TWI467054B - Additives for alkaline etching solutions, particular pattern etching solutions, and methods of making the same - Google Patents

Description

Additive for alkaline etching solution, especially grain etching solution, and manufacturing method thereof

The present invention relates to a product useful as an etchant additive or a synthetic component of an etchant and a method of making the same.

According to the prior art, when the material is etched, the industry often seeks or hopes to obtain a satisfactory etching treatment effect for different working conditions, work sites or work scales. This is especially the case when etching semiconductor materials, for example in the production of electronic components or solar cells. Semiconductor materials generally use germanium materials, and single crystal germanium or polycrystalline germanium is often used in the production of tantalum solar cells.

Since most etching solutions can cause severe etching of various crystal grains (including crystal defects), it is a cumbersome and costly process to perform specific etching treatment on crystalline materials (especially single crystal germanium or polycrystalline germanium). This case is particularly apparent in, for example, an alkali metal hydroxide alkaline etchant applied to industrial ruthenium etching, especially grain etching. Here, although another type of etching liquid which can uniformly perform etching treatment corresponding to specific grain direction and crystal defect characteristics is selected, it is limited by various safety regulations and waste disposal laws in the industrial field, and such an etchant also has many possibilities. Sexual problems and costly situations. In view of the foregoing reasons, the industry is still accustomed to first adopting an alkali metal hydroxide alkaline etching solution, although there is a problem in that anisotropy of etching action exists.

In order to obtain a predetermined etching treatment effect from such an alkaline etching liquid, it is necessary to adjust and match various etching processes for the specific conditions of individual semiconductor materials (for example, tantalum materials). Among them, the etching treatment parameters such as etching duration, etching liquid chemical composition and etching temperature have great influences, mainly in the form of crystals of semiconductor materials, such as ingot type or stabilized side drawing polycrystalline germanium or single crystal germanium. , mixing strength, crystal defect type and crystal defect density. In this case, even if the material is from the same manufacturer, it is necessary to use different etching parameters in practical applications. If materials from different manufacturers are used, the difference in etching process parameters is even greater. Especially in the grain etching process, for example, for the surface structure formation in the solar cell production process for improving the optocoupler stage, since the grain etching process is sensitive to the actual conditions of the materials used, the etching process parameters must be made very large. Variety.

In this context, it is highly desirable to simplify the conventional etching process, especially the grain etching process. An etchant additive for this purpose is disclosed in German Patent No. DE 10 2008 056 086. However, the production of such an additive requires decomposition of various density phases, and thus it is difficult to avoid cumbersome and expensive problems.

One of the objects of the present invention is to provide a preparation for simplifying the etching treatment method, in particular, simplifying the grain etching treatment method, and achieving the advantages of simple production and low cost.

In order to achieve the above object, the present invention provides a pharmaceutical product according to the first aspect of the patent application.

Another object of the invention is to provide a method of making the formulation.

In order to achieve the above other object, the present invention provides a production method in accordance with item 10 of the scope of the patent application.

The preferred construction of the invention is further clarified in the scope of the appended claims.

Items 8 and 9 of the scope of the patent application relate to the practical use advantages of the agent of the present invention.

The preparation of the present invention is firstly prepared by mixing at least one polyethylene glycol with an alkali material into a single phase mixture, then heating the single phase mixture to 80 ° C, and finally placing the single phase mixture in an atmospheric environment until Discoloration. The above alkali materials generally refer to any compound and any element which can produce hydroxide ions in an aqueous solution. The alkali metal hydroxide or ammonium hydroxide is preferably used as the alkali material, and it is of course preferable to use potassium hydroxide or sodium hydroxide. The alkali metal hydroxide content of the single phase mixture component (for example: tetraethylene glycol or potassium hydroxide) is from 1 wt.% to 10 wt.%, of which 7 wt.% is preferred.

The above single phase mixture means that a mixture of plural phases having different densities is not decomposed even if the shelf life is as long as several hours. The term "atmosphere" as used in the present invention refers to a common mixed airflow on a community of citizens. The concept of "holding" in the present invention does not necessarily mean that the mixture is in an absolutely stationary state, and usually the mixture is allowed to move. The discoloration of a single phase mixture means that the single phase mixture phase changes as compared to its primary color, especially when the transparent single phase mixture is dyed with a certain color. The hold time before the start of discoloration is affected by many parameter items, especially the parameters of the mixed substance. Shelving time usually ranges from 15 minutes to 16 hours.

