A wavelength screening method for uneven epitaxial wafer bars

Abstract

This invention relates to a wavelength selection method for bars on uneven epitaxial wafers, belonging to the field of semiconductor laser technology. The steps are as follows: The epitaxial wafer is divided into several bars using die-cutting technology; each bar within a region is coded; the bars are tested using an automatic bar testing machine under consistent testing conditions; unqualified bars are removed before production begins, with adjustments made based on production application. This invention is suitable for wavelength selection of bars on epitaxial wafers with varying wavelength consistency, and can perform wavelength selection on epitaxial wafers of different sizes, improving product wavelength matching rate and production efficiency, and reducing production and labor costs caused by wavelength mismatch and uneven epitaxial wafer growth.

Description

Technical Field

[0001] This invention relates to a wavelength selection method for bar strips on non-uniform epitaxial wafers, belonging to the field of semiconductor laser technology. Background Technology

[0002] Semiconductor lasers use semiconductor materials as a dielectric and emit laser light by applying a direct current or pulsed current. Due to their numerous advantages, such as high output beam quality, small size, high conversion efficiency, and relatively stable operation, semiconductor lasers have a wide range of applications and their market value is gradually increasing.

[0003] Different applications in different fields have different requirements for lasers. Among them, wavelength is a particularly important parameter in the practical application of lasers. Especially for some high-power semiconductor lasers, when used as pump sources, the wavelength needs to be fixed at the center wavelength as much as possible in order to maximize the utilization of pump source energy. Higher output power can be achieved through laser linear arrays and stacked arrays. However, at the same time, the wavelength consistency is difficult to control, which puts forward higher requirements for the wavelength selection process of semiconductor lasers.

[0004] Chinese patent CN206161280U discloses a wavelength screening device for laser packaging. This device includes a base, a stage, a horizontal moving mechanism, a support, an adjusting support, a piercing probe rod, and a spring needle. The horizontal moving mechanism, adjusting support, and support are all mounted on the base. The piercing probe rod is mounted on the adjusting support, and the spring needle is connected to the piercing probe rod. The stage is mounted on the horizontal moving mechanism, and a pressure plate is placed on the stage. An electron microscope is mounted on the support. The stage and spring needle are connected to the positive and negative terminals of a comprehensive parameter tester, respectively, and the electron microscope is connected to a display. A laser chip semi-finished product is fixed on the stage. A chip semi-finished product to be tested is positioned in the piercing direction of the spring needle tip, and the spring needle contacts the chip semi-finished product to measure the accurate wavelength of a single chip semi-finished product. However, this screening device performs the screening during the packaging process. If a chip has an incompatible wavelength, it must be discarded, resulting in losses in manpower and material costs.

[0005] In summary, existing testing methods are not very accurate in terms of wavelength for testing single bar strips or dies. Most tests are conducted on a per-epitaxy wafer basis. In actual production, due to the influence of external factors, some epitaxial wafers grow unevenly, resulting in differences in wavelength consistency. Discarding these epitaxial wafers directly would cause significant problems in terms of manpower and production costs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a wavelength screening method for uneven epitaxial wafer strips. This method can screen epitaxial wafer strips with differences in wavelength consistency and can screen epitaxial wafers of different sizes, thereby improving the wavelength matching rate of products and production efficiency, and reducing production and labor costs caused by wavelength mismatch and uneven epitaxial wafer growth.

[0007] The technical solution of the present invention is as follows:

[0008] A wavelength selection method for bar strips in non-uniform epitaxial wafers, comprising the following steps:

[0009] (1) The epitaxial wafer is divided into several bars by performing regional cleaving and segmentation of the epitaxial wafer through the die process;

[0010] (2) Encode the bar tags in each region to make each bar tag unique;

[0011] (3) Test the bar strips using an automatic bar strip testing machine, keeping the testing conditions consistent;

[0012] (4) Determine the wavelength fluctuation range of the bar strips, remove the bar strips whose wavelengths exceed the fluctuation range, and after selecting the bar strips with stable wavelengths that meet the requirements, organize the bar strip wavelengths in the area divided in step (1) as a unit, mark the wavelengths on the corresponding coded bar strips, establish a wavelength model, and facilitate the search for wavelength distribution patterns within the area.

[0013] (5) The qualified bar strips are carried out to the next production process. Wavelength testing is carried out on the subsequent products. If the wavelength of the subsequent products is consistent with the wavelength of the selected bar strips, they are put into mass production and applied. Dynamic feedback adjustment is carried out gradually. If the overall wavelength of the subsequent products is inconsistent with the wavelength of the selected bar strips, the epitaxial wafers are reselected for screening and testing.

[0014] Preferably, in step (1), a photomask is used to divide the epitaxial wafer into regions to facilitate cleavage and segmentation.

[0015] Preferably, in step (1), the epitaxial wafer is vertically divided into regions, with at least two regions, the specific number of which can be determined according to the size of the epitaxial wafer.

[0016] Preferably, in step (2), the encoding adopts a regional code or a combination of numbers to make the bar unique. The encoding is etched on the photomask to facilitate marking the bar.

[0017] Preferably, in step (3), the test conditions include maximum current, test temperature and probe test depth.

[0018] Further preferred options include a maximum current of 2A-10A, a test temperature of 20℃-25℃, and a probe test depth determined by the presence of a clear elliptical black dot mark on the bar.

[0019] Preferably, in step (4), the wavelength of the core in the middle of the bar is used as a reference, and the wavelength fluctuation range is 1nm. Bars with wavelengths exceeding the fluctuation range are removed.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention is applicable to wavelength screening of epitaxial wafers with different wavelength consistency, and can screen the wavelength of epitaxial wafers of different sizes, thereby improving the wavelength matching rate of products and production efficiency, and reducing the production and labor costs caused by wavelength mismatch and uneven growth of epitaxial wafers.

