RU2000850C1 - Device for forming poly-p-xylylene coatings - Google Patents

Abstract

Usage: the invention relates to the application of thin polymer coatings, in particular to devices for forming thin poly-p-xylylene coatings in the gas phase from cyclo-d-p-xipipene, and can be used in microelectronics and biology to reduce the size and thermal inertia of the reactor , increasing the uniform thickness of the coating on surfaces of complex configuration when creating sealing, moisture-proof, insulating and other functional layers. SUMMARY OF THE INVENTION: Internal or external ring electrodes connected to a high-voltage power supply are additionally installed at the edges of the reactor. An electron source is installed between the electrodes inside the reactor. In addition, an external or internal electrode connected to a voltage regulator is installed in the sublimation zone for quick inertial control of the sublimation rate of cyclodi-p-xylylene. 1 zp.f. 2 ip

Description

The invention relates to the application of thin polymer coatings, in particular to devices for the formation of poly-p-xylene coating, and can be used in microelectronics and biology to create a sealing, moisture-proof insulating and other functional joints

Poly-n xylylene (PPK, parylene) is one of the polymers with the most valuable performance properties. In terms of heat resistance in an inert atmosphere and in vacuum, chemical resistance and dielectric characteristics, it is only slightly inferior to the best representative of the class of fluorones - polytetrafluoroethylene. it is synthesized only in the form of In situ coatings directly on the surface of a part at low pressure

A known method and device for producing PPC coatings by pyrolysis of p-xylene in a tubular reactor at 1050-1300 K in vacuum at a pressure of up to 130 Pa and subsequent polymerization of the resulting p-xylylene on a cooled surface The device for implementing this method consists of a tubular reactor - a pyrolyzer, p-xylene feed system, a deposition chamber and a vacuum system

A drawback, in addition to some hardware complexity associated with the need to manufacture a high-temperature pyrolyator, is a low polymer yield, not exceeding 10–12% as a rule. In addition, the polymer formed due to the inclusion of by-products of high-temperature pyrolysis has poorer performance properties than PPC coatings obtained in other ways

A known method and device for producing PPC coatings from a cyclodi-p xylylene dimer (CDPC) The process of forming coatings by this method consists of several stages

a) sublimation of CDPC at 430-470 K

b) the decomposition of gaseous CDPK at a temperature of 820-1000 K and a pressure of 5-100

Pa per 2 molecules of p-xylylene

c) deposition of p-xylylene on a substrate with a temperature below 300 K

(20 10MK /. No 300K

GgAetG

PANAOKtWH

To IP II

5

fifty

fifty

fifty

5

0

5

A device for implementing this method consists of a tubular reactor equipped with heaters to maintain a temperature of 430-470 K in the sublimation zone and 820-1000 K in the decomposition zone, a precipitation chamber equipped with a thermostatically controlled sample holder, and a vacuum system with a nitrogen trap. A PPK coating is formed with a high polymer yield and has good performance properties.

However, the implementation of this method is associated with significant drawbacks, which include the high temperature of p-xylylene, high energy consumption, thermal inertia, and large installation sizes

The closest in technical essence to the present invention is a device for forming PPK coatings using electric discharge plasma. It consists of a glass tube reactor, at the sealed end of which there is a boat with a CDPC passing through a sublimation and decomposition furnace, and a chamber deposition, inside of which there is a cooled copper pipe with electrodes and a cooled sample holder. The reactor outlet, the evacuation hole and the cooled copper pipe are aligned, the glass pipe of the reactor terminating at the start of the copper pipe. The electrodes are mounted inside a copper pipe, the upper electrode being made of mesh and fixed in a plastic mandrel, and the lower one made of a brass plate. Samples are placed on the bottom electrode or between the electrodes. A nozzle is provided in the deposition chamber for the inlet of nitrogen or other inert gas.

The device operates as follows

a CDPC sample is placed in the reactor, samples are placed in the deposition chamber;

the reactor and the chamber are evacuated and nitrogen is admitted to a pressure of 1.4-40, preferably 6.7-135 Pa,

- the copper pipe is cooled to a temperature of 230-240 K;

the sublimation furnace is heated to a temperature of 370-520 better than 370-470 K, and the decomposition furnace is heated to 720-970, better than 870 K;

high voltage with a frequency of 30-300 Hz is applied to the electrodes and the electric discharge is ignited

The device allows one to obtain PPK coatings with high adhesion to the substrate with predetermined mechanical properties and heat resistance to some extent localize the deposition of n

