1. A process for producing a rigid polyurethane-polyisocyanurate foam C comprising the steps of
(I) reacting a polyester comprising carboxyl end groups with an epoxide of general formula (1),
where R1 represents alkyl or aryl,
by obeying a molar ratio of epoxy groups to carboxyl end groups at between 0.8:1 and 50:1, to obtain a polyester polyol having secondary hydroxyl end groups A1a which has a functionality of 1.8 to 6.5, and a hydroxyl number of 15 mg KOHg to 500 mg KOHg;
(II) foaming at isocyanate indexes of 180 to 400,
(i) a polyol component A1 comprising A1a
with
(ii) an isocyanate component B comprising
a) at least one isocyanate B1 selected from the group consisting of:
tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, xylylene diisocyanate, naphthylene diisocyanate, hexamethylene diisocyanate,
diisocyanatodicyclohexylmethane and isophorone diisocyanate,
or
b) an isocyanate-terminated prepolymer B2 prepared from at least a polyisocyanate B1 and an isocyanate-reactive compound,
or
c) mixtures of B1 and B2,
in the presence of
(iii) at least one blowing agent A2, and
(iv) at least one catalyst A3, except that carbanionic catalysts shall be excluded.
2. The process as claimed in claim 1 wherein said polyol component A1 in addition to said polyester polyol having secondary hydroxyl end groups A1a comprises at least one aliphatic polyether polyol A1b having a hydroxyl number between 15 mg KOHg and 500 mg KOHg and a functionality of 1.5 to 5.5.
3. The process as claimed in claim 1 or 2 wherein the polyester comprising carboxyl end groups is obtained from the reaction of
(i) at least one alcohol selected from the group consisting of
ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerol, pentaerythritol and 1,1,1-trimethylolpropane,
with
(ii) at least one carboxylic acid equivalent selected from the group consisting of
succinic acid, fumaric acid, maleic acid, maleic anhydride, glutaric acid, adipic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid and caprolactone.
4. The process as claimed in any of claims 1 to 3 wherein R1 in general formula (1) is
methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, cyclohexyl or phenyl.
5. The process as claimed in any of claims 1 to 4 wherein said polyester polyol having secondary hydroxyl end groups A1a is prepared in the presence of at least one catalyst selected from:
(i) amines of general formula (2):
where
R2 and R3 are each independently hydrogen, alkyl or aryl;
or
R2 and R3 combine with the nitrogen atom bearing them to form an aliphatic, unsaturated or aromatic heterocycle;
n is an integer from 1 to 10;
R4 is hydrogen, alkyl or aryl; or
R4 represents \u2014(CH2)x\u2014N(R41)(R42), where:
R41 and R42 are each independently hydrogen, alkyl or aryl; or
R41 and R42 combine with the nitrogen atom bearing them to form an aliphatic, unsaturated or aromatic heterocycle;
x is an integer from 1 to 10;
or
(ii) amines of general formula (3):
where
R5 is hydrogen, alkyl or aryl;
R6 and R7 are each independently hydrogen, alkyl or aryl;
m and o are each independently an integer from 1 to 10;
or
(iii) nitrogen compounds selected from the group consisting of:
diazabicyclo2.2.2octane, diazabicyclo5.4.0undec-7-ene, dialkylbenzylamine, dimethylpiperazine, 2,2\u2032-dimorpholinyldiethyl ether, pyridine;
or
(iv) mixtures of catalysts from two or more of groups (i) to (iii).
6. The process as claimed in claim 5 wherein in general formula (2)
R2 and R3 are each methyl, R4 is hydrogen and n is =2, or
R2 and R3 are each methyl, R4 is \u2014(CH2)2\u2014N(CH3)2 and n is =2, and wherein in general formula (3)
R5 is methyl, R6 and R7 are each hydrogen, m is =2 and o is =2.
7. The process as claimed in any of claims 1 to 6 wherein the preparation of the polyester comprising carboxyl end groups which is used in step (I) comprises the steps of:
(i) condensing at least one alcohol selected from the group consisting of
ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerol, pentaerythritol and 1,1,1-trimethylolpropane,
with
at least one carboxylic acid equivalent selected from the group consisting of
succinic acid, fumaric acid, maleic acid, maleic anhydride, glutaric acid, adipic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid and caprolactone,
while choosing the molar ratio of alcohol(s) to carboxylic acid equivalent(s) such that a process product having terminal alcohol groups is obtained;
(ii) reacting the process product obtained in (i) with at least one carboxylic anhydride selected from the group consisting of
phthalic anhydride, maleic anhydride, glutaric anhydride and succinic anhydride.
8. The process as claimed in claim 7 wherein step (i) is carried out at a temperature T(i) of 150\xb0 C. to 250\xb0 C. and step (ii) is carried out at a temperature T(ii) of 120\xb0 C. to 250\xb0 C.
9. The process as claimed in any of claims 1 to 8 wherein step (II) is carried out in the presence of
(v) at least one flame retardant A4, and
(vi) at least one foam stabilizer A5,
by first
preparing an isocyanate-reactive composition A comprising said components A1 to A5 by mixing said components in any desired order in an A:A2 mass ratio of 2.5:1 to 25:1, and then
foaming up said isocyanate-reactive composition A with said isocyanate component B to form said rigid polyurethane-polyisocyanurate foam C.
