JP2005238059A - Method and apparatus for cleaning electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for grinding and removing an attached substance such as an adhesive wax, a resist, or a bur used in the wafer process and mechanical working of a CPP-GMR (current perpendicular to plane-giant magneto resistive) head and TMR (tunneling magneto resistive) head to be used in the wafer process and mechanical working process for electronic parts, specially a next-generation HDD (hard disk drive). <P>SOLUTION: For cleaning the attached substance, an apparatus which has a nozzle for irradiating an object with fine carbon dioxide particles formed by adiabatic expansion of a liquid carbon oxide and coarse carbon dioxide particles formed by mechanical crushing of a dry ice, simultaneously or with a time lag, is used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for removing deposits adhering to electronic components, particularly organic deposits such as adhesives and resists, in an IC thin film process and an electronic component processing step involving machining.

  Organic deposits such as resists in the semiconductor IC thin film process have been removed by oxidizing the deposits with an oxygen plasma etching apparatus or the like.

In addition, magnetic recording components that have larger irregularities than semiconductor thin film processes such as MR (Magneto Resistive) and GMR (Giant MR) heads, and that require a cutting and polishing step for a substrate having a wafer thickness of 3-5 mm, which is thicker than silicon. For the removal of deposits, a cleaning method by adiabatic expansion of liquid carbon dioxide gas represented by Patent Document 1 or a cleaning method by mechanical pulverization of solid carbon dioxide gas represented by Patent Document 2 has been used.
US Pat. No. 5,766,061 Japanese Patent Laid-Open No. 10-506060

  In conventional MR and GMR heads, the thickness of the composed film is as thick as 100-1000A (angstrom, the same applies hereinafter), so the solid carbon dioxide jet caused by mechanical crushing is also partially used because the mechanical damage to the film is small. It has been.

  Moreover, when organic deposits are thick, or when unevenness is large and mechanical spray removal is difficult, a method of removing by dipping in a heated solvent containing hydrocarbons has also been performed.

In the case of the conventional cleaning method using plasma etching, it is composed of a combination of various materials compared to silicon materials such as magnetic materials, electro-active materials and alumina ceramics. In the manufacturing process of a magnetic recording head or the like having a large size, the plasma etching process can be used only for a part of the initial wafer process.
Further, in a system using carbon dioxide fine particles by adiabatic expansion of liquid carbon dioxide gas, the etching cutting rate is extremely slow, so that the processing takes too much time.
CPP (straight) -GMR heads and TMR (tunnel magnetic) heads used for next-generation high-density recording are as thin as 3-5A compared to current heads, with a maximum of 20 layers. Therefore, if processing takes time, a defect occurs in the film due to thermal strain due to the difference in the expansion coefficient of each layer, and the yield decreases. Further, in the solid carbon dioxide jet cleaning by mechanical pulverization with a large particle size, the yield is lowered due to mechanical stress generated by the collision energy of the particles and electrostatic breakdown, so that it is required to shorten the processing time as much as possible.
Further, when a heated solvent containing hydrocarbons is used, the solvent is likely to ignite, and therefore the removal operation is performed in a specially designed cleaning process with explosion-proof measures. For this reason, it was difficult to incorporate in a line with special equipment for yield reduction and explosion-proof measures due to mutual diffusion of multilayer films due to solvent heating.

  The present invention has been made in view of the above problems, and an object thereof is to provide a method and an apparatus for efficiently removing deposits adhering to an electronic component in a processing step of the electronic component.