In the production of the agent of the present invention, in principle all polyethylene glycols are suitable, and the use efficiency of tetraethylene glycol has been confirmed by practice. When such polyethylene glycol is used, the residence time before the start of discoloration can be as long as 15 minutes to 16 hours.

The results show that the mixture of the present invention and the alkaline etching solution, especially the grain etching liquid, has a remarkable etching treatment effect. With this blending scheme, the etchant is suitable for etching of semiconductor materials of various types or grades, and uses the same etching process parameters and can achieve equal etching effects, such as p- or n-矽. Thus, the necessary number of etching process parameter sets (i.e., etching process recipes) can be significantly reduced, and in turn, the efficiency of optimizing the composition of the etching liquid composition and the etching process parameters of the semiconductor material can be achieved. In addition, the shelf life of the etching solution is also extended.

The grain etching lye blended with the agent of the present invention has other advantages. For example, the single crystal or polycrystalline semiconductor material (especially the ruthenium) can be textured using the same etchant and using the same etch processing parameters. In the prior art, the ruthenium is generally treated with a textured etching aqueous solution, for example, isopropanol containing 0.5 to 6 alkali metal hydroxides and 1 to 10 volume percent alcohols (see, for example, US 3,998,659). Here, the grain etching operation is usually carried out in a temperature range of 70 to 90 ° C for 20 to 75 minutes. When the agent of the present invention is blended with an alcohol and added to an alkaline etching solution, the results show that not only the etching treatment time can be shortened, but also the alcohol consumption in the alkaline etching solution can be reduced. The test results also show that the alcohol consumption can be reduced not only, but also the complete cessation of alcohols (especially isopropanol) is also possible. Therefore, when the agent of the present invention is used as an additive, the alcohol is completely discarded as a preferred embodiment.

For semiconductor materials sawed from a billet, such as a saw blade cut from a crucible by means of a hole saw or a wire saw, it is often necessary to first remove the sawing from the saw by special sawing and etching techniques. Then, the grained structure is allowed to be textured with a grain etchant. The use of the etch etchant blended with the agent of the present invention not only eliminates the use of the slash etch process, but also enables the saw etch process to be performed in the same step as the surface finish of the semiconductor material.

Whether or not the same alkali material is used in the preparation of the agent of the present invention and the alkaline etching solution does not hinder the achievement of the above-mentioned efficacy advantages. When sodium hydroxide is used, for example, in the preparation of the agent of the present invention, the finished product can be blended in a solution containing potassium hydroxide.

In one concept of the present invention, a single phase mixture is placed in an atmosphere until the single phase mixture is discolored, and its color forming spectrum is between orange and reddish brown, wherein the preferred shelf time indicator is a single phase mixture. Red-brown. The test results show that the deeper the color tone, the more effective the effect of the agent of the present invention. However, although the action characteristics of the agent of the present invention are particularly high in reddish brown, attenuation begins to occur when a certain degree of color formation is reached. When the single phase mixture has turned dark brown or black, its effect is only very low.

In another concept of the invention, at least one alkali and water containing polyethylene glycol can also be blended into a single phase mixture. Preferably, an aqueous alkali metal hydroxide solution is mixed with at least one polyethylene glycol. Practice has shown that the alkali metal hydroxide content in the aqueous alkali metal hydroxide solution needs to be at least 20 wt.% in order to obtain a good effect. When selecting the water content, it is necessary to keep the single phase mixture formed smoothly, and to prevent the mixture from decomposing into a complex phase after a certain shelf life expires.

In one concept of the invention, a non-oxidizing acid may also be blended into the single phase mixture, with hydrochloric acid or acetic acid being preferred. Although the efficacy of the agent of the present invention is not very stable in time as described above, the stability can be improved and the storage property can be improved by the above method of blending a non-oxidizing acid. Therefore, a non-oxidizing acid-containing agent can also be stored for a long time. When a non-oxidizing acid is added, it is preferred to adjust the pH below 7 to less than 3. Non-oxidizing acids should be added after the single phase mixture has changed color.