[0022] 2. Before the packaging process, the present invention performs precise wavelength screening on the epitaxial wafers and cleaved bar strips. Epitaxial wafers or bar strips whose wavelengths meet the product requirements are processed in subsequent processes, while epitaxial wafers or bar strips whose wavelengths differ significantly from the product requirements are not processed in subsequent processes. This reduces the loss of manpower and financial resources caused by subsequent processes and effectively improves the wavelength matching rate of specific products after packaging. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process of the present invention;

[0024] Figure 2 This is a schematic diagram of the epitaxial wafer region division according to the present invention;

[0025] Figure 3 This is a schematic diagram of the wavelength model of the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0027] Example 1:

[0028] like Figure 1 As shown, this embodiment provides a wavelength selection method for bar strips on non-uniform epitaxial wafers, the steps of which are as follows:

[0029] (1) The epitaxial wafer is divided into several bars by performing regional cleaving and segmentation of the epitaxial wafer through the die process;

[0030] (2) Encode the bar tags in each region to make each bar tag unique;

[0031] (3) Test the bar strips using an automatic bar strip testing machine. Keep the testing conditions consistent. The bar strip test is a multi-point test, with points evenly selected on the bar strip for testing.

[0032] (4) Determine the wavelength fluctuation range of the bar strips, remove bar strips whose wavelengths exceed the fluctuation range, and after selecting bar strips with stable wavelengths that meet the requirements, organize the bar strip wavelengths by dividing the area in step (1), mark the wavelengths on the corresponding coded bar strips, and establish a wavelength model, such as... Figure 3 As shown, this facilitates the identification of wavelength distribution patterns within the region;

[0033] (5) The qualified bar strips are carried out to the next production process. Wavelength testing is carried out on the subsequent products. If the wavelength of the subsequent products is consistent with the wavelength of the selected bar strips, the products are put into mass production and application. Dynamic feedback is carried out gradually. The wavelength fluctuation range in step (4) is adjusted according to the actual application situation to meet the usage requirements. If the wavelength of the subsequent products is inconsistent with the wavelength of the selected bar strips, the epitaxial wafers are reselected for screening and testing.

[0034] In step (1), a photomask is used to divide the epitaxial wafer into regions to facilitate cleavage and segmentation.

[0035] In step (1), the epitaxial wafer is vertically divided into four regions: region A, region B, region C, and region D, as follows: Figure 2 As shown.

[0036] In step (2), the encoding uses regional codes, such as A101, A102...A1n, B101, B102...B1n. The encoding is etched on the photomask to facilitate marking of the bar strips.

[0037] In step (3), the test conditions include maximum current, test temperature and probe test depth.

[0038] The maximum current is 2AA, the test temperature is 20℃, and the probe test depth is determined by the clear oval black dot mark produced by the probe on the bar.

[0039] In step (4), the wavelength of the tube core in the middle of the bar is used as a reference, and the wavelength fluctuation range is 1nm. Bars with wavelengths exceeding the fluctuation range are removed.

[0040] Example 2:

[0041] A wavelength selection method for non-uniform epitaxial strips, the steps are as described in Example 1, except that in step (2), the encoding adopts a combination of numbers, such as 01, 02...n.

[0042] Example 3:

[0043] A wavelength screening method for non-uniform epitaxial strips, the steps are as described in Example 1, except that in step (3), the maximum current is 10A and the test temperature is 25℃.

Claims

1. A wavelength selection method for non-uniform epitaxial wafer strips, characterized in that, The steps are as follows: (1) The epitaxial wafer is divided into several bars by performing regional cleaving and segmentation of the epitaxial wafer through the die process; (2) Encode the bar strips in each region to make the bar strips unique. The encoding adopts a region code or a combination of numbers and the encoding is etched on the photomask. (3) Test the bar with an automatic bar tester, keeping the test conditions consistent, including maximum current, test temperature and probe test depth; (4) Determine the wavelength fluctuation range of the bar strips, remove the bar strips whose wavelengths exceed the fluctuation range, and after selecting the bar strips with stable wavelengths that meet the requirements, organize the bar strip wavelengths in the area divided in step (1) as units, mark the wavelengths on the corresponding coded bar strips, establish a wavelength model, and facilitate the search for wavelength distribution patterns within the area. (5) The qualified bar strips are carried out to the next production process. Wavelength testing is carried out on the subsequent products. If the wavelength of the subsequent products is consistent with the wavelength of the selected bar strips, they are put into mass production and applied. Dynamic feedback adjustment is carried out gradually. If the overall wavelength of the subsequent products is inconsistent with the wavelength of the selected bar strips, the epitaxial wafers are reselected for screening and testing.

2. The wavelength selection method for non-uniform epitaxial wafer strips as described in claim 1, characterized in that, In step (1), a photomask is used to divide the epitaxial wafer into regions to facilitate cleavage and segmentation.

3. The wavelength selection method for non-uniform epitaxial wafer strips as described in claim 1, characterized in that, In step (1), the epitaxial wafer is vertically divided into regions, with at least two regions, the specific number of which is determined based on the size of the epitaxial wafer.

4. The wavelength selection method for non-uniform epitaxial wafer strips as described in claim 1, characterized in that, The maximum current is 2A-10A, the test temperature is 20℃-25℃, and the probe test depth is determined by the clear oval black dot mark produced by the probe on the bar.

5. The wavelength selection method for non-uniform epitaxial wafer strips as described in claim 1, characterized in that, In step (4), the wavelength of the tube core in the middle of the bar is used as a reference, and the wavelength fluctuation range is 1nm. Bars with wavelengths exceeding the fluctuation range are removed.

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