The present invention has been made on the basis of the following knowledge obtained as a result of a spray experiment of adiabatic expanded carbon dioxide and machine-cut solid dry ice.
(A) Carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide have a very small ability to etch or grind the deposits due to the mechanical kinetic energy of the particles, and the delamination cleaning effect of the deposits is mainly between the deposits and the circuit board. Due to differences in thermal expansion.
(B) To remove the deposit that has been peeled off by mechanical energy, the kinetic energy of the particles is insufficient, and thus processing time is required, but the cooling effect of the deposit is large.
(C) Particles obtained by mechanical pulverization of solid carbon dioxide gas have a greater grinding effect due to the kinetic energy of the particles than the peeling effect due to the difference in expansion coefficient between the deposit and the circuit board.
(D) Since solid carbon dioxide by mechanical pulverization is difficult to control the particle size, it is difficult to perform etching grinding uniformly on a production line for a long time.
(E) In order to avoid damage to the laminated thin film due to the kinetic energy of particles, it is desirable to shorten the irradiation time as much as possible.
(F) Since the solid carbon dioxide coarse particles are carried by the carrier gas, the cooling effect of the deposit is smaller than that of the adiabatic expansion carbon dioxide fine particles.

In order to solve the above-mentioned problems, the cleaning method according to the present invention simultaneously applies carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide gas and solid carbon dioxide coarse particles produced by mechanical pulverization of solid carbon dioxide gas to an unfinished electronic component. Alternatively, the deposit is removed from the electronic component by irradiating with a time difference.
According to the above method, the sample is cooled by irradiation with carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide, and the mutual adhesion is reduced by the difference in thermal expansion coefficient based on the temperature difference between the deposit and the circuit board. Next, deposits are peeled off by solid carbon dioxide coarse particles having a large kinetic energy produced by mechanical pulverization.

Solid carbon dioxide fine particles made by adiabatic expansion of liquid carbon dioxide have a particle size of 5 μm or less, and solid carbon dioxide coarse particles made by mechanical pulverization of solid carbon dioxide have a particle size of 0.3-1. It is desirable to use a 0 mm one.
When the particle size exceeds 5 μm, the multilayer film is mechanically damaged by the mechanical kinetic energy of the particles. When the particle size is less than 0.3 mm, the kinetic energy is small and the grinding ability is low. In addition, when the particle size exceeds 1.0 mm, the kinetic energy is too large and the multilayer film is quickly damaged, which is not preferable.

  An electronic component cleaning apparatus for using the above method includes a liquid carbon dioxide supply source, a device for pulverizing and supplying solid carbon dioxide with a carrier gas, a liquid carbon dioxide supply port of the liquid carbon dioxide cylinder, and the solid Connected to the solid carbon dioxide coarse particle supply port of the carbon dioxide pulverization supply device, the nozzle for injecting carbon dioxide fine particles and solid carbon dioxide coarse particles by adiabatic expansion simultaneously or with a time difference is faced, and the nozzle injection port faces And a processing chamber for storing a processed sample facing the jet direction.

The electronic component cleaning device preferably uses 100 to 300 kPa of dry air, nitrogen or argon as a carrier gas for transporting the solid carbon dioxide coarse particles mechanically pulverized from the solid carbon dioxide pulverization supply device to the nozzle.
When the pressure of the carrier gas is less than 100 kPa, the kinetic energy of the particles becomes small, which is not preferable. If it exceeds 300 kPa, the kinetic energy becomes too large, which is not preferable. The reason why dry air, nitrogen or argon is used as the carrier gas is to avoid condensation of the object.

  According to the method invention of claim 1, in a state where the sample is cooled by irradiation with the solid carbon dioxide fine particles and the mutual adhesion is reduced due to the difference in thermal expansion coefficient based on the temperature difference between the deposit and the circuit board, Since the deposits are peeled off by the solid carbon dioxide coarse particles with large kinetic energy produced by mechanical grinding, the processing time is significantly shortened compared to removal by solid carbon dioxide alone or removal by mechanical ground solid carbon dioxide alone, and Yield is also improved. And since a deposit | attachment is peeled using a solid carbon dioxide coarse particle, the process of a contaminant removal is not required. In the case of using a non-extinguishing material such as abrasive grains, particles remain on the sample surface, and a process of removing contaminants is required.