10. The process as claimed in any of claims 1 to 9 wherein said catalyst A3 is selected from the group consisting of:
triethylenediamine, N,N-dimethylcyclohexylamine, tetramethylenediamine, 1-methyl-4-dimethylaminoethylpiperazine, triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, N,N\u2032,N\u2033-tris(dimethylamino-propyl)hexahydrotriazine, tris(dimethylaminopropyl)amine, tris(dimethylaminomethyl)phenol, dimethylaminopropylformamide, N,N,N\u2032,N\u2032-tetramethylethylenediamine, N,N,N\u2032,N\u2032-tetramethylbutanediamine, tetramethylhexanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, tetramethyldiaminoethyl ether, dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo3.3.0octane, bis(dimethylaminopropyl)urea, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, triethanolamine, diethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, dimethylethanolamine, tin(II) acetate, tin(II) octoate, tin(II) ethylhexoate, tin(II) laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dioctyltin diacetate, tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, tetramethylammonium hydroxide, sodium N-(2-hydroxy-5-nonylphenyl)methyl-N-methylaminoacetate, sodium acetate, sodium octoate, potassium acetate, potassium octoate and sodium hydroxide,
and wherein said blowing agent A5 is selected from the group consisting of:
water, cyclopentane, n-pentane, isopentane, hydrofluorocarbons and partially halogenated alkenes having 3 or 4 carbon atoms.
11. The process as claimed in any of claims 1 to 10 wherein the foaming step utilizes a polyester polyol A1a in which the molar ratio of primary hydroxyl end groups to secondary hydroxyl end groups is between 0:1 and 1:1.
12. A rigid polyurethane-polyisocyanurate foam C obtainable by a process as claimed in any of claims 1 to 11.
13. The process as claimed in any of claims 1 to 11 wherein the foaming is carried out against at least one covering layer D to form a composite element E comprising said rigid polyurethane-polyisocyanurate foam C and at least one covering layer D.
14. The process as claimed in claim 13 wherein said covering layer D consists of a material selected from the group consisting of:
concrete, wood, pressboard, aluminum, copper, steel, stainless steel and plastic.
15. A composite element E obtainable by a process as claimed in either of claims 13 and 14.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A semiconductor device, comprising:
a substrate having one or more dielectric layers formed thereon;
a top electrode and a bottom electrode in the one or more dielectric layers;
a phase change layer overlying the one or more dielectric layers and electrically coupled to the top electrode and the bottom electrode, the phase change layer comprising a phase change material;
a mask layer overlying the phase change layer;
a first sealing layer overlying the mask layer; and
a second sealing layer overlying the first sealing layer;
wherein the phase change layer overlies at least a portion of the top electrode and the bottom electrode.
2. The semiconductor device of claim 1, wherein the phase change material comprises a chalcogenide material.
3. The semiconductor device of claim 1, wherein the phase change layer material comprises Ge1Sb4Te7, Ge2Sb2Te5, Ge1Sb2Te4, or eutectic Sb69Te31+M, where M is Ag, In, Ge, or Sn.
4. The semiconductor device of claim 1, wherein the mask layer comprises silicon nitride.
5. The semiconductor device of claim 1, wherein the first sealing layer has a thickness of from about 10 angstroms to about 1,000 angstroms.
6. The semiconductor device of claim 1, wherein the second sealing layer has a thickness of from about 10 angstroms to about 1,000 angstroms and comprises a material selected from the group consisting of silicon nitride, silicon oxide and SiON.
7. A method of forming a semiconductor device, the method comprising:
providing a substrate having one or more dielectric layers formed thereon;
forming a phase change layer over the one or more dielectric layers;
forming a mask layer over the phase change layer;
forming a first sealing layer overlying the mask layer; and
forming a second sealing layer overlying the first sealing layer;
the method further comprising forming a top electrode and a bottom electrode in the one or more dielectric layers, wherein the phase change layer overlies at least a portion of the top electrode and the bottom electrode.
8. The method of claim 7, wherein
the first sealing layer is formed at a first temperature lower than a temperature at which the phase change layer outgases; and
the second sealing layer is formed at a second temperature higher than the first temperature at which the first sealing layer is formed.
9. The method of claim 7, wherein the phase change material comprises a chalcogenide material.
10. The method of claim 7, wherein the phase change layer material comprises Ge1Sb4Te7, Ge2Sb2Te5, Ge1Sb2Te4, or eutectic Sb69Te31+M, where M is Ag, In, Ge, or Sn.
11. The method of claim 7, wherein the mask layer comprises silicon nitride.
12. The method of claim 7, wherein the first sealing layer has a thickness of from about 10 angstroms to about 1,000 angstroms and comprises a material selected from the group consisting of silicon oxide, and SiON.
13. The method of claim 7, wherein the second sealing layer has a thickness of from about 10 angstroms to about 1,000 angstroms and comprises a material selected from the group consisting of silicon nitride, silicon oxide, and SiON.
14. The method of claim 7, wherein the first sealing layer is formed at the first temperature of from about 20\xb0 C. to about 300\xb0 C., and for a duration of from about 1 second to about 1,000 seconds.
15. The method of claim 14, wherein the second sealing layer is formed at the second temperature of from about 20\xb0 C. to about 1,000\xb0 C., and for a duration of from about 1 second to about 1,000 seconds.
16. The method of claim 7, wherein the phase change layer overlies only a portion of each of the top electrode and the bottom electrode.
17. The method of claim 7, wherein the first sealing layer has a thickness of from about 10 angstroms to about 1,000 angstroms and comprises silicon nitride.
18. The method of claim 7, wherein the first sealing layer and the second sealing layer comprise a same material.
19. The method of claim 7, further comprising:
forming a further dielectric layer over the second sealing layer; and
forming a contact through the further dielectric layer to make contact with a top surface of the top electrode in a region where the top electrode is not overlaid by the phase change layer, wherein the contact is formed without removing the first and second sealing layers directly above the phase change layer.