In another concept of the invention, it is preferred to add water and at least one alkali metal hydroxide to the single phase mixture after discoloration of the single phase mixture, with sodium hydroxide or potassium hydroxide being preferred. The fabrication of the etchant or grain etchant can be accomplished by employing any of the various forms described above. The volume fraction of the single phase mixture in the mixture is between 0.01% and 5%, preferably 0.01% to 1%, more preferably 0.07% to 0.3%. As described above, in the prior art, alcohols (especially isopropyl alcohol) have been conventionally added to such etching liquids. The solution prepared in the above form can, in principle, be added with an alcohol (especially isopropanol) as before, except that the amount required is small and can even be replaced by a single phase mixture. Therefore, when the agent of the present invention is used as an additive, the alcohol can be completely discarded.

All embodiments of the agent of the present invention can be incorporated as an additive into an alkaline etching solution of a semiconductor material, and are preferably added to an alkaline etching solution of an inorganic semiconductor material (for example, single crystal germanium or polycrystalline germanium), especially It is an additive for the grain etching liquid.

In the above-mentioned scheme of blending water and at least one alkali metal hydroxide, the agent of the present invention can be used as a separate grain etching liquid for a semiconductor material, preferably an inorganic semiconductor material and especially a germanium material (single crystal or polycrystalline germanium). The processing of the film, for example, is used for the surface texture processing of the cymbal sheet and to make some pyramids with random directions. In this regard, the effect on the surface treatment of single crystal germanium is particularly remarkable. The height of the pyramid is affected by the amount of the single phase mixture in the etchant used.

The agent of the present invention is prepared by mixing at least one polyethylene glycol with an alkali material and forming a single phase mixture, and then waiting for the single phase mixture to discolor. In the above, the definitions of the terms "alkali", "single phase mixture" and "discoloration" have been clarified. When the single phase mixture is stored in the open air in the open air, the color tone will change. Furthermore, it is not excluded that other atmospheric environments are also applicable to the discoloration treatment of a single phase mixture. Alternatively, atmospheric or other forms of the mixture may be charged into the single phase mixture or blown from the single phase mixture, thereby achieving a shorter waiting time.

In one embodiment of the process of the invention, at least one polyethylene glycol is mixed with an alkali material and water to form a single phase mixture. Preferably, at least one of the polyethylene glycols is mixed with an aqueous alkaline solution, such as an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide. The water content here, as described above, should be specifically selected based on the principle that the single phase mixture does not decompose into multiple phases.

The alkali material is preferably an alkali metal hydroxide, especially sodium hydroxide or potassium hydroxide. When the alkali metal hydroxide in a single phase mixture or a mixture of a plurality of alkali metal hydroxides is compounded, a component content of 1% to 10% is used, and a content of 7% is preferably used.

In a preferred embodiment of the invention, the coloration spectrum of the single phase mixture is expected to reach between orange and reddish brown. As noted above, the specific coloration of a single phase mixture has an effect on its actual efficacy. It is therefore necessary to wait for the single phase mixture to turn reddish brown, since the single phase mixture exhibiting this hue has exceptionally high efficacy.

In a preferred embodiment of the invention, the single phase mixture is first heated to at least 40 ° C, preferably between 40 ° C and 120 ° C (especially between 75 ° C and 85 ° C). The heating means for heating the single phase mixture preferably has a closing time point after the target temperature has been reached, but remains open during the waiting for discoloration.

In one concept of the invention, a non-oxidizing acid may also be blended into the single phase mixture, with hydrochloric acid or acetic acid being preferred. As described above, by this method, the efficacy of the preparation can be improved, and the storage characteristics can be improved. The acid material needs to be added after the single phase mixture has been discolored. In determining the concentration and amount of addition of the non-oxidizing acid, it is preferred to adjust the pH of the single phase mixture below 7 to below 3.

The test results show that the conventional formulations described in the German patent DE 10 2008 056 086 can also be used to improve the efficacy aging by adding a non-oxidizing acid. By using a mixture of at least one polyethylene glycol and an alkali material, which is subsequently placed in the atmosphere and having a temperature ranging from about 25 ° C to two phases and finally decomposing the surface of the low density agent, Non-oxidizing acid (preferred: hydrochloric acid or acetic acid) is added to the low-density decomposition phase to achieve stable efficacy. When a non-oxidizing acid is added, it is preferred to adjust the pH of the agent below 7 to below 3.