  According to the method invention of claim 2, since solid carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide are those having a particle size of 5 μm or less, the effect of cooling the deposits is large, and the solid carbon dioxide fine particles are produced by mechanical pulverization of solid carbon dioxide. Since the solid carbon dioxide coarse particles to be used have a particle size of 0.3 to 1.0 mm, the grinding effect due to the kinetic energy of the particles is large.

  According to the device invention of claim 3, the method invention can be industrially implemented.

  According to the apparatus invention of claim 4, since condensation on the object can be avoided, the grinding ability is increased and the injection time is shortened, so that damage to the electronic component multilayer film is reduced. Therefore, it is possible to efficiently cool the sample and remove the deposits at low cost.

  The method of the present invention is particularly suitable for use in the manufacturing process of the next generation CPP-GMR head and TMR head using an ultra-thin film laminated structure, but the deposit removal target is not particularly limited.

As one embodiment of the present invention, a solid carbon dioxide fine particle by adiabatic expansion is irradiated in the first step to cool the sample, causing a peeling stress, and then mechanically pulverized solid having a large particle size as the second step. The deposits can be removed by irradiation with carbon dioxide coarse particles. Moreover, as another embodiment, the first step and the second step may be alternately repeated to remove the deposits. This is because, in the case of an electronic component having a large aspect ratio, the deposit on the lower part of the unevenness is less likely to have a cooling effect and a mechanical grinding effect, so that the deposit on the upper part is sequentially removed. Moreover, depending on a workpiece, you may inject simultaneously.
The injection nozzle that injects the solid carbon dioxide fine particles and the solid carbon dioxide coarse particles toward the sample preferably has two injection ports. One of the spouts has a throttle valve for adiabatic expansion of liquid carbon dioxide. In addition, the first and second steps are preferably performed in a dry atmosphere in the processing chamber in order to avoid condensation due to moisture in the air. Also, in the case of production, the steps are controlled according to an automatic sequence program. If necessary, it is necessary to add static eliminator as a countermeasure against static electricity.

Subsequently, an example of the cleaning method according to the present invention will be described with reference to the drawings together with a cleaning apparatus using the method.
FIG. 1 is an overall structural view of the apparatus of the present invention, FIG. 2 is an enlarged sectional view of a nozzle in FIG. 1, and FIG. 3 is a conceptual diagram for explaining a cleaning action on a sample.

  In FIG. 1, 11 is a liquid carbon dioxide cylinder as an example of a cooling gas supply source, and 13 is a solid carbon dioxide pulverizing and supplying apparatus. This apparatus includes a container 131 for storing solid carbon dioxide gas and a solid stored in the container. A carbon dioxide gas block is pulverized by a fixed amount, and a pulverizing and feeding machine 132 for sending out the carrier gas through a filter. Reference numeral 15 denotes an injection nozzle connected to the supply port of the liquid carbon dioxide cylinder 11 and the delivery port of the solid carbon dioxide pulverization supply device 13 by connecting pipes 12 and 14, and 16 denotes a processing chamber, which accommodates or takes out the processed sample 17. The injection nozzle 15 is attached to the chamber with its injection port facing the sample.

  As the nozzle 15 illustrated in FIG. 1, a composite nozzle as shown in FIG. 2 is used as a preferred embodiment. This nozzle has a first flow path 151 on the inner side and a second flow path 152 on the outer peripheral side, and a throttle valve (adiabatic expansion nozzle) 151a is formed in the middle of the first flow path 151. One end of the same side is open to the outside. The connecting pipe 12 is connected to the other end of the first flow path 151, and the connecting pipe 14 is connected to the second flow path 152. A control device (not shown) for controlling the flow rate and time of each flow path according to a program is attached to the nozzle.