However, the described uroist has a number of drawbacks, the main one, of which is associated with the use of a high-temperature heater, which has significant dimensions, high energy consumption and significant TPM inertia, for example, to heat the gas stream at the decomposition stage to a temperature of 720 970 K and ensure the residence time CDPK molecules in the decomposition zone of the order of 01 1 s, a reactor length of 05 1 5 m is required, equipped with a powerful (1 N) Vg or more) heater that reaches the operating thermal regime in 0.25 1 h and even longer cooling This is also a noticeable difference in the growth rate and, correspondingly, a greater thickness of the coatings when deposited on products with a branch of the Gzczyszii beernernosyo. This is due to the high heat content of the monomer flow, the strong dependence of the deposition rate on g of the substrate temperature, and the difficulty of efficient cooling from divisions the developed surface will have a low temperature and stick to it. When hot (condensation of 720 x 970 p-xylylene stream is condensed, the temperature of individual flammable particles is increased, which leads to a decrease in the rate of and film growth When the substrate is heated, dr 300-340 K (depending on or pressure-i), deposition ceases on the other hand, for applying the PIC, the coating (micro-circuit microassemblies r - i have a fairly developed surface, individual sections of which are significantly broken by the efficiency of heat removal from transferred to them in the process of condensation and polymerization. In addition, the disadvantage of the known device is also the useless deposition of a large amount of polymer on the cold wall of a copper pipe and other cold degalch /

The aim of the invention is to reduce energy consumption, reduce the size and thermal inertia of the reactor, increase the uniformity of the coating on surfaces of complex configuration

The object is achieved in that in a device for forming a PPC coating consisting of a tubular reactor by heaters of the deposition chamber of thermostatting devices of sample thermostats, a device for creating an electric discharge in the chamber of the system for nanv auxillary gal and vacuum c1. topics along the edges of the reactor, additionally installed internal or external ring electrodes connected to a high-voltage power supply, and inside it between the electrodes a source of electrons

The goal is the operational white-light regulation of the sublimation rate of cyclodi-p-xylylene for which an external or internal electrode connected to the voltage pulse is installed in the sublimation zones

A significant difference of the proposed device is the installation of additional internal or external ring electrodes along the edges of the reactor, connected to the high voltage power supply source, and three wires between the electrodes of the electron source. In addition to this, an electrode connected to the voltage regulator is additionally placed in the sublimation zone of the CDPC This is achieved by technical PRS-nm, while the device as a whole is achieved, and a significant reduction in the size of the region’s energy consumption is achieved, and the heat of inertia increases the equal thickness of the coating on the surface of the i-configuration is manifested by the possibility of operational inertialess adjustment ci simplicity of sublimation of the CDPK

In Fig. 1, a schematic diagram of a device with internal electrodes is shown. Fig. 2 is the same with external electrodes.

The device (FIGS. 1, 2) consists of a glass tubular reactor 1 with a heater 2 rings and electrodes and 3 electrically connected to a high-voltage power source of discharge 4. An electron source 5 is installed between the electrodes between the electrodes from a low-voltage current source 6 The reactor is equipped with appropriate equipment for powering the heaters and temperature control (not shown) and is connected to the deposition chamber 7, containing a cooled table 8 with samples 9 mounted on its surface, ring electrodes deposition chambers 10 with an appropriate power supply system (not shown) In the zone where the CDC assembly 11 is mounted, an additional electrode 12 is installed outside or inside, connected to a low-frequency or high-frequency voltage regulator 13. When using an ohmic heater and an RF voltage to excite a discharge the heater is connected to the power source through decoupling filters with a delay band including the discharge current frequency

The device works as follows n (ipr-zom

f j l.int 1 end of the tubular reactor i ii mt n

i M p and ORAC chamber ORMIA pumping out kvVM i HP l J Pa i JM pv deposition and NEP reactor (i ri eo6 compatibility) argon or other i i i i and t u up to a pressure of 5 50 better

This system is thermo-matched at i, i p i-temperature; the image f will lie on them on table 8 within i i. 280 K

i the heating element 2 is heated, gerther 180 G70 better

1n f hi z in cucTfi n i tanavli

MI lfj (i best .P 10 Pa

(Mr. Milli u

 i h, where HI is ilts, i n i tech grids and, if necessary, k and ii Trg1 kame and judgments

1b and I am happy with DZN / | N IN N N t pe In Pro

 ying cover sub neigh

i n i | V by changing the emperagus in i; by means of the help of the Tsar III d, with the addition of i i | Ode t umbrella is diminishing by adjusting i stays three degrees on it Mokamer - D)

with I iHLCI I L NOOO of a single layer 1) | II N ON TRDORG) RL (40 FHIK 1

i “I ir n JK i and {iO Ш1.chk h hkron i i i i i I Hiie f

n g cib h) NRF of the renter up to 350 7 I Y is installed IBP, let in hell / and removed