The above-mentioned stabilization method for prolonging the efficacy time by blending a non-oxidizing acid such as hydrochloric acid or acetic acid is suitable for all subordinate structural solutions and embodiments of the formulations described in German Patent DE 10 2008 056 086, and is also suitable for its production. The method has a better effect. In the mixture, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is preferably used as an alkali material, tetraethylene glycol is synthesized as at least one polyethylene glycol or water is added.

When water and alkali metal hydroxide (preferred: sodium hydroxide or potassium hydroxide) are added to the low-density decomposition phase to form a textured etching solution, the addition of a non-oxidizing acid has considerable advantages. As for whether to add additional alcohols (preferred isopropyl alcohol) or to add non-oxidizing acids as described, the two are actually the same. Either way, you can abandon the use of alcohols and avoid the disadvantages.

In a production method disclosed in DE 10 2008 056 086, at least one polyethylene glycol is mixed with an alkali material, and then the low-density agent surface is released from the mixture after the two phases are formed, and then given The decomposed phase is added with a non-oxidizing acid (preferred: hydrochloric acid or acetic acid).

The color spectrum of the low density decomposition phase is then waited for between orange and reddish brown, such as orange or reddish brown. Preferably, after the discoloration of the low density phase is completed, a non-oxidizing acid is further added.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the fabrication of an embodiment of the present invention. As shown in the figure, this example uses tetraethylene glycol as at least one polyethylene glycol and potassium hydroxide (KOH) as an alkali component as a mixed component. These ingredients are mixed into a single phase mixture (step 10). The single phase mixture is then heated to 80 ° C (step 12). The single phase mixture is then left on (step 14) until its hue turns reddish brown. In the embodiment shown in Figure 1, the single phase mixture is placed in the atmosphere (step 14). In this embodiment, the heat source is turned off after the target temperature of 80 ° C has been reached to allow the single phase mixture to cool during the rest (step 14). After leaving for 10 to 120 minutes (step 14), the hue of the single phase mixture turns reddish brown. By continuing to heat during the rest (step 14), the discoloration of the single phase mixture can be accelerated, but the efficacy of the agent of the present invention is also attenuated.

2 is a schematic view showing an embodiment of a method for producing a pharmaceutical product of the present invention. As shown in Figure 2, the first step of the technique is to mix tetraethylene glycol with an aqueous solution of sodium hydroxide (NaOH-solution) to form a single phase mixture (step 20). The single phase mixture is then heated to at least 40 ° C (step 22), preferably from 40 ° C to 120 ° C (preferably between 75 ° C and 85 ° C). The single phase mixture will then be waited to turn reddish brown (step 24). This phenomenon usually occurs during a waiting period of 15 minutes to 16 hours.

The process illustrated in Figure 1 clearly pertains to another embodiment of the fabrication method of the present invention, as it is here that the single phase mixture is rendered reddish brown during shelving (step 14). Another embodiment of the agent of the present invention can also be made by the method of Figure 2, provided that the single phase mixture is subjected to the "shelving" of the present invention while awaiting discoloration (step 24).

Figure 3 is a diagram showing various steps of the embodiment of Figures 1 and 2, and Figure 3 illustrates the single phase mixture (52) poured in a container (50) being heated by a heating device (54) (step 12 and twenty two). The single phase mixture (52) in the embodiment shown in Figures 1 and 2 is originally transparent, but becomes reddish brown as shown in Figures 1 and 2 after being left (step 14) or waiting (step 24), and thus It becomes a single phase mixture (56) whose color tone has changed.

Either the mixture of one or any of a plurality of polyethylene glycols (especially tetraethylene glycol) synthesized in the embodiment shown in Fig. 1 or Fig. 2 may be added with any alkali metal hydroxide or any alkali metal hydroxide. Aqueous solutions, preferably using NaOH or an aqueous KOH solution, respectively. As described above, when the corresponding aqueous solution water content is selected, it is necessary to prevent the resulting mixture from decomposing into a plurality of phases.

Figure 4 is a schematic illustration of an alternative embodiment of the embodiment of the invention illustrated in Figure 1 and an alternative embodiment of the method of making the invention illustrated in Figure 2. As shown in Figure 4, the single phase mixture of Figures 1 and 2 is added with hydrochloric acid after standing (step 14) or waiting for completion of the color change (step 24) (step 26). As described above, in this way, the efficacy and stability of the finished product can be improved, and the storage time is longer.

