixture was stirred and refluxed overnight. The volatiles were removed by rotating steam at 40°C to obtain a white solid. The resin was dissolved in PGMEA to obtain a 10% by weight solution and the solution was filtered through a 0.2mm Teflon filter. GPC (relative polystyrene): Mw=12,450, Mw/Mn=2.95.

<b>Example 7</b>

T^(Ph)_0.07T^(H)_0.45T^(Me)_0.36T^((CH₂⁾₃^COOtBu)_0.12

PGMEA (600g), phenyltrimethoxysilane (13.9g, 0.07mol), triethoxysilane (73.9g, 0.45mol), methyltriethoxysilane (64.2g, 0.36mol), (3-third (Butyl) propyltrimethoxysilane (31.7 g, 0.12 mol), and deionized water (54 g, 3 mol) were charged into the flask. The solution was stirred at room temperature for 5 minutes and then nitric acid (70%, 0.64 g) was added. The mixture was stirred at 80°C overnight and then refluxed for 4 hours, thereby condensing and removing low-boiling volatiles. The solution was cooled to room temperature to obtain a clear, colorless solution. The solution was then rinsed with deionized water. Strip the remaining water with some PGMEA. Dilute the solution with PGMEA to 10% in PGMEA. GPC (relative PS): Mw=6300, Mw/Mn=2.58.

<b>Example 8</b>

T^(Ph)_0.07T^(H)_0.45T^(Me)_0.36T^((CH₂⁾₃^COOtBu)_0.12

PGMEA (600g), phenyltrimethoxysilane (19.8g, 0.10mol), triethoxysilane (32.8g, 0.20mol), methyltriethoxysilane (111.4g, 0.625mol), (3-third (Butyl) propyltrimethoxysilane (19.8 g, 0.075 mol), and deionized water (54 g, 3 mol) were charged into the flask. The solution was stirred at room temperature for 5 minutes and then nitric acid (70%, 0.64 g) was added. The mixture was stirred at 80°C overnight and then refluxed for 4 hours, thereby removing low-boiling volatiles. The solution was cooled to room temperature to obtain a clear, colorless solution. The solution was then rinsed with deionized water. Strip the remaining water with some PGMEA. Dilute the solution with PGMEA to a 10% solution in PGMEA. GPC (relative PS): Mw=5300, Mw/Mn=2.45.