I- 1Cl Gbrs) ZTs11

CD for CML for the use of low-temperature electric plasma (p) eris consists in replacing inefficient in surface energy supply to gas L o p flow (used in the ipoticiBe prototype) with a volumetric one

This allows one to significantly reduce the I ri3pippbi zone of the decomposition of the CDP (- and at the same time honor the onergy of the cost of the IVS) I / O to decompose FNIR. At the same time, it reduces (h the heat of the D1p-canyon because of the monomer since

1 tgren of ions and non-ionic molecules in the plasma ps of the low-pressure discharge practically O1 is present and the heating from the reactor

i u f there is no decomposition at all so mk i the temperature is the same as in the zone. / ii 1 IPOCI / nyu dka 430 K compared with

GO K in the prototype) Naturally, the energy of the day of heating and maintaining the humumete I decomposition zone in the limit of SO 450 K fs tct1 is much less than by word of mouth, then not tg with total (720 K) Ef} ect for 1 from cc HI. f hand features r,, i) Hui ok and dogti (ae 10

I D о Знт31ь нрр in in i

the plasma of the electric discharge is much smaller and even taking into account the efficiency of the power source (50 95% depending on the frequency of design features and quality

load balancing, they save a small fraction of energy saved on heaters. In addition, the plasma does not have thermal inertia, which significantly reduces the cooling time of the installation

0 Amount of teplum Q tolerated by

the monomer current is proportional to the difference in temperature in the decomposition zone (Ti) and deposition (T)

Q - CM (P Tg)

B where C is the heat capacity M mass

A decrease in temperature in the expansion zone P) from 720 970 K to 430 5 ° 0 K while maintaining the temperature in the deposition zone (T) of 27e, 300 K leads to a decrease in heat

0 to a monomer content of 2.5–5 times. This reduces the heat flux by soaking, which reduces the overtaking of areas with difficult heat dissipation.

5 on the surface of the product leads to equalization of the deposition rate and the thickness of the 1 coated coating on the products of a complex configuration;

0 long legs according to the known and claimed methods differs by almost 2 times

To create a plasma MOiyr, various sources of electric current are used, as well as the corresponding sources of electric current

5 electrode systems When supplying a plasma with a source of constant low-frequency current, internal electrodes are required. When using an RF discharge, the electrodes can be either internal or external

0 and the latter are preferable because they provide a higher purity of the gaseous medium and do not require complex vacuum tight 1-inputs into the system. It should be noted that if the device is used

5 spiral electric heater that it should be connected to the power source through fiber tubes preventing the removal of high-frequency energy from the plasma

It has been established that the plasma is in pairs of CDPK

unstable To increase the stability of the ignition and combustion of the discharge, an auxiliary plasma-forming gas may be supplied to the decomposition zone.

5, an inert gas can be used, for example, argon which is not included in the coating or a reactive gas of the molecule of which (or part of it or a separate atom) after activation in the plasma, the chemical structure of the coating is

However, in most cases, the stabilization achieved in this way turns out to be insufficient since CDPK introduces instability into the plasma burning in another gaseous medium

To eliminate this drawback, an electron source, for example, an incandescent tungsten filament, has been introduced into the interelectrode space. Other methods of introducing electrons into the reactor can be used, for example, using electron

guns.

As the starting material is consumed, in order to maintain a constant flow of gaseous CDPK, it is necessary to increase the temperature of the sublimation zone, which is inconvenient due to the considerable thermal inertia of the heater.

To eliminate this drawback and achieve operational inertialess control of the sublimation rate of the CDPK, an additional electrode connected to the voltage regulator relative to the nearest plasma-forming electrode is installed in the zone of its decomposition. In this case, the heater is put into minimum operating heating mode. and the change in the sublimation rate of the CDPK (due to the heterogeneity of the material, the decrease in its mass during the sublimation process, etc.) is compensated by adjusting the current from the plasma to an additional sublimation electron field. With this current flowing in the CDPC weight, additional energy is released by which the fluctuations in the sublimation rate are compensated. The device is implemented using modern technical means and can be used in industry, in particular in microelectronics technology

(56) U.S. Patent No. 3,178,374, cl. 260-2. 1965. US Patent No. 3,342,754. 260-2, 1967. US patent No. 4500562, CL. B 05 D 1/04,

1985

Claims (2)

1. DEVICE FOR FORMING POLY-PSYLENE COATINGS, consisting of a tubular reactor with heaters, a deposition chamber, devices for thermostating samples, devices for creating an electric discharge in the chamber, an auxiliary gas inlet system and a vacuum system, characterized in that the edges of the reactor are additionally installed They have internal or external ring electrodes connected to a high voltage power source, and an electron source is installed between the electrodes inside it. 2. The device according to claim 1, characterized in that in the sublimation zone an external or internal electrode is mounted connected to a voltage regulator. Fig g