FIG. 5 is a schematic diagram of another alternative embodiment of the embodiment shown in FIG. 1, FIG. 2, and FIG. 4. As shown in the figure, an additional step may be included after the steps shown in FIG. 1, FIG. 2, and FIG. 4 are completed. 28), adding at least one alkali metal hydroxide and water to the single phase mixture. The thus obtained agent can be used as an etching liquid and especially a grain etching liquid, and has a good grain etching treatment effect on the tantalum material, in particular, a grain etching process on the single crystal chip. As the at least one alkali metal hydroxide which is one of the components of the etching liquid, NaOH or KOH is preferably used, wherein the at least one alkali metal hydroxide is selected in an amount which is not affected by the alkali content in the single phase mixture (52). Practice has shown that the volume fraction of the single phase mixture in the mixture should be in the range of 0.01% to 5%, with 0.01% to 1% being preferred and 0.07% to 0.3% being more preferred.

The above-mentioned embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

50. . . container

52. . . Single phase mixture

54. . . heating equipment

56. . . Discolored single phase mixture

In order to fully understand the object, features and advantages of the present invention, the present invention will be described in detail by the following specific embodiments, and the accompanying drawings (the elements having the same function, the same reference numerals) Description:

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the fabrication of an embodiment of the present invention.

Fig. 2 is a schematic view showing an embodiment of a method for producing a pharmaceutical product of the present invention.

Figure 3 is a diagram showing various steps of the embodiment shown in Figures 1 and 2.

Figure 4 is an alternative to the embodiment shown in Figures 1 and 2.

Figure 5 is another alternative to the embodiment shown in Figures 1, 2, and 4.

Claims (13)

A preparation (56) is obtained by mixing at least one polyethylene glycol with an aqueous alkali metal hydroxide solution to form a single phase mixture (52) (step 10; 20); heating (step 12; 22) a single phase mixture (52) to 80 ° C; and a single phase mixture (52) is placed (step 14) in the atmosphere until the single phase mixture (52) is discolored and its hue spectrum is between orange and reddish brown or red Brown, wherein a non-oxidizing acid is added after shelving or discoloration, and water and at least one alkali metal hydroxide are added to the single phase mixture. The pharmaceutical product (56) according to claim 1, wherein an alkali metal hydroxide or ammonium hydroxide (preferably: sodium hydroxide or potassium hydroxide) is used as an alkali component (step 10; 20). The pharmaceutical product (56) according to claim 1, wherein tetraethylene glycol is used as the at least one polyethylene glycol component (step 10; 20). The agent (56) according to claim 1, wherein the non-oxidizing acid (step 26) is hydrochloric acid or acetic acid. The agent (56) according to claim 1, wherein the alkali metal hydroxide sodium hydroxide or potassium hydroxide is added after the single phase mixture (56) is discolored (step 28). A method for treating an inorganic semiconductor material, which comprises adding the agent (56) as described in claims 1 to 5 as an additive It is used in alkaline etching solutions for semiconductor materials, especially inorganic semiconductor materials. A method of treating a semiconductor material, which comprises the agent according to claim 5 of the patent application as a grain etching liquid, and is used for a semiconductor material, an inorganic semiconductor material, and particularly a method for treating a germanium material. A method for preparing a preparation (56) according to any one of claims 1 to 5, wherein: at least one polyethylene glycol is mixed with an alkali material to form a single phase mixture (step 10; 20); The single phase mixture (52) is heated to at least 40 ° C (step 12; 22); and waiting for the single phase mixture to change color and its hue spectrum to be between orange and reddish brown or reddish brown (step 14; 24), wherein, while waiting or A non-oxidizing acid is added after discoloration. The production method according to item 8 of the patent application, wherein an alkali metal hydroxide (preferred: sodium hydroxide or potassium hydroxide) is used as an alkali component (step 10; 20). The production method according to Item 8 or 9, wherein tetraethylene glycol is used as at least one polyethylene glycol component (step 10; 20). The production method according to claim 8, wherein the single phase mixture (52) is heated to between 40 ° C and 120 ° C. The method of manufacture of claim 8, wherein the single phase mixture (52) is heated to between 75 ° C and 85 ° C. The production method according to claim 8, wherein the non-oxidizing acid (step 26) is hydrochloric acid or acetic acid.