  In the above configuration, the liquid carbon dioxide gas in the liquid carbon dioxide cylinder 11 is supplied to the injection nozzle 15 through the connecting pipe 12, and is thermally expanded at the nozzle 15 to become powder-like solid carbon dioxide, that is, solid carbon dioxide fine particles P1. . The solid carbon dioxide block in the container 131 is mechanically cut and pulverized by the solid carbon dioxide pulverization and supply device 13 and discriminated to about 0.3 to 1.0 mm through a predetermined filter, that is, solid carbon dioxide gas. Coarse particles P2 are sent to the nozzle 15 by a carrier gas (carrier gas). The supply amount and injection time of both the solid carbon dioxide fine particles P1 and the solid carbon dioxide coarse particles P2 are controlled according to a program by a control device attached to the nozzle. The processing sample and the injection port of the injection nozzle are set in the processing chamber 16. The movement of the sample or nozzle is controlled according to the program.

  As described above, in this apparatus, after the sample 17 is cooled mainly by the solid carbon dioxide fine particles P1 ejected from the first flow path 151 of the nozzle 15 and the adhesion between the deposit and the substrate is reduced, The deposits are mechanically removed by the kinetic energy of the solid carbon dioxide coarse particles P2 ejected from the two flow paths 152.

  This will be described with reference to the case of the workpiece illustrated in FIG. 3. In FIG. 3, 18 is a head substrate, 19 is a resist film used in the head substrate wafer process, 20 is a substrate such as a CMP (chemical mechanical) polisher. Wax for fixing the substrate used for machining, P1 and P2 are incident solid carbon dioxide fine particles and solid carbon dioxide coarse particles, and m is a deposit peeled from the multilayer film L. Although the resist film 19 is several microns, the fixing wax 20 may have a thickness of several mm or more. In the head manufacturing process, only the fixing wax or the fixing wax and the wafer process resist may exist on the workpiece at the same time.

[Comparison between Comparative Example and Example]

  As is apparent from Table 1, in the case of the method of the present invention, the processing time is slightly longer than that of Comparative Example 2, but is significantly shorter than that of Comparative Example 1, and a good result is obtained that is almost equal to Comparative Example 1.

  As described above, the present invention is a magnetic recording head that uses a sample fixing wax for CMP polishing, etc. in addition to an electronic component that requires a thin film and a thick film manufacturing process with a large aspect ratio, such as a magnetic recording head different from a normal semiconductor manufacturing process. Although suitable for cleaning grinding of recording parts, the application is not limited to this.

FIG. 1 is an overall structural view of the apparatus of the present invention. The expanded sectional view of the nozzle in FIG. The conceptual diagram explaining the washing | cleaning effect | action with respect to a sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Liquid carbon dioxide cylinder 13 Solid carbon dioxide grinding | pulverization supply apparatus 15 Injection nozzle 16 Processing chamber 17 Sample P1 Solid carbon dioxide fine particle P2 Solid carbon dioxide coarse particle

Claims (4)

  By irradiating solid carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide gas and solid carbon dioxide coarse particles produced by mechanical pulverization of solid carbon dioxide gas to the electronic components during the processing step simultaneously or with a time difference, the electronic components A method for cleaning an electronic component, characterized in that deposits are removed from the substrate.   Solid carbon dioxide fine particles produced by adiabatic expansion of liquid carbon dioxide with a particle size of 5 μm or less, and solid carbon dioxide coarse particles produced by mechanical pulverization of solid carbon dioxide with a particle size of 0.3-1.0 mm The method for cleaning an electronic component according to claim 1, wherein the method is used.   Connected to a liquid carbon dioxide supply source, a device for pulverizing solid carbon dioxide and supplying it with carrier gas, a liquid carbon dioxide supply port of the liquid carbon dioxide cylinder, and a solid carbon dioxide coarse particle supply port of the solid carbon dioxide pulverization supply device A nozzle that injects solid carbon dioxide fine particles and solid carbon dioxide coarse particles by adiabatic expansion simultaneously or with a time difference, and a process in which a processing sample is accommodated facing the injection direction of the nozzle. An electronic component cleaning device comprising a chamber. 5. The electronic component according to claim 4, wherein 100-300 kPa of dry air, nitrogen, or argon is used as a carrier gas for conveying solid carbon dioxide coarse particles mechanically pulverized from a solid carbon dioxide pulverization supply device to a nozzle. Cleaning device.

Images